my rm125

[ZeRo02]

hey guys havent been on for a while(good thing)
well i have a 93 rm 125 that i picked up for 50 bucks!! the bike ran like a champ for the first 3 months. I was riding it the other day and went to a buddys house and left it outside. went out and the damn thing wouldnt start!!i took the carb apart made sure it was good . tore the reeds apart and they were good .only thing i havent done is take the topend apart.put sum gas in the cylinder and still wouldnt start. well today we towed it behind my buddys truck and it started up adn i tode it for a while but once you get past 3rd gear it has no topend and the powerband wont kick in.Shut it off and the bike still wouldnt start! i have to pop start the damn thing to get it going. i was gonna rejet it for winter but it ran great and started real easy so i said f it.now the damn thing wont run rite and have no clue why.the bike ok compression . dont know exact number because i just bought a house and have no money to go get 1 for awhile.some one help please..sorry for rambling on.

[gassrx.com]

sounds like a stuck ring no compression.

[ZeRo02]

well the bike feels like it has decent compression from my "sit on my ass and kick it "guage lol It feels like it always does . the bike didnt shut off or anything on me i left it out for a while went in drank a beer and came out and wouldnt start.if i dotn find out the problem in a day or two it will have to be sold! and i dont want that ha ha

[02yamahablaster]

Did you put a new plug in it?

[ZeRo02]

Originally Posted by 02yamahablaster

Did you put a new plug in it?

yup sure did . it has me stumped ran fine!!!! than nothing at all. i guess ima have to rip the topend apart. how will i know if its a stuck ring? never happened to me before

[lt250racer]

I would invest in a good compression tester. Just from reading that i would think that you were running lean & smoked your rings/crown of the piston. Having enough compression to run but not enough to start or get most of your power from. Just a guess...

[ZeRo02]

alrite man thanks. how much would a good compression tester be?? hopefully if the pistons ok ill be able to throw new rings in it and be on my way. really low on money because we just got into our new house.

[gassrx.com]

i seen them on ske bay for 40.00 not the greatest but works. should come with every 2 smoker sold . helps determin ring life..

[2002shee]

Harbor Freight, $14.99. http://www.harborfreight.com/cpi/cta...emnumber=95187 Not the greatest but it'll work. The gauge doesn't have to be super accurate in this case, here's a trick. Take the first compression test and write down the number. Now put a few drops of motor oil in the cylinder and take another compression test. Compare the two readings, if the second one is higher it means the rings are not sealing. The oil acts like a seal between the piston and wall. If the readings are the same it means you most likely have a hole in the piston or worn/burnt edges. This will give you a good idea of what you're looking at without tearing it down first.