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Bike is running horrible!

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So I took my bike to the mechanic to replace the piston and rings. He took it all apart and recommended new crank bearings as well. No worries, I figured it was time for the bearings, cam chain, water pump, etc. I picked up my bike last Friday so I could break it in last weekend. I had a hard time staring it, once it started it didn't idle well, on decel it would pop pop pop and when pulling out of a corner it would pop and completely shut off. Took it back to him to check the valves and timing. He said everything was in spec, I started it at home and rode it down the block ( but not enough to really see if it was ok) and it was "ok". I went out this morning to try it out in a Hare scramble and I barely made one loop. I was so pissed! It was doing the same thing.....I was so frustrated and tired from trying to kick the bike over I just gave up when I came in. I need some advice on what you guys think I should look for. I'm reluctant to take it back to the tech that worked on it and don't mind wrenching myself. Please help.:smirk:

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Get a new Tech or check it out yourself. They are the easiest bikes to work on and check timing/valves etc. Sure sounds like the timing is off? Or really messed the carb up?

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sounds like maybe timing is off one link, if nothing changed with jets..

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There is a sticky at the top of the forum with pics to verify the timing.

Also, verify the carb doesnt have something stuck in the pilot jet. It sounds like the screw is bottomed or the carb is dirty to me...

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verify the carb doesnt have something stuck in the pilot jet. It sounds like the screw is bottomed or the carb is dirty to me...

I have seen this happen while bikes are apart for awhile. Good place to start.

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Thanks for the help guys. I checked the timing and valves, they were all

In spec. Took out the carb, there was a little build up. Cleaned it all out and bumped up the pilot one size. The bike is running/idles great now. No more popping or crappy idle. But the real test is when Im riding. Hopefully the rain will hold up a little this weekend and I'll get a chance to run it.

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Thanks for the help guys. I checked the timing and valves, they were all

In spec. Took out the carb, there was a little build up. Cleaned it all out and bumped up the pilot one size. The bike is running/idles great now. No more popping or crappy idle. But the real test is when Im riding. Hopefully the rain will hold up a little this weekend and I'll get a chance to run it.

I'm sure that's what it was... One weekend on my 04 CRF450 my bike ran great and then on the very next weekend my bike had the same symptoms yours was having... Thought is was the valves so I checked and then rechecked them and even had a friend check them just to make sure I wasn't going crazy... Ended up taking the carb apart and 3 of the jets were 1/2 clogged up... And bike ran perfect after that...:smirk::thumbsup:

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triple check the timing:

http://www.thumpertalk.com/forum/showthread.php?t=877910&highlight=cam+timing+sticky

once you know the timing is correct, then more than likely you have a problem in the carb. clean all the jets with cleaner and compressed air, including the 1 way valves in the carb bowl and carb body, the AP leak jet and emulsion tube. ALso remove the fuel screw make sure it comes out in this order: fuel screw, spring, washer, rubber O ring. Then reinstall in that order. If not, well you are missing something. Also remove the hot start pluger, clean and apply a light coat of grease to it, reinstall and make sure there is slack in the hotstart cable.

If you have done all that and still have problems, well the next place is bad news. remove the left side stator cover and inspect the pickup there where the wires are soldered to the leads. more than likely you will find a ton of metal shavings that are stuck to the 2 terminals causing it to short out. reason why the metal particals are there, simply put your crank needs replaced.

hope that helps

oh and if you split the cases, replace the counterbalancer shaft bearings and seals also.

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triple check the timing:

http://www.thumpertalk.com/forum/showthread.php?t=877910&highlight=cam+timing+sticky

once you know the timing is correct, then more than likely you have a problem in the carb. clean all the jets with cleaner and compressed air, including the 1 way valves in the carb bowl and carb body, the AP leak jet and emulsion tube. ALso remove the fuel screw make sure it comes out in this order: fuel screw, spring, washer, rubber O ring. Then reinstall in that order. If not, well you are missing something. Also remove the hot start pluger, clean and apply a light coat of grease to it, reinstall and make sure there is slack in the hotstart cable.

If you have done all that and still have problems, well the next place is bad news. remove the left side stator cover and inspect the pickup there where the wires are soldered to the leads. more than likely you will find a ton of metal shavings that are stuck to the 2 terminals causing it to short out. reason why the metal particals are there, simply put your crank needs replaced.

hope that helps

oh and if you split the cases, replace the counterbalancer shaft bearings and seals also.

I think he already said he replaced his crank... :smirk:

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