Yamaha 90hp ETLF rebuild

[zjackster]

I am rebuilding my 1989 90hp Yamaha. The number 3 cylinder is scraped up and I will have the cylinder bored out.(I will have all three done). What is the size of the over sized pistons, .50mm or .30mm?

I also broke a crank main bearing tearing it down and now need to press the crank apart...can this be done without too much trouble on an arbor press?

[grouper sandwich]

I don't have an answer to your question, but do have a question. Did you have any problems with broken bolts, and if so how did you resolve them?

[zjackster]

No problems with broken bolts. If possible file flat, center punch, then drill completely through bolt. Use another bolt to determine how far to drill. Start with small drill bit and work your way up to a size big enough to use an Easy Out.

[grouper sandwich]

Thanks for the tip. I need to open up my 1993 70 TLRR to clean the cooling passages and the thought of broken bolts has me scared to death to do it. Good luck with your build and give updates on the progress.

[99yam40]

I also broke a crank main bearing tearing it down and now need to press the crank apart...can this be done without too much trouble on an arbor press?

No, you will need to send to a shop that has the proper tooling

[rodbolt17]

carolina machine and tool,formerly Akermann marine, in wilmington NC can do all your machine,crank issues.
they have two of mine right now.

[zjackster]

Well, I have talked to a few people about the crank bearings. There isn't any wear on the shaft but the question I have is on the bearing itself. Is it a two piece? It looks like it's broken but is it?

I have also heard that boring only one cylinder is common practice for a 2 stroke engine. Is that acceptable? I plan on keeping this around for a long time and want to do it right. What's the verdict?