'83 atc 250r blowback problem

[Justin 200x]

Hey guys. I have been a member for a while but I haven't really posted before so I'm posting in here. I have an 83 atc 250r. It starts absolutely fantastic! It spits a little out the carb at idle but the real problem is from half throttle on. It just starts bogging and and fogging out the carb. The further you push the throttle the more gas comes out. The reeds look fine and compression is about 160. I've been searching like crazy and I can't find anything quite like it. Most people say if it's reeds it won't start, but it starts and has good power up to half throttle. Could it still be reeds? I'm about at my wit's end. Oh and I don't really want to spend $150 on a new Reed block if it isn't going to fix it. Thanks for any help in advance.

[arlaunch]

Have you had the carburetor off the machine yet to have a look?

These are indeed strange symptoms.

Right off the bat i would say its your carb floats but.... It is unclear.

[Justin 200x]

Oh sorry. Ya several times. Everything looked good but I put it through my ultrasonic cleaner anyway. Didn't make any difference. What do you mean by carb float? Like it's defective or set to high or to low or what? AFAIK it's not running out the overflow. Oh I should say too, it used to run awesome and this problem has slowly gotten worse over time.

Edit: I should clarify a little on my first post. It doesn't really spit at idle it's more of a mist. Exactly what it does at full throttle but just barely.

To me it seems the carb is working correctly it's just the fuel/air is going out the intake not into the engine...

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[RIDE-RED 250r]

I would pull the intake and have a look at the reeds.

Check for damaged/broken reed petals. If none are obviously broken, check that all edges of the petals are laying down flat on the reedblock. If there are any gaps the petals are worn and should be replaced.

I think you will probably find that you have some broken reed petals. If so you shouldn't need to replace the entire reedblock unless there is wear/damage to the reedblock itself. I haven't searched myself, but I would wager that Boyesen offers replacement reed petals for your Air-Hammer.

And yes, an engine with worn/damaged reed petals will still start, experienced it a dozen times myself.

[Justin 200x]

And yes, an engine with worn/damaged reed petals will still start, experienced it a dozen times myself.

Thankyou Ride-Red! I did say the reeds looked fine but I can see how you missed it. I reread my first post several times before I could find it! [emoji23]

Anyway I also didn't know you could just get the reeds. I will look for that. The reeds esp. on one side don't quit lay down. You might fit a piece of paper under them just a very small gap. There is a small recess under each reed. Is that normal or has it worn into the rubber? Thanks again

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[atc300r]

As Joe mentioned check your reeds.Also have you tried new plug.Another thing to check is your coil.

[RIDE-RED 250r]

Thankyou Ride-Red! I did say the reeds looked fine but I can see how you missed it. I reread my first post several times before I could find it! [emoji23]

Anyway I also didn't know you could just get the reeds. I will look for that. The reeds esp. on one side don't quit lay down. You might fit a piece of paper under them just a very small gap. There is a small recess under each reed. Is that normal or has it worn into the rubber? Thanks again

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Did you pull the reedblock out of the engine when you checked the reeds?? Or did you pull the carb and look inside? If you didn't pull the reedblock, it can be easy to miss damage to reed petals on the very ends where they typically break off.

Sorry I missed where you stated you checked them... I suppose I overlooked it as the problem you are experiencing is typical of bad reed petals.

Beyond that, have you made any alterations to the trike since it ran well before??? IE: Exhaust, no airbox lid, things like that??

[Justin 200x]

Did you pull the reedblock out of the engine when you checked the reeds?? Or did you pull the carb and look inside? If you didn't pull the reedblock, it can be easy to miss damage to reed petals on the very ends where they typically break off.

Sorry I missed where you stated you checked them... I suppose I overlooked it as the problem you are experiencing is typical of bad reed petals.

Beyond that, have you made any alterations to the trike since it ran well before??? IE: Exhaust, no airbox lid, things like that??
Yes I pulled the reed block. Pulled the reeds off the block in fact. Are the small indentations under the reeds supposed to be there or is the block worn?

No mods. The only thing changed at all since we got the bike is a new silencer.

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[RIDE-RED 250r]

I would not venture a guess on the condition of your reedblock without some good close up pics. I would hate to steer you to spend money on reeds and/or reedblock and have it not fix your issue.

One thing I would try just to help in pinpointing the issue: I would swap the entire carb for a known working carb if you have one available from a friend or family member. Something I recently experienced and worth mentioning: I was working on a carb on an '86 TRX350 4x4 for a friend that was spewing fuel and running extremely rich. It turned out to be some sort of flaw in the carb itself inside the choke plunger housing.... For some reason it wouldn't "shut off" the fuel enrichment circuit. I tried swapping a known good choke plunger in and no change. Swapped in the entire carb from my wife's 350x and the thing ran like a watch.

Long story short: A carb can develop an issue in the carb body itself that can only be remedied by a whole other carb. Worth a try if there is one available for you to swap in... If you do, make sure and swap in the jets you are currently running if the test carb is jetted differently

[RIDE-RED 250r]

And generally speaking from my experience, I wouldn't consider indentations on the reedblock to be normal. I'm guessing you have the stock steel reed petals in there??

[Justin 200x]

I would not venture a guess on the condition of your reedblock without some good close up pics. I would hate to steer you to spend money on reeds and/or reedblock and have it not fix your issue.

One thing I would try just to help in pinpointing the issue: I would swap the entire carb for a known working carb if you have one available from a friend or family member. Something I recently experienced and worth mentioning: I was working on a carb on an '86 TRX350 4x4 for a friend that was spewing fuel and running extremely rich. It turned out to be some sort of flaw in the carb itself inside the choke plunger housing.... For some reason it wouldn't "shut off" the fuel enrichment circuit. I tried swapping a known good choke plunger in and no change.

Long story short: A carb can develop an issue in the carb body itself that can only be remedied by a whole other carb. Worth a try if there is one available for you to swap in... If you do, make sure and swap in the jets you are currently running if the test carb is jetted differently
I'll get some pics of the reeds/block tonight. As for the carb, I don't know anyone else that has a 250. And used carbs are VERY expensive. I may have to just take a chance on the reeds... Boyeson has some for $40.

The thing that makes me lean towards reeds is that there's quite a bit of air with the fuel coming out the carb. I could def be wrong though.

I was thinking about putting a little pressure in the sparkplug hole with the piston in the intake position to pressurize the reeds from behind. Would this tell me anything?

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[Justin 200x]

And generally speaking from my experience, I wouldn't consider indentations on the reedblock to be normal. I'm guessing you have the stock steel reed petals in there??
Yes, stock steels reeds. Man I wish I had access to another motor to compare. That makes things so much easier!

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[RIDE-RED 250r]

I don't think that method of testing the reeds would work very well... A visual inspection looking for broken/warped petals should tell you all you need to know.

I think I have a stock carb from an '85 250r (Keihin PE) in my parts bin. It is going to be bigger than your stock Air-Hammer carb, but alot guys swap in the '85 carb as an upgrade for them... If I still have it and if I feel it is in good usable condition I would be willing to send it to you for shipping cost only.. Trouble is we are leaving for a 10 day camping trip on monday and I'm not sure if I can get it to the USPS before we leave... If I still have it, it hasn't been run in quite a long time, but if I recall correctly, it is clean inside.....Only thing I'm not sure of is if it will fit in your stock intake.. I would defer to the fellows more familiar with the Air-Hammers on that.

I will go out today and see if I still have that carb and what condition it is in... Will get back to you..

[RIDE-RED 250r]

Yes, stock steels reeds. Man I wish I had access to another motor to compare. That makes things so much easier!

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Man those old steelies are getting long in the tooth! I would probably replace them just on principle in favor of modern carbon fiber....

When you pull the reedblock, please get pics with reed petals mounted as well as removed.

[yaegerb]

Hey guys. I have been a member for a while but I haven't really posted before so I'm posting in here. I have an 83 atc 250r. It starts absolutely fantastic! It spits a little out the carb at idle but the real problem is from half throttle on. It just starts bogging and and fogging out the carb. The further you push the throttle the more gas comes out. The reeds look fine and compression is about 160. I've been searching like crazy and I can't find anything quite like it. Most people say if it's reeds it won't start, but it starts and has good power up to half throttle. Could it still be reeds? I'm about at my wit's end. Oh and I don't really want to spend $150 on a new Reed block if it isn't going to fix it. Thanks for any help in advance.

Your reeds are ghandi. Replace them with a set of these, its about a 30 minute job.

http://www.ebay.com/itm/Boyesen-Power-Reeds-for-Honda-Atc250r-250r-1981-1982-1983-1984-1985-1986-/351777411252?hash=item51e79150b4:m:mfOg3gyrh-WNItZ7o2OSgGQ&vxp=mtr

[Justin 200x]

OK. Here's some pics. Hopefully they're good enough. You can see the small indentations I'm talking about. You can see the wear marks on the reeds but you can't feel anything. http://uploads.tapatalk-cdn.com/20160716/69e4fe3d7c0ff8bc22f78cb1f35bf96a.jpghttp://uploads.tapatalk-cdn.com/20160716/3529943658be2ef427e9f260b423b306.jpghttp://uploads.tapatalk-cdn.com/20160716/13bc23272c131384603afb1f34e6eca9.jpghttp://uploads.tapatalk-cdn.com/20160716/00eb9b7cccaff57bc17143e5d0eaee2d.jpg

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[Justin 200x]

Hey guys. Any ideas on the pics yet? I need to figure out if the reed cage is good before I get new reeds. Thanks

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[yaegerb]

I don't see an issue with the reed block, however I do see a gap with the two reeds on the bottom right. Buy reeds first, you need them. If you still have an issue afterwards, buy the reed block. Unless someone has jacked with the reed block, they aren't known to go bad (in my experience). Its not like you are wasting money buying a new set of reeds, that's already a sunk cost.

[Justin 200x]

I don't see an issue with the reed block, however I do see a gap with the two reeds on the bottom right. Buy reeds first, you need them. If you still have an issue afterwards, buy the reed block. Unless someone has jacked with the reed block, they aren't known to go bad (in my experience). Its not like you are wasting money buying a new set of reeds, that's already a sunk cost.
Thanks. I've never had one of these apart, so I wanted to make sure the small recess under each reed was manufactured that way and not worn. That was my real concern

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[bkm]

Has a compression test been performed on this engine, from the looks of the reeds there is excessive blow-by past the rings.

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[Justin 200x]

Has a compression test been performed on this engine, from the looks of the reeds there is excessive blow-by past the rings.

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Yes. In my first post. It's 160.

I just remembered my bro has a kx125 that is torn down. I'm going to check out the reed cage on that for comparison's sake. Then I'm going to order a new set of reeds. If that doesn't work i guess I'll have to look into the carb as suggested by Ride-Red

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[bkm]

Yes. In my first post. It's 160.

I just remembered my bro has a kx125 that is torn down. I'm going to check out the reed cage on that for comparison's sake. Then I'm going to order a new set of reeds. If that doesn't work i guess I'll have to look into the carb as suggested by Ride-Red

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Sorry about that, I must have skipped right over that. I'd lean towards carb issues if the engine is mechanically sound.

[Justin 200x]

Sorry about that, I must have skipped right over that. I'd lean towards carb issues if the engine is mechanically sound.
Hey no problem. As several others have said my reeds are definitely suspect. So now that it looks like my cage is fine that's my first step. After that my carb.

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[Justin 200x]

OK guys, so after much silence I finally have an update. I got the new reeds and put them in and the first time I revved it was fine then back to the same old story. Absolutely no change.

But the fact it rapped clear out once seemed to point either fuel or air. After some more research, I realized the air screw was all the way in. I never realized it, because I just put it back the way it was when I took it apart. At some point someone lost the spring so I suppose it just worked itself in. I know. You're NEVER supposed to assume something is right but..... [emoji15]

Anyway it's running a lot better! However, it still fogs a tiny bit out the carb at high rpms. Is that normal? I don't have a lot of experience with 2 strokes.

Also since I'm asking questions anyway, what's the procedure for adjusting the air screw. If I go by the manual, it still bogs a bit. I'm at 1500 elevation.

Thanks a lot.

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