421 Chettah PV 1cyl not firing

[RatherBeStrokin]

Im stumped on the motor i bought and built i geuss im over looking somthing.. Story is that i seen the motor run. Ran good stator side crank bearing when bad. Then I bought the motor cut off old bearing pressed new crank bearing on put it all together on my wheeler with new gaskets, crank seals, rings and head O rings.. First time staring motor 3 kicks with both chokes on purred like a kitten runs great with chokes off... Went to break it in noticed only running on one cylnder. Run it for a wile and it ran good but it would just bogg in the powerban. Swaped pulg wires checked fire every thing is good.. Swaped over carbs, cleaned filters still same cylinder not running.. Fresh 110 Gas timing on +10 like someone said had to be on.No vibes from crank Did compressing check 100 PSI on both cylinders.. (also what Oct is good for that?) Anyone got any ideas.. Thanks everyone ready to see this thing eat the 18'' holeshots off

[pabansheematt]

Im stumped on the motor i bought and built i geuss im over looking somthing.. Story is that i seen the motor run. Ran good stator side crank bearing when bad. Then I bought the motor cut off old bearing pressed new crank bearing on put it all together on my wheeler with new gaskets, crank seals, rings and head O rings.. First time staring motor 3 kicks with both chokes on purred like a kitten runs great with chokes off... Went to break it in noticed only running on one cylnder. Run it for a wile and it ran good but it would just bogg in the powerban. Swaped pulg wires checked fire every thing is good.. Swaped over carbs, cleaned filters still same cylinder not running.. Fresh 110 Gas timing on +10 like someone said had to be on.No vibes from crank Did compressing check 100 PSI on both cylinders.. (also what Oct is good for that?) Anyone got any ideas.. Thanks everyone ready to see this thing eat the 18'' holeshots off

Is it sparking on both sides? 100 psi sounds low to me?

[RatherBeStrokin]

Yeah i was wondering if that 100psi was to low or what.. But yeah you can pull the plugs and there are firing ive even switch the plug wires and tried that.. Has anyone ever herd that if the gaskets or O rings whatever that is on the power valves have a small leak that it will make it do that? Ive been trying to get together all the parts to make a leak down tester. but no luck yet.

[RatherBeStrokin]

Yeah i was wondering if that 100psi was to low or what.. But yeah you can pull the plugs and there are firing ive even switch the plug wires and tried that.. Has anyone ever herd that if the gaskets or O rings whatever that is on the power valves have a small leak that it will make it do that? Ive been trying to get together all the parts to make a leak down tester. but no luck yet.

[dajogejr]

Set the timing back to 5. 100 PSI is TOO low. Seal the Oring for the PV, but that's not gonna change much.

What is your squish? What kind of compression tester are you using? does it have the same reach as a spark plug? (Thread depth)

 

I unless you put 28 cc domes in there...or you live at 10000 feet, 100 PSI is way too low. Do the plugs have antifreeze or coolant on them by chance?

 

Something ain't right, you've got some checkin out to do.

[Handyman]

100psi is way low...even for a stock motor..On my P.V. motor with 20cc domes at +4 timing at 200ft elev. I'm running 175 psi in both cylinders....Check your torques and do a leak down test....

[kawiking]

the title to this thread got me laughing....,. runs good but only on one side..... sounds like its not running worth a crap.

 

sorry, it just tickled me.

 

but,100psi.. thats low.....

 

hope u find the problem !! i hate those little gremlins.

Edited February 6, 2008 by kawiking

[RatherBeStrokin]

Lol what i mean by runs good is that if it were a Blaster it runs good. The compression checker i used was for boat motors but im thinking that the spark pulgs threads are longer then the checker's threads. I dont know what the squish is on the head but its a reg ol chettah head.. And about the coolent on the spark plug their might be i kno when i took it out and looked at it It was wet but i thought it was gas.. Also The O rings for that head are they reuseable or do i need to get new ones if i take it off and re Tq it??? Thanks for the help everone ive learned a lot from this site.

[dajogejr]

Lol what i mean by runs good is that if it were a Blaster it runs good.

 

Damn that's funny....

 

Compression tester shouldn't matter, if the spark plug hole and depth are the same as a spark plug. I use a snap on that has a shorter reach, I estimate 5 to 10 PSI greater than what the gauge reads. This tax season, I'll be picking up even more specialty tools....just like this.

 

You basically take solder, bend it in the spark plug hole parallel with the wrist pin, kick the motor over by hand, and measure how thick it is. You probably want .040 to .050 for that configuration.

 

You can reuse the Orings as long as it hasn't been ran too much or too long, in my opinion. If you take the head off after a year or a season of use, get new ones. A lot of people reuse them, for 20 bucks I won't. Personal preference...

[RatherBeStrokin]

Thanks man. If the squish is not betweem .040 and .050 what would i need to be changing to get it their.. base gasket?

[Handyman]

When I ordered new pistons for my PV from Trinity I also ordered the gasket kit and they were the correct kit... If you want you can call them and get what you need.