need help...compression problem after engine rebuild

[xrider23]

Need help boy...don't know what to do with this

Let me explain you my problem
Completly rebuilded my phazer engine after one of the two clip that hold the air filter in place pass through the throttle body and finish on the top of piston 1. I sleeved both cylinder with a cast iron sleeve and put oem std piston and ring. Sent the cyl head for rebuilt. Put everything back together, fired up and everything was find...No check engine, oil pressure ok... I take care to bled the coolant and check the temp with an infrared. The RPM went to 2500 for a couple minute for warmup and then go back to idle after several minute. My first problem was that I have problem to kept the idle at 1800 like it's supose to be, even with the ajustment screw fully turned in...My second problem was that the motor is really hard to start when hot...my third problem is that the motor is blowing oil by the vent but not that much
I check my throttle angle...ok
fuel pressure ok
poor fuel directly on the throttle body when the motor hot...no start
recheck timing ok
recheck valve clearance ok
check resistance of ignition coil ok
make a compression test...full throttle,cold,at 270 rpm, only 80 psi both cylinder( which i think is very low )
check the decompressor....work fine
the motor run about an hour after the rebuilt, fired up cold run perfect still run fine after the warm up but veru tricky on the throttle and if it shut down, almost impossible to restart
piston clr is 0.00015 like it's supose to be for a NIKASIL CYLINDER
THE QUESTION THAT I'M ASKING IS THE PISTON CLR ENOUGHT FOR A SLEEVE CYLINDER???
I read that the clr should be greather if you sleeve a nikasil cylinder???
Maybe the piston already score the liner

Need your help on this one

 

[APEX 06]

If you have a bore cam I would check the walls, but Im thinking its something in the head.

 

[cannondale27]

You are correct.For a Nikasil bore its about .0015 in clearance for Castiron you need .003 or more clearance.So yes you are too tight.I would also wonder how you managed to bore it for the liner?I would not think there is enough material.

 

[xrider23]

The next step will be to check if the piston scored the the liner cause lack of clearance
And yes the shop did a a intake cam bore. I bought this cyl head on ebay and the intake was sticking

 

[marpolsdofer]

Did you check you grounds on the harness? I had a dealer replace my grounding block it would start cold but then when it warmed up it would die and then not be able to start until it was cold again. Found out grounding block fired witch to me forever to track it down until I found the TB.

Another thing make sure you have your TPS set right, throttle cable within specs. Ran like crap until I got that fixed and I barley rode the sled for the first 4 months I had it.

Little blow by will be common during engine rebuilds until the rings are seated.
Typically you want to promote little wear (witch why even Amsoil does have a non synthetic oil for this) in the cylinder. This will take down the sharp peaks and valleys witch cause it the ring to not seat and seal. You still need some so the oil can lubricate the cylinder but will not be as sharp.
Once its broken in you should see a little rise in compression and no oil.

I am not sure what the cylinder PSI is to be but when you check it I think the Phazer has a decompression mode to make it more easy to start becaues of battery size. Witch is why you might be seeing low pressure. That is if you are using the starter to turn the engine and not operating it.

 

[xrider23]

I removed the throttle body and checked in the cylinder when the intake valve open and i didn't see nothing wrong in the cylinder. no score and still see the criss cross pattern. The next thing i'm gonna try is to make it run next snow fall
Throttle angle set to .67v
Cable free play ok
Maybe a bad ground
The thing I don't understand is why idle ajustement screw fully in I can't get a good idle????????

 

[xrider23]

Someone know where to plug the vaccum hose for the fuel pressure regulator. I'm pretty sure it should hang cause the hose is cut ^ like this at the end

 

[Pakko]

I cut the vacuumhose between the trottlebodies and put a T there, Mine seems to run much better, but I have only tested for a few km

 

[cannondale27]

Its been awhile but yes it is just supposed to hang there.In some applications such as a turbo if it were connected it would raise fuel pressure when vacuum is applied.

 

[Pakko]

why do they even put a hose there, when its not supposed to be connected somewhere?

 

[marpolsdofer]

Most hose that just hang are drain hoses but in this case I think it just to match ambient pressure.
or to make it look better, for ad on later, protect it from dirt and what not.

 

[xrider23]

yesterday i ran the sled in the street( in two inch of snow) for 10 minutes no problem until it reached 105 celsius, than the temp light came on. the sled stall by itself(i have to keep the thumb on the throttle to keep it running) I wait 10 minutes until it started again. Code 30 appear twice after that and shut down the sled. I will have to check the oil pressure again to make sure it's within specification???

 

[Lite]

I'm running a turbo setup, mcx.
My idle was crazy when the exhaust cracked. Or first it cracked some welds, it got crazy up and down +/- 200rpm all the way down to 1400rpm and stalled sometimes. After it was welded it was good and steady, then one of the flexpipes sayd goodbye, and it started to go the same way. (almost burned down ) Anyhow, see how youre exhaust is.