Custom Triple Trees - CB350/400/550/750/GL1000 - Other designs available

slikwilli420

Been Around the Block
Anyone who has seen my build has seen the custom triple trees that I made to accommodate the forks/brakes I wanted to use. I found it very difficult to find custom triple trees, both with regard to dimensions and style. The designs I have created thus far are shown below.

I will be offering CB750 clamps in the early and late offset, as well as GL1000 clamps. I am also willing to work with someone who needs something even more custom, like specific offset or spread. Custom offset/spread items will need to be designed for the customer specifically and will take additional time, but NOT additional cost. I can also offer trees for any other stock application but will need your trees dimensions (offset, spread, fork diameter and stem diameter).

I realize there are many options available for the vintage bike enthusiast, but I think there is room for low volume, high quality hand-made items.

This stuff is not coming off of a $100k CNC mill but rather is rough cut via waterjet, then hand finished. Each triple will come standard with stainless Allen hardware for the stem pinch (if included) and the fork pinch. Each will also be media blasted for a uniform finish ready for powder. The work involved in hand polishing these items is more than I am prepared for currently, but others on the forum offer polishing for very reasonable prices.

I am currently offering the designs you see listed for $175. The dimensions I have set up currently will fit the early/late SOHC CB750 and GL1000. If there are features from multiple trees you would like to combine, I am happy to work with you on that venture. They will be cut from 1” stock to match the originals in dimension. There will be an additional $15 added for 1.25” to make up for the added cost of material. Generally speaking, cost for the finished product will vary about $15 per 1/4" of material from the 1"/$175 stated here.

Options available to the buyer for no additional cost are:

Recessed or standard stem pinch (where applicable) and fork pinch bolts. I can also add a relief (about 1/4”) to the underside of the clamp where the spanner nut for the stem goes to help drop the tree a bit and hide some of the nut. Please note that some of these designs are such that the rear part of the nut (closest to the rider) will show from the back.

Regarding any question of risk on the buyers’ part, I will stand behind these items 100% in the even that something does not fit correctly. I will do my best to make it right and to make you a happy customer.

I welcome any and all questions or discussion regarding these items.

Below are the designs I have so far as well as some in various states of completion.

You can see more at the site I setup at MysteryCycles.weebly.com
 

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I need a lower GSXR clamp made to Busa top clamp offset, if I were to send the clamp/fork dia and the top clamp USPS what would it cost to do that one off? Bussa uses a fork leg with two sizes for top and bottom, stoopidest thing ever, but they have a nice top mount bar clamp so wtf's a guy to do.

Are you planning to make stems also or just clamps?
 
Hey Tune-A, I just posted on your Kerker listing asking about the bolts.

As for a lower clamp, its all about the thickness of the material, assuming you don't go crazy with wanting a bunch of extra cuts and contouring. We can work on a design or I can copy the top. $175 for 1" material but I'm guessing the lowers are more like 1.5-2". Add $15 per 1/4" of thickness above 1". It may come out a bit cheaper than that but that's a very good approximation. Shoot me a PM.
 
Oh hell, I was thinking 2.5" with gull wing contour, Tune-A-Fish engraving and speed holes for sure... $200?
 
those are dandy
i think 1-1/4 for bottoms would be plenty the key is stacked pinch bolts top and bottom
instead of the larger centered bolt
more efficent even clamping and your profiles of the bolt bosses could be slimmed a bit
if you are tapping n holes in the aluminum then a roll form tap is the way to go stronger thrreads no chips !
but lubrication and exact hole size is critical
65-75% thread is fine as long as you have more than 1.5 x the diameter in full theard depth engagemment
what are you using to final size/make round and axially align the clamp bores ?
a sunnen kingpin hone lash with them stacked together sure would do nicely
 
Thanks XB! I agree that stacking pinch bolts would be most ideal, and it can be done with 1" material, provided M6 bolts are used. I have found that a single M8 will clamp extremely tightly as well so I don't worry too much about that. Thicker lowers would allow for something like double M8 pinch bolts since they tend to be thicker than uppers so that is doable.

Regarding threads, although not roll formed, cut threads in 6061 will still be extremely strong, and no doubt much stronger than any internal threads cut into a stock piece, which are almost always cast, especially with older bikes. I did look at roll form taps, but it sounds like extreme precision and car is needed with when forming threads this way.

To final bore the fork and stem holes, I am simply using an adjustable boring head, nothing fancy. As long as the mill head is trammed in properly, there isn't worry of boring the holes crooked. These holes are typically 0.003-0.010 bigger than the fork tubes so as long as the boring head will replicate that, there is no need for other equipment. I did look into adjustable reamers but have not had any experience with them so I cannot comment on their usefulness in my application.
 
I wonder if the tool supply has roll form tools that come with undercut taps like the Time Sert kits... with those you have double process by cutting the thread then roll form to add strength and it eases the sharp edges??
 
But is all that extra effort really worth it? Cut threads in a material that is much stronger than cast aluminum should present no issues.
 
No, most likely not. The only reason you would benefit is if it were a race application where the bolts would see 100's of tear down and reassembly's, the techs know not to use cordless stuff during the assembly, but it happens anyways and even a heavy hand on a T bar can shred thread.
 
Totally agreed. At that point, I might look into studs that are permanently set into the tree with a recessed nut for the pinch. That way you would never bother the threads in the aluminum and still be able to set a high torque over and over without fear of tearing up threads.

What say you Tuna-a, taking the plunge? Lets get something designed!
 
slikwilli420 said:
Totally agreed. At that point, I might look into studs that are permanently set into the tree with a recessed nut for the pinch. That way you would never bother the threads in the aluminum and still be able to set a high torque over and over without fear of tearing up threads.

What say you Tuna-a, taking the plunge? Lets get something designed!

Yeah. I will get in the shop this weekend and setup what I have and get some measurements. It's for a pipe dream right now but I have the bike and have been collecting most of the parts.
 
Tune-A-Fish said:
I need a lower GSXR clamp made to Busa top clamp offset, if I were to send the clamp/fork dia and the top clamp USPS what would it cost to do that one off? Bussa uses a fork leg with two sizes for top and bottom, stoopidest thing ever, but they have a nice top mount bar clamp so wtf's a guy to do.

Are you planning to make stems also or just clamps?

FWIW all years 'busa are 214mm fork centers with 32mm offset. busa fork clamps are 55mm lower while all but GSXR600 lowers are 54. Some GSXR1000 are 53mm lower or 56mm lower. all GSXR and busa top clamps are 50mm. GSXR forks are 207mm apart.
 
focusinprogress said:
FWIW all years 'busa are 214mm fork centers with 32mm offset. busa fork clamps are 55mm lower while all but GSXR600 lowers are 54. Some GSXR1000 are 53mm lower or 56mm lower. all GSXR and busa top clamps are 50mm. GSXR forks are 207mm apart.

I just need to verify what all I have. The whole idea is to use the Busa top on GIXER legs to get the bars up.

One way er another I,m getting a clamp. Oh and I need it bored to press fit a stock 1973 KZ1000 stem that I will provide to have a snap ring groove added because of the incompatible metals for welding.
 
there's nothing wrong with cut threads per say my dad was in heavy machine design and they were building everything out of aluminum M113's and P7"s armored personell carriers that was at FMC
they found that in the aloys they used 55-60% was all the thread that was needed (flat tops not sharp)as long as it was 1.5x dia or more a grade 5 course thread bolt would snap off before the threads were stripped in the aluminum ,there is no extra value strenth wise to have the theads any more full in form but trying to do so just leads to broken taps in many instances

back in the day when i was one on the aluminum enduro hanguard mfg's my local machinist's tool dude sold me on the "form" tap i was doing 1/4-20 threads in 6061,it was blind hole and not overly deep
the form tap really made a huge difference in ease of production time and and enrergy spent.
from memory the drill size was .223 like a bullet and i did buy a lil tapmatic what a jewel of a tool that is .you set/locate your part and the tap matic has a clutch and it automatically reverses back out of the hoe once full depth is reached on yer setting,so you don't break shit and before long i had this lil half mexican spinner chick sittin' on a high stool tappin parts
it would go zing zing zing zing clack clunc zang zang zang zang as fast as you can say that then next nole is being tapped
but yeah even a through hole,in aluminum i feel the form tap is such a beautiful thing mainly when doing like 100's of parts but you got no chips ! no swarf to plug up the tap and make a huge oily mess neither
and for a blind hole no contest
and the thread is a bit stroger because it is formed/extruded not cut

outstanding to hear mention of a guy that trams 'is head :D and single point hole bores , keep up the good work ;)
 
Tune-A-Fish said:
I just need to verify what all I have. The whole idea is to use the Busa top on GIXER legs to get the bars up.

One way er another I,m getting a clamp. Oh and I need it bored to press fit a stock 1973 KZ1000 stem that I will provide to have a snap ring groove added because of the incompatible metals for welding.

Totally understood. I don't see any reason that will be an issue.
 
Taking me forever, but I ordered new parts.

I decided to go with GSXR600 trees so the bottom now works. However the top is all wrong for what I want to accomplish. I need a top clamp drilled for fat bar clamps: but I also want it thick as I can to lower the fork legs as much as an inch if possible. I don't know how to explain it, but I was thinking removing material under the stem section to lower it and on top to lower the legs with a chamfer radius to give it a gullwing look

I trim off the inset to mount flat.

anclajes-clamps-protaper-manubrios-fat-bar-1-18-powertech-16365-MLA20118296841_062014-O.jpg


My BSA with the modified clamp and bars

index.php
 
Exactly, but it seems like a big chunk of billet no? are these usually cast? the GSXR forks are low even with stiffer springs so if I can get an inch overall I have room at the bottom clamp area with the stock lower clamp. If I have to build the whole set I'm afraid it wont be cost effective and I should just sell out what I have and keep looking.
 
Tune, I had a similar puzzle recently and found that the CBR954 gull top had the same offset and fork spacing as a bottom triple I had lying around. I believe it's a 'busa bottom at 114mm but you would need to check.

You can also get bar clamps with a single central bolt as well as riser styles which bolt to the stock lower clamp.
 
Hey Tune-A, it could be done but would need to be a thick piece of billet. If you went with 2" material, you could cut a 1" drop into it at the tubes and probably drop it another 3/8" by recessing the tree onto the steering neck. You could go further on the neck if you didn't have a pinch bolt back there. Also, adding the bar clamps isn't an issue either.
 
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