Need some help

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Oct 24, 2007
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#1
Hello out there!! I just joined and have gained a ton of information. I just bought a 1989 RM250. The bike bogs down in first and second gear. Once I get into third gear it takes off like a scladed ape. Sometimes it seems like it wants to run the way it is supposed to run. It also smokes a lot in those two gears. I have only changed the pilot jet. The stock one is a 55. I put a 50 and it did the same thing. I put a 45 and it did the same thing. Do I keep going down on the pilot jet to a 40? The motor has been rebuilt and the only modification it has is a pro circuit pipe. I also checked the reeds and they seemed ok. Plug keeps fouling. The bike starts easy. 3 kicks at max. Any input would be greatly appreciated. Gracias.
 
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#2
Sounds like it could be a plug trying to foul. Have you tried a new one?

Are the power valves stuck?

Crank seals been replaced?

Got a manual?

Rotor
 
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#3
I have gone through a couple of plugs. I am using NGK B8EGV gapped at .024. All the seals are good. I do have the manual for it. It is a clymer. I am a little leary of checking the power valves. Is there an easy quick way to do this? Do I have to tear things apart? Thanks for your help.
 
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#5
razor said:
I have gone through a couple of plugs. I am using NGK B8EGV gapped at .024. All the seals are good. I do have the manual for it. It is a clymer. I am a little leary of checking the power valves. Is there an easy quick way to do this? Do I have to tear things apart? Thanks for your help.
You can take the cover off the right side of the cylinder and watch the valve linkage working.

Rotor
 
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#6
I will try that next. Is it possible to use NGK B8ES on the 89 RM250? I will also check the thread. thanks for your help! I appreciate it very much. it is starting to get cold and I would like to ride a good running bike.
 
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#7
razor said:
I will try that next. Is it possible to use NGK B8ES on the 89 RM250? I will also check the thread. thanks for your help! I appreciate it very much. it is starting to get cold and I would like to ride a good running bike.
I use BR8ES, or BR7ES in my RMX all the time, with no problems. The ES plugs are cheaper than the EGV plugs.

Rotor
 
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#8
Ok thanks for the info. Do the plugs need to have the BR8ES? A friend gave me some, but they are only B8ES. is there a difference?
 

BSWIFT

Sponsoring Member<BR>Club Moderator
N. Texas SP
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#9
The NON "R" plugs will work but can cause unusual problems. The "R" is for resistor and is used due to the design characteristics of the CDI (capacitive discharge ignition). I've used them with no noticable problems but you are better off using the "R" plug, especially if you are having any other issues with the way the bike is running. Don't add an unknown to your problems by using the non "R" plug.
The BR8ES is a very common plug, use a 7 if you are really bogging the engine most of the time, a 9 if your WOT alot. The 8 is the best median for most riding conditions.
 
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#10
Ok thanks for the information on the spark plugs. You are right. I do not need toadd more problems to it. Will a 7 be to hot of a plug? Gap is the same .024? I am mostly riding with my son. He has a PW50. We ride in our front pasture most of the time. I can maybe get it up to third gear then I have to slow down. I wondered if I could use the 7. I thought it was to hot of aplug and I did not want to damage the engine. New to this dirt bike riding. I appreciate everyones help on this.
 
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#11
Ok I put the BR7es plug in and it seemed to run better. The bad news is that the aluminum bracket broke off on the silencer where it mounts to the fender. I happened to pull the packing out and it was pretty wet with blackk oily stuff!!! I also checked the baffle, and that had quit a few holes that were plugged up. I cleaned each hole, and I have ordered so repacking stuff. Hopefully this will cure my troubles. I have one more week to ride. I hope. I saw some flurries today at lunch.
 
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#12
Solution

Ok I think I found the problem. Persistence pays off. I happen to pull of the exhaust to replace the seals. There was a wire coming from the left side of the motor to the coil? Anyhow it was melted and three of the four wires were stuck onto the pipe!! I spliced and fixed the wires. I am waiting for the carb to come back from the local suzuki shop. I have been reading the clymer book and I guess this helps the spark plug fire or something. Does it make sense that these wires melted onto the exhaust would ground out the spark making it difficult to start the bike, and also does it make sense that this would cause the plug to foul because the spark was not hot enough because of the grounding? One more thing, would this also simulate like the bike was loading up in 1st and 2nd and run great from third on because the revs were high enough to produce enough spark to make the bike run fine? Anxious to get the carb back and see what happens. I hope the dirt bike gods have taken some pity on me and decided to help me out. Thanks to all of you for the replies and the help. I will keep you guys posted. Chilly up here in Minnesota.
 
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#13
Cha Ching!!

Thanks to all of you who helped out on this. That was the problem. The plug was grounding out on the pipe. Fixed the wires, put a new spark plug in there and BAM!!!!! No more fouled plugs, starts on the 1st or second kick and the best part, it takes off like a scalded ape!!!