F3 Fork Conversion Diagram & Notes - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 80 (permalink) Old 07-16-2009, 05:43 PM Thread Starter
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F3 Fork Conversion Diagram & Notes

Hi there... With some encouragement and details from Thrux-Tonup (and others) regarding the Honda CBR600F3 cartridge fork conversion, I went ahead ad did it!

I won an ebay auction for a nice complete F3 front end assembly, fork legs w/ internals, sliders, triple trees... the whole shebang for under $200 delivered. The forks appear to have had little use, good overall condition. BTW...you only need the tubes & internals...the F3 sliders are not used.

So... I tore into the F3 forks, and removed the fork tubes, bushings & internals from the lower sliders as an intact assembly.

Here are some details that are fairly important:

1) The lower screw that secures the damper to the slider is a different size on the F3 than the Triumph screw. Use the F3 screw when assembling the hybrid fork (meaning use of Triumph sliders on F3 legs & internals) Also, be sure to use the Triumph copper washer for a seal, and replace if worn

2) Use the F3 lower (split) bushing on the F3 fork leg. Replace if worn per Honda specs, i.e. teflon coating is worn away.

3) Use the Triumph upper (non-split) bushing, washers, and seals in the Triumph legs.

4) Fill each leg with 460ml fork oil. I used 15W, and it might be a bit thick but I like the increased damping

That's about it! Not too hard really. The F3 legs are about 1.3" longer than the Triumph legs, so they must stand proud of the upper triple clamp. I mounted my clip-ons up there and have a much more comfortable bar position.

The F3's have adjustable spring pre-load. I set it on the lightest setting for now but may tighten it up a bit. The forks also offer adjustable rebound damping. I have it set on the minimum setting and it feels just about right.

In looking at the workshop manuals for the Triumph and the F3, the exploded view drawings are confusing. I believe the drawings are actually drawn incorrectly, but hey...I only do that kind of thing for a living.

I made a composite drawing using AutoCAD of the two separate drawings, and labeled the parts either (H) or (T) for either Honda or Triumph parts that are placed in the new assembly. I did not spend too much on it so don't look too closely!! Also, any input on the drawing is appreciated in case I mislabeled something or perhaps got the order wrong. These parts really can only go together one way, so the only thing that might throw you is if you are missing some parts.

Here's the drawing (jpg) You can PM me if you would like a PDF with much better clarity. (Photobucket will not accept PDF's currently...)


BTW, I just took the bike for a shake-down cruise today over to the 7-11 for some gas & munchies. Everything felt fine...no noises, nice firm ride with no wallowing, overall it feels good.

I'll give it a better test report on Laureles Grade later this afternoon and let you know the verdict on handling effects.

Cheers,
BLIGHT
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post #2 of 80 (permalink) Old 07-16-2009, 06:38 PM
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Blight,

Nice bit of documentation...it actually saved me having to figure out the bushing arrangement on my own (thanks!!). I'm glad the bits went together well for you.

My turn to change out my forks has to wait for winter since I'm not slowing down until its too cold to ride...

Cheers,

--Rich
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post #3 of 80 (permalink) Old 07-16-2009, 08:53 PM Thread Starter
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Originally Posted by beemerrich View Post
Blight, Nice bit of documentation ... it actually saved me having to figure out the bushing arrangement on my own (thanks!!). I'm glad the bits went together well for you. My turn to change out my forks has to wait for winter since I'm not slowing down until its too cold to ride...
Cheers,
--Rich
Thanks Rich, and your information was helpful as well from earlier posts! I really haven't lost any riding time... with the swap. I did this last night out in my garage after dinner. Took about 2 hours. The hardest part was getting the %^&*# damper fixing bolt out of the bottom of one of the Thruxton legs!!!!!

It was torqued in so hard at the factory I bent one of my big hex wrenches trying to loosen it! Then, after it finally broke loose, it spun the damper inside the leg. I eventually figured a way to stop the damper from spinning...whew, that stupid screw cost me about 45 minutes!

Anyway...if all goes well you can do it easily in one evening, and be ready to ride the following morning. I just took it on a quick run over Laureles Grade at around 80% of my usual pace...just to feel it out. Verdict? Very impressive! I like a firm front end, it is definitely firmer (compression damping), but still not harsh. You can really feel it working to absorb the big bumps, and damp them out. There is no mushy wallowing as with the stock forks.

I haven't even tried adjusting them yet for rebound compression or pre-load. Just getting a baseline feel for the new front end. If you get all your parts together and want to do it-- just go for it!

Hope my diagram is useful for you and others wanting to do the swap. Here's a coupla pics of my new zero-degree bend clip-ons up on top of the triple clamp. I adjusted the pull-back angle to my liking.

Just out of curiousity, I went over and grabbed the SuperBar I had purchased (in case I ever do a bar conversion) and held it up to the clip-ons...it's a darn near exact match for pull back and flatness! The new setup is 28" end to end.




Cheers!
BLIGHT
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post #4 of 80 (permalink) Old 07-16-2009, 10:18 PM
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Thanks Blight, nice drawing. I've got that project on the bench right now waiting for new seals. Good to have confirmation on what to use from each fork.
Mike
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post #5 of 80 (permalink) Old 07-16-2009, 10:54 PM
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Blight, Good job as always. I recently went down the Intiminator path and was happy with the results. Had I not had any success with this then I was looking at the F3conversion. What clips on are you using? I don't recognise them. They look hollow - how's the vibrations (if any)? I have a vibration with my OEM clips ons which I am trying to reduce.

FCR, Uni, 813 cams, Works shocks, drilled Ricor valves, Pieman ignitor, green springs, Beringer caliper, preds, damper, brace, Corbin, custom tinware, JMC swingarm, Brembo radial M/C, oil cooler, rearsets, clip ons, tubeless rims, Acewell, T/Clamp
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post #6 of 80 (permalink) Old 07-17-2009, 12:29 AM Thread Starter
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Originally Posted by Aussiematt View Post
Blight, Good job as always. I recently went down the Intiminator path and was happy with the results. Had I not had any success with this then I was looking at the F3conversion. What clips on are you using? I don't recognise them. They look hollow - how's the vibrations (if any)? I have a vibration with my OEM clips ons which I am trying to reduce.
Hey Matt... thanks very much! The billet clip-on bars are from Rockwall Performance (purchased on ebay for $95 USD). They are 41mm with zero degree bend. And yes... they are hollow 7/8" bars. The stock Triumph clip-ons have about an 8 degree downward bend that is uncomfortable for me. The 'flip and flop' option is too 'upright' for me, so I chose to get the flat bars. Incidentally, the CBR600F3 came with zero degree (flat) clip-ons, and among sport-bikes was one of the most comfortable in it's day.

I think there must be an amount of 'flex' in a tubular handlebar that can either eliminate vibration or enhance it depending on vehicle harmonics. All I can say is there is no discernible bar vibration with this setup. My bar-end mirrors show the rear view clearly at all rpm. The riding position is very comfortable with the 'flattening' of the bar angle, and the adjustable pull back to suit your comfort level.

I was actually pretty happy with the OEM forks after I installed the Progressive spring kit, and put in 15W BelRay fork oil. However, I was still looking for a more comfortable bar position. Having looked at tubular handlebar conversions (about $500 USD) I thought, why not get some flatter clip-ons, and mount them up high, on top of the triple clamps.

So, the F3 conversion makes sense for me because the fork legs are 1.3" longer, allowing the same bar mounting as the Honda CBR600 over the top clamp. The adjustable rebound damping is a definite plus... the preload adjuster is welcome, but already a feature of the Thruxton forks.

For the bars, I wanted some adjustable, flat (zero-degree) bars with some rise, and found the billet Rockwall units fit the bill for a reasonable price.

Anyway... I hope this information is useful to you!

Cheers,
BLIGHT
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post #7 of 80 (permalink) Old 07-18-2009, 03:45 PM
 
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What year model is the F3? It isn't called that over here so I'd like to know what yeats to look out for.
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post #8 of 80 (permalink) Old 07-19-2009, 03:57 PM Thread Starter
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Originally Posted by Brit Twin View Post
What year model is the F3? It isn't called that over here so I'd like to know what yeats to look out for.
From the BikeBandit online 'fiche' it shows the CBR600F3 was made from 1995 to 1998. I know in 1999 the F4 went to 43mm legs so you'll want to stay away from that model.

Still very happy with the new front end performance by the way... it's been a few days of riding here and there and it feels great! Especially with my new higher and flatter bars!!!

Cheers!
BLIGHT
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post #9 of 80 (permalink) Old 07-20-2009, 06:37 AM
 
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thanks blight - appreciate the info
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post #10 of 80 (permalink) Old 03-29-2011, 01:13 PM
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blight,

Excellent job on the CBR 600 F3 Conversion for the Thruxton. I completed the conversion with zero trouble. I was wondering what you wound up with on the preload and dampener adjustments? I haven't figured out the best settings for me yet.

Pictures to follow!

Cheers!
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