TW200 Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
Seeing its my first post i would like to say hi to everyone
I'm working on my first 4 stroke in a long time,its a 89 Tw200 with the turqois tank,The bike starts easy and idles very smooth but when i touch the throttle it wants to die and if i roll the throttle it will rev and backfire throught the exhaust, Then i discovered after going through the carb,pulling the flywheel off checking for a sheared keyway and valve clearance it will run after its good and warm and even had it out for a 10 minute ride,but after it sits for awhile and cools down the same thing over again. I checked all threads on here and only found one guy mention this but no replies to it, It may be the ignition coil ? what iam going to do in the AM is take my heat gun and start heating up the key electrical components and see what gives,If anyone else has any ides let me know. Thanks Don
 

·
Registered
Joined
·
12 Posts
Discussion Starter #3
Have you cleaned the carb?






Hi, Yes i found a chunk of rubber debri just under the screen on the needle and seat and cleaned it again for a second time to make sure. its odd that it will run normal after the engine warms up but takes 10-15minutes, i want to find out whats the problem before it fails for good. I will try heat the coil with my heat gun today and update what happens then,i have spare coils also so i may swap it out, i hope its not the CDI




I also noticed the fuel pet cock will not stop flowing fuel in the off position and the exhaust is missing the end cap and some of the baffle,the guy said it blew out on him when this all started.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #5
have you tried adjusting your pilot screw it may be running to lean. just something to check. what does your plug look like.




Ive got the pilot turned 3.5 turns out,my OEM manual doesn't say what to set it at on the slide carbs so,Maybe i will try another turn and see what it does, The plug is nice and dry and light brown when running good but black if i pull it before it warms up.



After 10-15 minutes it takes to warm up i work the throttle to get it to run proper and it works itself out so thats why i wonder if its a fuel issue or electrical. I will be going out to the garage in a couple hours and see what happens. Ty
 

·
Registered
Joined
·
12 Posts
Discussion Starter #6
Ive got the pilot turned 3.5 turns out,my OEM manual doesn't say what to set it at on the slide carbs so,Maybe i will try another turn and see what it does, The plug is nice and dry and light brown when running good but black if i pull it before it warms up.



After 10-15 minutes it takes to warm up i work the throttle to get it to run proper and it works itself out so thats why i wonder if its a fuel issue or electrical. I will be going out to the garage in a couple hours and see what happens. Ty
-------------------------------------------------------------------------------------



UPDATE



Okay, So i just came in and sure enough i heated the coil with the heat gun and no difference,then i tried the CDI box located on the right side cover beside the tool kit just on the otherside of the exhaust pipe and the bike ran good almost instantly, I will try one more time tonight or in the morning to make sure before i order one simply becuase i had it running breifly while doing the ignition coil. So i will update this tommorow, If anyone has any of the parts mentioned pls message me, he wants to replace the exhaust also but seen something on ebay. Don
 

·
Registered
Joined
·
158 Posts
Does your carb have a round black lever on the left hand side of it? [starter plunger] When i first got my tdub i had similar issues of it starting but not running well until warmed up.i discovered how to fine tune the starter plunger choke knob thingy by pulling it out to start then let it idle high until idle dropped then slowly push in knob until it idles and revs without cutting out. you can usually ride the bike like this for the first few minutes until it warms up then push the starter plunger all the way in and the bike should rev ok without bogging. just the cold nature of some of these older carbs. There may be some tweaks that can smooth this issue out by carb cleaning rejetting etc , but i have learned to live with my cold natured tw by using the starter plunger.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #9
you may want to find out where that chunk of rubber came from.




I pulled the pet cock apart today and instaled a inline filter,i found out the peice of rubber came from the rubber gasket inside the pet cock, not the "O" ring but the flat rubber peice that fits between the selector and housing, So that solves where it came from, it seems to be running better off the "get go" without warming now so what i will do is order a new pet cock rebuild kit becuase the seal is no good and in the OFF position the fuel still leaks,For now i flipped it over and it stopped leaking,



I noticed air in my line with the filter on and it wouldn't run so i pulled the line and got the air out and now it runs again, Anyways this could have fixed the problem and will update once i try it again tommorow cold and order a new rebuild kit meanwhile. Thanks guys for the help and hopefully we dont need a CDI becuase by the sounds of things these CDI's just quit usually so i could be dealing with a fuel issue all along.
 

·
Registered
Joined
·
1,702 Posts
I pulled the pet cock apart today and instaled a inline filter,i found out the peice of rubber came from the rubber gasket inside the pet cock, not the "O" ring but the flat rubber peice that fits between the selector and housing, So that solves where it came from, it seems to be running better off the "get go" without warming now so what i will do is order a new pet cock rebuild kit becuase the seal is no good and in the OFF position the fuel still leaks,For now i flipped it over and it stopped leaking,



I noticed air in my line with the filter on and it wouldn't run so i pulled the line and got the air out and now it runs again, Anyways this could have fixed the problem and will update once i try it again tommorow cold and order a new rebuild kit meanwhile. Thanks guys for the help and hopefully we dont need a CDI becuase by the sounds of things these CDI's just quit usually so i could be dealing with a fuel issue all along.


You are correct. The soft parts of a petcock are simple to install and while relatively inexpensive, you can buy an entire petcock for around $15. I'd fix that whatever you think the warmup problem is. It should not take 10 or more minutes to warmup this bike. I typically leave the choke on for 15 or 30 seconds in the summer and probably less than 90 seconds pass in the winter before the bike tends to bog a bit from being warm enough to run on a leaner mixture. I'd suspect carb/fuel problems, but then again I'm not there. Good luck. Tom
 

·
Registered
Joined
·
50 Posts
Seeing its my first post i would like to say hi to everyone
I'm working on my first 4 stroke in a long time,its a 89 Tw200 with the turqois tank,The bike starts easy and idles very smooth but when i touch the throttle it wants to die and if i roll the throttle it will rev and backfire throught the exhaust, Then i discovered after going through the carb,pulling the flywheel off checking for a sheared keyway and valve clearance it will run after its good and warm and even had it out for a 10 minute ride,but after it sits for awhile and cools down the same thing over again. I checked all threads on here and only found one guy mention this but no replies to it, It may be the ignition coil ? what iam going to do in the AM is take my heat gun and start heating up the key electrical components and see what gives,If anyone else has any ides let me know. Thanks Don


Don, I'm having this exact same problem with my 2001 TDub. I've removed the carb, cleaned and lubed everything, put everything back together and it still sees to have the same issue. I'm at 2.5 turns on my idle mix screw. The bike starts and idles fine, but when i go to twist back the throttle it wants to bog and/or stall. It does this until it's good and warm. Once it eventually revs with a twist of the throttle, the problem disappears until the next tim I do a cold start.



Have you solved your problem yet?



Anyone else got any suggestions?





Vrroom

(Jamie)
 

·
Registered
Joined
·
14 Posts
Hey Don. My 93 has done that since the day it was brand new. I've read alot on the net about this specific problem and came away with the idea that this is just a problem inherent to this specific bike. I started running mid-grade gasoline in mine and it improved the cold performance a little - to the point where it won't spit and sputter, it'll just die if you touch the throttle when it's cold. It also seems to have shortened the warm-up time to about 5 mins. on a 60 degree day, still about 10 min. in the dead of winter here in N.C. Todd-
 

·
Registered
Joined
·
10 Posts
"Thumper Talk" Where I learned about the "TW" had a post, This is a regular issue with the bike. Also suggested start with half choke. Warm up from there and go. Pushing in choke down the road. My issue is when I get down the road mine is heated and is hard to start.
 

·
Registered
Joined
·
42 Posts
Clean the carb again, and run a small wire through the pilot jet. Flush the jet liberaly with carb cleaner. This is a common problem with Mikunis on bikes, boats etc. ,because they tend to sit unused for months at a time. The jet is extremely small and can easily harbor a "clinker." The symptoms you describe are typical for a "lean-at-idle" condition.
 

·
Registered
Joined
·
2 Posts
Same problem here on my new '06. I do what was mentioned above: start at full choke, cut to half choke after maybe 20 seconds and let the bike run for another minute, then cut choke and let it run a little longer until I can blip the throttle and it does not bog. The problem solves itself once the bike has warmed up completely. Nonetheless, I am going to clean the carb and play with the air screw a bit.
 

·
Banned
Joined
·
10,664 Posts
The reason the pilot screw adjustment is not given in the literature is that the adjustment affects EPA emissions mandates and tampering with the agjustment is therefore illegal. That is why the blockoff is installed over the screw at the factory.



Carefully inspect the intake pieces between the carb and the engine. A small leak anywhere in the intake can cause the lean condition.



An engine that dies when given throttle is running lean. The fact that pulling the enrichment knob cures the problem verifies the lean condition.



I use the enrichment knob at start. The bike idles high, then after about 10 seconds slows by itself. Push the knob half way in. That's all the warm-up T-dub gets. I then ride 150 meters to the first stop sign with light throttle. Ride 75 meters to the next stop sign with light throttle. Push the enrichment knob all the way in. Ride normal. After about 5 minutes, ride like an idiot. The 5 minutes is to allow the metal and oil to attain operating temperature, Nothing to do with the carb.



The idea that poor cold starting and running and'or the necessity of running expensive higher octane fuels are something with which TW riders must live is ludicrous. Invest a few hours in rejetting your carb as described in the carb tuning sticky and enjoy instant starts, fast warm-ups, and the ability to ride away in about the time it takes you to put your gloves on. Hot or cold.
 

·
Registered
Joined
·
105 Posts
My bike (~500 miles on an '06) is also cold blooded. I have to run the full choke for maybe 1 minute, then 1/2 choke for another few minutes. Otherwise it just dies by itself or for sure if I crack the throttle. Once it's warmed up, everything works pretty good (may occasionally die during an extended idle) with good throttle response. If the bike then sits for 1/2 hour or more, the process needs to be repeated, though abbreviated. I'm no carb guy, but most the directions seem rather clear.



Questions:



1) I suspect I have to wait an extended interval between tests, so that I'm not testing a warmed up engine?



2) My travels cover wide elevation changes (trip to trip). How would these elevation changes affect my tuning and how would I try to get an "all purpose" tune?
 
1 - 20 of 24 Posts
Top