2150cc Evo Custom Updates

Bevelheadmhr

Member
DTT BOTM WINNER
The alloy swing arm is progressing surprisingly well (touch wood).... 15 hours of machining so far, and this is how its looking.

Harley parts aren't known for being lightweight, and sure enough the original swingarm of my aftermarket chassis weighs a hefty 34lbs. My target is to halve that with this new alloy copy, so far with all components it weighes 20lbs, but there's still a pound or two to lose, so the target is possible. 17lbs is still a boat anchor in sports bike terms but its better than 34lbs.

Note the 'V' shaped grooves machined into the arm where two pieces are bolted together. This is where its going to be welded, as the groove allows for a neater stronger weld.
 

Attachments

crazypj

Split personality, I fake being smart
While I admire the work you've done and are still doing, you obviously have more money than sense 8)
I still have no idea why people fit 10,000rpm exhausts on 'Harley's' though?
With the torque that motor is making I guess next thing will be strengthen left side of frame to make sure it stays in line 'in compression'.
At least your not setting things up 'on the curve' so they get pulled straight during acceleration. They are outrigger bearings on belt cover?


Luugo86 said:
How much did you punch the jugs out and what type of heads are you using ?
You can't bore much further as even with special 'waisted' bolt in th centre of 'V' you run out of crankcase. 1250 is probably as big as you can bore, to get more capacity you need a stroker crank but that needs special rods and pistons (or, about another £3,000)
 

Bevelheadmhr

Member
DTT BOTM WINNER
The XL is 1250cc, though I see that Hammer Performance now have an updated 1275cc conversion kit. I seem to recall the biggest you can go with a std crank is 1440cc or there abouts?

Not sure what you mean by 10,000rpm exhaust on a Harley?

The Primary belt drive does indeed have outrigger bearings to support the pulleys, though the front one had to be redesigned after it failed at speed.

Since the frame and swing arm is aftermarket and non standard, the only way of having an alloy swing arm would be to commission one from one of the few decent frame builders in the UK. Last time I asked (a few years ago) Spondon wanted £3000, so I didn't bother!

So far the new swing arm has cost £130... £40 for the bearings and £90 for the alloy, so not too bad. Though it may end up in a new project, haven't decided yet.
 

crazypj

Split personality, I fake being smart
If you work out 'tuned length' for exhaust you'll find almost every HD system is way too short.
Some of the worst are 'drag pipes' for Sportsters. I did the math one time, sure enough, just about every after-market set were tuned for 9,000rpm. (in Florida people still believe 'loud pipes save lives' ::) )
We dyno tested an 883 with 'drag pipes', even with carb set as good as it could get it lost 8bhp from a stock system (38bhp is pretty pathetic from almost 900cc) 'Sounded fast' though ;D
With your Merch motor I'm pretty sure it won't self destruct at 6500rpm but even so a longer system will make more power and (gulp) even more torque. That could be an issue as you already have a ton of torque at 'low' rpm. Wheel-spinning 'everywhere' may sound like fun but just gets to be more trouble than it's worth after a while. Personally, I always thought the 1994/98 Ducati 916 under-seat exhaust was to get longer pipe length more than styling, although it is still my favourite Duc.
£130 is damn cheap for 'custom' swing arm, I guess your not paying for CNC time?
 

Bevelheadmhr

Member
DTT BOTM WINNER
Oh I see ref header length. I don't have the numbers to hand, but in general the shorter the header length the higher peak torque (all other thinks being equal). Minimum length for a Evo Big twin is around 26 inch, any shorter and the engine will never run right. Max length you'll find for HD exhaust headers is around 40 inches (so peak torque low in the rev range). I made mine with 32 inch headers, so slightly shorter than average, to move peak torque in the upper half of the rev range. Sure enough the dyno gives peak torque at 3500 rpm. The ignition is adjustable, and I have it set to cut out at 6,000rpm. I don't think it'll last long at 6,500.
Peak power is at 5200 so no point in revving it much more. A bigger carb may give me a bit more power at the top end, but I'm happy with it as is.

Drag pipes are great ... for drag racing lol... With an OE cam with sod all valve overlap they don't do too much damage to power, but as soon as you add a performance cam, drag bikes can really cause problems.

I don't have access to a CNC miller, its all done by hand on a miller made around 1965.. that's why it takes so long.
 

crazypj

Split personality, I fake being smart
Far more impressed when you 'twiddle the knobs' by hand ;D
Doing some nice work.
Just watched the vid and took a look at pictures, should have noticed chain drilling sooner.
I've done a lot of HD cranks over the years, big end is weak spot when you rev them, you can tell by wear pattern if it was oil failure/dirty oil, over revving or ignition problem that caused failure.
Haven't done any of the later 'pressed up' cranks, 50 ton presses scare me ;)
The total length of exhaust is also important, megga gives much broader spread of power than 'sharp exits' and will give more power than a parallel pipe in almost all applications. Personally I don't have any faith in US published header length numbers, they are always shorter than optimum but using larger diameter pipe often compensates for incorrect length.
Of course, that messes up fuel needing much richer than optimum levels to make bike ridable. There is actually very little scientific information on exhaust design, it's mostly trial and error until you find what works
 

Bevelheadmhr

Member
DTT BOTM WINNER
There's plenty of research on exhaust design, even for Harleys, ... its just v complex, so most folks follow what everyone else is doing. RB racing have some interesting pages on their site about exhaust design etc...

https://www.rbracing-rsr.com/exhausttech.htm

They were v helpful when I was building the exhaust for my old 120ci drag bike. Both the 131 exhaust and the 120 use 2 inch diam tubing for the headers instead of the OE 1 3/4 inch. Worked out ok..
 

Attachments

crazypj

Split personality, I fake being smart
Just read through the RBRacing link., well written, gues writer is a good storyteller?
Pretty much mirrors my experiences with some people ;)
Most just want 'give us your money and STFU'
Exhaust gas sonic speed can vary a bit more than they say, down as low as 12~1300ft/sec although higher rpm with right F/A mixture is 16~1800ft/sec
Lean mixture can give a much higher speed, until lean miss-fire messes things up ;D
I doubt it's still in the 'Dynomation' literature but the exhaust designs it comes up with used to be +/- 10% which was fine for majority as it almost always showed a power increase throughout rpm range
I've built stepped exhaust systems, they need to be shorter than the math says they should be, usually about 4" on a <36"pipe but need a longer tail-pipe or velocity slows too much plus collector gets 'complicated'
I did have to look up Manolo Blahnik. though
One thing that has always amazed me with HD (and clones) why doesn't anyone make a decent downdraft head for them? It would be real simple to machine a pair of head's, weld in tubes with flanges and put some fuel injection or downdraft Dellorto (off Alfa Romeo, 'racing' air-cooled Beetle or Ferrari) 45~48mm should be good ;) It would be way more efficient ten the 'updraft' system fitted (they are ALL updraft systems on HD due to the angle of cylinders) I've seen some weird 'air-filter' systems tat need tank cut away but carb is still down in the 'V' ???
 

canyoncarver

'hacking is learning'
When I was in the midst of my 93" shovel build, I looked at and read about the RB Racing pipes. They make nice LSR 2-1 pipe for the Shovel. I ended up with a Thunderheader but the RB pipe was a very close second choice.
 

Bevelheadmhr

Member
DTT BOTM WINNER
crazypj said:
Just read through the RBRacing link., well written, gues writer is a good storyteller?
Pretty much mirrors my experiences with some people ;)
Most just want 'give us your money and STFU'
Exhaust gas sonic speed can vary a bit more than they say, down as low as 12~1300ft/sec although higher rpm with right F/A mixture is 16~1800ft/sec
Lean mixture can give a much higher speed, until lean miss-fire messes things up ;D
I doubt it's still in the 'Dynomation' literature but the exhaust designs it comes up with used to be +/- 10% which was fine for majority as it almost always showed a power increase throughout rpm range
I've built stepped exhaust systems, they need to be shorter than the math says they should be, usually about 4" on a <36"pipe but need a longer tail-pipe or velocity slows too much plus collector gets 'complicated'
I did have to look up Manolo Blahnik. though
One thing that has always amazed me with HD (and clones) why doesn't anyone make a decent downdraft head for them? It would be real simple to machine a pair of head's, weld in tubes with flanges and put some fuel injection or downdraft Dellorto (off Alfa Romeo, 'racing' air-cooled Beetle or Ferrari) 45~48mm should be good ;) It would be way more efficient ten the 'updraft' system fitted (they are ALL updraft systems on HD due to the angle of cylinders) I've seen some weird 'air-filter' systems tat need tank cut away but carb is still down in the 'V' ???
The famous Duckman has a Shovelhead with downdraft Webbers, His site is full of amazing builds... if you haven't seen it before, well worth the time... http://www.dbbp.com/
 

Bevelheadmhr

Member
DTT BOTM WINNER
While today I went to the workshop to pay the bill for all the work they'd done, as the bike is complete now. Just need to source / make a pair of bar ends and that's it.

They did me a good deal on the labour, which I'm v grateful for.

The cost for this 'Mid Life Update' is as follows

New Risers / foot peg mounts £0 (as they were homemade)

Modify the swing arm £140 (£70 Welding + £70 powder coat)

New Tacho/Speedo Unit £140

Moto Gadget M Unit & Switches etc £450

Ceramic Anodising Oil Tank £90

New chain £100

Incidentals (Wiring, Oil, filter etc) £60

Labour £400


Grand Total £1340






It'll be delivered home next week, when we'll load up my Guzzi Cafe Racer to take back to the workshop. I'll be able to work on it myself at the workshop, something I dont have the space to do at home at the moment. I may bite the bullet and re do all the wiring I've already done, and use another Moto Gadget M unit and switchgear. Its not cheap but I think the Guzzi deserves it...
 

crazypj

Split personality, I fake being smart
Unless it had Bosch electrics the Guzzi will need it ;) I know Italian electrical systems are better than they were but if you ever had an Italian bike with Spanish electrics,...................well you either know or don't want to.
BTW, I like Guzzi's even better than Duc's
Didn't know about shovel with Webber's, too much 'stuff' not enough time 8)
Looks like a manifold onto stock heads?
I can't remember but don't tink there is clearance between intake and rockerbox on Shovel? I have some Evo heads but never got around to taking 'proper' angle measurements to machine them. Do remember intake runner can run almost parallel to intake valve stem which is way less work than the welded up/re-machined intakes I've seen on a few 'local' drag bikes (I'm not much into drag racing, unless I'm the one racing but being lousy at it, I 'don't' I did get on TV once (so I'm told, never saw it) around 1995~96, at Landow. BBC were doing something there and I was 'just having fun'
 

Bevelheadmhr

Member
DTT BOTM WINNER
The only standard part left of the Guzzi electrics is the Saprisi charging system... which is a weak point.. As for downdraft carbs on Harleys, the problem has always been the lack of space between the heads. The solution, as used by the XR race bikes is to reverse the inlet of the rear head, so you have two carbs. I'd love to fit those heads on my Ironhead, but they are as rare as hens teeth and v expensive when they appear.

Interestingly I've got a mate who owns an engineering company who has plans to make his own twin carb heads to fit an Evo Sportster. He's done a lot of work on race spec E Type Jag engines, so he could be the man to do it.
 

crazypj

Split personality, I fake being smart
I know a little about the XR's, even the 4 valve heads Harley never made ;)
You can fit two 'front' heads without too much trouble but as exhaust ports at front are such a horrible angle it's more a styling exercise .
I spent way more time at HD than I should have considering I was teaching Suzuki ;D
 

Bevelheadmhr

Member
DTT BOTM WINNER
The alloy swing arm is making good progress, this weekend the holes for the wheel adjusters will be milled out, along with removing some material from the inside of the spars to lose some weight. It shoulds be ready to be welded up early next week..

While here's the last short vid of the bike now the electrics are all done..

https://youtu.be/5ZOD8qWaees
 

Attachments

Bevelheadmhr

Member
DTT BOTM WINNER
The slots for the adjuster blocks have been milled out of the two swing arm spars, while another half kilo has been saved by milling out the inside of the spars. I quick guesstimate says it'll be less than half the weight of the original steel arm when finished.
 

Attachments

The Jimbonaut

Active Member
Whilst your bike - respectfully - may not be exactly my thing, your dedication and enthusiasm to customizing it exactly to your taste is infectious. I've been reading with great interest, and will continue to do so. 10/10 for balls-out originality!
 

Bevelheadmhr

Member
DTT BOTM WINNER
Cheers, I guess I have odd taste lol.. actually that swing arm will probably be used in a bike that doesn't exist yet, I will build it, and the swing arm will be the first piece of the jigsaw..
 

The Jimbonaut

Active Member
Anyone that builds a Harley Norton mash-up that looks as good as the one you built has anything but odd taste!

Nothing odd about it my man, just...different. And thank goodness for that.
 

Bevelheadmhr

Member
DTT BOTM WINNER
It would be a dull old world if everyone liked the same thing.. Like today I had the chance to look over a couple of new factory built Italian V twin specials... one a café racer with full exquisite alloy bodywork.. they were both a bit 'different' but I thought they were great. I was told one had cost over $70K to build, with the Ti exhaust being a hefty $10K.. And they weren't Ducatis or Aprilias... I wasn't allowed to take any photos, as they hadn't been announced to the world yet.

As for the new project... I have a race bike that doesn't fit into any race category anymore and would be too loud for the noise limits that more tracks are having to instigate.. so I'm planning to have a nice man build a new frame for the race bike and convert it into a road bike.... well that's the plan anyway.
 
Top Bottom