RMX250 problem

[matrox02]

Hi lads and gents, I finally got my rmx completely together today and got her fired up, albeit it took a long time to start, I could each time I bumped the kill switch a few times it kicked fine which could be a coincidence, but one started the bike was hella smokey and was clearing up and slowly bringing the revs up too, so I was easing the idle adjuster down while twisting the throttle a few times for it to warm up when while i was bringing the idle screw down, The bike revved up by itself and the kill switch wouldnt kill it, at this point is wasnt smoking heavily, just looked like i guess it should but it was revving smoother and higher than I had managed to get it to up to at that point, felt like it was revving to the moon, then while I was looking to kill it some how else it then returned back to idle where the kill switch became functional again during the revving I think there was no smoke, its a 1990 rmx250 with FMF fatty and FMF can, 260 main and 45 pilot on recommended carb settings, can anyone shed light on what's happening? I noticed the breather pipe on the back of the barrel is also smoking a bit, is that normal? I cant see any air leaks around the carb, and i dont think the crank seal would have been at fault, but could be wrong?? or is it just a random act ?? I put it away after that happened because I dont want to blow it up after just spending big money getting it to a running condition, ( I really should learn to get rid of it and buy a new 4 stroker! )

Its a 1990 RMX250 btw

tldr : bike revved by itself and scared me when it wouldnt shut off with the kill switch, why did it do that?

[FJRider]

: bike revved by itself and scared me when it wouldnt shut off with the kill switch, why did it do that?

Maybe the kill switch isn't properly earthing ...

Pull the plugs and check for spark with the switch on AND off ...

[matrox02]

Maybe the kill switch isn't properly earthing ...

Pull the plugs and check for spark with the switch on AND off ...

Ill do that, but what happens if the switch gets fixed and the engine does it again, ie, running by itself??, I suppose the spark plug could be at fault if it is actually not sparking but getting a hot spot on the electrode or something...I guess its the only part other than the casings that i havnt replaced because it looked brand new :S ( there goes my assumptions biting my ass again! )

[Kickaha]

bike revved by itself and scared me when it wouldnt shut off with the kill switch, why did it do that?
I had the same thing one time with my IT200 and it was an air leak at the cylinder base

[Grumph]

I had the same thing one time with my IT200 and it was an air leak at the cylinder base

+1 - You're onto it, but given the breather at the back of the barrel is fuming - and that's the gearbox breather, I'd suggest there's an air leak from the gearbox into the crankcase.

[matrox02]

+1 - You're onto it, but given the breather at the back of the barrel is fuming - and that's the gearbox breather, I'd suggest there's an air leak from the gearbox into the crankcase.
I checked the base, its torqued down properly, and the head too, and the breather is o the power valve, maybe its the power valve leaking instead?? its not leaking around the case as far as i can see, the only leak is a coolant leak from a shitty hose/ hose clamp by the radiator ( i intend to remedy this )

[Grumph]

I checked the base, its torqued down properly, and the head too, and the breather is o the power valve, maybe its the power valve leaking instead?? its not leaking around the case as far as i can see, the only leak is a coolant leak from a shitty hose/ hose clamp by the radiator ( i intend to remedy this )

Any power valve is on the exhaust side of the barrel. What you're seeing is characteristic of an air leak somewhere either cases,barrel base or a seal.

[Drew]

Sounds fucked. Give ya a hunded bucks for it.

[matrox02]

Any power valve is on the exhaust side of the barrel. What you're seeing is characteristic of an air leak somewhere either cases,barrel base or a seal.
looks like ill be pressure testing the seals them, I skipped this because " nah it ran fine before and its all new seals and gaskets now " < that right there is an assumption and im annoyed that i do that all the time now, So otherwise, i should check the crank seals the barrel base, head and the casings?? hard to check the inside of the casings , Id hate to pull it right apart again, just after a full rebuild...

[matrox02]

looks like ill be pressure testing the seals them, I skipped this because " nah it ran fine before and its all new seals and gaskets now " < that right there is an assumption and im annoyed that i do that all the time now, So otherwise, i should check the crank seals the barrel base, head and the casings?? hard to check the inside of the casings , Id hate to pull it right apart again, just after a full rebuild...

though if you look at the barrel diagram, its only the power valves that could be leaking here... 23 is the breather pipe im talking about, and the arm that operated the valves is in there nicely, hmm I have a spare set of valves i may swap them out...

though Ill still pressure check everything else, someone else online also mentioned smoke out the vent and said he had to plug that off to get pressure testing the cases to work properly
http://a3.bikebandit-images.com/schematics/schematics/suzuki/suz010/SU0230_002.gif

[F5 Dave]

Pv vent will smoke. If carb runs out of gas under no load the revs increase for a while. When revving that high the kill may be a little ineffective if the earth is not that good.

[matrox02]

Pv vent will smoke. If carb runs out of gas under no load the revs increase for a while. When revving that high the kill may be a little ineffective if the earth is not that good.

Yeah I noticed that when I was free hand kicking it with the kill switch off then as you would expect it sparked fine, then when on it sparked once or twice then dropped off completely, so the kill switch is rather a bit snotty or not earthing right, buying a new one to be safe though , and I suppose the running out of gas bit does explain it a bit, I remembered seeing the same on rc gas's cars, revving before during... Well that puts me at ease for now, I'll make some more pre mix and fill her up as I had only put 2 liters in from the get go

[gwynfryn]

Air getting in somewhere on inlet side; crankcase seals , cylinder gasket, carb boot, gasket either side of reed valve.
Carb idle set way high and or lean pilot circuit (air screw/PJ)
Throttle Stuck.

[cheese]

RM seals are outside the bearing so they can be done without splitting the crank.

My 96 RM did the same thing once. It was fine and never did it again.freaked me out too. Turn the fuel off next time.

[Blat450]

It didn't rev up like this did It? Perhaps ya just need a bigger rag ;-)
http://youtu.be/vbiNndfNNKI

About 2 minutes in for people with no time

[husaberg]

Air getting in somewhere on inlet side; crankcase seals , cylinder gasket, carb boot, gasket either side of reed valve.
Carb idle set way high and or lean pilot circuit (air screw/PJ)
Throttle Stuck.

Ya beat me too it..... occasionally when the routing is wrong on the cable and or with no freeboard it can pull on it with the handlebars.
also the idle goes up way silly when returning to idle after running when too lean on the pilot and idle.

[matrox02]

RM seals are outside the bearing so they can be done without splitting the crank.

My 96 RM did the same thing once. It was fine and never did it again.freaked me out too. Turn the fuel off next time.

hmm yeah.. I was busy just about to when it stopped revving, Leased i know its nothing too dangerous, Ill fire her up again and see if it happens again, i also found my idle screw way far in and the throttle cable waay tight so i adjusted them properly, which i hope helps with the starting issue i was having

[matrox02]

hmm yeah.. I was busy just about to when it stopped revving, Leased i know its nothing too dangerous, Ill fire her up again and see if it happens again, i also found my idle screw way far in and the throttle cable waay tight so i adjusted them properly, which i hope helps with the starting issue i was having

Hey All, looks like the issue was sorted with a new kill switch and makign sure the throttle cable wasnt sticking, On another note though... im unable to find anywhere on the internet what the ignition timing should be in either degrees or mm BTDC, Its currently set at 1.8mm btdc, and it runs ok, but id rather be sure on the ign settings

[Pornstar]

You didn't put the stepped crank seal spacer on the wrong way? I did that on an RMX rebuild, smoked like crazy.

[matrox02]

You didn't put the stepped crank seal spacer on the wrong way? I did that on an RMX rebuild, smoked like crazy.

I dont think so, you are talking about the spacer that needs to be pressed on the web after the bearing is pressed on??

Item 17 in this??

http://www.partzilla.com/parts/search/Suzuki/Motorcycle/1990/RMX250T/CRANKSHAFT+%28MODEL+L-M-N%29/parts.html

[husaberg]

I dont think so, you are talking about the spacer that needs to be pressed on the web after the bearing is pressed on??

Item 17 in this??

http://www.partzilla.com/parts/search/Suzuki/Motorcycle/1990/RMX250T/CRANKSHAFT+%28MODEL+L-M-N%29/parts.html

For stuff ask here
http://dirtrider.net/forums3/threads/will-it-fit-rmx250-question.178844/

[matrox02]

Thanks, I signed up and asked, I was also on thumper talk but they seemed a bit useless..

[FJRider]

Thanks, I signed up and asked, I was also on thumper talk but they seemed a bit useless..

You are the one asking questions on THIS site ... calling THEM useless seems a bit stupid (almost funny). Take your bike to a motorcycle workshop an PAY to get YOUR issues sorted.

[husaberg]

Thanks, I signed up and asked, I was also on thumper talk but they seemed a bit useless..

One thing I will add is if it has a Keihin Pwk Carb it will highly likely be shagged.
Symptoms include heavy smoking mid range richness and bog. Heavy oil build up in pipe.
The keihin's don't have a replaceable needle jet like the mikunis do.
Why they can be compensated for with a thicker needle, it will take some fiddling if that is what it has.
The RMX is worth preserving with as they are a bike that will never be built again, they were a genuine close to mx bike put on the road by the factory.

[matrox02]

One thing I will add is if it has a Keihin Pwk Carb it will highly likely be shagged.
Symptoms include heavy smoking mid range richness and bog. Heavy oil build up in pipe.
The keihin's don't have a replaceable needle jet like the mikunis do.
Why they can be compensated for with a thicker needle, it will take some fiddling if that is what it has.
The RMX is worth preserving with as they are a bike that will never be built again, they were a genuine close to mx bike put on the road by the factory.

Yeah I have a mikuni, im running a 45 pilot and a 260 main as FMF recommends, since i have a Fatty pipe (damn am i lucky i could buy one new! )

[matrox02]

You are the one asking questions on THIS site ... calling THEM useless seems a bit stupid (almost funny). Take your bike to a motorcycle workshop an PAY to get YOUR issues sorted.

I seem to read that you are taking a bit of offense at me calling another forum altogether useless, im not calling anyone here useless, and id rather not take it else where the last time i had someone work on my RMX they went full retard on me and called my bike "an old piece of crap" So no thanks, Im fine on doing the work myself, I just like learning and asking about issues that im getting.

[FJRider]

I seem to read that you are taking a bit of offense at me calling another forum altogether useless, im not calling anyone here useless.

No offense taken by me ... but there will be a few members in this site ... that are members/frequenting that site too ...

[Jay GTI]

No offense taken by me ... but there will be a few members in this site ... that are members/frequenting that site too ...

Cool, well if they do take offense, hows about you let them sort it out themselves?

[matrox02]

Im almost ready to biff this thing off a cliff, got everything back together, went to kick start it, as usual with no foot peg on, only this time the kick start lever decided to go right through the clutch cover... I'm a bit calmer now.. but yet again, im waiting for another part to repair it...while I was there I noticed that my timing had moved from where i wanted it, so at leased i get to fix this while waiting for parts from S'traya

[gwynfryn]

Character building.

[matrox02]

Character building.

yeah.. about a years worth almost!