I just rebuilt the top end of '93 LT80, cleaned carb, air filter and exhaust pipe. there's maybe an hour on the engine. the plug was quite black and sooty. I notice it pumps out blue smoke and almost burns my eyes. atv is 100% stock, except Boyesen reeds. is it possible it over-injects the oil?do I need it to break-in more? maybe i'm burning some of the extra oil that was in cylinder, rings and bearings from assembly?

sorry, I'll shut up and listen to your feedback.

thanks

 

Did you empty the oil tank and put fresh oil in? Did you use a good brand of motorcycle injector oil and not outboard oil? All two stroke oil is not the same, even Yamalube. Look for two stroke air cooled injector oil. Synthetic being the best choice. Mine tends to smoke more when it's cold. After about 5 minutes of above idle riding it smokes much less.

 

To compare your current plug colour to "the chart ranges", surf: Press Here

Based on your descrition, it sounds like your system is too rich (re: picture #3 from its top).

Note: Well worth saving this URL for future reference...

Hope this helps...

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Do a compression check and see what you come up with. Let us know what you find out.

 

spike99, I'm #3 alright. I was wondering about heat range. do you guys run NGK BPR7HS, or BPR6HS on stock engine?what difference does it make/do you notice? I see my float could need adjustment too, I never touched it.

The oil resevoir was full of blue 2-stroke oil, no idea what brand, but I'd bet it's at least a couple of years old. guess I shouldn't be so cheap and replace with good stuff. LT80 has posted the brand he recommends, I can't remember...anyone else?It does smoke less once it's warm. I was told to use Belray 2 stroke by our local shop.

 

The Lt is jetted fat stock. Wouldn't hurt to go to a 87.5 or 90 main.
Plugs: get rid of the "P".... BR8HIV is the plug to use. It's a 12$ plug but will last a season of high ignition performance.
The P is for protruded. It dont need to be and fires better w/o it.

 

I wondered about the purpose of the protruded insulator. I thought it protected the electrode from breaking off. I'm glad you told me that, because I noticed my local store had a better selection of the non-insulated plugs. I'll try the BR8HS.

On jetting, do I buy an after-market main jet with the spec you gave me?, or am I supposed to drill mine out?i'm lost because I don't know what the 87.5-90 means.

thanks.