EC200 compression

[Bearman]

G'day,
I just did the top end on my bike. The bore was fine, and the piston was good, so I just put new rings, gaskets and o-rings in it. The compression was down to about 90-100 PSI. Now that I've re-done it, its only up to 150 PSI cold. I remember someone talking about a 250 or 300 and were quoting 175 or 180 PSI. Is this right for a 200? It had two green gaskets when I pulled it apart, so thats what I ordered. If my reading is low, would removing one of these fix up the problem if I had enough head clearance? Everything was put back together correctly. we've checked that. Dad's a full on mechanic, and he's pretty good at it too.

Any thoughts on what the compression should be for a 200? I checked all the manuals I've downloaded form the GasGas site, but havent found anything

Thanks guys

[ferguscawley]

I'm not sure about the 200's compression figures. My 2006 EC300 showed over 140 psi on the standard puiston and rings with well over 250 hours use on it. I was quite impressed with that figure.

I reckon your figure of 150 psi is probably OK for your bike. How many hours has it done ? - the barrel could be worn/polished if the bike has plenty of hours on it.

[thenutt]

Originally Posted by ferguscawley

I'm not sure about the 200's compression figures. My 2006 EC300 showed over 140 psi on the standard puiston and rings with well over 250 hours use on it. I was quite impressed with that figure.

I reckon your figure of 150 psi is probably OK for your bike. How many hours has it done ? - the barrel could be worn/polished if the bike has plenty of hours on it.

SORRY for going off track here, how do you check the compression,

[ferguscawley]

Remove spark plug, screw in compression tester, open throttle to stop and kick several times as quickly as possible. Record reading on compression tester. (It records the highest pressure attained during kicking)

[thenutt]

Originally Posted by ferguscawley

Remove spark plug, screw in compression tester, open throttle to stop and kick several times as quickly as possible. Record reading on compression tester. (It records the highest pressure attained during kicking)

i thought 2strokes were'nt supposed to be kicked with the throttle open, { I'M A NEWBIE TO 2 STROKES}

[jostby]

opening the throttle fully allows as much air as possible to enter the cylinder, to allow an accurate reading when checking compression.

[thenutt]

Originally Posted by jostby

opening the throttle fully allows as much air as possible to enter the cylinder, to allow an accurate reading when checking compression.

cheers for the advice guy's, my bike is 2002 model, ec250, and estimate reading on clock was 1600, 2 weeks ago before it went all tits up, THE CLOCK THAT IS, i will get mine checked as soon as just out of curiosity,

[stay_upright]

My KTM 200 had 195-205psi with new rings and after about 1 years use would read about 170-180 and would feel noticeably down on power throughout the rev range. My GG 300 had 150 when I bought it, I replaced the rings (thinking it was low) and it read 150 after that (i.e. rings were not worn at all) I think the different porting in the GG's my contribute to lower readings? I can just about use all of the power of my ec300 so am not in a big hurry for more. I'd ride it and if you want more power then look into it more.

As an aside I would recommend all 2t riders to measure compression after a new set of rings and then subsequent checks is a robust way of determining how much your rings have worn. If you go by the seat of your pants you don't notice the power loss until it is quite large.

[Bearman]

Thanks guys. I'll put her back together and take it for a run.

Cheers