Blaster Not sure what went wrong

[ghostrider117]

Well I got another top end w/cylinders that I know are good. Ran it for like 10 hrs then went to something else. It was in my X2 701 conversion ski, so I know its good. Will bolt that on this afternoon and try again. Thanks for the help so far.

DRE

did the red pipe get to hot????.......what was the digital temp. of the motor?.........when you called me and asked if the red pipe is suppposed to be hot and i said to the touch but not scallding....is this the culprit??????

 

[Dre0256]

did the red pipe get to hot????.......what was the digital temp. of the motor?.........when you called me and asked if the red pipe is suppposed to be hot and i said to the touch but not scallding....is this the culprit??????

I dont think so. The pipe was hot to touch but not to the point where it burnt me. I even put wanter on the head, pipe and motor and nothing sizzle at all. Like I said it was warmer than my Bpipe, but not hot to the point that it burnt my hand. It was pissing out of both pissers, 1st one from the head and 2nd one from the stinger. And have no way to tell digital temp of the motor since I don't have nothing to meassure it with!!!!!!!!!!!!!!!

 

[escore]

I had similar problems with a similar build. My compression was around 175 with my head and it kept seizing 3 times in 1 hours of running The piston said it was a lean condition but I ended up doubling up the base gasket which lowered compression and changed timing a bit and it rips now. It wasn't a great solution but after 3 seizes in 1 hour on a band new motor I'm afraid to change anything at this point.

 

[extreemthrottle]

a couple things i would be looking at.
what type of pistons were they, where were they seizing, and ring end gap.
those answers will rule out a few things

i have seen when a spark plug comes loose it can cause a lean condition, its rare that it would make it seize, but it has happened.

double check your hose routing and make sure its right. the riva pipe i believe was a little different then the fpp.

also where is the timing set at?

 

[Dre0256]

a couple things i would be looking at.
what type of pistons were they, where were they seizing, and ring end gap.
those answers will rule out a few things

i have seen when a spark plug comes loose it can cause a lean condition, its rare that it would make it seize, but it has happened.

double check your hose routing and make sure its right. the riva pipe i believe was a little different then the fpp.

also where is the timing set at?

Pistons were sudco. The front seized on the side near where the gap is. Ring gap no idea. timing is set to stock possition. Checked all the hoses on the pipe all seems ok.

 

[Dre0256]

Ok so I changed top end and cylinders (another set I had on the shelf) changed carb and intake to the wetjet 46mm. Took it out today, big difference was running good, until it started loosing power. So I came in and did not mess with it at all. Came home checked compression and front cylinder down to 90 psi and back down to 140 WTF is going on? getting really really frustrated with this ski.

 

[WFO Speedracer]

At this point you might think about taking the cylinder and pistons to a machine shop and finding out what the piston to wall clearance is, it won't fix a damn thing but if its too low it would give you some piece of mind. I have a micrometer and snap gauges I use to check this with, a lot easier with a bore gauge though.

 

[Dre0256]

Well it was a whole different cylinders and pistons tho! Ok what about the CDI its from a 62t but in a 61x I was told it make no difference!

 

[WFO Speedracer]

Ita a set of piston and cylinders that were bored, we don't know who bored them. we don't know what the clearances were and we don't know if they knew WTF they were doing or not, even people that bore cylinders every day make mistakes, I have had it happen two or three times, one time they bored the cylinders 1mm too big and tried to give them back to me that way, really ?

 

[Dre0256]

But what am saying is the 1st set of pistons and cylinders went up, I had another set of pistons and cylinders that I put on yesterday and took ski out today to water test and started to loose power so I stopped riding, checked compression and its 90 front 140 back from 175. What about the head?

 

[WFO Speedracer]

Check the crankshaft to see if it is out of phase, thats my next suggestion, I didn't know it had smoked another top end

 

[Dre0256]

yes 2nd one in a week UGH:261:

 

[tor*p*do]

what is the jetting in the carb?
may be jetted really lean

 

[Dre0256]

what is the jetting in the carb?
May be jetted really lean

150 h 120 l

 

[tor*p*do]

150 h 120 l

that sounds OK. i ran the same jetting in a 61x/61x bpiped 46mm mik commerical
how many turns lo/hi?

 

[Dre0256]

that sounds OK. i ran the same jetting in a 61x/61x bpiped 46mm mik commerical
how many turns lo/hi?

1 full turn L 1.5 h

 

[Waveblaster785]

Crankseal? Air leak? Cylinder deck or head aren't true. Did you use the same head both times?

All things I would check. As suggested I would take it to a machine shop to get it all checked out as well.

 

[escore]

Sounds like the same I dealt with man. I never really figured it out passed lowering compression seemed to solve it. But the pistons were not reading that was the issue. It runs now though and thats good enough for me for a few months anyway.

 

[Dre0256]

Crankseal? Air leak? Cylinder deck or head aren't true. Did you use the same head both times?

All things I would check. As suggested I would take it to a machine shop to get it all checked out as well.

All the seals are fine, I preassure tested put 10 lbs air and it held for 30 minutes no problem no leaks. Yes same head which its also making me wonder.

 

[Dre0256]

Ok took motor out yet again yesterday and am starting to think that it might be the head, since I took it off and the front oring that goes around the domes was broken in three places (yes they were new orings). So I have taken yet another top end (stock bore) I've honed the cylinders and am putting new rings. (compression was 140/150 when taken off) So I am going the route of a stock head and bore with just the red pipe and cross my fingers and see what happens. I will be using the same bottom and I will also preassure test the engine before intallation. This will also be using a stock 44mm carb. All stock except the pipe. Wish me luck ;-)