Triumphrat

Siskiyou

If it helps, I took a (somewhat crude) measurement to compare the stock Triumph
wheel to a CBR wheel. I measured the distance on each rim from the center of the
wheel to the sprocket to see how far off from center the rear wheel would be with the
sprockets lined up. The difference was about 2mm, so if you get the chain line straight,
the wheels will be pretty close.

Actionabe

thats a pretty helpful mesurement, that is really close.... I was planning on doing this http://www.yamahafz1oa.com/sportryde...ntmethod.shtml once I get the wheel installed, seems like a pretty simple way to know for sure.

cashmore1985

That sounds close enough to me. I like it.

__________________
'09 Bonnie SE Blue and White
MODS- Lots of 'em

Host and Producer - Cafe Racer Podcast
www.caferacerpodcast.com

beemerrich

The hard part about getting the spocket aligned without shimming it to the right is moving the brake caliper/rotor as a unit. I suppose you could try shimming the brake rotor in lieu of the sprocket to move the entire wheel to the right. An equal amount would then need to be added to the left side axle spacer and removed from the right side spacer. The right side already provides very little space for movement to the right, so that constraint would likely drive how far the wheel can be moved over.

Personally, I'm much less comforable with shimming the rotor than running the wheel ~2mm (~0.079") off center and then putting some washers under the sprocket/on the rather substantial spocket carrier studs to get the chain to align. The rotor bolts are soft and don't have tons of shear strength. The sprocket carrier bolts, however, were engineered for a machine that puts out 100+ crank HP.

Regards,

--Rich

cashmore1985

I had a conversation with Pieman today and in order to get everything lined up he had to get new spacers for both sides of the wheel, spacers behind the brake rotor, machine the face of the cush drive to allow the sprocket to sit closer to the rim, and a spacer behind the front sprocket to line up the chain.

__________________
'09 Bonnie SE Blue and White
MODS- Lots of 'em

Host and Producer - Cafe Racer Podcast
www.caferacerpodcast.com

Actionabe

Wow sounds like ill be hitting up the machinist a lot more once I get everything bolted together and make some measurements. Thanks to you and pie man for the information!

cashmore1985

I don't know the exact measurements for the rotor but he had 7mm machined off the face where the sprocket bolts up. He also had to have the studs that hold it on made shorter so they wouldn't hit the chain or something

__________________
'09 Bonnie SE Blue and White
MODS- Lots of 'em

Host and Producer - Cafe Racer Podcast
www.caferacerpodcast.com

beemerrich

Mike is meticulous in his work, so I'm assuming his goal was to precisely center the wheel in the swingarm. The cush drive sits pretty tight to the right side (i.e. the spacer doesn't have much meat to allow movement in that direction), so I'm assuming he moved the wheel 7mm in that direction?

If all he did was move the sprocket inboard, then this runs counter to what I see on my bike...which is that the sprocket needs to move outboard to get better alignment with the countershaft sprocket. When I get some time in the shop, I'll measure how far the sprocket has to move to the right to perfectly line up, but it can't be more than 2-3 mm. Any shimming of the rotor would take that amount out of this distance...

Regards,

--Rich

PieMan

Correct Rich, my wheels are exactly centred. All the existing spacers required replacing as the CBR600 rear wheel complete with sprocket carrier and spacers is around 2mm narrower than the factory rear wheel complete with sprocket carrier and spacers. The sprocket carrier required 7mm taken off the outer face to give enough clearance to centre the wheel, and the sprocket studs required shortening to clear the swinging arm. To help compensate for the rear wheel moving over, I added a 3mm spacer behind the gearbox sprocket, I could have done with another 1mm, but that is the max you can get away with so the serrated sprocket tab washer still sits on the splined shaft. 2.5 years later the discrepancy between the front and rear sprockets has had no effect on chain or sprocket wear.

The front wheel also needed new spacers as the factory spacers moved the front wheel too far to the left. My wheels are inline to the millimetre and there is absolutely no bias in taking left or right handers.

If anyone is thinking about carrying out the F3 mod, go ahead, you won't regret it. It improves the caperbility of the Bonnie or Thruxton in every way. The factory CBR600 front calipers are more than enough to stop you very quickly and they work great with the factory Triumph master cylinder. The F3 cartridge forks, although old technology compared to modern cartridge forks, are far better than the antiquated factory damper rod forks and also seem a perfect match for the ZXR rear shocks with lighter springs. Also using 160 rear and 120 front rubber on rims that they are intended for, is excellent. It's not easy to lock front or rear when braking hard and unusual for the rear to break away when accelerating hard out of a corner.

__________________
Mike (UK)

04 Bonnie Black Special

http://www.triumphtwinpower.com

beemerrich

Thanks for the information Mike. For it to be done properly, it seems there's a bit more involved than the laundry list of details I've previously come across on the forum.

Or I can do what most other's have done and just shim the wheel sprocket to align it with the countershaft sprocket and call it good. I guess it's a good thing I like right-hand corners...

Regards,

--Rich