posted
I have a problem with my old x12t engine as the engine just keep on shutting off and it's very hard to tune. I've tried so many things like replacing the carburator,glowplug, fuel line, fuel tank and even a sleeve but nothing works. The engine still has quite a good compression although it's not as tight as before but the compression's still there. My friend suggested that maybe the conrod's gone bad and lead to a wrong ignition timing. I think I know this engine well enough and there'r definitely something wrong with it right now. However, this engine has quite a high mileage though (should be about 8-10 gallons with 8 races). Your input would be greatly appreciated, thanks. Regards. Guy
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posted
Don't think its the conrod, have you tried another type of fuel, or have you ever used some kind of silicone oil in your engine, I have seen some similar problems not too long ago in this forum.
posted
I used Byron and Tornado, I never had any problem with either of them. As for silicone oil, no I've never used any, and to be honest with you, I don't know what is a silicone oil??
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Guy
unregistered
posted
One more question, how do I know when is the time to replace conrod, piston and sleeve apart from trying to push the piston through the sleeve? Would the engine give any sign at all? Thanks.
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posted
When you speak in your first question of shutting-off, what is exactly happening?
There is no real reson why an engine stops, since the engine is a mechanical device and unless compression is very low there is no real reason why is should not run.
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It's just shut off, I can get it started but it then shut off almost immediately. Eventhough I kept revving on it, it'll shut off no more than 5 seconds. The only way that I can make it stay longer is to adjust the idle needle so high (about 3 mm. wide!!) And even that the engine will shut off no more than a minute on the track. Today I tried replacing the cornod but it didn't work. Everyone at the track said that it'd lost its compression already.... I think I'll have to replace piston and liner. One more question, I saw that the conrod of my old rbx12 5 ports is longer than my new rbx12 5 ports, why is that so? (I've heard that the longer the conrod the more torque it produces...is it true?) And if I want to replace the piston and liner, is there any different between the old piston/liner and crankshaft of the old 5 ports and a new one? Are piston/liner and crankshaft of the new and the old 5 ports interchangable? Thank you very much indeed.
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Have you checked your clutch?? Sometimes a problem of the engines shutting down can be found there.
Posts: 43 | From: Windsor, Onatario, Canada | Registered: Jul 2002
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Guy
unregistered
posted
Yep, I have checked the clutch, I've even tried to start the engine without the clutch. Thanks for your reply.
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If the engine shuts of like this for me it can only be a fuel or glowplug problem, unless there is really no more compression when the engine is warm.
Concerning the conrods of our .12 engines, please pay attention, the conrod of the X12(rear-exhaust) engines are shorter then the conrods of the C12(side-exhaust) engines, you cannot interchange these.
There is no old version of the X12 5-port engines, there has not been any change since the release of this engine.
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Ah, no compression when the engine is 'warm'? I've never thought about that, I knew that there's a compression when it's cool but haven't tried it when it's warm. As for the fuel and growplug, I've tried replacing both of them (several new one for growplug). Thank you very much, I really appreciate that.
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Mad Max
unregistered
posted
could be a worn o ring in the carb. have you rebuilt the carb.
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Guy
unregistered
posted
Mad max: I have actually replaced a carb with a new one (I got 2 x12t) but it didn't help. Thanks.
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