valve job

headwrench · 01-23-2010, 03:55 PM

my 90 g8 needs a valve job. at least thats what i think it needs. it smokes really bad @ start up then clears up after running a little bit. it seems to me that oil. is getting in the cylinder past the valve guides. could that be the problem? next ? is, can i pull the head with the valve train still attatched & leave the push rods in the block? i have never pulled one of these apart, just want to know what to expect. thanks

sabercat · 01-23-2010, 06:27 PM

have you tries adjusting the valves?

headwrench · 01-24-2010, 10:38 AM

yes the valves were adjusted and still have the smoke problem. thats why my next guess is to do a valve job. your thoughts are..............

spriddle · 01-24-2010, 10:53 AM

Do a compression check. It could also need new rings. But it does sound like your valve guides are worn.

smallblock450sl · 01-24-2010, 11:29 AM

I agree with Sprid. Compression should be 155 to 175 lbs (with good cranking battery and throttle at wide open). Is the spark plug oily/fouled? Are you useing a NGK BPR2ES ? I've not had to change alot of valve guides, Yamaha's only came with a valve stem seal on the intake, but the exhaust is machined for one, so when rebuilding, put new one's on both. Good luck

01-23-2010, 03:55 PM	#1
headwrench Not Yet Wild Join Date: Oct 2008 Location: centerburg, ohio Posts: 68	valve job my 90 g8 needs a valve job. at least thats what i think it needs. it smokes really bad @ start up then clears up after running a little bit. it seems to me that oil. is getting in the cylinder past the valve guides. could that be the problem? next ? is, can i pull the head with the valve train still attatched & leave the push rods in the block? i have never pulled one of these apart, just want to know what to expect. thanks

01-23-2010, 06:27 PM	#2
sabercat gone yamaha! Join Date: Sep 2008 Location: ontario, canada Posts: 1,424	Re: valve job have you tries adjusting the valves?

01-24-2010, 10:38 AM	#3
headwrench Not Yet Wild Join Date: Oct 2008 Location: centerburg, ohio Posts: 68	Re: valve job yes the valves were adjusted and still have the smoke problem. thats why my next guess is to do a valve job. your thoughts are..............

01-24-2010, 10:53 AM	#4
spriddle Admin Join Date: Dec 2006 Location: TN Posts: 101,855	Re: valve job Do a compression check. It could also need new rings. But it does sound like your valve guides are worn.

01-24-2010, 11:29 AM	#5
smallblock450sl Sometime's............ Join Date: Oct 2007 Location: Tacoma Washington Posts: 11,874	Re: valve job I agree with Sprid. Compression should be 155 to 175 lbs (with good cranking battery and throttle at wide open). Is the spark plug oily/fouled? Are you useing a NGK BPR2ES ? I've not had to change alot of valve guides, Yamaha's only came with a valve stem seal on the intake, but the exhaust is machined for one, so when rebuilding, put new one's on both. Good luck

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Forum
Can I get rid of exhaust valve on G1	Gas Yamaha
Gas tank air valve	Gas Yamaha
Valve adjustment	Gas Yamaha
Valve Adjustment	Gas EZGO
valve ajustment	Gas EZGO