So I bought my second blaster. This one is a beast. Keeps burning up pistons tho. When I first got it I wasn't able to open it up real good due to lotation. I got it home and really opened it up. It died on me and seemed to overheat, also wasn't smoking much at all. one burnt piston. Replaced that, still had oil injection so I deleted that and premixed. It got a lot better but is still getting too hot and burning pistons. Please tell me recommendations for a solution. This was supposedly built by a yamaha tech. Vitos bb 73mm hotrod stroker crank fatty expansions dg exhaust. Mikuni carb possibly stock with 31 pilot jet. I put a 34 in it and vito blue needle. Thanks for your time.
Help! Blaster problems
- Thread starter Jdbtdb10
- Start date
was it bored/honed to fit a new piston each time ? or just slapping new pistons in worn bores ?
It's now possible you're out of bores on that BBK cylinder as they only get 3 per sleeve.
if that's the case it'll need re-sleeved and bore/hone to new piston to proceed with it.
I don't think any of us recommend using the stock carb on a 240BBK ?
but the stock settings are 32.5 pilot, I think I've seen guys jump to 35 pilot for BBK's ?
stock needle only on middle clip position, throw that vitos needle in the garbage !
I don't even know where to begin with main jet suggestions for a BBK with stock carb, but I'd guess in the mid to high 340+ area ?
have you been doing plug chops to confirm main jetting ?
are these rebuilds being leakdown tested for airleaks before tearing them down or at least running them ?
you will continue to fry everything you through at it if it has an airleak.
It's now possible you're out of bores on that BBK cylinder as they only get 3 per sleeve.
if that's the case it'll need re-sleeved and bore/hone to new piston to proceed with it.
I don't think any of us recommend using the stock carb on a 240BBK ?
but the stock settings are 32.5 pilot, I think I've seen guys jump to 35 pilot for BBK's ?
stock needle only on middle clip position, throw that vitos needle in the garbage !
I don't even know where to begin with main jet suggestions for a BBK with stock carb, but I'd guess in the mid to high 340+ area ?
have you been doing plug chops to confirm main jetting ?
are these rebuilds being leakdown tested for airleaks before tearing them down or at least running them ?
you will continue to fry everything you through at it if it has an airleak.
I'm fairly new to the blaster life. I have a stock bore blaster I bought cheap and completely rebuilt. It now has wiseco piston, crank and bearings. It runs good. Then I bought this bb blaster and it's gave me nothing but problems so I'm just now working the kinks out. Basically your saying I need a new sleeve and smaller piston because from what Ive read, there a 72, 72.5 and 73mm piston for BBK (meaning the 3 you were talking about I assume.) a larger carb and a leak down test in that order. Was already looking at a nibbi racing 34mm. The cylinder was in pretty good shape when I did the first piston swap, new one went in smooth.
I had a similar issue on a recent blaster purchase. Air leaks everywhere. Probably the biggest was where previous owner had reed gasket on the wrong side of the reeds. Also had bad seals and no cap on deleted oil line to carb. I good clue is if revs high inappropriately. Leakdown test up front.
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