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Author Topic: Rickman CR parts sourcing, rear wheel spoke hub manufacturer, etc?  (Read 11635 times)

Offline Drey6

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Rickman CR parts sourcing, rear wheel spoke hub manufacturer, etc?
« Reply #30 on: Nov 28, 2015, 03:08:59 »


                ^^^^^^ALL DAY^^^^^^
1975 Honda CB550
1980 Suzuki GS550 (673cc project)
1981 Honda CM400

Offline Chuck78

  • Posts: 252
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I had to get some more advanced suspension and braking up front, although I will never go with a modern looking and improper height upside down fork, I had to pick something that was a big upgrade over cartridge emulators in GS1000 37mm or GS1100GK 41mm forks (still a very excellent option, but this is a RICKMAN CR900, it's simply THE BEST road handling vintage styled twin shock chassis!), was proper height, and easily allowed use of GS wire spoke wheels still (with minor machine work of all new axle spacers, and larger 20mm axle bearing and speedometer drive swap), so I picked 6 bolt GS pattern 296mm Honda rotors and Honda Superhawk vtr1000f forks, same as pictured on this Dunstall GS1000. Also, the most clearance to wire spoke wheels using opposed piston modern calipers was to be had with the 01-02 GSXR1000 6 piston calipers, the VTR's calipers, even with the smallest diameter pistons of any Tokico or Nissin 62mm mounting 4 pot calipers in this category, are very close to the wire spokes...

Honda VTR1000F forks and Honda 296mm rotors on a Dunstall GS1000:


$100 eBay VTR1000F forks, they'll get stripped and polished:


But with these blingin' calipers... I would prefer something a little more low key looking but they stop really well and will give me the most clearance to my spokes. The stock calipers are crap on those forks even though they look just like a dozen other calipers of this spec that all stop very well, they all have larger pistons than the Superhawk calipers, which puts them even closer to the spokes since the wire spokes are angled from the widest point at the hub. These are a direct bolt on to the Superhawk forks as in photo. the other 4 piston calipers that stopped as well as these would need minor clearancing at the lower bolt hole on the outside of the piston bores, and also would likely need angle milled to shave a little extra clearance in next to the spokes, on the inside lower edge nearest the wheel hub.
GSXR1000 6 pots bolted to a VTR1000F fork:


And these Honda CB1 rotors, the most offset of all Honda 296mm 6 bolt rotors that fit GS hubs: (EDIT- sources told me wrong, this CB1 rotor is 310mm & single disc front, 74mm bolt pattern, 20mm offset. Still may use on the GS500 forks on the GS425-475cc build, CB400SF SuperFour & 98-99 CB600F rotors used r impossible to find, may run aftermarket for that application or bigger spacers behind 92-93 cbr900rr rotors)


Any other feedback on the engines? I'm leaning towards the big bore 894cc GS750, or if I could ever find one, GS1150E. the convenience (local,  w/all ignition& oil cooler parts on it) and power and advanced technology in the katana gixxer mill is still appealing, and maybe pulling  the rotors off the bike and being right next to it might sway me... but the classic fins on the other engines definitely give the look for this build. A modern fork and possibly YSS rear shocks will be plenty of modern appearing enhancements, and I still tried to keep those somewhat subtle and tame to fit in with the vintage look but still give top-notch performance. I am really looking for another vintage pair of Fox or Ohlins or Works rear shocks...eventually, rear shocks are a quick&simple bolt-on and always are at the end of my priority ($$budget) list.
« Last Edit: Dec 07, 2015, 17:03:58 by Chuck78 »
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline grandpaul

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Very nice score on those forks!
It ain't braggin' if ya done it.

Offline Chuck78

  • Posts: 252
    • my bike photo album
Not much new to report here other than I got a super score on a set of 01-02 GSXR1000 6 piston gold Tokico calipers and dual stainless braided lines for the $140 VTR1000F Superhawk forks that I scored.  Hoping to snag the repro long solo seat fuel tank cover from the Australian manufacturer and a seat/tail section.  I guy on the GS Resources forum thought highly of my long-windedness and helpfulness and offered me a Christmas present of a free original black gelcoat Rickman front fender shipped from Canada to me even!  Nice score, thanks Steve!
Also was tipped off by Billy from the GS Resources forum on a recommendation for mixing and matching the .380" lift Megacycle intake cam and the .354" lift exhaust cam as not as much is typically needed on the exhaust gasses being forced out vs intake charge being sucked in, then he referred me to another member who deals in performance parts who has a Yoshimura "Road and Track" GS750/1000 8v cam set in .378" intake and .354" exhaust for $330!  I likely will use them in this project ass the 894cc build.

The last thoughts I have had more recently have been to consider some NOS 798cc 67mm GS750 11:1 pistons, which I planned to snatch up a few more sets of, but in this case, I had thought of attempting to resleeve a GS650 cylinder block with either GS750 sleeves with the top step flange turned down in a lathe to only 1mm larger than the 650 sleeves to squeeze them into the 650 block, or else custom made sleeves for this application to run these pistons and use a GS550 77-79 bottom half, resleeved 650/750 cylinders bored +2mm to 67mm for 789c and 10.9:1, and use an 80-82 GS550 BS32 CV carb head with Keihin CR29's or else the 77 GS550 VM22 head that I have here but massively ported and intakes enlarged to squeeze some Keihin CR26's onto it...

The power of an extra 100cc's and the fact that I have 3 spare 750 engines and only one 550 still has me loving the 894cc GS750 CR900 idea still, but at 789cc with good cams and high compression and possibly bigger valves installed in a 550 head, I get a substantially narrower (more cornering clearance) and substantially lighter weight 800cc powerhouse! 

The GS750 was Suzuki's first big stake in the  UJM 4 stroke market, so they could not afford to lose with their design and subsequently overbuilt the 750 so much that the GS1000 crank in 78 was substantially lighter and smaller.  What we have then is a very large 750 crank roller bearing setup that fits no other bikes, 4 out of the 5 bearings...  AND they are obsolete now.  All other GS400-GS1000 2 valve per cylinder engines and the GS1100G use common crank roller bearings that are still available, same ones in the 550 roller crank.  Luckily, they are roller bearings and pretty much never wear out. I believe the actual rollers are available at any bearing supply house, but the races I assume, same with the swingarm needle bearing inner races, are likely the proprietary Suzuki part.  A machinist could make some hardened races if needed I suppose. 

Anyhow, the 894cc GS750 Rickman would be a blast, quite the brutish rocket, but a 789cc powerhouse GS550 Rickman would be likely a good 50 lbs lighter (I can pick up a 550 engine myself, a 750 is a bear to lift solo). The 6 speed 550 gearbox may have too narrow of gears and components however, and may not handle the power.  I have two 550's here, one in the wife's bike, and both have shifting difficulties (I suspect bent/worn shift forks from hard riding, they are fast bikes just with pods and pipe).

I need to weigh both engines soon and see what I come up with, as that will help compare a lot more, but I am so curious as to how the Rickman would handle with that GS550 BIG BIG BORE rocket engine in it, that I may just build both engines up...  Tell the wife the extra 550 is a spare for if she ever blows up the 673cc GS550/650 hybrid I'm going to be building for her!
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

  • Posts: 252
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What do you all think of these engine choices? A lot of the guys on the GS Resources are telling me to forget about my stockpile of GS750 engines, and forget about my crazy desire to have a starter delete kickstarter-only engine, and just run a GS1000 with minor mods. That's too easy! the weight with starter assembly and larger battery would be the same as the 750 engine with the heavier crank, but starter assembly deletes and a tiny battery.

Here are my poll options that were the most popular on the GS forum with their pros and cons, let me know what you guys think:

#1 894cc 11:1 GS750 Megacycle or Web cams Keihin CR29 smoothbore carbs maybe some head work
*uses 850 cylinders bored out +2mm, and custom JE Pistons that I can order duplicates of from a friend's past order ($700 pistons)
*I need 2 of these pistons anyway to build a 475cc GS425 road racer, and have 3 spare 750 engines
++big cc's = big smiles, big power potential
++I have plenty of spare parts
+It is a CR900 frame, 894cc's just makes sense if you're nostalgic!
--750 engines are quite wide, I come close to scraping the stator cover on extreme corners on my GS750-920cc. racers have cut and welded an angled piece on there for same reason)
--weight: 750's have a massive crank, GS1000 engines are lighter by a good 12lbs with lighter crank, no kickstarter. (I do battery delete/downsize& starter delete kickstart only to save weight)
--4 of 5 crank main bearings are obsolete from Suzuki, but they are roller bearings and hardly ever wear out, bearings are available from suppliers but the races I assume are proprietary, replacements would need to be custom made. I have not checked the rod bearings or the thrust washers for availability. I do have 3 spares though!




#2 789cc GS550 (Resleeve a GS650 block with 750 sized sleeves but with smaller steps at the top flange, and only *IF* the 550 combustion chamber measures out the same or similar as the 750 head chamber as I suspect from comparing pistons in person and photos of the 550 heads - will pull mine in Jan to compare)
*10.9:1 789cc using some NOS 798cc 67mm GS750 11:1 pistons I have acquired, 80-82 GS550 BS32 CV carb head ($250 pistons)
*requires resleeving a tightly spaced GS650 block even tighter, custom sleeves or the top step flange on 750 sleeves machined down
++789cc 10.9:1 with good cams will make a very fast "little" 4 cylinder!
++much lighter than a GS750 engine, better cornering, frees up some hp, + starter delete+battery downsize makes it an ultralight 4cyl vintage rocket!
++much narrower engine than a 750, more cornering clearance
++crank bearings are common to all other 2 valve per cylinder Suzuki's except 4 of the 5 GS750 crank bearings, all still available
+I have 1 spare 550 engine with a shifting issue, but 77-82 parts are common
+I have a GS650 MAC 4:1 header I could use on this
-may run a bit hotter due to less metal in the cylinder block (+ could possibly run WIseco 844cc GS750 pistons as well, -but even less cylinder wall thickness)
-may need to add even more additional engine mounts to the frame, already need to bronze weld different lowers for the 750 and touch up some previous repairs.
-can the 6 speed GS550 transmission handle this much power? Can a GS650E 5 speed fit in place of it, it's gears are 1/5th wider per gear so I assume)


Other options -
*GS1000 mostly stock (have to source and rebuild an engine, may bore to Wiseco 1075cc to be fresh, no spare parts in my hoard. not a kickstart engine, boooo)
*798cc 11:1 GS750 for very cheap ($250 pistons - my cheapest option, Megacycle/Yoshi cams and Keihin CR29 carbs),
*844cc 10.25:1 GS750 (using the common $400 Wiseco kit, plus the Megacycle or Yoshi cams and Keihin CR29 carbs)
« Last Edit: Dec 23, 2015, 08:08:33 by Chuck78 »
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

  • Posts: 252
    • my bike photo album
I can handle the twistiest roads quite well on my 920cc GS750 with a 1" longer than stock swingarm, so the bigger engine in a lighter frame and component package can only be easier to handle in tight turns, especially with a swingarm that is only about 18" long compared to the 20"+ GS1100E alloy swingarm on the 920cc GS750...  AND I will be building a 330lb stripped down 475cc GS425 little road racer that will be ultralight for burning through corners, so that will be my featherweight twisties machine for day trips in the Appalachian foothills in southeast Ohio, but the Rickman would be a rocket with either powerplant, just a little more of a blast accelerating with the 894, but easier to whip around with the 550-798 and still quite fast but not as torquey... no passengers, and my 165lbs with full gear won't load this thing down much however.
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

  • Posts: 252
    • my bike photo album
Steve from the GS forums sent me this xmas eve present, an original Rickman fiberglass fender! I can actually trim a cracked section off the Rickman fender and use the vtr1000f upper fender mounts on the top fronts of the fork lowers, then make a custom arched center section of the Superhawk Coerce brand fork brace, and drill the fork brace & fender and bolt it there in the center of the fender for the 2nd mounting point. Excellent fit with minor trimming!



Also in the photo are the GSXR1000 6 piston calipers that will allow me more clearance for my beloved wire spoke wheels & cbr900rr/cb400sf/cb600f "599/hornet" rotors that are a near bolt-on to GS & Goldwing hubs...

Hiding in back are old cb400 fitting Koni 76F alloy body twin tube shocks with red springs destined for the GS425-475cc featherlight barebones racer build with GS1100E swingarm & relocated swingarm pivots to shorten wheelbase while running a longer swinger for better cornering exits like modern bike geometries...

May do the same on the Rickman if I tuck a GS550-789cc engine forward in the frame. Bronze weld on a 1"x1.5" cromoly box tube in to the front of the Rickman swingarm mounting plates and move the arm forward to lengthen it while retaining the same wheelbase and running a trick looking Zephyr ZR550 aluminum swingarm for a revised modern geometry...
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

  • Posts: 252
    • my bike photo album
Doh! Hit a snag with the Rickman front end plans! Should've checked with Rickman owners a while back to learn that the Betor 38mm (dual disc) Rickman forks are a mere 715mm/28.149" tall axle center to top of stanchion!!! Offset on the triples is a whopping 60mm/2.362"!!!! So much for plans to use a standard vintage height (gs750/1000/kz1000) fork at 775mm!!!

I did find a flat track racer supplier that makes custom offset steering head bearings for +/-1 rake, and they also have custom Billet adjustable offset triples for 41mm forks in 7-5/8"  spacing for $460 with 55-75mm offsets available.

I was having trouble finding triples with 50mm or so offset, but now looks like I may need to just go custom.

Now I'd probably resort to jacking up the rear 3/4", and dropping the front only about 1" lower than stock, and run these offset steering head bearings (sounds like an alignment nightmare or test in patience). I'd ideally like to get to 24.5-26.2 rake and 3.75-3.8" offset...

Not sure if I should slate the Superhawk forks for the daily rider GS750-920cc at this point for something shorter, as a 715mm Rickman fork vs a 775mm Superhawk fork even with 35-40mm eaten up by clipons - that's A LOT sticking out up top. I suppose it would enable me to run the clipons higher for more comfort!

I could travel limit the vtr1000f forks with topout spacers down to 4.1" travel from 4.7", and find clipons with the biggest clamping area possible, and that's put me at stock Rickman height... lose 1 with offset bearing adapters, take the rear end 3/4" higher and drop the front 1/4" more. There's 26 and may be able to run an ebay Honda oem triple.

The RF 900 43mm forks slated for the GS425 seem great for this at 730mm, run big clipons up top, but triple would likely mean even more searching and more likely to need a $550 custom billet triple, as a 43mm fork is going to be harder to find large offset cruiser bike and standard  triples to use, as 41's seem more prevalent thus far in my searches with large offset triples and not being incredibly wide like the vn800 Vulcan or vf1100 magna triples...

May expand my search to shorter 41mm RSU forks after this discovery... more Hondas probably. Finding out heights of modern forks as well as triple clamp offsets are two very critical missing pieces of info on database lists of conversion info. All I find are steering stem bearing sizes, and fork tube diameters. The stem sizes are on the Allballs site slready.  Lengths/spacings/offsets of modern fork swaps would clearly be far more useful info to compile... have to harass some ebay sellers for the info I suppose.
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

  • Posts: 252
    • my bike photo album
So I've spent some time planning the past few days after long hard days at work and no motivation to work on house projects...

I got an angle finder so that I could prop the chassis up to a 24.5 to 25.5 degree rake angle and assess how much the jacked up rear and dropped front would really have be sliding into the tank forward and putting all the weight on my wrists on this aggressive riding position solo racer machine... 1.75" or so riser clipons ON TOP of the upper triple clamp yoke and angled down and back will really help out with the riding position and lessen strain. Couldn't believe the comfortable position on a 1st gen ninja I was on last year, angled down and back, riser clipons, same ones on the Rick actually, but not using that triple.

Reading an article about modern suspension designs, I ascertained that the ideal swingarm angle in terms of anti-squat powering out of turns is as much as 12.5 degrees from horizontal, but many vintage bikes will have trouble getting over 9 degrees. Somehow sprocket size plays into the equation as well, but I have not read that far to see how that affects things as far as chain pull trying to raise the rear end vs weight transfer trying to squat the rear end. With the swingarm between 9 or 12 degrees and horizontal, accellerating out of a turn will keep the swingarm fairly planted at a constant angle under power, but as it nears horizontal and goes beyond horizontal squatting the rear, the weight transfer increases greatly and gives you substantially more rake and trail, causing you to have to back off the throttle as you lose your good cornering steering geometry, and thus not being able to keep the tight turning radius exit under power. I am shooting for 10-11.5 degrees, and plan on YSS shocks with 10mm ride height adjusters so I can play around with rake/trail and swingarm angle changes, which will also work great with the two sets of shock mounts on the Rickman CR 2nd gen swingarm (MUCH more stout AND HEAVIER than the first gen CR arm). Moving the 13" shock that came on the bike from the rear to the front gives me 5/16" or 8mm higher ride height in the rear. The rear suspension will be slightly softer, but in terms of rear end lift under power, the leverage gain against the shock springs will help keep things in check in terms of allowing weight transfer to balance out the steeper arm's tendency to pull inward under chain pull force.

Porn, on the dining room table of all places (hope wife doesn't read this while she's away for 6 weeks training for the wall of death thrillshow!):


^^^^^^^ This is propped up in position with the rake at 25.4 degrees so that I could measure the frame pitching forward being a minor 3 degrees, not too terrible! No offset neck bearings needed after this discovery!

So I set this all up so that I could check out how much the seat would be sloping forward if I got the rake set where I wanted it, or rather needed to get it based on the triple clamp offset achieving a desirable amount of trail... Turns out that with approximately 25.48 degrees rake, the frame is only pitched forward 3 degrees, as in photo! Heck, I can offset that with differing seat and tail section rubber mounts, and level the the tank to match the body lines of the angle of the tail! May not even bother, seems pretty good to me. I could try undoing Corbin's job of reupholstering the seat and stuff some more foam in the front and stretch the vinyl out more with the help of a hair dryer... will try as is first before any of the above.


After the rake and frame pitch conclusion, I determined how I was going to arrive at that. 715mm was the original Rickman 38mm dual disc fork length. 94-97 43mm cartridge Suzuki RF900R forks are 730mm and run a common diamater rotor as with many 6 bolt 78mm pcd Honda floating rotors. Clipons on top will eat up at least 35mm of fork tube, so 695mm effective fork length drops the fork just a bit at 20mm to help reduce the rake and trail, but not too much to cause major clearance issues. 

Then the biggie, Loooonnngggg shocks! $479-$999 range in whatever offering I can afford at the time from http://www.YSS-USA.com, shocks in the range of 360mm with their +10mm ride height adjuster to quicken the steering in the twisties when needed... With the angle finder, I didn't want to get all the way down to the modern ideal of 12.5 degrees, but I toyed around at 11.5-12 degrees, and looking at the exhaust mounting boss, not much clearance with a large bolt head there, figured I'd limit it below 12. 14-11/16" was the absolute max I could run in the forward shock mount position. This may require a larger front sprocket and rear sized in perspective, just to keep the chain off the swingarm... geometry update is worth it though. 520 DID chain and Vortex/SuperSprox cogs will save weight, a few more links will be offset.

So I didn't want to drop the forks any more, and I wasn't comfortable with any more swingarm angle or any longer shocks.... where else to go? Tires, of course! Sadly, my top pick Pirelli Sport Demons took the backseat... I have DID 2.50x18 front wheels and 3.50x18 rear wheels. Shinko and Avon say 140/70 fits best on a 3.75 rim, but acceptable on a 3.50. that tire is 26.2 diameter and looks not quite meaty enough on the rear of a vintage bike, but is a superb handler for sure (shredded 2 of them, awesome grip and profile). 150/70 looks right at home with a taller section at around 26.8" in an Avon Am26, but only comes in 17" in the Pirelli, bummer. 3.50 is the narrowest allowable rim, 4.00" is ideal. Now, my 3rd or 4th pick was the Bridgestone BattleAxe BT45V, and it comes in a rare 140/80-18, nearly the same width as the 140/70, but the same height as the 150! Now we're talking! I hate adding extra unnecessary rotating weight, but my only other option to get the geometry right on target was hassle around with custom offset steering bearing adapters to un-rake the front end, opposite of what most chopper guys use them for! real pain with alignment, and a hassle to calculate all the machining angles for the bearings. Only one flat track place advertises this custom service anyways. 1 degree steeper (less) rake for $120 and a nightmare of aligning the eccentric adapters.



The other bonus (cosmetic detraction though) was that the BattleAxe BT45V's 110/80-18 is smaller diameter than an Avon RoadRider, 24.8" vs 25.2"! smaller front tire means more help reducing trail with a limited choice in offset of only one good OEM swap triple clamp option! I was shooting for trail between 3.75 and 3.85, with hopes of adjustment options towards 3.85"-3.9" for long hauls and a steepened switcheroo for say when I arrive in the West Virginia mountains or in the Red River Gorge for the DoTheTon.com annual Spring Thaw campout...

I've heard great things from a very few about Continental Attack tires, or Attack 2's or something (they come in a 150/70-18 I was told), but I have not looked into them yet. The BT45V's get great reviews, but when compared to Pirelli Sport Demon's, the Pirelli always "Goes to Eleven."
« Last Edit: Jan 15, 2016, 01:02:36 by Chuck78 »
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims

Offline Chuck78

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Very suprising to me that the frame didn't end up pitched forward drastically with 1.68" longer rear shocks, .73" more forward slope from the combined tire radius differences vs stock Rickman sizes, and 20mm drop in the forks.... Wow! Over the 58" wheelbase, the length has cushioned the impact on the seat's preferred horizontal persuasion! With dropping only slightly in the front end and keeping most of the steering-quickening in the revised swingarm angle/increased shock length, I didn't lose too much ground clearance on the extra wide GS750/Z1 big four engine cases.... Exhaust I will probably custom fab from the back of a MAC collector out of aluminum tubing, so that I can tuck it nicely. An Italian made Marving flat collector 4:1 upswept road race pipe at $500+ would be nice, but dreaming... or a Predator stainless system from the UK. Both have flat collectors I believe. More clearance. I may angle mill the ignition and stator covers and weld on a flat aluminum plate in order to gain a slight but more lean angle advantage yet.

Uber ground clearance from these Italian masterpieces from Marving, only one US distributor though:
'77 Suzuki GS750B 920cc's 4-1, 3.50&2.50 Sun rims, Ninja/CBR900RR/GS1150ES brakes, GS1100E alloy swing arm, emulators/spring mods/Tarozzi, Fox Factory Shox, kickstart-only
'74 Rickman Montesa VR250
'99 Kaw KDX220 rugged terrain 2-stoke ripper
PROJECTS:
'77 Rickman CR900 ex-racer project: GS1000-1105cc, Yoshimura Isle of Man cams, ported head, Yoshi Series 1 exhaust, 89 GSXR1100K forks/brakes, Fox Factory Shox, 4.25&2.50 Akront TR rims, 310mm brakes
'79 GS425 racer project  489cc 10.5:1 in GS850 sleeves, megacycle cams, GS500 forks, cbr900rr 310mm brake, 3.50&2.50 DID rims, Dresda style swingarm, Fox Factory Shox, kicker-only
'77 GS550B gs650 top end, Wiseco 740cc, CBR900RR/Ninja 310mm front disc, Fox Street Shox, Excel rims