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FZR carb conversion

Started by Walt_M., May 18, 2016, 06:09:43 AM

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Ron_McCoy

  The handling is much improved. All the flex and twisting of the stock forks is gone, or at least reduced so much it's no longer noticeable. I live in the mountains so most of my riding is on twisty roads. A few years ago I had two Visions, one with stock forks and this one so I've had opportunity for comparison. I was going to leave the stocker stock, but ended up changing the forks on it too. The improvement was too good to pass up. I was commuting about 110 miles a day on a mixture of mountain roads and freeway.
  The reason I had to fab my own fork stops was that I only got the fork legs without clamps and had to fab my own triple clamps. It would probably be just great luck to find forks that worked with the stock fork stops without modification or fabrication.

fret not

Fabricated your own triple clamps!  OK, so you are a machinist then.  Did you calculate for trail or not?  I know there is some geometry that needs to be respected when working with the front end.

I have a set of '87 FZR 1000 forks I would like to use but the triple clamps don't have enough set back for the stem.  The legs would bang into the radiator shroud and probably the tank.  I know stops must be fabricated so that's not a huge problem.  I tried installing them last year but lock to lock reminded me of my old road racers with very limited steering, and that was without stops yet. Triple clamps, yet another project to add to the list.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Ron_McCoy

  Not only calculated for trail, but experimented with eccentric bushings, stem into triple clamps, to get it where I like it best. A little more offset on the top triple clamp than the bottom gives more steering lock. That also allows more trail with more offset which is what gives more lock.  Trail is just under four inches. The last forks I had on the Vision started out at the stock 4.5 inches of trail, but as I brought it down some the tendency to oscillate on turn in went away and stability remained excellent.

fret not

So what is the difference between the stock triple clamps and the new ones you made?  I mean how much difference in off set from stock.

This may well bruise my thinking muscle before I'm done.  It's old and not well developed.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

#144
I had PM'd Ron about this but some of these details are new - like the eccentric Bush theory. And no, that's not a political jab.   ;) If you look at the top triple you can see weld joints where the larger tubes have been accommodated by a welded on clamp section. Ron can correct me but it seems the offset (at least on the top clamp) is very Vision-like.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

fret not

It would be nice to see a pic or two.  I'm trying to mentally formulate a design and process to end with a good set of triple clamps.  My first thought is to cut them out of aluminum billet.

Is the stem threaded into the lower clamp or is it pressed into place?
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Walt_M.

Thanks to Ron for the relocation. We should start a new thread on the fork offset.
Whale oil beef hooked!

Ron_McCoy

Sorry to be so long in replying, but I finally found my notes from 1985 when I did the fork swap. The top clamp is offset 2.30 inches center of steering stem to center of fork tubes. The bottom clamp offset is 2.20 inches. These offsets were arrived at by fabbing a set with oversized holes for the steering stem and pressing in bushings with offset bores to change fork offset. That way I could experiment with offset and trail without having to machine a whole new set of triple clamps for each change. It took a while and a lot of work to get it where I wanted it, but the bike handles really well with great front end feel and feed back.
Back to the carburetor swap. It was running really well, but I found that on really long uphill pulls, several miles, it was surging and losing power like it was running out of gas. Checking out the FZR specs, seeing that it ran an electric fuel pump and noting that Walt M is running an electric fuel pump, I ordered an FZR pump. Problem cured. It really runs great now everywhere. Starts even better than the huge improvement before the new fuel pump.




Rikugun

Good stuff there - thanks for the updates Ron. I like the solution of having replaceable bushings to experiment with offsets.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

cvincer



Tried to view the   Walt_M   July 01   2016    photos of his FZR carb conversion but always got:-

           404   Attachment Not Found

Does anyone know how to view old photo attachments   (& 2016 isn't really so long ago)

Thanks


Walt_M.

I will try to locate them and repost.
Whale oil beef hooked!

Jirik

#151
I have the same problem with attachments as cvincer, but in WHOLE forum. I can't see any photos, nothing :'( :'( :'(

Walt_M.

This looks like a job for Ron. I can't even repost the photos. I get an error,  can not access path for upload.
Whale oil beef hooked!

turbosteve84

I don't know if this is helpful or not, but you need to be logged in to view images. You can read the posts WITHOUT being logged in, but you won't be able to view the images. At least that's been my experience.

--Steve
Steve
saddlebums.tumblr.com

The Prophet of Doom

Pics are all gone.  Can't post new ones either.  I emailed Ron yesterday, but no reply yet


fret not

Ron McCoy, I just re-read some of your postings and have come to the conclusion that you might have been commuting to the JPL facility all this time.  You are a bit more than thorough in your R&D process, and certainly more thorough than 99% of the bike riders I know, and I know some decent fabricators.  I tip my hat to you.  Thanks for the information and insight.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Ron_McCoy

Thanks Mike, but never worked for JPL though I have done work for Lawrence Livermore Laboratories and Northrop at a large machine/fabrication shop I worked for. I learned most of my methods from my dad, a really good mechanic who also built engines and speed equipment for dirt track midgets back in the V-8 60 days. Quite an education. After my tour with Uncle Sam, I worked as a welder/fabricator, machinist, industrial maintenance tech/manager, and engineering project manager so I learned a lot of skills that come in handy for building hot rods and motorcycles and even bicycles.

fret not

Wow!   Very interesting career path.  Do you have a wizard hat? ;)
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Ron_McCoy

Can't be afraid to jump in and try something outside your comfort zone. Great to be retired though.

artbone

I want to do this mod on my 82 which I'll have here before the end of the year. I was looking at V Max carbs but you guys have done so much work with such good results I don't think I want to reinvent the wheel. I'm checking carbs on ebay and the prices are all over the place but it looks like I can get a set for about $100 so that's cheap enough. Would you post a sketch of what the carb to manifold adopters look like and the dimensions?
Art Bone

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