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Dropped valve

1643 Views 6 Replies 6 Participants Last post by qwerty, Oct 2, 2010

trail200

Discussion Starter · Sep 23, 2010

I received bad news yesterday. I have a 1999 TW 200. I was told a valve droppedand there is a nick on the cylinder wall. I'm looking at $1000 for the repairs. There are currently 2 engines available on ebay. One is from a 2003 and the other from a 1988. My question. Will the 2 optional engines bolt right on to my 99? Will there be any modifications needed? Or should i rebuild what i have? The bike has 8000 miles.I'm not to good at this kind of stuff and want it done right. With all of these options I have in mind that it's value (running) is $800. What should I do? Did i mention that i love this bike.

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assquatch20

· #2 · Sep 23, 2010

Well as far as value goes, that's totally up to what you think it's worth.

The engines should drop right in though, regardless of what year. I'd hold out for a top end on ebay since it's just the cylinder wall.

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davidsonsgccc

· #3 · Sep 23, 2010

i would get a second opinion on rebuild price. that seems high.

this is just my opinion. aftermarket parts may be cheaper

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qwerty

· #4 · Sep 28, 2010

The newer engine has an automatic cam chain adjuster and a more powerful lighting system. Further upgrades to the electrical system might be called for with the newer engine. This could be a psoitive thing, with a 55/60w halogen bulb replacing the older 35w incandescent.

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silverhorse47

· #5 · Oct 1, 2010

I'm not sure about the diagnosis. Usually when a valve 'drops', either the stem has broken off, or the guide has slipped. The valve usually hits the top of the piston, not the cylinder wall, though maybe if the stem broke a shard of metal scored the cylinder wall?

This is a simple little engine and parts aren't that expensive. If the engine is in otherwise good shape, I would take the motor to a decent mechanic and have the head and cylinder removed, so that you can actualy see what happened, if you haven't already done so. I think that once you got the head removed you would be able to see exactly what the damage was, and proceed from there. I personally wouldn't replace an engine unless there was damage to the bottom end, which there could be if metal shards from a broken valve got into the guts of the engine.

Best of luck,

S.

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lizrdbrth

· #6 · Oct 1, 2010

qwerty said:
The newer engine has an automatic cam chain adjuster and a more powerful lighting system. Further upgrades to the electrical system might be called for with the newer engine. This could be a psoitive thing, with a 55/60w halogen bulb replacing the older 35w incandescent.

This looks simple, but isn't. The wiring is substantially different, all the connectors are of a different configuration and different sex from one another, as are the regulator, safety switches, relays, component layout, brackets, wire lengths, etc. Without a complete LATE-model parts bike and wiring harness this can become an expensive, confusing conversion. The lever perches, for example, are drilled for a different sized tail light switch plunger, have completely different connectors to the harness, etc. It can be done, but it gets kinda ugly, with a lot of splices.

The good news is that you can transfer your existing electrical system and kicker over to the '03 (or even an '87) motor in about an hour, if you know what you're doing. Just transfer your sidecovers, stator, rotor, kickstarter and carb over to the new motor, plug everything back in and yer good to go. The most difficult part of the job being pulling the flywheels.

You could even recoop some of your munny by selling the late-model sidecovers, carb, stator, etc. on eBay.

I've converted both one-year '87's and post-'01 motors to the 90's system. Piece o' cake.

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qwerty

· #7 · Oct 2, 2010

Thanks for filling in the details, lizrdbrth. I have not done much work on the old style bikes other than jet a couple carbs and an oil change or two.

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