1992 VMax-4 just got it and have some questions

Latest update:
Carbs haev the 50 pilots and 140 mains, so I am thinking they were never updated.

Measured cylinders (on spec @ 2.481") going to hone the glaze out of them.

Measured Pistons (look OK, but a little worn @ 2.475-2.476" on the skirt). Book says .004" max piston to wall clearance. I have .005-.006". I really don't have the money to buy pistons right now, unless someone knows a place to get them cheap. You guys think it will be fine to keep running these?

Rings were shot. .029" gap on top ring, and .024-.025 on 2nd ring. Book is calling for .014-.020". New rings are on their way.

The other item that I have a question on is the splined coupler between the secondary shaft and the chain drive box. Chain input shaft splines look good, but the female spline coupler is pretty worn. I looked at Yamaha and the coupler appears to be sold only as one piece with the shaft. Is the coupler removeable? and does anyone know where/how to get a replacement?
 

Yes the coupler is removeable, it can be pressed off. The only way to get one that I am aware of is to purchase the entire shaft from Yamaha. When you put it back together make sure that you align the shaft to prevent it from wearing out again. I ended up with .100" shim under the jackshaft pillow block on mine and then .050" on the motor mounts to bring the clutches back into alignment. Not to mention doing the alignment is free HP.

Ken
 
vincentblackshawdow said:
Latest update:
Carbs haev the 50 pilots and 140 mains, so I am thinking they were never updated.

Measured cylinders (on spec @ 2.481") going to hone the glaze out of them.

Measured Pistons (look OK, but a little worn @ 2.475-2.476" on the skirt). Book says .004" max piston to wall clearance. I have .005-.006". I really don't have the money to buy pistons right now, unless someone knows a place to get them cheap. You guys think it will be fine to keep running these?

Rings were shot. .029" gap on top ring, and .024-.025 on 2nd ring. Book is calling for .014-.020". New rings are on their way.

The other item that I have a question on is the splined coupler between the secondary shaft and the chain drive box. Chain input shaft splines look good, but the female spline coupler is pretty worn. I looked at Yamaha and the coupler appears to be sold only as one piece with the shaft. Is the coupler removeable? and does anyone know where/how to get a replacement?
Click to expand...

so your total piston to wall clearence is .006in max..that`d be .003 per piston side so to speak..I`d run it!

AL P
 
Thanks Ken for the alignment reminder. I am trying to find a standard spline coupler that might work. I have run out of money on this project :( so can't swing for a new shaft. I have also thought about trying to press off the old couler, flip it around and engage just enough of the good splies back onto the jackshaft to align it and weld it on. That way there would be fresh splines on the open end for the chain-drive input shaft to use. Anyone tried this?

Al, you are exactly right! I feel kinda silly for not thinking about the wall clearance being HALF of the total difference. Good feeling though to know that puts the clearance right on spec in the manual, so I should have a pretty tight motor I am hoping once I hone it, and install the fresh rings! My gauge was reading 120psi on 3 pulls before, so we shall see what it pulls to now.

I spoke with Pete today, and he hasn't gotten to my cranks yet, sounds like he is a little busy right now. I was hoping to start putting it back together this weekend, but looks like I won't have the cranks back until next week.

All of my gaskets, rings, and clutch weights/spring will be here Friday, so I can at least keep busy with the clutches, and steam cleaning the engine bay while it is sans-engine.
 
50's on the pilots are too fat for a stock engine and stock pipes, install 47.5's and 135 mains and set screws to 2 turns.
 
Finally got it back together and ran a Saturday 2weeks ago in Ft Wayne, IN with my buddie on his Mach-Z 800. Couldn't believe I could run side by side with him to 95mph!

Thanks for all the help, lovethe site. Still need a brake disc and top shaft for the chain case.
 
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