something bad, no compression

radish150 · Post by **radish150** » 17 Oct 2006, 23:28

This thing and I have had our final battle, I'm threwww. I have an 89, NEW FU*&^%$ motor from LT. I have had some freakin carb problem that no one could fix for months, lately I decided to give it another go. I eliminated the \"racing\" problem, but it seemed not to want to rev right this time (after wanting to rev out of control). I thot I was making progress, it was at least running like something resembling a motorcycle but it seemed like it was starved for gas on the top end. Seemed like it had a little something stuck in it's craw, so I held it wide open for a few moments hoping it would clear out, well I saw a puff of steam and it died. Now, I have very little compression and wont start. So, what did I do, blow a head gasket? I'm really sick of this thing to tell the truth, has fought me from day one. I'm in south america, you think there is anything to be gained from parting it out? This engine is brand new. Honestly I have no more patience and I'm about ready to tie it to the back of a truck and drag it though the streets like a dead cow, throw gas on it, light it on fire and then throw it in the river.

Barring that, *sigh*, on a calmer note, ya think I just blew a head gasket and really all is not lost? Is the head gasket on this bike a standard CR part or is it one of those lovely CRM specific pieces?

radish150 · Post by **radish150** » 18 Oct 2006, 00:40

I have this 89 in South america, low miles bike with a new motor (bottom to top) and I just screwed up the top end somehow, will need at least to be rebored and a piston. I'm through messing with this thing, going to sell it as is. The parts worth anything? It was a pretty nice bike but it has been bad karma from day one, If I could re-coup say 500$ for some of the parts I'd be happy.

Mark Sheldon (Peru)

CRMR · Post by **CRMR** » 18 Oct 2006, 09:22

Hi dude , So sorry to here the crm broke you and your finally giving up . Too bad ,, If all your after is $500 then youl easily get the for the engine / cdi/and regulater , If you did sell these parts then youll have a lovely oppertunity to jam enouther engine in the bike you have left , Like a cr500 / yam350lc/ xl250/400/600 .. What about a 600 bandit and supermotard it....anyways , Give the crm one last go , Strip the head down
and look see if its the head gasket/rings or piston //Fix it and try one last time , ..What did you do to the carb to fix it , what was wrong with it ??

radish150 · Post by **radish150** » 18 Oct 2006, 17:11

CRMR wrote:Hi dude , So sorry to here the crm broke you and your finally giving up . Too bad ,, If all your after is $500 then youl easily get the for the engine / cdi/and regulater , If you did sell these parts then youll have a lovely oppertunity to jam enouther engine in the bike you have left , Like a cr500 / yam350lc/ xl250/400/600 .. What about a 600 bandit and supermotard it....anyways , Give the crm one last go , Strip the head down
and look see if its the head gasket/rings or piston //Fix it and try one last time , ..What did you do to the carb to fix it , what was wrong with it ??

CRMR, I took it apart last night and the piston is badly galled on the front side, it came really close to seizing. As far as a new engine, honestly it would still be alot easier to fix this one than to do that. So, a few questions while the day is young and I"m still feeling foolish. The piston is standard size, the cyl scoring is not terrible, that is just a plain steel bore in there so can be taken oversize with normal procedure correct?

Honestly, the reason I think it did that is cuz I heard that some of you were running these at leanest needle position so I tried that to see if it quickened up the throttle response (hey I'm a 4stroke guy) and combined with my over zealous wrist, that was that.

So my original problem after the rebuild was uncontrolled engine racing and that has been a long standing problem even before the rebuild that would come and go (getting worse and worse). After the rebuild it was fine for a while, then got worse again so I left it sit for several months. Two days ago got the urge to get it sold so took the carb apart and found it very dirty so cleaned and blew it out and this time seemed to have no over rev... this time though it seemed not to want to rev at all unless you held it wide open for extended period of time where it seemed to eventuall climb up and "almost" scream like it should. But, something was not right and I pushed it (very stupid) and it blew. Sad thing is I think I was making progress, it was wierd that it suddenly did not want to rev... super sluggish on the acceleration. So, for about the hundredth time on this little red meanie, any ideas??? I will checkwith LT on a piston. Oh, I pretty much did all the air leak checks and came up with nothing... thanks.

edarter · Post by **edarter** » 19 Oct 2006, 17:36

I don't have any ideas based on sound engineering principles, but model aircraft 2 stroke engines won't transition from tickover to full power if the bottom end mixture is out.... that coupled with the fact you seem to have cooked it may suggest you are running way too lean bottom end ????

just a thought

Ed

radish150 · Post by **radish150** » 20 Oct 2006, 00:21

[quote="edarter"]I don't have any ideas based on sound engineering principles, but model aircraft 2 stroke engines won't transition from tickover to full power if the bottom end mixture is out.... that coupled with the fact you seem to have cooked it may suggest you are running way too lean bottom end ????

Well, honestly I think that is what cooked my piston as I had moved the needle all the way down, but that was only the reason for the high rpm cooked piston. Becuase, the thing was running great on the top end for a while, then crappy on the top end for a while, all without changing any aspect of the fuel burn towards either lean or richer, it stayed the same but the running characteristics changed. My movement of the needle was just a very very bad idea to expermiment with due to my hearing some folks here were running in top needle position. So yes, that cooked my piston but that is not why it was running like "cwap".

I'm going to another piston, but I sure would like to get this carb straightened out before I do it again. Really this machine does not like me, I have a yamaha that doesn't treat me like this!

something bad, no compression

something bad, no compression

parting out?