Wheel conversions for 1986-1987

Great advice all around. The 12mm (-6mm each side) was a ruff measurement. I have access to a good caliper for exact measurement. Thanks again!

 

Yea, me again..
I probably missed in in a prior post, and didn't find it in a search, but, could you describe or point me towards prior info regarding what areas of the speedometer drive, or areas of the front rim, need to be machined as well? Comparing the stock '87 VFR700 front width at the axle compared to the F2 frt rim looks like the F2 is about 1/2" wider..

 

I have only replaced the whole front end (91+ CBR, 90+ VFR) for my wheel swaps cuz I didn't want to deal with high-risk machining the wheel, and wanted 41mm forks. I am getting a modified F2 wheel and hardware for the stock forks from a friend soon, he is returning to stock wheels. I don't know if it was done properly, but hopefully I can check it out soon and report back. I might install it on my 86 guest/rain bike if it looks usable.

I think I remember people using the VFR drive unit, machined thinner where it meets the fork and using a custom nylon plastic adapter to make up the difference in diameter from the drive to the original wheel seal. ???? I think I found a seal in the correct dimensions that eliminates the need for an adapter in the past. But I could be thinking of VF-F wheel swaps. So much shit floating around in my head.

If this was me, I would mount it up without the discs (or with discs after machining) and see what I needed to do to center the wheel (or discs in brackets). I usually do that using spacers that are a little too short and then start adding washers and finally thin shims. Measure what it took and compare to speedo drive, that's how much needs to be removed. Same for custom spacer on opposite side. Make sure what you end up with and create in total matches what the stock hardware adds up to (total width of stock speedo drive and spacer mounted in stock wheel). I think I said that right.

I'll do some digging around, but a quick search just brought up that Jamie Daugherty was modding the speedo drives, but didn't come across actual dimensions. He no longer has that section on his website. Perhaps reach out to him, but I know he's out this area now and might not be forthcoming in a timely manner.

https://daughertymotorsports.com/

 

Once again, my sincere thanks. Just for reference, my measurements show that the axle / spacer / speedo drive width, between the forks is 10mm narrower between the stock '87 VFR700 and the '92 CBR600 F2 rims that I have. My F2 assembly came with it's axle and spacer for the right side (no speedo drive), thus I used the VFR speedo drive for both measurements. I did look up part #'s for both the VFR & F2 speedo drives, and they are different ( 44800-MV9-003 / 44800-ML7-691) . Is it possible that the F2 drive is narrower? With the 10mm difference, would it fundamentally come down to removing 5mm from both the spacer and drive? I agree with you no matter what, it'll be best to mount it in the forks and measure with spacers/shims. I will reach out to mr Daugherty as well. As always, great advice!

 

I have both sets of hardware. I will dig them out and see what's what. I think I need to dig out a VFR speedo drive for my friend anyway.

 

Greetings, I have a 86 VFR750 that I bought (a long time ago) which had the wheel conversion done already- except the front is an entire 90-93 VFR front end. Currently has Dunlop Qualifiers on it but it has always turned in quite slow and wants to stand back up in a turn. Any suggestions for tire choices to help alleviate this? Feels like it sits about an inch lower than a stock bike which I'm fine with since I'm short and light but I'd like to sort out the handling...

 

I'm in the midst of converting my totally stock '87 VFR700 over to '92 CBR600 rims. From what I've been advised here, you have to get the rear end raised to compensate for the shorter 17" rear rim. I've obtained a rear shock linkage from an '86 VFR which raises the rear for my '87 (different shocks between the 2 years).

 

Gotta get the ass in the air and/or the front end down. Are the fork caps even with the top of the clipons?

The chassis geometry on the VFR can handle quite a bit of tweaking for positive results, without repurcussions.

And speaking of handlebars, wtf is on there? (VF1000F?) They are tall.

I'd also like to see some pics of the rear brake solution. And pics of the upper and lower triple clamps.

 

Not sure what the handlebars are off of but they fit perfectly and the stock hoses and wiring are long enough. Here are some of the pics you asked for. I've heard that the 87 shock is longer than the 86- does it bolt right in?

 

Interesting, thank you.

Yeah, VF1000F bars, or maybe Hawk GT. Lower triple appears to be RC36, could you snap a pic looking up at the stem (bottom of the triple)?

Rear brake solution is good. Modified F2 carrier and custom stay.

Fuse box mounting is interesting too.

87 shock is 10mm longer, bolt in. The hydraulic preload is slightly different, but is no issue. I have an 87 shock mounted on one of my 86. Slide those forks up in the triples 10mm too.

Cheers!

 

I'm wondering if the forks are already slid up a bit since they are even with the top of the handlebar bases- which are very tall, almost 1.5 in. Is there a good dimension for measuring how far the belly pan should be off the ground? This bike seems to sit pretty low already.

Stuff I see on ebay usually lists the 86-87 shocks as the same. Is there a good option other than putting a 87 (almost 40 yr old shock) on this bike? Even the YSS shocks list the 86 and 87 as the same shock.

Fusebox was just tie wrapped when I got the bike. I made some brackets and mounted it to the bottom of the triple. Hard to get a good pic of the bottom of the lower triple with everything in the way...

 

86 shock is 265mm
87 shock is 275mm

I have both on my bench right now.

EDIT 1/20/24: 86 shock is ~270mm, 87 shock is ~280mm. Measured with height gage on granite surface. See: https://vfrworld.com/threads/shock-lengths-86-87-vfr.61427/

Application charts, especially YSS, have errors. You have to decode the YSS parts numbers to ensure you are getting what you want (like length). The VFR shocks are so short that YSS doesn't provide any ride height adjustment, unlike most of their other shocks.

They say it's a 275mm shock, so that's good on an 86 to compensate. On an 87, I would install an 86 linkage piece to gain ride height for compensation. Yes, the linkage ratio is different between the two, but I have done it many times without blowing up or going straight into a ditch. (translation: It worked just fine. Quite good actually.)

Thank you very much for the additional pics. Looks like the original stem on the RC36 lower triple was long enough, which is interesting.

Forks are already slip up from what? Those aren't the original forks for that bike. How do the overall lengths between 1986 and 1990 compare?

 

I don't know about the difference in original length since the 90-93 front end was already on the bike and I don't have any original forks or handlebars. Do the original handlebars have as tall a base as these do? If they do, it's not an issue, if they don't, sliding the forks up 10mm is an arbitrary number. I'm guessing getting original dimensions shouldn't be too hard so I could do the arithmetic.

I had the whole bike apart when I got it and this front end was completely bolt on and still had original steering head bearing as far as I could tell. Steering stops are also perfect...

 

I guess what I was driving at is that the chassis can take quite dramatic changes and still be stable. If it feels slow turning, than make a change and see if it is better or not.

One of my 86 has +20 mm in back and CBR-F2 forks (which are a little shorter than RC36). Turns in great, holds it's line under braking, and has never hinted at head shake.

 

By the way Speedfrk... what size tire do you have on the rear? It looks really wide in your pic for some reason.

 

It is... 180. My friend who was Dunlop's proving ground manager said I could use it since that generation of Qualifiers were actually narrower than 180. But it may be too wide. It's just what I had sitting in the shop.

 

There is a BIG part of your problem right there. A 180 on a 4.5" rim (I'm assuming it's an F2 rim) is not good, regardless of what it actually measures at. You can see it in the pic, the profile is ruined. Even a 170 needs a 5.0" rim (F3).

4.5" rim uses a 160, and is PLENTY of tire for that chassis and power. I am very surprised a tire guy would say that, he is ill informed.

From Dunlop's website, applicable rim sizes for 180/55-17: 5.5" recommended with 6.0" being acceptable.

 

It's an F3 wheel. He was head of their proving grounds... he said it would work not that it was optimal. At any rate, I think the main problem is in the front forks and the rear shock so I want to figure that out first. Do you know the length of the 90-93 forks? I found a reference to the 86 being 835mm.

 

It is still not correct for that wheel. Look at your wear pattern. The profile is ruined and the sides are pinched in. It "works" in only that it mounted on the wheel and beaded up.

Ultimately, it doesn't matter exactly how long those forks are. They are long enough. Longer than the CBR600F2/3 forks I have installed on my other VFRs. I also have 93 VFR forks installed on a VF1000R wheel swap, which had way longer forks originally than the 86 VFR.



You have a low profile 55 series tire, on a now 17" rim with a stock shock. Your ass is sagging, you can see it in the pics. Your front end actually looks a little high to me as well. With a 17" front wheel, I would want the gap from the fender to the upper cowl to be less than that.

You need to get your ass in the air, with a correct tire, and your bike will handle great. The F3 came with a 160/60-17 tire.

 

This is my VFR with 12mm lift in the rear and VFR700 forks... forks are up 20mm as per the Cap.