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640E Not Cooperating

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Okay guys, so I picked up a couple 640e bikes--a '99 and '01. The '99 has no compression so I know a rebuild is in order for that one.
However, the '01 has good compression, good spark and fresh gas but I can't get so much as a fart or backfire out of the thing.
It spins over nice and quick off the button. With the plug out, it has nice blue/purple spark with the plug laying on the cylinder head. I've drained the carb by removing the bottom 17mm plug. The gas didn't smell skanky and I didn't see any debris roll out. Even poured a little gas down the plug hole just in case the pilot jet's plugged--nothing.
I'm kind of at a loss here. Spark, compression and gas, it should do SOMETHING.

I'm really not too familiar with these bikes. Is there something common I'm overlooking that goes south on these things? Ignition timing? Cam timing?

Any help would be great!

Thanks.

Bruce

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That's a good question. I emailed the previous owner this morning and asked if the '01 bike ever ran and he said it did. He went on a couple 100 mile dirt rides on it.

He was riding the '99 and it lost compression so he picked up the '01 to replace it but ended up with a BMW X Challenge, so the KTMs needed to go. That's where I came in.

I don't think either one has sat for terribly long as both the batteries were fairly charged and neither one looks like they have been sitting much. I could be wrong though...

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If they have been sitting for a while chances are the carby jets will be gummed up

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Absolutely but as I stated in the first post, I did dribble some fuel down the plug hole and should have at least got a pop or something. Also tried shooting some flammable brake clean into the carb and plug hole and still nothing. Will try ether next. I hate using that stuff but if I can get it to at least fire off with it then I'll pull the carb and go through it. But so far, it's acting like it's not firing in the combustion chamber, even though I have good spark when checking the plug laying on the head.

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Okay, so I removed the carb--mounting clamps weren't tight--and discovered the external pick-up tube for the fuel enrichener was bent and pulled away from the carb body on one side. The carb overall was beat so I ordered a new BST and bolted it on. Three kicks it lit off and idled great. Starts off the button super easy. Seems to run well with no smoke or abnormally loud mechanical noises.

I'd always heard how powerful these things were but so far, I'm a little underwhelmed. It's not a turd and it feels pretty good in the mid and upper RPMs but nothing like my old Husaberg FE650, Husky TE570 or even my former uncorked XR650R. Those bikes had power right off the bottom and all through the rev range. This bike feels lazy on the bottom and just okay everywhere else. Besides the jetting and pipe mods, what's the secret to unleash this engines true potential? Any LC4 specific mods?

Thanks guys.

Couple pics.

 

DSC03218.JPG

DSC03217.JPG

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Thanks wrk2surf!

I ended up trading this bike for a 2003 450EXC just a few days ago. I'm now working on the '99 bike and it needs a carb as well--never got one with the bike. So, I'll keep my eyes open for an FCR; maybe find a kit with everything I need for the swap.

I found a company in Australia who offers a complete kit for a Mikuni TM42 pumper--about $485.00 with exchange rate. That seems pretty reasonable to me. Haven't checked on the shipping charges yet, though.

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