The neighbor boy decided that I needed to work on his buddy's grizz so here we go. It will start and run but really doesn't rev. It fights the starter to turn over. I see some fuel spray coming out of the carb, I think I want to go at the valve lash. 3200 mi, 3800 hrs. What are the valve settings for this thing I don't know the year yet. Thanks Doc

 

The 660 valves get set at 0.004" Intake and 0.006" Exhaust (cold) There are 3 intakes and 2 exhaust

We've replaced a lot of timing chains on the 660 - such a long stroke and a lot of torque seems to stretch them pretty good - I would suggest checking the valve timing, especially with the "fuel spray" - it may have jumped 1 or 2 teeth, which would still let it run but give no power. Chains are cheap through Yamaha (rather than something like DID), they run around $22 retail vs $60+ aftermarket

Search the 'net as there are OEM service manuals floating around out there for free download............

 

Thanks, I'll take a look

 

I'd start with just taking the carb off and completely cleaning it...

How long has this thing sat?

I would start with the small stuff before checking the timing and such...

The valves probably do need an adjustment... any idea when the last time that happened was??

 

I have zero history on this thing. I went thru the carb all is good in there. Checking to see if the timing marks are lined up is the next project. I'm a Polaris guy so this is all Greek to me. thanks Doc