We recently picked up a used yamaha moto 4 yfm200dx quad. 2x4.


In pretty good shape, however I feel it has low compression.


It smokes, blue smoke for about 10 to 15 minutes, fairly good. then seems to not be much at all.


I have changed oil filter and oil. first tried 20/50 yamaha lube, it smoked pretty bad, so after a few weeks, went to 10 w 40 atv oil.


starts right up and runs nice and smooth, minus the smoke issue.


So does anyone know the compression specs on this model ?

I fgured the top end is week or maybe something else, just comfirm my thinking on this.

I was hoping to get the min and max compression for this model.

I went to rent a tester today from autzone, but they did not have the right one. So Im gonna have to buy one to test it.

And anyone know the max spec on the cylinder bore, once I get this torn down at some point, im gonna need to know after I check the cylinder wall, if its still in spec enough for a hone or bore job.

Thanks

Ryan

 

Not sure on the cylinder specs. Most engines start losing power and have trouble starting at around 100-110psi. Usually they completely give out at around 90-95psi.

 

Thanks for the reply.


I was thinking 100psi, thats what my manual says for my suzuki 300. 125 to 185 with min 100psi.

but was not sure for the yamaha 200.


thanks