Quote from: Pat Conlon on September 23, 2025, 02:48:58 PMBoth the FZR1000 and YZF750 front ends use a mechanical speedo drive that the FJ cable plugs into.

I switched from the FZR1000 USD's over to my current YZF750 USD's and here's what I've learned.

Stay away from the YZF750 front end, it takes too much work. You have to use the YZF lower triple, punch out the short fat YZF stem (too short too fat for the FJ steering neck) then weld up increasing the diameter of the skinner FJ steering stem to fit in the big hole in the YZF lower, then press the modified FJ stem into the YZF lower clamp.  It's very involved for little benefit .  .
 The only thing you gain with the YZF750 USD forks vs the FZR USD's are that the YZF forks have external compression adjusters...the FZR forks do not. You set compression on the FZR forks via a shim stack inside the forks.  Both forks have external rebound and preload adjusters.
 I thought the ability for easy compression adjustment was a big deal but in reality, it wasn't...
I thought I would be adjusting my fork compression more than I actually am. Perhaps on a track bike it would be true but on my street FJ once I have it set, I've left it alone. It did take me 3 tries with FZR forks to get the shim stacks exactly where I wanted (you gotta take the forks apart ) but once done, all was well.

The FZR USD swap is plug and play by comparison to the YZF.
 Get the entire FZR front end, rim, axle, spacer, speedo mech drive, forks, upper triple lower triple w/ stem and fender. It will make things easier.

This is exactly what I was looking for Pat. Modification for the stem, etc.. this is not an issue for me. I was wondering only if that make sense to do more work for compression adjustability and looks like for street use not so much.
Thanks Pat

Hello guys,

what is the recommended piston to wall clearance on fj1200/xjr1200 (bored to 78) cylinder block for wiseco 1219 piston set?

Thanks

Both the FZR1000 and YZF750 front ends use a mechanical speedo drive that the FJ cable plugs into.

I switched from the FZR1000 USD's over to my current YZF750 USD's and here's what I've learned.

Stay away from the YZF750 front end, it takes too much work. You have to use the YZF lower triple, punch out the short fat YZF stem (too short too fat for the FJ steering neck) then weld up increasing the diameter of the skinner FJ steering stem to fit in the big hole in the YZF lower, then press the modified FJ stem into the YZF lower clamp.  It's very involved for little benefit .  .
 The only thing you gain with the YZF750 USD forks vs the FZR USD's are that the YZF forks have external compression adjusters...the FZR forks do not. You set compression on the FZR forks via a shim stack inside the forks.  Both forks have external rebound and preload adjusters.
 I thought the ability for easy compression adjustment was a big deal but in reality, it wasn't...
I thought I would be adjusting my fork compression more than I actually am. Perhaps on a track bike it would be true but on my street FJ once I have it set, I've left it alone. It did take me 3 tries with FZR forks to get the shim stacks exactly where I wanted (you gotta take the forks apart ) but once done, all was well.

The FZR USD swap is plug and play by comparison to the YZF.
 Get the entire FZR front end, rim, axle, spacer, speedo mech drive, forks, upper triple lower triple w/ stem and fender. It will make things easier.

Quote from: Pat Conlon on September 23, 2025, 12:48:45 PMYou are describing pilot jets not main jets.
Who told you #42.5 pilots were wrong?
 US market FJ's were jetted lean from the factory. Other non USA FJ's had #42.5 pilots installed in the factory.
Lean #37.5 pilots run hotter.

After cleaning be sure to replace all your o rings, especially the o rings on your float needle seats.

I was going by the Clymer shop manual I have. Which marks 42.5 pilot's for the 1200 but 37.5 for the 1100. All the o-rings and gaskets were already refreshed.

You are describing pilot jets not main jets.
Who told you #42.5 pilots were wrong?
 US market FJ's were jetted lean from the factory. Other non USA FJ's had #42.5 pilots installed in the factory.
Lean #37.5 pilots run hotter.

After cleaning be sure to replace all your o rings, especially the o rings on your float needle seats.

My money is on dry leaking o rings on the float needle seats.

Very common.

Quote from: MarioR on March 18, 2025, 12:13:19 PM

Quote from: Pat Conlon on March 14, 2025, 09:36:05 PM

Quote from: JohnnyTheCraneGuy on March 14, 2025, 09:00:48 PMComing back to this, with the FZR front end, will it accept gold dots from a '03 R1?

Yes...
 I needed to grind a very small relief on the forks to clear the cast hose line fitting on the R-1 caliper body.
You've got to look closely to notice it.
 

Pat, do you think FZR 92 USD fork set is better than Thunder Ace big conventional fork?

Pat,

Since you are modification GURU , this is what I understand for this conversion:

1. Use 92 USD up side down forks with lower triple and custom upper or FZR modified, wheel, shaft, bushings,  fender, calipers choice you want
2. What about speedo drive?
3. Alternate option use for an example 96 YZF 750R KAYABA forks (since adjustable forks with 92 FZR lower triple and custom upper or FZR modified. What about wheel than? Shaft probably will be different..... Speedo drive?
4. FZ1 handle bar or custom tall risers mounted under upper
5. Blue dots calipers or 6 pistons caliper tokico

Correct me if I ma wrong. Thanks Pat

THAT was fun!

Got to ride with many of The Usual Suspects, and got to ride Saturday with Kurt Pierce from Utah, veteran of many West Coast and Colorado rallies.

Photos to follow.

Update

Parts finally arrived and I got some time to look into this again.  Installed new choke vent lines on all carbs.  Installed 2 new float bowl vent hoses as well.  Replaced fuel line from petcock to carbs with new.  Routed as per diagram and removed fuel filter that previous owner had added.  Installed new diaphragm and spring in petcock.  Petcock now holds closed unless vacuum is applied.  Tank was flushed and is free of debris. 

Put everything back together and started bike.  Bike started up nicely but fuel started leaking badly out of choke vent for carb #1 and #4, maybe 2 or 3 too - it was hard to tell, fuel was gushing out, had to stop bike immediately.  Fuel stopped leaking a couple minutes after I stopped the bike - so petcolk seems to be doing its job.  So I guess my next step is to clean and rebuild the carbs. 

It seems very coincidental that I would have a bad needle o-ring or stuck float on two (may more than two) carbs at the same time.  I'm wondering if I missed something when I put it back together.  One thing I wasn't sure about is the hose on bottom of the gas tank.  I suspect this is a vent hose for the tank?  Anyhow, I couldn't remember if it was connected to anything so I routed it down the back of the engine along with the carb vent hoses. 

As close to perfect weather for a rally as there could be.  A good time for sure!