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Discussion Starter · #1 ·
I know this has been covered before, but I'm still not sure. I have a 91 Formula MX that was recovered from the bottom of a lake. The sled sat for about two years before it came to me. I've replaced about everything on it and it runs well, except for excessive smoke (even after warm up). The head gasket is good, the oil pump is will adjusted, there is no fouling of the plugs, coolent level is good and the carbs have been cleaned. I'm using bolt-on Uni filters instead of the original airbox since that was pretty much toast. I read somewhere that this could be a rotary valve issue, or perhaps I need to change the jetting due to the non-stock air resistance?

Any help would be greatly appreciated. Thanks.
 

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I am Spartacus
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See how the plugs look. RThey should be a dark brown. If they are a very light tan or almost white, it's jetted too lean. If they are black and oily, it's too rich.
 

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Discussion Starter · #3 ·
Solution

After much frustration I fineally found the source of my problem. The rotary shaft seal located behind the rotary valve was bad. As the oil leaked from the shaft, it was pushed into the block and intake area causing the excessive smoke. I replaced the seal and no more smoke. :)
 
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