Spooging 2 stroke. Mechanic?

[matrox02]

Hi All, Been fluffing about with my 1990 RMX250 for a little bit now and im growing tired and getting a bald spot from all my head scratching, Problem is, when hot, My rmx runs next to mint, when been sitting for a day + it doesnt want to start all too easy unless on a new/cleaned plug, and when i get it started it spooges something chronic, I know its got to do with jetting and float height and how hard you ride it vs oil mix setup ( running 42:1 ) , but im tired of fiddeling , i just want to have the issue fixed so i can just mix and go ( so to speak ), So, Who can point me to a decent 2 stroke guy in the Auckland Area?? I have friends that have had 2 strokes buy they even say its hard to get a decent 2 stroke mechanic these days

[awayatc]

Next time you got it running, before parking it up turn off fuel and wait till bike stops...
See if that makes starting easier next time....

otherwise carb adjustments not that hard to do...
All you need is google and a bit of spare time

( taking carb of and giving it a good clean would be a good start....)

[nzspokes]

Next time you got it running, before parking it up turn off fuel and wait till bike stops...
See if that makes starting easier next time....

otherwise carb adjustments not that hard to do...
All you need is google and a bit of spare time

( taking carb of and giving it a good clean would be a good start....)

Yes was thinking the same.

[scott411]

what sort of oil are you running? 42:1 is an unsual mixture ratio but within ball park, how many ml to 10 litres are you using?

how long does it sit between uses? unleaded fuel goes off pretty quick in carb's, if it has been any longer than a week, put the bike on its side before starting it to get the fuel out of the carb,

[matrox02]

Oh bugger, I was at the beach today with the bike and I wished a read this thread today, I would have been keen on trying to run the fuel off to see if it kept the plug from being too oily to spark proper every time I needed it to start, I'll try that next time, otherwise I'm using castrol power1 tts I think its called, otherwise if I run it and then then ride then stop it starts OK, leave for 15 + minutes its a bit harder to start, half hour + id have to pull the plug clean it then try, I'm wandering if maybe using a hotter plug may help, I usually run a b8ev but can only get b7ev at the moment unless I order them in, will it help or harm?

[matrox02]

what sort of oil are you running? 42:1 is an unsual mixture ratio but within ball park, how many ml to 10 litres are you using?

how long does it sit between uses? unleaded fuel goes off pretty quick in carb's, if it has been any longer than a week, put the bike on its side before starting it to get the fuel out of the carb,
I'm using 235ish ml to 10 liters, castrol power 1 tts I think its called, but I think I'll move to motul or repsol since my local stocks it

[scott411]

ok, all good on that front, if its only 15 minutes before its hard to start its not the fuel going off, try turning the fuel tap off, it might be leaking though the float valve, it would be a good way to check something off,

[husaberg]

Hi All, Been fluffing about with my 1990 RMX250 for a little bit now and im growing tired and getting a bald spot from all my head scratching, Problem is, when hot, My rmx runs next to mint, when been sitting for a day + it doesnt want to start all too easy unless on a new/cleaned plug, and when i get it started it spooges something chronic, I know its got to do with jetting and float height and how hard you ride it vs oil mix setup ( running 42:1 ) , but im tired of fiddeling , i just want to have the issue fixed so i can just mix and go ( so to speak ), So, Who can point me to a decent 2 stroke guy in the Auckland Area?? I have friends that have had 2 strokes buy they even say its hard to get a decent 2 stroke mechanic these days

If its in general running about and it isn't incorrect float or weeping float needle set up its running rich on the needle either the needle and the needle jet will be worn drop the needle by positioning it in a higher clip it will run better if it is a keihin ya f-ed without a thicker needle, you will have to find one to suit.
likely out of a similar but 125cc Keihin equipped engine.

One other point is the slow running on some Keihin is partly controlled by the choke,you twist the knob around it raises and lowers as they pw's have a different setup make sure this is correct refer to manual and keihin info of the net

If it is a Mikuni ya fine replace both with factory parts either way they are not expensive.

[matrox02]

If its in general running about and it isn't incorrect float or weeping float needle set up its running rich on the needle either the needle and the needle jet will be worn drop the needle by positioning it in a higher clip it will run better if it is a keihin ya f-ed without a thicker needle, you will have to find one to suit.
likely out of a similar but 125cc Keihin equipped engine.

One other point is the slow running on some Keihin is partly controlled by the choke,you twist the knob around it raises and lowers as they pw's have a different setup make sure this is correct refer to manual and keihin info of the net

If it is a Mikuni ya fine replace both with factory parts either way they are not expensive. I'm glad its a mikuni then, I'm running the recommended 260 main and 45 pilot according to the FMF site for my FMF expansion chamber, and dropped the needle to leaner as it was smokey as all hell before and took ages to clear up, it runs better like this too, I think im running stock needle according to the part number, but haven't touched it , so I think I'll replace that next, the carbs float valve appears to be good as its not flooding and purging when sitting but I'll try starting with the tap off in case its doing something it shouldn't

[husaberg]

I'm glad its a mikuni then, I'm running the recommended 260 main and 45 pilot according to the FMF site for my FMF expansion chamber, and dropped the needle to leaner as it was smokey as all hell before and took ages to clear up, it runs better like this too, I think im running stock needle according to the part number, but haven't touched it , so I think I'll replace that next, the carbs float valve appears to be good as its not flooding and purging when sitting but I'll try starting with the tap off in case its doing something it shouldn't

Yes but replace needle and needle jet at the same time, as they both wear together. Don't worry, re he main or the pilot it is not a factor in the splooge.
If you're mentioning hard staring when hot rather than cold that also points to rich running. So is the needle now set to fully lean?

[Ocean1]

I'm glad its a mikuni then,

That Mikuni has a delicate float assembly, they have a reputation for sticking when worn a bit. Check the float where the valve touches, and you should be checking the valve tip and seat on any carb with those symptoms anyway.

Edit: this the beastie? 307654

[matrox02]

Yes but replace needle and needle jet at the same time, as they both wear together. Don't worry, re he main or the pilot it is not a factor in the splooge.
If you're mentioning hard staring when hot rather than cold that also points to rich running. So is the needle now set to fully lean?
No, just 1 leaner, I can go one more if I need to, I'll look into getting both, not that I remember that the needle jet can come out...

[matrox02]

That Mikuni has a delicate float assembly, they have a reputation for sticking when worn a bit. Check the float where the valve touches, and you should be checking the valve tip and seat on any carb with those symptoms anyway.

Edit: this the beastie? 307654

Yeah delicate is definitely the word for it, such a prick to set even with the right tools, and yep that looks to be the beasty

[husaberg]

No, just 1 leaner, I can go one more if I need to, I'll look into getting both, not that I remember that the needle jet can come out...

Well go full rich and see what happens then go full lean.........indulge me, it only takes a few minutes, then order the needle and needle jet.......:msn-wink:

[gwynfryn]

From memory the rmx's that had the mikuni with the combined choke/idle circuit were terrible to set up even when new.
Swapping for a pwk was common and thats what I would do now. Even better go for a lectern carb and forget about jetting again!

[matrox02]

From memory the rmx's that had the mikuni with the combined choke/idle circuit were terrible to set up even when new.
Swapping for a pwk was common and thats what I would do now. Even better go for a lectern carb and forget about jetting again!

I'm taking you are talking about a lectron jetless carb?, looks like a 36-38 should fit and maybe I will go for that... But I'll do some more fluffing around first

[F5 Dave]

So what does it run like on just opened throttle? Clean or a bit blubbery at first? Try next pilot down, it could just be rich at closed to just opened throttle which the needle won't fix. Idle mixscrew will be richer as turned in.
Rich jetting will produce spooge, not the oil so much.

That said do check the needle valve with a bright torch. Any ovality will mean globuals of wet fuel. Any.


Us jetting specs won't be the shizlle on our fuel.

[matrox02]

So what does it run like on just opened throttle? Clean or a bit blubbery at first? Try next pilot down, it could just be rich at closed to just opened throttle which the needle won't fix. Idle mixscrew will be richer as turned in.
Rich jetting will produce spooge, not the oil so much.

That said do check the needle valve with a bright torch. Any ovality will mean globuals of wet fuel. Any.


Us jetting specs won't be the shizlle on our fuel.
Its a bit blubbery at first actually, you need to give it a few revs to help it out before trying to move off, once moving it really moves well, I'll see if adjusting the mixture screw helps a bit first, I set it and really haven't touched it as I'm scared of seizing it but at this point I don't think it will with all the oil it has

[gwynfryn]

I'm taking you are talking about a lectron jetless carb?, looks like a 36-38 should fit and maybe I will go for that... But I'll do some more fluffing around first

Contact these guys if your serious http://www.motosportz.com/lectron.html they will be able to advise on fitment .
Pwk will be cheaper though.

[scott411]

Its a bit blubbery at first actually, you need to give it a few revs to help it out before trying to move off, once moving it really moves well, I'll see if adjusting the mixture screw helps a bit first, I set it and really haven't touched it as I'm scared of seizing it but at this point I don't think it will with all the oil it has

sounds like the pilot jet is too rich with that discription, not much chance of seizing the bike by altering the pilot jet, try 1 size down, the mixture screw only really does the very bottom of the throttle range,

FMF jetting specs are ball park, but we have different fuel and atmosphere conditions down here,

[matrox02]

sounds like the pilot jet is too rich with that discription, not much chance of seizing the bike by altering the pilot jet, try 1 size down, the mixture screw only really does the very bottom of the throttle range,

FMF jetting specs are ball park, but we have different fuel and atmosphere conditions down here,

Will the Pilot also effect the idle setting as i noticed that i have to have the idle screw almost all the way in for it to idle?? I suppose because its flooding it?

[F5 Dave]

Totally, you are describing rich pilot, an affliction every dirt bike I've owned has had until fettled. There are reasons they set them up like this from new. But a bad compromise for most.

Previously I've jetted that cct by going down in pilot until you can blip it from idle and have it falter when you blip it from low revs closed throttle. You wind the screw in until it no longer falters. You now have it perfect for this but too lean for under load (riding) so it needs to be a bit richer, but at least you know what is too lean. More applicable for trials bikes.

But I'd just go down one size pilot and twiddle the screw till it runs best.
Remember jetting a slide carb you are concentrated on throttle position not revs. Write this down and stick it to the tank. If you start using expressions like `down low` - slap youself. CV carbs are different.

But do check the needle and jet it runs in for ovality. Vibey bigger bore bikes wear carb parts after a decade.

[scott411]

Totally, you are describing rich pilot, an affliction every dirt bike I've owned has had until fettled. There are reasons they set them up like this from new. But a bad compromise for most.

Previously I've jetted that cct by going down in pilot until you can blip it from idle and have it falter when you blip it from low revs closed throttle. You wind the screw in until it no longer falters. You now have it perfect for this but too lean for under load (riding) so it needs to be a bit richer, but at least you know what is too lean. More applicable for trials bikes.

But I'd just go down one size pilot and twiddle the screw till it runs best.
Remember jetting a slide carb you are concentrated on throttle position not revs. Write this down and stick it to the tank. If you start using expressions like `down low` - slap youself. CV carbs are different.

But do check the needle and jet it runs in for ovality. Vibey bigger bore bikes wear carb parts after a decade.

very good advice here, i have seen alot of people over the years try to jet down kids or ladies bikes to try adn stop them fouling plugs, they always go main jet first, but the kids dont usually open the throttle to above half anyway, most fouling plugs is because of to rich idle and pilot circuits, you can get the pictures off google that shows what each jet does,

[matrox02]

Totally, you are describing rich pilot, an affliction every dirt bike I've owned has had until fettled. There are reasons they set them up like this from new. But a bad compromise for most.

Previously I've jetted that cct by going down in pilot until you can blip it from idle and have it falter when you blip it from low revs closed throttle. You wind the screw in until it no longer falters. You now have it perfect for this but too lean for under load (riding) so it needs to be a bit richer, but at least you know what is too lean. More applicable for trials bikes.

But I'd just go down one size pilot and twiddle the screw till it runs best.
Remember jetting a slide carb you are concentrated on throttle position not revs. Write this down and stick it to the tank. If you start using expressions like `down low` - slap youself. CV carbs are different.

But do check the needle and jet it runs in for ovality. Vibey bigger bore bikes wear carb parts after a decade. pH, thank you for that I'll ring Coleman suzuki see if they have and get one
Maybe I won't get a lectron just yet, but I have enquired through an ausy bloke who is a listed distributor

[F5 Dave]

Thanks Scott. Whites or erm can't remember the other will be able to get the jets just deal with your local if they are any good. Cheap to source. Kiehin slides are another matter.

[scott411]

Thanks Scott. Whites or erm can't remember the other will be able to get the jets just deal with your local if they are any good. Cheap to source. Kiehin slides are another matter.

northerns will have genuine mikuni ones, and R2 do them as well, any bike shop should be able to get them for you,

MR Motorcylces in Puke used to stock them, but unsure if they still keep the jet boxes full,

[matrox02]

So I ordered and Picked up the 42.5 jet ( the next leanest from 45 ) and when picking it up the guy at the counter kept going "thats really lean, are you sure nothing else is wrong??" which has me a bit worried, Havnt installed it yet, still yet to pull the carb apart and check that the fuel bowl valve is fine and not out of round but will do soon

[F5 Dave]

So in mikuni 50 is the biggest available. If 45 is std then its one step to 42.5.

[scott411]

So I ordered and Picked up the 42.5 jet ( the next leanest from 45 ) and when picking it up the guy at the counter kept going "thats really lean, are you sure nothing else is wrong??" which has me a bit worried, Havnt installed it yet, still yet to pull the carb apart and check that the fuel bowl valve is fine and not out of round but will do soon

I dont think its that lean, we used to run down to 32.5 ' s in some bikes with Mikuni carbs,

[matrox02]

Just an update installed the new 42.5 pilot, and checked the float valve, the needle is mint and so is the hole the gas passes through, put everything back together but haven't fired it yet, was way too tired to bother kicking her over haha, will update once I have though

[nzpoontang]

From memory the rmx's that had the mikuni with the combined choke/idle circuit were terrible to set up even when new.
Swapping for a pwk was common and thats what I would do now. Even better go for a lectern carb and forget about jetting again!

Where is best place to buy a PWK carb? wanting one for my 98 rmx250. I find no matter what I do with jetting etc I can either get it to run really well but not idle, or idle well and not run 100%

[husaberg]

Where is best place to buy a PWK carb? wanting one for my 98 rmx250. I find no matter what I do with jetting etc I can either get it to run really well but not idle, or idle well and not run 100%

Sudco will sort you out with any sort you desire jetted to proper specs http://www.sudco.com/Carburetor01.html

Or try a oko copy if you want to fiddle heaps more(which I am guessing you don't).... but I think they only go to 36mm.
http://www.akunar.com/CARBURETTORS.html

[nzpoontang]

Sudco will sort you out with any sort you desire jetted to proper specs http://www.sudco.com/Carburetor01.html

Or try a oko copy if you want to fiddle heaps more(which I am guessing you don't).... but I think they only go to 36mm.
http://www.akunar.com/CARBURETTORS.html

Sweet as cheers for that. So no NZ companies to use?

[husaberg]

Sweet as cheers for that. So no NZ companies to use?

No idea who is the importer in NZ I guess I could google it for you:bleh:
I had a guess at mikuni this is the distributer I guess for sudco for both keihin and mikuni
http://www.northern.co.nz/products/367-mikuni_carbs.aspx
http://www.northern.co.nz/brands/43-keihin.aspx

[F5 Dave]

My experience of oko carbs (trying to fix them on mates bikes) is don't. Esp on a dirt bike that gets knocked around.