My blaster won't start

[Clark2112]

I have a 04 yamaha Blaster, bored 40, it will not start. I bought a brand new spark plug, 32:1 mix with 89 then switched it to 87 can this cause it to not start?
Also the COMPRESSION is only a 45!! It's getting gas and spark, and lastly right from the engine head to the exhaust, it's leaking oil/fuel, sealing that, will this fix compression and if so how would u fix that??!

 

[Awk08]

89/87 fuel...nope
exhaust leak...nope


45 psi. compression
should be above 100 psi, 110-120+ preferably.
45 is extremely low, try a different tester, if it's still 45...time to pull the top end off and see whats wrong...rings, piston, head gasket ?
that low on compression will surely be hard/impossible to start

a leakdown test before the teardown will tell if it's gasket related....

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/

 

[Blaaster]

I have a 04 yamaha Blaster, bored 40, it will not start. I bought a brand new spark plug, 32:1 mix with 89 then switched it to 87 can this cause it to not start?
Also the COMPRESSION is only a 45!! It's getting gas and spark, and lastly right from the engine head to the exhaust, it's leaking oil/fuel, sealing that, will this fix compression and if so how would u fix that??!

Leaky exhaust has possibly caused a lean mixture which could explain the lack of compression.

 

[Clark2112]

Ok, thank you.
I pulled it out, ended up seeing the piston melting on the rings. That's the compression right there. So if my four wheeler is bored 40, what size piston and rings would I need?

 

[blasterfast]

you would need to go a size up if it has a "wobble" or cyl. bad shape.

 

[Larry's Shee]

Ok, thank you.
I pulled it out, ended up seeing the piston melting on the rings. That's the compression right there. So if my four wheeler is bored 40, what size piston and rings would I need?

Have to have the cyl measured, IF it's well within spec (less than half) you can use new piston/rings with hone. Any more than that get a fresh bore. It's only another $50-60.

 

[Clark2112]

The top of my piston says 71.95mm, so what size piston is this??

 

[Wifesblaster]

You got yourself a big bore kit there!