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View Full Version : 81 300R compression PSI?



fabiodriven
04-29-2012, 05:26 PM
I had my R out a few months ago in some slop it shouldn't have been out in. The bike quit that day and I was so disgusted with myself for bringing it to where I did that I pushed into a corner and didn't look at it.

Fast forward to today. I pulled her out, hosed her off, and TecateDan went at her with an air filter cleaning and new plug. She started right up after about 3 kicks and ran really well. It's got a bit of a piston slap now that it didn't have before which I'm not overly concerned about because my Tecate had piston slap the entire time I owned it and it ran like a raped-ape.

Dan put the compression tester on there and we ended up with a hair over 150 psi with the motor warmed up. Is that about normal would you guys say?

rgthree
04-29-2012, 07:03 PM
seems about normal... and most guys runnning 300 kits say there top end is oddly noisy... even mine but after i heard more complain kinda figured its just normal

Dirtcrasher
04-29-2012, 07:19 PM
John, you may just wanna pull the cylinder off.

You took in allot of water on a mountain that trike wasn't meant for...... Those open filters don't like being exposed to water.

My 200X is suppose be about 190PSI......

rgthree
04-29-2012, 07:48 PM
250r top end should be between 142-170

bkm
04-29-2012, 08:42 PM
I agree with DC. Do you know if the head has been cut or what the PSI should be for the 300 kit? That sounds on the lower side to me. If it was a stocker I'd say run it.

rgthree
04-29-2012, 08:51 PM
If you'd like I can throw a compression test on mine tomorrow to compare? Mine brand new with about 15 min on the top end

yamaha driver
04-29-2012, 09:06 PM
above 120 at 120 you will start to have starting issues