Last August, while perusing the local classifieds, I came across an individual who had a non-running Trail Boss. The bike itself was in great condition, but they could not get it to run, they installed a fresh piston, so I figured it was a carb or electrical problem, and for $300 I figured I couldn't go wrong.

Long story short, they installed a stock bore piston into a jug that was bored .020 over. I sent the jug to SLP who bored, honed, and chamfered it. They sent me the corresponding Wiseco piston to accompany it. While apart, I noticed the lower crank bearing was bad, so I installed a new crank and connecting rod, replaced all bearings, seals, etc. On disassembly I marked the stator so as to install it in the correct position again. Got it back together, and immediately started, and sounded very healthy at idle. At roughly 3k rpm it knocks. Up to roughly 3k its fine, it knocks in that rpm range and goes away at higher rpms. Increasing octane rating to over 100 with Klutz octane boost, and saw no change in knocking.

Located a timing light, and tach, and checked it just a half hr ago with the engine cold at roughly 3k rpm. I'm reading roughly 27* advance, when I understand it should be 25*. Is that enough advance for the engine to knock? If I go in and retard timing, how far should I turn the stator to retard timing? (ex: rotate the stator 1/4"?)

Side note: I assume that timing should be at 25* exactly. Is there an "acceptable" range?

Thanks in advance!

 

If you marked the stator plate the ignition timing should be ok. I'd pull the black wire from the reverse limiter to defeat it as they can limit in forward range same as they can in reverse when the module starts to fail. Item#33.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse Also recently a member went through the same sort of problem on limiting in forward. May be the same thing you're experiencing. https://atvconnection.com/forums/pol...ml#post3328436

 

Lots of guys have 5 degree advance timing keys in their bikes, no issues running 91 or 93 octane. How does your spark plug look?

 

Spark plug looked fine, if anything looked like it was running too rich. Pulled the stator off, and timing was off. Looking to readjust and reassemble. However, i've run into this. Please see the red wire on the left side of the screen. Anyone know if I can soldier this one back on, if so, where?




Through the process of pulling the flywheel, I screwed in the bolts too far. Is a new stator in line? If it's risky, I'd sooner get a new stator to prevent damaging other electrical components.