Yamaha Motor Questions

[BGilly]

Hey guys thanks for the help! I will look for TRS first. I know of Permatex products and found it to be reliable for other applications. I partly agree with you on it not being part of the gasket kit, but gaskets are not always paper and copper either........... ahh, no win argument I guess.
Hey Rob, will pecan shells work. I live in Louisiana and we have pecan trees by the zillions down here. I was figuring on sitting down and splitting a buckets worth and stick in my blaster. Just kidding of course!
See ya!

[BGilly]

Hey Rob Raider, look I joined the SBT forum, thanks to you!!
I have 3 questions on Yamaha motors.
1) I heard that if you mill your head to boost compression, it is better to pull the crank to have it welded (and trued of course). I was told this by the local Yama shop. The guy said the higher compression beats harder on the crank. Sounds believable, but is it true? I was thinking of boosting my pressure up 50 pounds and I have a stock crank.

2) When I go to peel my crankcase apart, what is the best sealant to use to after I clean the surfaces? A full gasket kit doesn't come with the sealant (at least mine didn't, why do they call it a full gasket set??).

3) I have a older crankcase and cylinder set. I want to clean them up to the bare aluminum (some corrosion). Besides sandblasting, what is the best way to remove all the old paint and corrosion that is safe for aluminum. Bryan, what does SBT use to clean casings when they get old motors in. I seen some of your motors and the look new and it's not just the paint job.

Thanks guys!

[Bryan Glynn]

1) True. Welding will hold up better to the increased stresses. Trueing insures proper timing and elimiates power losses, and lessens stresses on the crank.

2) Permatex "The Right Stuff". You could argue the wording of the kit, but no one expects sealers or treatments to come in a gasket kit. That would be more like a "Complete Assembly Kit". But then someone would say - "Where are the tools?"

3) We use special aluminum blasting materials.

[raider1100]

Hey there Mr B
glad you joined up.
anyway you can run 150 PSI on a 3 cylinder and about 170 on a 2 cylinder without any real difficulty. Anything past that you shoudl have the crank trued and welded.

for the crank case sealant well i am a firm believer in 3 bond 1211. I think it works best for crankcase sealing.

for the motor sand blasting you can go to a sandblasting place and ask to have the case sandblasted using walnut shells. the walnut shells will remove the paint, but will not pit the metal. Make sure you mask off any areas you dont want painted
Rob

[Bryan Glynn]

1211 is very good stuff. We used to use it, however we would have the very occasional leak, if the case surfaces were particualrly 'used'. Since switching to TRS, we have had virtually zero leaks. It's just a grade better stuff for the use. I would have no problem using 1211 if i couldn't get TRS though - odds are it'll be fine.

[CaptToyota]

Take the block to a local auto machine shop and have the part tanked/cleaned. Most times will remove all paint, ask them how they clean their aluminum heads. I would not blast with any abrasive material as you run the risk of altering the finely machined surface at the case to cylinder, reed/ intake surface, case half surface.