need help fresh rebuild and 30bls of compression!

[ridein'red7]

like said 30lbs of compression on a 10:1 wisoc i had it bored at a machine shop do u think he went to far? it smoke till warmed up or are my vales way to tight? i had to pop start it and it would go like a raped ape and on the electric starter it wont even start :( everything is brandnew should i just get a 426 piston and have amy dad bore it this time? and the valveseals and everying is new:confused: :huh

[honda400ex2003]

find a new builder lol. if you know for sure that you only have 30 psi then that is the issue. I dont think it would run at all on that though imo. way too low. anyway either see what the dia of the cylinder is and go oversize rings or bore it to a 426. steve

[CJM]

Open it up and actually look and see what the clearances look like. If you can clearly see space then obviously its bad.

I could see easily that mine was shot in this manner.

[ridein'red7]

piston is tight in there no sloppy ness but i think im gona bore and hone it and have my dad do it right we wernt getting along so i took it somewhere else iguess thats why lol now i got a 416 piston that basicaly new haha owell

[honda400ex2003]

dude find out why you only got 30 psi. either your valves are stuck open or you did it wrong. it wont even run with 30psi compression. steve

[CJM]

Yes, steves right..30 lbs doesnt make sense at all. Either your gauge is bad or you tested it wrong or something.

If everythings tight in the cyl its gotta be valves imho.

[honda400ex2003]

http://www.dootalk.com/forums/index.php?showtopic=183683


correct procedure to do the test. I bet you didnt hold the throttle open while doing the test. steve

[bherriman]

Keep in mind compression will be lower on a fresh build until the rings get seated properly, but it should never be that low...I'm gonna go with steve and say that you ran the test wrong.

[dalejiw25]

"I bet you didnt hold the throttle open while doing the test. steve"
On a compression test - Say What.... Why ????

[ridein'red7]

yea throttle wide open and its a brand new snap on blue point do anyone think i could sell the piston i got now for like 100bucks?? and whats the highest compression i can go on pump gas on the 426? and this thing ran like a sob but that was before i fixed the starter now it wont run of the starter but will run pop started

[honda400ex2003]

11:1 is doable on 93. it would depend on if the piston is all messed up or not as to if you can sell it or not. get the piston and take it with your cylinder when bored. dont take it back to the same place. or else take it apart and spec it out and make sure that is the piston and ring gap. if this is the case you may be able to go back on the person who did the work and see if they will rectify the situation. sounds like it is time for a tear down again at least and see what you got before buying more stuff again. you may be able to get it honed and bored again and put the correct over size rings in for a 87mm piston or something in. take it to a professional and get their opinion on it. steve

[ridein'red7]

well my dad is a professional haha i just didnt have him do it because we got in a rguement but we are good now so he will do the work and 11:1 or stay 10:1?

[CJM]

The rings could not be in the right places, strange as it sounds Ive seen it before. You did make sure to put them on properly and stagger then according to the papers that came with the piston-right?

[ridein'red7]

yea i did it all to what the paper was and called wiseco to be sure(im not a 4stroke guy) and did it right and went slow!