Yamaha 1200 help prevent blowing engine.

[Bama1981]

2002 Yamaha XLT 1200. Rebuilt top end had the pop at 45 and blew hole in front cylinder, I missed read documentation for 1200cc not the 1200r. Rebuilt again with pop off at 70 on all 3 carbs (should be 65-75). Ran it to warm up for 10 min let cool down for 30 min ran again warm up then ran for 15 min not exceeding 5500 RPM and varying throttle. Checked plugs and front is dry looks rusted (new plugs to start). What do I need to do to fix this problem before I blow another cylinder?

[jetskiga@gmail.com]

Re: Yamaha 1200 help prevent blowing engine.

You need to verify oil is pumping thru the oil pump and line check any oil filter/valves in the oil system. things can get slimy and junk up clean the oil tank. refer to shop manual for how to check and for spec like oil flow/rate always replace the oil lines as the 1200 is prone to line shrinking and falling off on I think the back/3rd cyl I don't have alot 2stroke knowledge under my belt as we have transition over to mostly 4 stroke but I work on a few dozen of these and I must admit I never look foreword to servicing 1200 carbs.

[Bama1981]

Re: Yamaha 1200 help prevent blowing engine.

Thank you for the response. I converted to mixing and removed the oil pump and added the block off kit. I re-verified the pop off for the carbs. I am mixing at 4oz of oil per gallon. I have not pulled the engine at this time.

[jetskiga@gmail.com]

Re: Yamaha 1200 help prevent blowing engine.

awesome! I prefer premix my self on units that can be. Dont forget if not already if you have issues with cat converter an they do break apart and cause power/temp issues sbt has a d-plate and chip to fix that issues. I have done so many of these mods research it.

tip if the temp sensor is bent that's a good sign of broken away converter but to really know... remove exhaust and shake exhaust and visual check