Update on plug fouling RM250

[SoFlo]

Just thought I'd post up again, I started a thread about 2 or 3 weeks ago stating my problems, mainly plug fouling and hard starting when cold.

I did a leakdown test, and it held 100% of the pressure perfectly, I was preety happy about it. I had three leaks, one on the tester, and two runaway hoses, but after that, not a leak at all. So that rules out a leaking right hand seal.

I peaked in the cylinder from the exaust port to catch a glimpse of the insides, and from my angle, I could see some burn marks on the piston, black top for sure, and maybe some scorring on the cylinder walls, but couldn't be sure.

Can I just pop off the head and look, without getting new o-rings for it? And how much coolant do I have to drain out about before pulling it? I'd like to maybe take some pics and post them up to see what you guys say. The compression read about 185 about 30 to 40 hours ago, and I've been trail riding that whole time, but it is probably do for a new setup.

Again, the main problems I'm dealing with is fouling a plug every 30 to 40 minutes. I've currently got a 165, 52, and second clip right now. It runs great I think, but it's fouling like a madman.
I want to check the reeds, because they can cause hard starting. But I look at the OEM, and there's no replacement reed gaskets for my year?!! And I couldn't find any Tusk ones on Rockymountain either?!! I ordered a '95, and a '02, closests ones they had. But I haven't pulled it off yet to see if those reeds are the same size/shape. Will the gaskets off the '96 RMX work? The OEM has those.
BTW, I usually run BR8's, I tried a 7 just to see if it'd help at all, didn't at all.

This problem really increased when I plugged a pipe leak out of the engine to pipe seal. With the leak, it'd take a full day to foul out a plug, after the patch up, it took about 2 hours the first ride after. Within the last 4 rides (15 hours about) it's progressed to every 30 minutes having to swap the plug. Is this just a sign of the topend wearing out very quickly?

And just to ask, what are some other places besides Eric Gorr that I could send my cylinder for replating, that might have a faster turnaround, and maybe a little cheaper?

Sorry for the 224324 page book, I was rambling at certain points there. :blah:

 

[WillyM]

Well if the leak down test is good then you need to change the jetting.
With a worn cylinder it can do strange things also, they can be a pain to jet with worn piston/rings ,and cylinder.

 

[ellandoh]

how does it run when it is running?? sputter anytime or need to be cleaned out after running gingerly for a couple minutes??

 

[apb]

I've currently got a 165, 52, and second clip right now. It runs great I think, but it's fouling like a madman.

Are you sure that 52 pilot isn't too rich? I assume this is a keihin pwk carb on that bike?

 

[SoFlo]

The carb is a PJ, the older style. I'm almost positive, because that's what's on the side of the carb. I can try going down a few sizes on the pilot, I've got plenty of ones to try.

With a new plug, you can lug it around a little, it runs preety good. When I'm trailing for a long time, and not revving, it'll load up fairly solid. On the other hand, whether I trail ride, or keep it pinned in 5th the whole time, the plug just will not last over an hour.

Does an old topend make it run richer, or just weirder?
And any word on the intake gaskets or the head gaskets questions?

 

[sick 96 250]

hey man, i'm pretty sure you should have a keihin carb on there and not a PJ or maybe it is a mikuni(sp?). Pull the head still. Take out the carb, drain the rad fluid and its only like 10 bolts to pull that sucker off. did you ever get a manual for that bike, it helps wonders. If you need a gasket set for a new top end i believe i still have one somewhere in my garage as well. It is prob just a worn piston causing everything, when my piston was worn no jetting would solve the problems, it may temp the situation but it always came back with problems. You need to pull the head anyway, you may not need the cylinder bored or plated, prob just a piston and ring will do you good. Check the auction website for a piston, can be had very cheap on there. Then its only about a 2hr process to put the new one in if you have the MANUAL!!!!! Good Luck

 

[SoFlo]

Hey, I'm 100% positive that I have a PJ carb on there, and yes, PJs are made by Keihin, just like PWKs. It says that I have a PJ in the manual, and it says PJ on the carb itself. I'm going to take a picture today and post it, so you guys can help me decide what kind of condition the cylinder walls are in. I've changed a topend once before, I'm confident that I wouldn't have any problems, unless something squirley pops up with the powervalve.
Yes I do have a Clymers manual for it, but I also have a clue on how to do things, but the manual is very helpful, that's true.
And if you could send me an email, toomeyb12001@yahoo.com, I'd like to get that gasket kit if you still have it and don't need it, since I might pop in a new piston soon. If not, any difference between Cometic and Tusk? I'm guessing that Cometic or OEM would be best.

And anyone have any clues why it's fouling faster the more I ride it? It's been getting colder even, which should be helping the problem... Is the piston wearing out that fast, or is it something like the silencer packing making that huge a difference. Or maybe the reeds are getting trashed. That's another thing, I couldn't find any replacement V-Force reeds for my model/year. :bang: I'll probably be on the look out for 2001 or something, just for parts and the newness of it, I'd love to find me a CR500 though. ;)

hey man, i'm pretty sure you should have a keihin carb on there and not a PJ or maybe it is a mikuni(sp?). Pull the head still. Take out the carb, drain the rad fluid and its only like 10 bolts to pull that sucker off. did you ever get a manual for that bike, it helps wonders. If you need a gasket set for a new top end i believe i still have one somewhere in my garage as well. It is prob just a worn piston causing everything, when my piston was worn no jetting would solve the problems, it may temp the situation but it always came back with problems. You need to pull the head anyway, you may not need the cylinder bored or plated, prob just a piston and ring will do you good. Check the auction website for a piston, can be had very cheap on there. Then its only about a 2hr process to put the new one in if you have the MANUAL!!!!! Good Luck

 

[SoFlo]

Alright, got a bad news update. I did another leak down test, and I got it to stay at six pounds, but I went ahead and took off the oil filler cap, and all the air comes out!! So I guess the right side IS leaking after all!!
Any special tools needed to swap out this seal? How hard is it to get the clutch basket off? And how many gears need to be removed? Dang...

 

[SirHilton17]

spliting the cases is pretty easy, just a pain, and its kinda time consuming.
The clutch basket is easy to take off if u have a air impact wrench.
I made a special flywheel puller myself... but it is kinda hard to make because of the lefthanded threads and stuff... i had to cut the threads on a lathe insted of just using a die.
other than that there are no special tools NEEDED to split the cases.. but with a case spliter and other stuff im sure it can be loads easier.
when spliting the cases dont pry on them with a screwdriver... Sometimes bikes have little "pry spots".. if you do pry on the pry spots be VERY careful.
The cases can be split just with careful tapping with a soft hammer, and the way you hold the cases when taping efects it ALOT...
Once the cases are split about 3/8 of a inch or so, you can pry with somthing (wooden things are good) that will spred the load evenly and over a large surface, but be extremly careful...
when u get the cases split the crank will be lodged in one of the main bearings on one of the cases... but it is not very hard to get out.
when you remove the seals just pull them out with anything you can get in there, when the main bearings are removed it makes it really easy to get the seals out...
when putting the seals in, grease them, and put them just under flush with the case, and make sure they are not put in at an angle or anything.
...
As for gears that would have to be removed... umm the primarys gear, the one coming right off the crannk... umm i dont know of the top of my head, just take off what ever needs to come off...

When ur down inthere i would suggest u replace the mains too... and big end bearing.. ect.

 

[Rog]

If it's the same as a 97 you don't need to split the case. Just take off the clutch and the primary drive cog and theres your seal

 

[SirHilton17]

really... Thats cool

Umm.. i dunno.. maybe you can do that on all bikes.. but im not sure, ive always split the cases and done the mains and whatnot...

If you cant get to the other sides seal you should just split the cases.. cause it is worth it to do both seals at once, it can save alot of time later on!!!

 

[TimberPig]

really... Thats cool

Umm.. i dunno.. maybe you can do that on all bikes.. but im not sure, ive always split the cases and done the mains and whatnot...

If you cant get to the other sides seal you should just split the cases.. cause it is worth it to do both seals at once, it can save alot of time later on!!!

Kawasaki's are the only manufacturer that requires the cases be split to change seals. Honda, Yamaha, and Suzuki can all have the seals changed without splitting the cases.

To pull the clutch basket, you will either need a clutch holding tool or an impact wrench to pull the basket, as it will spin when you try to remove the retaining nut. The same will be true for reinstallation. Other than that, it is pretty simple, and not much more involved than changing a clutch out, as its only 1 step further.

 

[SirHilton17]

That is good to know...
i have always just went ahead and split the cases...

 

[ellandoh]

Kawasaki's are the only manufacturer that requires the cases be split to change seals. Honda, Yamaha, and Suzuki can all have the seals changed without splitting the cases.

To pull the clutch basket, you will either need a clutch holding tool or an impact wrench to pull the basket, as it will spin when you try to remove the retaining nut. The same will be true for reinstallation. Other than that, it is pretty simple, and not much more involved than changing a clutch out, as its only 1 step further.

one of my riding buds was freaking out about oil leaking around his CS sprocket, honda rider, when i told him it was gonna be about $13 to go the extra mile and chage the o-ring also, he was about to go knock on the parts counter kids forehead for the advise he got :laugh:

 

[SoFlo]

Alright, here's a bunch of pics of the head and piston. I'm thinkink poping off the cylinder and maybe try and move the rod up and down, and also move the flywheel up and down to check for looseness in the bearings.
What does all this look like? And is the cylinder in good enough shape to go without replating? Or does it need to be measured? Anything in these pics lead you to see it fouling every 30 minutes? And don't forget, it's a problem that's been getting worse within the last 30 hours of use. And the bike doesn't smoke alot like a leaky right side seal would say. The only thing that I can say, is to pop in a new piston, ride for a few hours, and measure my oil once I change it again. How much would I be losing in ml's after a day of riding?

 

[SoFlo]

 

[grim sweeper]

I had a 96 rm250,it came with a Keihin PJ carb,had problems with fouling plugs(the stock NGK pkug was 25$!!!), it was replaced with a PWK from a company I think called "carb parts".

 

[SoFlo]

Anyone have any clues as to how the engine is running by looking at these pcis? Does it looks like it fouls plugs like crazy, or is burning tranny oil?

 

[TimberPig]

Anyone have any clues as to how the engine is running by looking at these pcis? Does it looks like it fouls plugs like crazy, or is burning tranny oil?

Where are the pics at, I'm not seeing any, and can't find a link? Is anyone else able to see them?

Ok, I can see 3 pics of a clean combustion chamber that looks pretty normal. Guess they were just loading slow.

 

[SirHilton17]

i cant see any pics... just little red X's

 

[SoFlo]

 

[SoFlo]

 

[SoFlo]

Or try this link, http://www.imagestation.com/album/pictures.html?id=2109474475

 

[abran46]

RMX250 '97 problem!

Hello everyone,
I bought a Suzuki RMX250 1997 a few months ago. I was never too happy with it as it died from time to time. We couldn't find anything causing this problem as we disassembled, checked and cleaned the carburetor, exhaust, electrical system (including fly-wheel) and the spark plug. I have got the Clymer manual for the 95 model and tried my best with that. Always after we disassembled the carburetor and cleaned or replaced the wet and black sparkplug it run for a distance of 60km at the start. It just kept dieing and each time the running distance decreased from 60km to 40km to 20km down to just a couple of meters. Now it only runs for 2-3 seconds after I clean the spark plug. :coocoo: .

Doesn't matter how much you rev it or which position the adjuster screw or jet needle is on. Especially the air adjuster screw seems to have completely no affect on the running at all (I’ve tried as she was running all right).

Could that have to do with some old worn or broken sealing where she gets air through?

I also thought about replacing my standard Keihin PJ 38mm with a PWK 38mm as the PJ is quiet hard to tune with the idle at the choke etc. but couldn't find one so far. :bang:


Thanks for any input!

Regards
Arvid

 

[2strokerfun]

I can see the first batch of pics and it looks like you are about ready for a new top end. At least a light hone and new rings, but I'd measure and put a new piston and wrist pin bearing in while I'm at it. Nice burn pattern on the top of the piston. Just has some hours on it, it looks like.