help needed on rebuild ASAP!!!!

[pinkpantherusmincus]

Hey Guys,

I need some help, i have been rebuilding a 800ho out of a 04 summit. Used new crank (cvtech) and MCB dual rings on the top end. I finally got round to getting everything connected (reeds, y pipe, carbs etc etc) and when i pull the starter rope it feels like there is too much compression at TDC and will not turn over easily. if i take the plugs out, it turns over just fine. no noise, smooth as silk. i can't test the compression as i do not have the gauge for it. I used the 6mm base gaskit for the top end and ring gap was .016 (checked with filagauge). What could be causing the motor to not want to turn over easily?

thanks in advance

Pinky

 

[007sevens]

Stock head?

 

[CUSO]

What kind of plug are you using? Sounds like either the plug is too long, or you have wicked compression.

 

[pinkpantherusmincus]

yep stock head. tried both a 04 and 05 heads, both did the same thing. using the stock plugs.

 

[CUSO]

Bust the arms off of the plugs, so it's shorter, put them back in (just make certain it doesn't protrude past head) and then see if it does the same thing. If it's the same as before, I would think you're ok.

I think it's just the compression. Just make sure you have the proper ring end gap.

 

[LBZ]

IIRC when I did my MCB's, stock head, I set them at .020" and .022.
.016" may have been a little tight but if it pulls over fine with the plugs out it shouldn't be a clearance issue unless it's hitting a plug. I did notice mine was tight as hell (two hands on the handle tight) the first few times I went to start it and compression was around 160. It dropped to 150psi after a couple rides and held strong there till I sold it.
You really should get a compression gauge for it. I'm sure you can get one from Princess Auto or an auto parts store for a reasonable price or the guys at Route 99 motorsports may be able to help you out too.

 

[pinkpantherusmincus]

i dont think its hitting the plugs at all, i had new plugs in it, and after i tried turning it over and stopped due to obvious reasons, i removed the plugs and the head, i seen no damage to the plug or piston.

 

[ferniesnow]

Not de-railing your thread but did Bogger help you???

 

[POWDERSLUT]

you got ur primary clutch on??if not theres ur problem..

 

[markoo]

you got ur primary clutch on??if not theres ur problem..

X2. A fresh motor with no primary clutch will not pull over very easy at all. Put your primary on and it will create the momentum needed to get the pistons over TDC.

 

[SidewaysInto3rd]

compression gauge is $30 at crappy tire .. lordco sells them too..

you could use a cheapy caliper gauge to measure the depth at TDC .. but it shouldnt be touching your plugs

you probably just have wicked compression .. PULL IT LIKE A MAN .. NOT A GIRLY MAN !!!!

I think my ring gap turned out to be .023 on rktek pistons when i did my 800r

 

[neilsleder]

Yah I tried to pull my sled over without the primary on, it felt like I was trying to turn a v8 over.

 

[maxwell]

Clutch......also i use oil when assembling engines and it creates a better seal in the cylinder. Once that burns off it pulls over like normal if you did that also.

 

[vodoo103]

Did you do a squish test? Believe spec is 47 thou., but not certain. If you're too tight, compression will be way high.

 

[Sun Sport]

Like said before your primary clutch must be on , it acts like a flywheel.

 

[pinkpantherusmincus]

primary was on, it was not torqued down, but it was on. lubed the cylinders and pistons with oil at assembly. i will try it with the clutch torqued down later today and let you guys know what happens.

 

[Modman]

If it rolls over fine without the plugs in and there is no binding, it is likely just compression. As mentioned, when oiled just after assembly they will gain a certain amount of pressure. Put a small dot of grease/plastigauge on each plug and put them back in separately, pull it through one or two rotations, then pull the plug and check if the grease etc has contacted the top of the piston. If not, there isn't a clearance issue with the plugs.

 

[Slamnek]

I bet its just the oil in the cylinders. i had the same problem on an 02 summit 800 and an 05 summit 800. once it fires up and burns the oil out she will be just fine and pull like normal.

 

[pinkpantherusmincus]

Torqued the primary down at 74 ft lbs. pulled the starter cored like a boss (thanks sidewaysintothird) with full choke and 9 pulls it started. Thanks guys. Kept me smiling today!

 

[neilsleder]

Nice! I like it when when it starts up, it's hard not to smile!