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1986 rm250 problems

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I just traded a cr80 for an 86 rm250 and there's a few things I have questions about. One problem is that the kick start lever doesn't come back when you kick it, do I just need a new spring?

 

Also the couple times I got it started it didn't seem to have the power that it should. The guy I got it from said it probably wasn't getting gas and there was a good amount of gas coming out the overflow so I took the carb apart and there was a bunch of green corrosion looking stuff on everything. I cleaned it up pretty good but there's still some gas coming out the overflow. Does anyone know what could be causing this?

 

Photo144.jpg This is the spring that was under the power valve adjuster and I'm no expert but I don't think it's supposed to look like that. Could this be part of the reason it's lacking power? And I don't have a manual for the bike so can anybody tell me how the power valve should be adjusted once I get a new spring?

 

Any help would be appreciated

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I fixed the kick start. The part of the spring that sticks out wasn't in the hole that it was supposed to be so I just put it back and it works fine now. 

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The rear shock is really bouncy and I'm pretty sure the air canister is empty because when I pushed on the valve nothing came out. Could this cause the shock to be bouncy or does it just need to be rebuilt? Also what is the canister supposed to filled with, air or nitrogen? Any help would be appreciated.

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Yes, if the canister is empty it would be like having a spring with no shock absorber = bouncy. The shock and reservior are filled with oil and nitrogen.

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Yes, if the canister is empty it would be like having a spring with no shock absorber = bouncy. The shock and reservior are filled with oil and nitrogen.

 

Alright so I'll try just refilling the canister with nitrogen before I take the shock apart. Do you know how much nitrogen I need to put in it?

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Not really, the manual for my 89 RM125 says 142psi. I guess you can start off with 100psi and see if that helps.

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Not really, the manual for my 89 RM125 says 142psi. I guess you can start off with 100psi and see if that helps.

 

OK I'll look around and try to find the right pressure. Thanks for the help

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The gas overflowing is more than likely that the carb needs a needle and seat ( needle worn or seat o-ring rotted ) or it needs the float adjusted , float adjusted too high will cause it to overflow and run rich = not running at full potential.  :ride:

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The gas overflowing is more than likely that the carb needs a needle and seat ( needle worn or seat o-ring rotted ) or it needs the float adjusted , float adjusted too high will cause it to overflow and run rich = not running at full potential.  :ride:

 

I took apart the carb and there was a bunch of green corrosion looking stuff on everything, so I cleaned it the best I could,  soaked it in carb cleaner, and made sure all the ports are clear. Now I don't see it overflowing and I ran the bike a couple times but it isn't running right. It idles on choke, but when the choke is turned off it'll run for a minute then die unless you pull the choke again or rev it. Also when I ride it, it seems like I can't get more than 1/4 throttle and there's no power band with the choke off, but with it on there seems to be a little more power but the throttle response is real bad. Could this be a carb issue or something else?

Edited by beastybaconman

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I took apart the carb and there was a bunch of green corrosion looking stuff on everything, so I cleaned it the best I could, soaked it in carb cleaner, and made sure all the ports are clear. Now I don't see it overflowing and I ran the bike a couple times but it isn't running right. It idles on choke, but when the choke is turned off it'll run for a minute then die unless you pull the choke again or rev it. Also when I ride it, it seems like I can't get more than 1/4 throttle and there's no power band with the choke off, but with it on there seems to be a little more power but the throttle response is real bad. Could this be a carb issue or something else?

It needs rejetted I found this 300 MAIN.. 50 pilot, 6DJ33-3rd needle. R-O needle jet. 3.0 cutaway. Edited by Beau 88

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It needs rejetted what bike is it again ? I'll see if I got a factory jet chart .

 

It's a 86 RM250 and it's got a DG pipe and silencer.

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It's a 86 RM250 and it's got a DG pipe and silencer.

300 MAIN.. 50 pilot, 6DJ33-3rd needle. R-O needle jet. 3.0 cutaway.

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300 MAIN.. 50 pilot, 6DJ33-3rd needle. R-O needle jet. 3.0 cutaway.

I have the carb apart and the main jet is a 330 and I don't know how to tell what pilot jet I have, the needle jet is a R-O. I don't have much experience with carbs so I don't know what a cutaway is.

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just took a real close look, the pilot is a 40 something, it's just corroded a little so it's hard to see. Thanks for the help man I'll try changing the main and pilot jets. 

Edited by beastybaconman
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Were you able to fix the leaky carb? I just finished my 07 yz125 and my carb was poring out gas. I went to advanced auto and bought there pack of gas resistant o-rings and one of them fit perfectly. I would say run down there and pick up a set for $7, plus you will have a ton of spares (all different sized) in the future.

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Were you able to fix the leaky carb? I just finished my 07 yz125 and my carb was poring out gas. I went to advanced auto and bought there pack of gas resistant o-rings and one of them fit perfectly. I would say run down there and pick up a set for $7, plus you will have a ton of spares (all different sized) in the future.

It doesn't seem to be overflowing anymore. I think mine was just dirty and something must have been clogged, but since I have the carb apart I'll take a look and make sure the o-rings are good too.

Edited by beastybaconman
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It doesn't seem to be overflowing anymore. I think mine was just dirty and something must have been clogged, but since I have the carb apart I'll take a look and make sure the o-rings are good too.

 

Yeah I would just double check them, becuase my 07 even had some o-rings that just fell apart the second I touched them. Good luck with the build! I am restoring a 1986 rm125, just a little brother to yours, here is a picture.

 

IMG_1356_zpsbe9d751c.jpg

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I replaced the jets and it was running better, but it still wasn't running right. It smokes a lot more than it should and I think it's because I'm running gas that is mixed richer than 32:1. I had this gas for a 80 that I just rebuilt and I wanted to make sure it had plenty of oil so I mixed 5 oz oil to a gallon of gas. Is that too rich and would it cause the bike to bog alot? Also the other day I was riding a bit and decided to take it down the road to open it up some. I only took a quick spin and it didn't feel like the powerband kicked in until I was in 3rd gear. When I got back to my house I looked down and my leg was covered in what looked like oil and coolant. The bike vibrated a lot when I went down the road which caused some of the side cover bolts and the oil fill plug to fall out. I'm pretty sure I need a new clutch cover gasket, but what would cause the coolant to mix with the bottom end oil?

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You may be leaking coolant into the oil and oil into the coolant. I would open the radiators and see if there is some gunk in there as well. This happend to my 86 rm125. I found that the water pump oil seals were eating into the crank shaft and allowing oil and coolant to run past each other. If you see in my pictures, there are small groved that the oil seals made in the crank shaft. I had my local shop help me polish the crank shaft and as you can see there is only a slight little line left now. Hopefully this will fix my problem as well. OH AND REMEMBER THAT THE CRANK SHAFT NUT IS LEFT HAND THREADS!!!

 

photo4_zps8cd04c5c.jpg

image2_zps4b109240.jpeg

Edited by blbiker56
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You may be leaking coolant into the oil and oil into the coolant. I would open the radiators and see if there is some gunk in there as well. This happend to my 86 rm125. I found that the water pump oil seals were eating into the crank shaft and allowing oil and coolant to run past each other. If you see in my pictures, there are small groved that the oil seals made in the crank shaft. I had my local shop help me polish the crank shaft and as you can see there is only a slight little line left now. Hopefully this will fix my problem as well. OH AND REMEMBER THAT THE CRANK SHAFT NUT IS LEFT HAND THREADS!!!

Just looked at the shaft and that's exactly what the problem is. How did you fix it on your bike?

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