carby dramas at angle, yx150

[1fifty1wheel]

away at work at the moment but for memory the 150 has a molko carb, so called 30mm. love hill climbs and love the back wheel but with this carb after a few minutes on decnt angles it seems to severely bog down then stall.

question is which carb to go for that wont have this problem or not so badly.
have heard these are notorious for this.
have searched a fair bit but found nothing in relevance to carb damas at angles.

when changing the carb will probably give the head a bit of a port job, and play with a few other things

cheers in advance for your help.

 

[MasterSpoon]

hmm kind of a weird issue, not really sure of the answer sorry but have you checked your intake setup ? like is there a lip where the carbie joins the manifold? i'm thinking your issue might be along the lines of say a 30mm outlet from the carbie hitting a 26mm manifold, so a 2mm edge / ledge, when your on a angle (hill climbs i'm guessing?) its trying to pull the fuel over that edge but some of the fuel is not making it and starts to create a little pool of fuel behind the edge, then it starts pulling the extra fuel that has pooled up in and richens the hell outta the mixture.

Might not be the issue but worth a look i suppose

 

[ducar.r.spec]

KTM's are notorious for it up jumps especially the 250sx's and 300 exc's
most people just swap carbies

 

[I_THUMP]

KTM's are notorious for it up jumps especially the 250sx's and 300 exc's
most people just swap carbies

My Ktm never has this problem and I could stay on the back wheel all day, but its a 400. Ive never heard of this happening before though

 

[Sidney]

you need a port and polish so the intake lines up with the head.

 

[ducar.r.spec]

you need a port and polish so the intake lines up with the head.

do u even know what ur talking about???

 

[Sidney]

isnt a port and polish where they grind down the intake so it matches up with the manifold? or am i thinking of the valves?

 

[themountain]

you better shut up on technical issues, Sidney!!

 

[1fifty1wheel]

cheers for the input guys,
Yammy R6's also suffer from the same problem, thats why there is more stunt riders using gsxr's (not that i stunt the mini)
feels more like lack of fuel than too much once built up. will have to just try another carby and see how it goes.

 

[MITTZ]

isnt a port and polish where they grind down the intake so it matches up with the manifold? or am i thinking of the valves?

thats mach porting

 

[Sidney]

ah yeah thats it cheers mittz

 

[foolsp33d]

off the mini bikes but on the topic of carbs, the zuki suffers this when u swap the original carb to a webber or a 4k corrola, we normally extend a piece of piping going into the fuel bowl that changes the float level, or the pick up, im not to sure, as im going off the top of my head here, but it sounds like a similar problem.. it starves the carb of fuel on certain angles, but at othertimes, it wont.. might be a totally different kind of problem but it might be very similar.. just an opinion.. and a thought let us know how you go in fixing it as im sure another member will have the same problem, if not now but in the future.

 

[1fifty1wheel]

will keep ya informed.

true about the webbers, we race 4x4's tried webbers for while on an old and lux, they need alot of work to be any good at angles or bouncing

 

[ducar.r.spec]

if u have the cash id switch to an o.k.o 28mm or 30mm will solve ur problems and give u performance

 

[1fifty1wheel]

the 28mm oko is what i'll try first if i can't find a genuine keihin

 

[ducar.r.spec]

ur gonna pay out the ass for the keihin id buy the oko to start off with that way ur sure it will work

 

[coolmodee01]

my vert used to do this
i found a big dose of fuel over the motor at the top of the hill but mainly when the revs go to low
and it stalls out
so when i rip up the hilz now i just richen it up a lil seems to through the fuel into the bowl a lil quicker
and it doesn't run out when the fuel starts flowing out the back

i've also seen shorter angled manifolds that help keep ya carby more level when your on the back wheel

hope i helps

 

[1fifty1wheel]

short coarse (mx style events) mud drags and the odd hill climb.

never been on outers, heard a rumour of it possibly being hacked

 

[1fifty1wheel]

my vert used to do this
i found a big dose of fuel over the motor at the top of the hill but mainly when the revs go to low
and it stalls out
so when i rip up the hilz now i just richen it up a lil seems to through the fuel into the bowl a lil quicker
and it doesn't run out when the fuel starts flowing out the back

i've also seen shorter angled manifolds that help keep ya carby more level when your on the back wheel

hope i helps

cheers, thats the problem, although high revs, low revs, mid revs, it oes it at all of em. and like you said with fuel going everywhere.
not to keen on a short angled manifold or richening it up either though.

 

[ducar.r.spec]

just go the new carb dude
those molkt/molket/molko carbs are shit as to tune to weather so i heard