99' Blaster won't run above idle...Stumped.

Yes complete sense! Most times compression under 100 won't even start! With that said I'd do a leak test on it since you had the top end off, It may not hold compression because the base gasket area leak, reedcage area leak, head gasket leak, maybe the hissing isn't the normal sound?

Any chance of a video?

Well the gasket are all brand new for the top end and came with the Wiseco kit. They are Athena. I mean it is a slight hiss and I haven't done a leak down test yet for two reasons.

One because I don't have a kit or haven't had a chance to go get the stuff to do it. Two because like I was saying with the cylinder and head on the bench turned upside down, spark plug in and tight, and the piston with the rings on and compressed in the cylinder, I can push it down to where it gets past the ports and where it is supposed to start to compress and it will do so but as I push harder and faster it slowly goes down and that is when I hear the hiss that sounds like it is coming past the rings or through the ring gap which seems to me that the leak is nowhere under the ports in the cylinder.

What I mean is that if it is leaking off the compression around the piston as it goes from 1/2 up the cylinder to TDC then the first leak would be that one. So if there were any leaks below the compression range then I would find those after the compression area is sealing. Right? Unless it is normal for it to slowly hiss off that fast or that much which I don't think it is unless you stop putting force on the compression stroke.

I know it wouldn't hold it like an air tank would but I would think that it should hold fairly tight even pressure until you let up off the piston. It does however take a whole lot more force to pull it back up. I will try to get some video of what I am trying to explain as soon as I get a chance and assuming my stupid phone video format will work otherwise I will have to covert it to a usable file format to work on here or youtube.
 
I thought ya left! The rings will seal only under high pressure from combustion! It's gonna leak past them all day doing it that way. With cylinder installed putting your hand on the kicker is it easy to push down now try your foot easy? If quite a bit of resistance you have compression, what it is however you can only find out by testing it. I'm gonna pm you in a minute.
 
I thought ya left! The rings will seal only under high pressure from combustion! It's gonna leak past them all day doing it that way. With cylinder installed putting your hand on the kicker is it easy to push down now try your foot easy? If quite a bit of resistance you have compression, what it is however you can only find out by testing it. I'm gonna pm you in a minute.

Yeah. I read somewhere that they expand more as the explosion happens which makes them seal tighter. It felt like it had decent compression but if I put the tester on and kick it over 6-10 times to get a reading with no heat for them to expand then the normal cold compression should be around 125 I would think. It will start, idle, and even rev up just a tiny bit but as you push the throttle it doesn't go any higher. If you let off the throttle it takes a couple seconds and dies. So even if I needed to go through the three heat ranges by sitting and steadily revving it as Ken Conners suggests I don't think the compression would increase that much. If it won't rev up like that after an initial hone then I don't even think I could do the seating right.
 
Yeah. I read somewhere that they expand more as the explosion happens which makes them seal tighter. It felt like it had decent compression but if I put the tester on and kick it over 6-10 times to get a reading with no heat for them to expand then the normal cold compression should be around 125 I would think. It will start, idle, and even rev up just a tiny bit but as you push the throttle it doesn't go any higher. If you let off the throttle it takes a couple seconds and dies. So even if I needed to go through the three heat ranges by sitting and steadily revving it as Ken Conners suggests I don't think the compression would increase that much. If it won't rev up like that after an initial hone then I don't even think I could do the seating right.

Really sounds like a carb issue. when you rebuilt the carb did you notice a small brass washer under the main jet? sometimes it looks like it's part of the jet seat, make sure that's there! And if it won't hold idle either the pilot jet (slow jet) passage is clogged or the space where it sits and goes into the body of the carb is clogged. You know it's getting gas to the carb by taking off the fuel line and opening the petcock for steady good flow right?
Like I said before, I would dissasemble the carb completely and clean every passageway then blow dry with compressed air. Those reeds look fine to me. If after that it still does it, the next check would be the stator/coil/plug cap.
 
Have you done a leak test, if so how long did the bottom end hold 7 psi for?

Another thing comes to mind, is the piston in the correct way?

Ah, just read post 21 again, it really would help to do a leak test, most of the problems with not running above idle point to a leaky motor.

What fuel/oil ratio is being used and is it jetted to suit that ratio?

Have you taken into consideration the cooler weather and jetted accordingly?

Is the cold start circuit in the carb scrupiuosly clean?
 
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well any progress on this???

Not yet. Waiting on a used stock 66mm jug then having it bored, honed, and chamfered correctly to fit the new 67mm piston we already bought. It will be about 2 weeks before everything gets done but I'll post as soon as I get it all done. B)
 
Hey folks. Sorry it has been quite a while since I posted on this thread but I got pissed at the Blaster so it has sat for a while now. I found what the bogging problem was at idle. It was the crappy Chinese stator that I had in it that came from eBay. Even though it was brand new it was junk. I got a used stator and flywheel from a 2000 Blaster and put it in and it fired right up! I also just to cover the bases and be safe went ahead and put in a proper oil pump block off plate and replaced all the seals and sealant in the block along with changing the trans fluid since I had to split the case anyway. It revs up great and with quick response but still has an issue apparently because as soon as you throw it into gear and try to take off it spits and sputters and smokes more and won't go. If you pull in the clutch and feather it for a minute it will catch back up and run good again but only when sitting in neutral. Weird. I have no clue what else could be going wrong to cause something like that.
 
The Blaaster parrot again says, what were the results of the leak test that should have been done before you started it.