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Old 09-28-2008, 11:52 AM   #1636
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It sounds like to me...that the compression of piston/sleeve is going out...usually after it heats up like that..and cant get it running rite again or get it running period untill it cools down...means that normally. i've had that happen to 2 of my motors already...and thats exactly what it was. is the compression low? or tight?
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Old 09-28-2008, 12:15 PM   #1637
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it seems like it has good compression when i spin the flywheel
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Old 09-28-2008, 12:17 PM   #1638
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Hmmm..best thing u could do is go to ur hobby shop and get them to check it out..ask em bout it.
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Old 09-28-2008, 01:37 PM   #1639
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im starting to think its dead, going to try and find someone to check it out for me
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Old 09-28-2008, 02:55 PM   #1640
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is there anyway to take it apart and check if its shot, or like something i can try easily to see if its shot? not sure how ready i am to try and tear it all apart.
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Old 09-28-2008, 03:23 PM   #1641
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Your best bet is to find someone -- local shop or track would be likely -- to take it apart with you, both the check the motor and show you how to do it for yourself.

You can check the bearings by feeling for side-play of the crank. You can measure runout on the crank pin with a micrometer... 1/1000th of an inch is max acceptable. You can check the lower rod bushing by placing a drop of oil on its connection with the crank pin, and turning while watching how the oil moves (this one takes some experience). You can do a pseudo-compression test by holding the motor by the crank, supporting it's bulk from turning over by compression... in theory, it should hold itself for about 15 seconds, although this does vary quite a bit.

You haven't really described the behavior of the motor, and without detail it's impossible to guess what the situation might be. There's no substitute for getting an experienced guy's hands on the motor.
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Old 09-28-2008, 03:39 PM   #1642
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Quote:
Originally Posted by pgaert View Post
Your best bet is to find someone -- local shop or track would be likely -- to take it apart with you, both the check the motor and show you how to do it for yourself.

You can check the bearings by feeling for side-play of the crank. You can measure runout on the crank pin with a micrometer... 1/1000th of an inch is max acceptable. You can check the lower rod bushing by placing a drop of oil on its connection with the crank pin, and turning while watching how the oil moves (this one takes some experience). You can do a pseudo-compression test by holding the motor by the crank, supporting it's bulk from turning over by compression... in theory, it should hold itself for about 15 seconds, although this does vary quite a bit.

You haven't really described the behavior of the motor, and without detail it's impossible to guess what the situation might be. There's no substitute for getting an experienced guy's hands on the motor.

well it seems to run just fine until it gets to like 200-230 and then it just stalls and doesnt want to start again. i put it on the starter box and try to restart but it wont i even try to give it some gas and all it does is make a bogging sound. i have changed the plug and checked the tank with no real problem. i think im going to buy some new fuel lines, and seeing if that does anything, im at the point im going to have to save some and buy a new motor.
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Old 09-28-2008, 03:56 PM   #1643
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What are you using to measure temperature? 230 is too cool to vaporlock, but that sounds like what it's doing. Unless you're using an Exergen, there's a reasonable chance it's actually hotter... might give it a spit (or water) test to confirm. Hot enough to vaporlock (300+, perhaps), you should see violent boiling. If it's that hot, you could have an airleak... around carb base, at the banjo fitting, around backplate, through front bearing. Seal these areas with high-temp silicone or Air-Seal.
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Old 09-28-2008, 04:13 PM   #1644
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Racer's Edge.....Three Bond 1211....and Lucky 7 are all fuel proof sealants.....RTV copper IS NOT.
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Old 09-28-2008, 04:16 PM   #1645
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Is there going to be a Losi 8ight T 2.0 ?
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Old 09-28-2008, 04:44 PM   #1646
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Is there going to be a Losi 8ight T 2.0 ?


there's been No word of it as of yett....But i would be real hardpressed if losi didnt do the same with some of the 8T parts.
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Old 09-28-2008, 05:44 PM   #1647
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could a clutch problem be causing this? the bearing for the clutch r shot and the shoes look horrible, also i think maybe there was some fuel leaking out from around the clutch if that is possible.
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Old 09-28-2008, 06:52 PM   #1648
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The front bearing can leak, usually noted as fuel, oil, or dirt/oil buildup on the front bearing area. Replace bearing, although you can also repack it with success sometimes if it's mechanically tight.

Clutch bearing issues can cause a motor to die at idle, but generally not above idle. A clutch issue should not cause your motor to be difficult to restart.
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Old 09-28-2008, 09:38 PM   #1649
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idk either the clutch shoes and bearings r shot but that doesnt answer the question about it not wanting to restart, unless the motor is just shot? no one around me locally seems all that helpful.
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Old 09-28-2008, 09:51 PM   #1650
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RJS, How much fuel have you run through your engine? It sounds like it might be lack of compression/pinch when the sleeve heats up and expands. The sleeve expands more/faster than the piston and compression goes away until the motor cools back down I have had a couple motor do this. They will run fine for awhile and flame out and not refire until they cool. If you remove the glowplug, does the motor have much compression, if any? You may need to decide if you want to get the sleeve pinched by a good motor guy. Depending on your motor, you may want to evaluate the cost of a pinch, the new bearing that leaks, maybe a rod and piston,,, or if it is more cost effective to replace the engine.

If you still have mechanical pinch, when the piston fits tightly in the sleeve when the motor is cool, then this is NOT your problem. Have an experienced motor tuner take a look. I wish you luck. Chasing engine issues is very frustrating
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