I bought a blaster w couple months ago and rode it very little but now I've started riding it more. It has a ton of piston slap because it was rebuild with a numera piston and a weisco crank before I got it, but when I rev it up it makes a loud thumping noice when it's trying to rev down, I'm thinking it might be a firing issue but I'm not sure. It has stock jets and a stock pipe any thoughts?
Engine acting weird
- Thread starter Joel Stewart
- Start date
Namura pistons can and will last IF and a big IF you take care of them and bore correctly for them. Other than that I am not sure what you mean by loud thumping?
Any history on who rebuilt it and what exactly was done? Sounds like someone splapped in a new piston in a very used bore. The wiseco crank kits have had many issues.
Blaner
Your Friendly South African Ambassador
I had a funny noise once after a rebuild too. Particularly on deceleration. I pulled the jug off and found my dad had put both wrist pin clips in on the same side!! and the pin was floating into the cylinder wall...
Blaner
Your Friendly South African Ambassador
Haha, he was most upset with himself. Luckily though, the scoring on the cylinder was below the ring height and so never really caused any further effects, so that was a bonus.
@ Joel Stewart. I dont think its a firing issue, being its a single cylinder. I suggest you take the intake (reed cage) off as well as the exhaust and have a look at whats potting in there with a decent light. look for any funny scoring on the piston and/or cylinder wall. It may be crank or bearing related if its not anything up top.
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