Honda CBR600 Wheels & Front Suspension Swap

[J6G1Z]

I found a 1989 Honda CBR600 that was being parted out.
http://en.wikipedia.org/wiki/Honda_CBR600F

This model has 17" wheels on each end & the rear wheel is only 3.5" wide. I bought the complete set of forks, both wheels, all the brakes, disks, etc.  The CBR forks slide right up through the OEM Ascot triple clamps. Just loosen the bolts, slide out the old forks, then slide the CBR forks into place & tighten the bolts. Simple as that.

The rear wheel slips right into place as long as you have the entire assembly including the cush drive/sprocket carrier, left hand axle spacer, right hand axle spacer & brake mounting bracket. The Ascot axle & the CBR axle are almost identical. I used the OEM Ascot axle.

I will have to fabricate a short strap type of bracket to mount from the right side of the swingarm to attach to the brake caliper bracket. The OEM Ascot bracket could most likely be modified to work by cutting it, but it is somewhat of a homely looking bracket.

This swap is incredibly simple & it goes together like it was designed for the Ascot. The CBR forks are shorter than the Ascot forks & lowers the bike substantially. The oil sump & the footpegs are starting to become pretty close to the ground. I plan to adapt some rear-set pegs from a GSXR to gain some cornering clearance, but you need to keep the sump in mind. Right now the rear wheel has a 160 series of tire on it. It is too wide & rubs the right side of the swingarm. I will be replacing the rubber with the most narrow size that I can mount on a 3.5" wheel.

My gearing has been changed also. Not only is the CBR wheel 17" instead of the OEM 18", but the CBR rear sprocket has 44 teeth vs. the Ascots 42 teeth. I don't know how much that will affect the bike. I usually change the countershaft sprocket to a 16 tooth instead of the OEM 15 tooth, but have not done that yet. I'm considering a 520 chain swap also, but need to learn more about it.

That's about all I can think of to share with you all on this swap. I will take some pictures at a later date when the bike is cleaned up & assembled.

J.

[J6G1Z]

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[J6G1Z]

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[J6G1Z]

Here is my rear caliper stay that I fabricated real quick. Unfortunately it rubs on the OEM shock. I'm hoping that the new Hagon shock will clear.

[J6G1Z]

My original front master cylinder was damaged & needed to be replaced. I started looking on eBay for one & found this Brembo front master cylinder & lever off of a fairly new Ducati for the same price range. Now I have some cool Italian Super-Bike parts on my Ascot.

[J6G1Z]

Just for the "Trick" factor. LOL!

[cdntfindanAscot]

Cool! I was hoping to do something similar with the front end on my VT. do you know if the triples are the same on both ascots?(the thumper and the twin).
cheers
nev

[J6G1Z]

Cool! I was hoping to do something similar with the front end on my VT. do you know if the triples are the same on both ascots?(the thumper and the twin).
cheers
nev

That I don't know. I haven't had a VT in front of me in a long time.

J.

[FT500R]

I might be getting a second FT to turn into a classic racer.
I am looking at the Hurricane swap but am in doubt due to the difficult tire size.
What is your experience so far? Can you get any decent tires for it?
Did you manage to fit the 160 or did you have to go narrower?

regards,
Paul

[patrino]

I'm running Hurricane wheels, forks, and front brakes on the FT500 (which I am selling:
 https://portland.craigslist.org/mlt/mcy/d/portland-1982-honda-ft500-ascot/7119399351.html).

Bought it as a rolling basket.  To move it around the shop, and on initial shakedown rides, I ran take-off Dunlop radials from a friend's RC390 KTM.  I don't recall the exact sizes but I believe ~100 up front and ~130 in the back. 

I ended up swapping the radials for BT45 Bridgestone bias plys because they're 'taller', with a lot more sidewall than the radials.  The extra height means a lot more ground clearance.  You're already losing at least a half-inch of ground clearance with the smaller-diameter wheels, plus I believe the Hurricane forks are shorter than the stockers, too.  I made up for that somewhat by dropping the forks low into the triples and buying slightly longer Hagons.  I didn't go so far as to fit rearsets, which would help.

I've run the BT45s on a number of bikes, they're good.  They wear well, with good traction.  I've done a few 'track days' at a large (~0.6 mile) go-kart track just south of me with the tires; good laptimes, dragging knees and pegs with confidence.

Below are my notes from researching tires back in 2017.  Please bear in mind things may have changed since then!

FT/Hurricane:  2.5" front wheel, 3.5" rear wheel
Michelin OKs, for that wheel size:  110/80 bias, 130/80 bias
Bridgestone BT45s, for that wheel size:  100/80 or 110/80 bias, 130/90 or 140/80 bias
Conti Twist SM / Sport SM offers: 100/80 bias, 130/70 bias
Avon OKs, for that wheel size: 
   -- AM22 race:  110/80 (Medium or Soft) bias
   -- AM23 race:  130/80 (rec is 3.0 but OK'd for 3.5) bias
   -- Streetrunner:  130/70 bias
   -- Roadrider:  100/80 bias, 130/70 bias

[FT500R]

Thanks, thats great info.
Your bike has a lot of nice goodies on it!

You stayed with the 130 width, never considered a 140 or 150?
140 would fit best on the 3.5 rim I think but I don't know about clearance in the swingarm espescially with the chain.

I run a 130/70 17 on the BMW spoked wheel and would have clearance for the 140 I think but so much has been changed on the bike that it's hard to tell with a CBR wheel

[patrino]

Whoops, typo in my previous post (which I've fixed) - the 130 Bridgestone has a 90 aspect ratio, not a 70.

That's what I've got on my bike now:  130/90-17 bias ply Bridgestone BT45.  No swingarm clearance problems on the LH side, ~4mm of clearance on the RH side.  No centerstand clearance problems either, but about the same #s as with the swingarm.  Plenty (~1") of chain clearance.

I appreciate folks have different philosophies on the matter, but as a rule of thumb I fit the narrowest tires that'll fit, to get the performance/handling I'm looking for.  I started with the 130, it met my needs, so I stuck with it!

[J6G1Z]

I might be getting a second FT to turn into a classic racer.
I am looking at the Hurricane swap but am in doubt due to the difficult tire size.
What is your experience so far? Can you get any decent tires for it?
Did you manage to fit the 160 or did you have to go narrower?

regards,
Paul

Went narrow. No need for extra width & weight on a bike with less than 50HP. http://ascot500.com/index.php/topic,79.msg660.html#msg660