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Discussion Starter #1
Hi guys.

I'm having a hell of a time trying to get my tw200 running, I have set the timing and valve clearances following the instructions in the manual and all I am getting is the starter turning over and the occasional back fire. I would appreciate any and all help that I can get. Thanks .
 

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Welcome to the forum! We'll try to help if we can. It would help if you shared with us the year of the bike and any past history that you know of. What were the settings you used? Did the bike sit awhile? If so, how does the tank look? Old gas? Information from the previous owner if you just got it and are trying to get it running? Things like that....
 
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Backfire through carb or tailpipe? More details please as requested above.
 
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Had the engine bee taken apart and put back together (cam chain timing)?
 

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Discussion Starter #6
The back fire is coming out of the pipe not the carb, the gas is fresh and tank is 100% clean, engine was rebuilt by a mate, and have been told it is set correctly, if anyone has any detailed instructions on how set the cam chain timing so i can pull everything apart and check i would be most gratefull.
 

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Double check the timing and valves. It is possible to "time" the engine incorrectly and set the valves on the wrong rotation. I know, I have done it.

So, when timing, you MUST know when the piston is at TDC on the compression stroke. Remember, the flywheel goes around twice for each complete engine cycle (compression/combustion/exhaust/intake). If you line-up the timing marks when engine is on the "exhaust/intake" cycle and set the valves, all kinds of strange shit happens -- back-fires being one.
 

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The back fire is coming out of the pipe not the carb, the gas is fresh and tank is 100% clean, engine was rebuilt by a mate, and have been told it is set correctly, if anyone has any detailed instructions on how set the cam chain timing so i can pull everything apart and check i would be most gratefull.
Double check the timing and valves. It is possible to "time" the engine incorrectly and set the valves on the wrong rotation. I know, I have done it.

So, when timing, you MUST know when the piston is at TDC on the compression stroke. Remember, the flywheel goes around twice for each complete engine cycle (compression/combustion/exhaust/intake). If you line-up the timing marks when engine is on the "exhaust/intake" cycle and set the valves, all kinds of strange shit happens -- back-fires being one.

puzzled1, fishguy mentions a little better what I was trying to say with the cam timing. No way to tell if this is the problem, but you can verify the cam chain timing fairly easy. I'll post a video from forum member B-Dub from the Technical Write-ups in the Technical Sticky thread when he re-timed his engine after replacing the base gasket.

In words, you will check the cam chain sprocket mark and the flywheel timing marks are lined up properly. This video shows that very well, so here goes. On post #38, page 4 of the thread is the description B-dub wrote for timing. In your case, you just need to verify and rule this out as a culprit of the backfiring.






Also, as fishguy mentioned, you also need to verify the valves are adjusted properly. ...and you need to make sure your carburetor is set correctly. For instance; my new 2015 TW has been backfiring on decel since new. I know the carb pilot screw (fuel mixture) is set to be lean from the factory. Last night I adjusted the pilot screw which eliminated 99% of my backfiring. I removed the plug on the bottom side of the carb exposing the pilot screw. The pilot screw was set at 1-1/2 turns out. I then turned it out too 2-1/2. This is a good starting point when making this adjustment. I went for a test ride and no more backfiring on decel, so I think it's good to go. I will continue to monitor and make sure this is the setting I should leave it at. I'll check the spark plug to make sure I'm not to lean or to rich, but based on my past experience from my old TW, I'm pretty confident this is the right setting for me.

Here are a couple photo's showing the location of the pilot screw. First one is with the plug in and the second out exposing the screw. Give thanks to jbfla for these picture's.





Hope this helps in finding your backfiring cause. Backfiring can be caused by many things including electrical problems, but making sure timing, valves set, and proper carb tuning usually cures it. Good luck.
 

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Discussion Starter #10
Thanks guys, I'm due for a day in the workshop next week, will have a look,check and come back to you with a status update.
 

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Double check the timing and valves. It is possible to "time" the engine incorrectly and set the valves on the wrong rotation. I know, I have done it.

So, when timing, you MUST know when the piston is at TDC on the compression stroke. Remember, the flywheel goes around twice for each complete engine cycle (compression/combustion/exhaust/intake). If you line-up the timing marks when engine is on the "exhaust/intake" cycle and set the valves, all kinds of strange shit happens -- back-fires being one.
Don't panic. You probably made the same stupid mistake I did. Or, maybe one of the lock nuts on a valve adjustment bolt came lose. I did that too.

Live and learn ( I dated a woman with that tattooed on her back -- I learned). The good thing is these "one lunger" 200cc TWs are tough little f**kers. They are hard to kill and have lots of lessons to teach.
 

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Discussion Starter #12
Hi guys, well went over everything and double actually triple checked clearances and timing the lot, then for the moment of truth.
A back fire first then it started !!
Honestly was not expecting it to as this has been an on going battle for a while now, so thank you all for help to get me to this stage, for a bike that was found at the tip with the rear subframe hacked off and seized piston in the barrel there could be life in the old dog yet.
Will post some pics of the rebuild if anyone is interested?
 

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Discussion Starter #14
Well it appears I may haver spoken too soon so its back to HELP.............
So after the last post the bike has been on the ramp and started first kick every time, and ran fine, from here I have completed the wiring for the headlight and indicators etc.
After spending all afternoon with the wiring i thought now was a chance to spin the bike around the garage, so kicked it and it started warmed up great I thought, took it off the ramp and out into the main garage area. Into first ok and pulled away lacking power (but I am putting that down to usually riding a 1200 ducatti), so up to one end and back but as I pull up it coughs and stalls.
Go to kick it and nothing won't fire, check the plug and its fouled up, I have cleaned it and still nothing won't start so once again if anyone knows anything that I could try or do PLEASE PLEASE HELP.
 

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Fouled how? Wet? Sooty? Oil? Gas?

What do you have the mixture screw adjusted at? Do you have a fuel filter on it? Did you have the carb apart? Air filter clean and lightly oiled?
 

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What year is this TW? How many miles?
 

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Figured it was going to be the plug choking up …..

Unfortunately, these bikes have cut outs all over them, so the first thing to do is short them out to eliminate a bad connection. Side stand – clutch – neutral switch – and kill switch.

After that – it’s either a failing ignition coil (or the lead to the plug, or the plug cap itself) – or a dodgy CDI. Before you start swapping parts for money, it’s worth checking the block connectors and wiring to various components.

In any event, you need to either tell us the year (because the way they are wired up is different, and one particular year was prone to CDI issues) – or post up a pic of the bike – and we should be able to tell from that.

Without that information, we can’t really help you out in more detail – simply because we don’t know “which” bike it actually is ……..
 

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Discussion Starter #18
Sooty plug, will double check connectors, its a 2007 but had been butchered in the past.
new air filter, will check carb again but have had it apart and cleaned properly.
 

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You didn't change any settings on the carb did you? Or change jets? How many turns out is the pilot jet adjusted? What size jets are in it now? What is your altitude where you live?
 

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Discussion Starter #20
Carb has not been reset, the pilot jet is as it was originally and would not have a clue about the jets, why would this cause it to work fine and the cough stall and not restart ?
 
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