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1990 Yamaha DT200R advice

gt750

Member
I have a 1990 DT200R, with only 3500 km on it. Have had it for 6 years or so, and have not ridden it much. It was working well, a couple years ago, but is now using a LOT of fuel and will not run cleanly at a steady speed. Compression is 140 p.s.i.. It's stock. Cleaned out the carb and replaced the "float needle and seat". Replaced the pilot jet and cleaned out the main jet. Had to coat the tank two years ago, due to rust, but it looks good now. Spark looked good when I kicked it over with the plug out. Noticed the petcock is leaking a bit right now, and have ordered a "rebuild kit" from Wemoto in England. My intuition says I am missing something in the carb.?
Do any previous/current owners know what speed a person can cruise on the highway at, reasonably? Top speed? Also, what fuel mileage would you get out of a tankful? Maybe at hwy. speeds and at slower off road/gravel road speeds? Any help would be appreciated.
I'd lusted after a DT200R since I first saw them in Cycle Canada in the late 80's. Then when I saw one in a dealership, I was hooked! When it's running well, it'll keep up to a lot more expensive iron, I believe. Also, it's a TWO STROKE! Thanks again for your help.
 
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cactusreid

Active member
I'll second Shuswap's thoughts. Pull the carb, tear it down to nothing, clean every little orifice twice, and then methodically put it back together again. Make sure you check/set your float height, as this is often over looked, and assumed that it's good, when it can cause a host of issues if it's to high or low. You can probably find specs online, but most carbs like the seam on the side of the float to be parallel with the carb body when the little neoprene tipped needle just closes off the flow of fuel. I use a piece of fuel line to gently blow through the fuel line as I'm moving the float open and closed to check at what point the needle bottoms out and closes the flow of fuel. Not super scientific, but it works for me.
 

Buck

Moderator
<<Do any previous/current owners know what speed a person can cruise on the highway at, reasonably? Top speed? Also, what fuel mileage would you get out of a tankful? Maybe at hwy. speeds and at slower off road/gravel road speeds? Any help would be appreciated.>>

I own a 96 DT with 24,000 km. About 9 years now. As was said it does sound like a carb issue. Mine runs very lean after a cold start, the fuel enrichener must be left on for quite some time or it will stall. It will cruise with stock gearing easily about 100 km/hr but will pull 140 in 6th at redline if you're in the mood. 200 km max average on a tank, 10L if I remember.
 

vortexman

New member
I'll second Shuswap's thoughts. Pull the carb, tear it down to nothing, clean every little orifice twice, and then methodically put it back together again. Make sure you check/set your float height, as this is often over looked, and assumed that it's good, when it can cause a host of issues if it's to high or low. You can probably find specs online, but most carbs like the seam on the side of the float to be parallel with the carb body when the little neoprene tipped needle just closes off the flow of fuel. I use a piece of fuel line to gently blow through the fuel line as I'm moving the float open and closed to check at what point the needle bottoms out and closes the flow of fuel. Not super scientific, but it works for me.

It is best to check float level dynamically and keep in mind composite plastic floats get heavy after years of just sitting. Start with good new parts and your likely hood of success in diagnostics will be greatly increased.

Bore scope is my best friend when dealing with two strokes and carb issues.
 

vortexman

New member
I have a 1990 DT200R, with only 3500 km on it. Have had it for 6 years or so, and have not ridden it much. It was working well, a couple years ago, but is now using a LOT of fuel and will not run cleanly at a steady speed. Compression is 140 p.s.i.. It's stock. Cleaned out the carb and replaced the "float needle and seat". Replaced the pilot jet and cleaned out the main jet. Had to coat the tank two years ago, due to rust, but it looks good now. Spark looked good when I kicked it over with the plug out. Noticed the petcock is leaking a bit right now, and have ordered a "rebuild kit" from Wemoto in England. My intuition says I am missing something in the carb.?
Do any previous/current owners know what speed a person can cruise on the highway at, reasonably? Top speed? Also, what fuel mileage would you get out of a tankful? Maybe at hwy. speeds and at slower off road/gravel road speeds? Any help would be appreciated.
I'd lusted after a DT200R since I first saw them in Cycle Canada in the late 80's. Then when I saw one in a dealership, I was hooked! When it's running well, it'll keep up to a lot more expensive iron, I believe. Also, it's a TWO STROKE! Thanks again for your help.

I rode an RZ350 to work every day for many months and the two stroke commuter idea is not new. Sitting in traffic on a two stroke breathing smoke and waking the neighbours at 5 am is a bit of an issue.

Thank fully I am know as a master irritator so this was no big deal in the 80 s for my neighbours. If you are under 30 (tough) and are dead set on commuting on this machine you will have to make sure it is in proper running condition for sure.

The questions you pose are difficult to answer as so many factors affect performance and fuel consumption. Like I always tell people anything is possible it is just a matter of time and money.
 

cactusreid

Active member
"Bore scope is my best friend when dealing with two strokes and carb issues"

Once again, a tool that not everyone has kicking around just waiting for the occaisional carb issue.
And i'll bet that not that many have a set of digital calipers, to actually measure float height either?
That's the reason i suggested the fuel line, blowing trick.
I guessing that getting a new float for a 26 year old bike, might be a bit of a stretch as well.
I'm in the automotive industry (ICBCcollision repair shop), and one trend we have noticed in the last # of years is Diagnostic to a lot of mechanics just means replace stuff (at the customers expence of course) till it runs /works again.This often costs the customer much more time and money than nessasary.
 

Shuswap

Member
I have a sort-of borescope....well....rather it is a dental camera converted (all-in cost $22), but I don't know how I would use it for diagnosing a 2 smoke running issue? Can you elaborate/educate me just a bit Mr. Vortexman?
 

Shuswap

Member
I'll second Shuswap's thoughts. Pull the carb, tear it down to nothing, clean every little orifice twice, and then methodically put it back together again. Make sure you check/set your float height, as this is often over looked, and assumed that it's good, when it can cause a host of issues if it's to high or low. You can probably find specs online, but most carbs like the seam on the side of the float to be parallel with the carb body when the little neoprene tipped needle just closes off the flow of fuel. I use a piece of fuel line to gently blow through the fuel line as I'm moving the float open and closed to check at what point the needle bottoms out and closes the flow of fuel. Not super scientific, but it works for me.

Good method, also you can attach length of clear hose to the bowl drain, if equipped with one, and wrap it up the side of the carb to visually confirm the fuel level.

Further......if dynamic is taken literally, then I'd call it pretty dang dynamic if the engine was running at the same time! Of course any error with this method could result in a very dangerous fuel-fed fire. I won't being doing this, can't see the point
 
Next time you go in to the dentist, take the stripped carb with and run it through the ultrasonic cleaner. A little clandestine technique may be required. [Just kiddin]
 
Borescope/Endoscope is a great tool, and they are CHEAP. And the cheap ones are good enough for the local bike tinkerer. Here is one for $14 http://www.dx.com/p/6-led-7mm-lens-android-endoscope-inspection-borescope-black-426999#.V_aNqfArLEI


Digital calipers are also a must have, and the cheap ones work just fine for putzing around with bikes. $19 http://www.dx.com/p/digital-150mm-caliper-2306#.V_aOCfArLEI[/QUOTE


I think canadian tire has cheap digital calipers on sale for $14. Should work just fine for setting carb float level ...
 

vortexman

New member
"Bore scope is my best friend when dealing with two strokes and carb issues"

Once again, a tool that not everyone has kicking around just waiting for the occaisional carb issue.
And i'll bet that not that many have a set of digital calipers, to actually measure float height either?
That's the reason i suggested the fuel line, blowing trick.
I guessing that getting a new float for a 26 year old bike, might be a bit of a stretch as well.
I'm in the automotive industry (ICBCcollision repair shop), and one trend we have noticed in the last # of years is Diagnostic to a lot of mechanics just means replace stuff (at the customers expence of course) till it runs /works again.This often costs the customer much more time and money than nessasary.

My advice is free and my work is guaranteed, no one is compelled to read any of my posts.
 

vortexman

New member
Remain Calm it is just Vortexman

Remain Calm it is just Vortexman

Once again much emotion with regard to simple straight forward mechanical diagnostics. When a novice or individual with little mechanical knowledge is looking for assistance I do feel compelled to set them on a course dictated by conventional industry standards and trade practices. This seems to upset some.

Those easily upset may wish to stop reading. Those interested in modern motorcycle mechanical repair strategy may wish to read on. Carburetors as well as two stroke engines are very mis understood devices and most back yard mechanic advice well intention ed as it may be is about 20 years behind the times.

Pointing someone at a carb and telling them to start tinkering without seeing the bike and confirming integrity of cyl, exhaust and fuel supply is not really helpful in my opinion. Every week or so I get this type of thing and the mind set of it is a two stroke they are easy to repair or my favourite carbs are easy to rebuild well no need to articulate the rest.

So the DSBC debate club once again is not debating me or helping a fellow rider and I am not really sure what the motivation is but we did dance this tune two weeks ago with another carb issue.

I do not marginalize people nor their capabilities but I sure wish the DSBC debate club would actually repair someones bike problem (the way we use to do it in the 80s). I can post diag routine for two stroke motorcycles if requested.
 

vortexman

New member
Borescope/Endoscope is a great tool, and they are CHEAP. And the cheap ones are good enough for the local bike tinkerer. Here is one for $14 http://www.dx.com/p/6-led-7mm-lens-android-endoscope-inspection-borescope-black-426999#.V_aNqfArLEI


Digital calipers are also a must have, and the cheap ones work just fine for putzing around with bikes. $19 http://www.dx.com/p/digital-150mm-caliper-2306#.V_aOCfArLEI

Looking in the cyl with a scope is one of the quickest ways to confirm cyl integrity on a two stroke. We also vacuum the crank case to test crank seal integrity.

http://www.dansmc.com/vacuum_testing.htm
 

vortexman

New member
Good method, also you can attach length of clear hose to the bowl drain, if equipped with one, and wrap it up the side of the carb to visually confirm the fuel level.

Further......if dynamic is taken literally, then I'd call it pretty dang dynamic if the engine was running at the same time! Of course any error with this method could result in a very dangerous fuel-fed fire. I won't being doing this, can't see the point

Danger is my middle name I guess you have never seen me ride
 
I'd sure be interested in a diagnostic flow chart or sequence for 2t. I have an old 200exc that sometimes makes me go nuts, and it acts up halfway through the ride when i'm 20 miles out.
I say go for it.
 

gt750

Member
Oh Yeah!

Oh Yeah!

All right! Wow! A response, or rather, responses!!! Wonderful. Though I do not have a bore scope, I will get one as that is an excellent idea. Do have a vernier caliper though. I kinda like testing my rusty brain by using a non digital one, though. My battery keeps dying, anyway.
I was getting 80 k.m./tankful, til reserve. That put me at 10l/100k.m.! I had pulled my carb off but didn't follow any real procedure in cleaning it, the first time(s). After reading all of the advice, I agreed with your responses and went back into the carb. The float level was out, by over a 1/4". I hadn't cleaned the emulsion tube, which seemed to have petrified fine dirt on it. The pilot air jet, or orifice beside it was also partially plugged. Hadn't taken the pilot air screw out to clean. Did that. Made sure that all of the other jets were good. Also, all other passages. Actually followed the manual and disassembled/reassembled all the parts. I even blew into the fuel line to test the needle and seat. I am amazed at how well it actually seals!
Then the test. I started it up and wanted to see if it ran nicely. Idle was weak and I still needed to give it a small dose of throttle to keep it running. Then, once partially warmed up I went for a ride. I think a quartet of two stroke friendly Angels with small trumpets played a tune as I cleanly accelarated by them! Wow! She accelerated hard and clean. Ran at a steady RPM. I could blast up to 80 km/h like nothing. It was quite cold, so I went up to 100km/h once only. Did a lot of roll on testing, also tried to go at a steady pace. Like a new bike again. Sweet!
Now the bad news... It snowed today. Grrrrr! Hopefully, will be able to get a ride in before winter sets in.
Any help in tuning a two stroke carb would be very much appreciated. Your help up to this point IS appreciated.
My lesson from this is to not just open up the part and go through what I see to go through. I have a service manual, but chose to ignore it. I never followed ALL of the steps outlined. I figured the float height really couldn't be out of spec., as I had never ever changed it! Somehow, it did change though. Though I looked at the needle and seat and found them to be o.k., I was getting desperate, so I spent $40.00 for a new one from Yamaha!(Never knew the "blow" test!) Got a spare now, anyway! I do appreciate every one who posted. Got me thinking, then acting. Cheers!
 
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