[loriiloo]

I have a 1989 tw200 and the carb has some major problems I think, It appears someone actually broke the pilot jet portion of the carb at some point and fixed it with JB weld (no leaks), I have taken the carb off cleaned it made sure all orfices were clear, put it back on the bike and it only runs with the choke in the on position, adjusting the pilot screw makes no difference, the engine starts right up but will not take any throttle at all. The bike ran well when i got it but needed about 1/2 choke on to run, it always starts up and it idles with choke on but not with the choke off, it also seems to pop through the carb and exaust a little. My other tw200 is a 1990 and will only run with the choke completely off but it runs well.

I don't know where to start now, (new Carb?) or is it somethine else, How is the timing adjusted? and could it be a timing issue since it pops through the exaust and carb.



Help Muledeer

 

[qwerty]

JB weld in the carb body pilot orifices. Either unplug the stoppage or find another carb.



You can swap carbs between the bikes and see which is then the sicker.



Timing is not intended to be adjustable.

 

[loriiloo]

JB weld in the carb body pilot orifices. Either unplug the stoppage or find another carb.



You can swap carbs between the bikes and see which is then the sicker.



Timing is not intended to be adjustable.

Thank You I am going to try that, switching carbs, Will all the carbs fit this bike I saw one the other day for sale off of a 2008, looks like there are a few differences, mostly idle andjustment stuff. I thought maybe there was an air leak on the intake, which required the choke be on to make it rich enough to run, after i switch out the carbs I will know for sure.



Muledeer2

 

[mhomadness]

qwerty is right! Switch the carb. Also check your valve adjustment, and your timing chain adjustment. It's easy to do both at the same time, and most likely has not been done for a long time, and can sometimes make a difference. m.

 

[loriiloo]

qwerty is right! Switch the carb. Also check your valve adjustment, and your timing chain adjustment. It's easy to do both at the same time, and most likely has not been done for a long time, and can sometimes make a difference. m. Thanks will do that as well. Muledeer2

 

[mhomadness]

As far as the 2008 carb goes, Good question. I think it will work, but I seem to remember somewhere in this forum reading that there was some changes made around 2003? that might be an issue. qwerty, I know you have a good write-up in a thred here about this carb thing, I remember reading it, I just can't find it! Little help please? m.

 

[jbfla]

... Will all the carbs fit this bike I saw one the other day for sale off of a 2008, looks like there are a few differences, mostly idle andjustment stuff. ...

Muledeer2

The newer CV carb, 2001 to present, is nearly a direct bolt-on replacement for the older slide carb.



The intake manifold side (carb to engine connection) on the new carb is the same size (33 mm), so it should slide right in.



The throttle cable is on the opposite side. You can re-route the cable.



The newer carb is about 7 mm shorter in length (intake to outflow) and the intake diameter is about 3 mm wider.



Get a boot (airbox to carb) and a carb joint (carb to engine) from a newer TW to solve both problems.



jb



Edited: due to faulty memory...

 

[loriiloo]

Valve and timing chain may not be too much of an issue, both my bikes have very low miles like 2,600 on one and 2,800 on the other one. One bike is an 89 the other one is a 90, but i will check valves and timing chain, switching carbs fisrt as soon as weather permits. Muledeer2

 

[mhomadness]

Thank you for the update on the carb model / year issue, good to know that. You would be surprised how fast the valves can go out of adjustment, things tend to move around & seat in a lot in an engines first miles. m.

 

[loriiloo]

Thank you for the update on the carb model / year issue, good to know that. You would be surprised how fast the valves can go out of adjustment, things tend to move around & seat in a lot in an engines first miles. m.

Can you give me valve info., never done these bikes before and timing chain adjustment info. Thanks for all your help MuleDeer2

 

[mhomadness]

It's not that it's difficult to do these adjustments, but I would strongly recomend getting a service manual for your bike. They are easy & cheap to get, & I think there is even a link here to get them. I'll get right back with more info on that. m.

 

[mhomadness]

Under technical help, the second pinned item is service manuals, I think the links will give you pdf on line, that’s instant info there! Down the line in the pinned items you will find a thread for valve adjustment, but it is for a different model of Yamaha. The TW is actually easier to do a valve adjustment on than the one in the link, but it would be worth a look just to give you some idea. But don’t let it intimidate you, the TW is far easier to adjust the valves on than the other bike in the thread. Also, I was able to remove the alan screws on my valve covers with a regular alan wrench, and if you are careful, you can use needle nose pliers to hold the center screw while tightening / adjusting the valves. Although the factory tool was way cool, & if you can get one easy, go for it!



Let us know if you can not access a manual. m.

 

[qwerty]

A square-drive drywall screw is excellent for holding the screw while tightening the nut.

 

[loriiloo]

A square-drive drywall screw is excellent for holding the screw while tightening the nut.

Thanks I have thousands of them, another tip I use allen head bolts for nut drivers in a cordless drill/driver they come in all sizes and lengths.

I have had 50-60 bikes in my time and valves adjustment is not a problem, Time is LOL. You would think after 30 yrs as a maintenance operations manager and 10 as a machinist now retired I would have the time, but somehow some other projects just gets put in front of mine, I have two tw200s, a Honda VTX 1800 classic, A Rokon Trailbreaker, a polaris 500HO atv, a 300 kawasaki atv and a 6x4 JohnDeere Gator to name a few. Thanks for all your help I am selling the 1989 tw200 wife doesn't ride anymore $1,500 with the carb fixed or 1,300 without the replacement. Muledeer2 (central Calif Coast)

 

[loriiloo]

JB weld in the carb body pilot orifices. Either unplug the stoppage or find another carb.



You can swap carbs between the bikes and see which is then the sicker.



Timing is not intended to be adjustable.

Ok I just got another carb off of a guy on craigslist it came off of a 1992, looks like new, put it on the bike, with a fresh battery, plenty of fuel in the tank and it would not start, So I pulled the spark plug and it was dry no fuel, just like the other carb, If I give it a shot of starting fluid in the air box it will fire right up so it does not appear to be electrical, bike has 2,400 miles, could the intake or exaust valves be sticking or not fully closing on the intake stroke so not fuel is being drawn into the carb?, What are the valve clearances? and how do you adjust the timing chain? as soon as the starting fluid is gone it stops running.



Help please my other tw200 a 1990 runs fine it even starts with no choke needed. there is plenty of good fuel getting to the carb and the fuel bowl is full as well.

Muledeer2

 

[Omega Man]

Ok I just got another carb off of a guy on craigslist it came off of a 1992, looks like new, put it on the bike, with a fresh battery, plenty of fuel in the tank and it would not start, So I pulled the spark plug and it was dry no fuel, just like the other carb, If I give it a shot of starting fluid in the air box it will fire right up so it does not appear to be electrical, bike has 2,400 miles, could the intake or exaust valves be sticking or not fully closing on the intake stroke so not fuel is being drawn into the carb?, What are the valve clearances? and how do you adjust the timing chain? as soon as the starting fluid is gone it stops running.



Help please my other tw200 a 1990 runs fine it even starts with no choke needed. there is plenty of good fuel getting to the carb and the fuel bowl is full as well.

Muledeer2

I'd go easy with the starting fluid-if it's ether. I prefer to use Gumout aerosol carb cleaner as it's less volatile and works as well. As it runs with an alternative fuel source, I'd stay in that direction without changing a lot of other settings. As the carb was shipped dry, you can hope it's just the float kinda stuck and preventing the gas from flowing. If no luck, I think you will have to drop the float bowl to see what's going on. The carb may have looked like new but it's the inside that really counts. Good luck. OM

 

[mhomadness]

Don't think this is a valve problem. Bike is too new, & if it were valve related, it would not run very well under starting fluid. I tend to agree with the possibility that you have a stuck float needle on your new carb. This still sounds like a fuel delivery problem. Your intake boot between the carb & cylinder could also be suspect, and where that boot meets the cylinder, it is sealed with an O-ring. ANY intake leak in that area can cause poor running. $$ is still on a lack of fuel. See if anything comes out of the bowl drain, I think that carb has one. No fuel, read the carb repair post, & see if you can get fuel. Don't take short-cuts when cleaning out the carb either. Make sure to do a thorough job, Nuf Said. Mike.