1990 DR250 carb setting
Posted July 31, 2011 - 01:55 PM
Posted July 31, 2011 - 06:21 PM
Posted August 03, 2011 - 05:27 PM
Posted August 03, 2011 - 09:35 PM
A glowing header after a few minutes of idling is actually very common. It's even addressed in the owners manual.
After I cleaned it it will now run, but I think that the pilot screw is not set right, if I let it run, the exhaust ends up glowing red hot by the engine.
Suzuki says the cure is not to let the engine idle for extended periods if possible.
You can play with the fuel screw to try to get it to run a little richer without loading up but there is no "standard setting" for the fuel screw.
If it's an S model the fuel screw comes pre-set and capped off from the factory.
Posted August 04, 2011 - 02:04 AM
Posted August 04, 2011 - 03:24 AM
Start with 1.5 turns out on the pilot, and adjust from there.
Check out the DR350 Wiki for a good page on CV carb. tuning, esp. pilot mixture. Your 250 will not be significantly different, other than the actual size of the carb. & the sizes of the jets.
Take notes of what your current settings are, and note what you change & what effect it has on running. You'll have her purring in no time!
Posted August 04, 2011 - 05:11 AM
Yup, that's the kind of red I'm talking about. If the bike idles ok and runs good right off closed throttle then you're worrying over nothing.
Yeah, the header was SOLID RED though.
Is this bike an S model or a Dirt model?
I agree with Judas, a jet kit is a waste of money.
All you need is an adjustable needle and a couple jets from Kientech.
If you have the dirt model then you already have the adjustable needle.
Posted August 04, 2011 - 02:37 PM
Posted August 04, 2011 - 04:28 PM
Another thing I noticed come to think of it. There is a "ribbed barrel" shaped piston riding on a spring in the lower bowl casting. That piston does not seem to rise and fall very smoothly and seems to get stuck down there rather easily. Is there a lube I can use on it that will remain effective in that environment? The manual doesn't say anything about lube either though. I'm using the CLYMER Suzuki DR 250-350 1990-1994 Service, Repair, Maintenance Manual too by the way.
Posted August 04, 2011 - 05:08 PM
Rebuild the engine for what reason???????
As far as the engine work goes... Let's just say that I would not put it past me to rebuild it,
Another thing I noticed come to think of it. There is a "ribbed barrel" shaped piston riding on a spring in the lower bowl casting.
The DR's can and do run over 1,000 degrees at the header. It's not a big deal.
That "barrel" shaped piston" is part of the accelerator pump and has nothing to do with the idle circuit.
What I'd be worried about is the problem you are eventually going to run into with the carburetor wearing out. All Mikuni TM31 (The DR250 Dirt model came with the TM31) and TM33 pumpers have a design flaw where the channel in which the slide rides up and down in wears out from constant operation. Since it's part of the casting it can not be repaired or replaced and then the carb is junk.
I'm actually surprised that a 1990 TM31 has not warn out by now.
You'll know it's shot when it will no longer maintain a steady idle because of too much slop in the slide channel effecting proper air/fuel flow.
The TM33, which was stock on the DR350 dirt model is still available and a very popular performance mod but the TM31 is no longer available as far as I know.
Posted August 04, 2011 - 05:27 PM
Posted August 04, 2011 - 06:03 PM
The TM33 fits the DR350. The DR250 takes the TM31.
The tm33 is a bolt on option?
Posted August 06, 2011 - 04:51 AM
Posted August 10, 2011 - 12:31 PM
Posted August 10, 2011 - 03:34 PM
Posted August 11, 2011 - 12:15 PM
Posted August 11, 2011 - 12:22 PM
The tm33 is a bolt on option?
I used a TM33 with my DR250S. My mechanic had it installed for me, but it shouldn't be that complicated.
Posted October 07, 2012 - 06:33 AM
All this time, I've known that if the bike is running fine on half choke, then the reasoning is that it is not getting enough fuel, but I've just never gone out and looked into it. Well, yesterday was the day, I went out, put the bike up on my motorcycle jack and started checking things out. Pulled the fuel line off and it looked like it was replaced, it looked new. Pulled the petcock out of the tank to see if there was a filter on there, and there was, one of those screen jobs, actually two, one level for the regular, and another for the reserve level. They looked fine. Pulled the petcock apart, all good in there. Then I looked at the connectors the fuel line go on, sure looked bigger than 1/4", looked at the line I was using, it was 1/4" ID, I had some 3/8" from my Camaro Project car, it was a bit loose, so I put some of that on. I really could use some 5/16", but for a test of theory this was just what I wanted.
Bike runs great! So, I'm keeping it, I need to see what is all in getting a lost title for a motorcycle in the great state of Illinois, and proceed to make this thing street legal so I can ride it around.
I'll be looking around at what I can do to get it up to speed, how to add turn signals and a brake light and license plate mount, electric start would be so nice, speedometer and tach, passenger footpegs and then once the car is done, I'm going to make this my project and pull it all apart, powdercoat the frame and rebuild the motor, basically make it like new. I would also love to make all of the plastics black.