Jetting advice - VM29ss on a FXR150?

[Damien_Toman]

I also had spitting back but I don't notice it now with the airbox on .

[Henk]

Is that because it's not doing it or because you can't see it through the airbox?

[richban]

after talking with a few people the posiblity of having to much air, so I covered up half the intake and it seemed to improve things a little..

29mm is not to big. If anything you will get better top end and a little less bottom end performance. I would say there is no such thing as to much air just the wrong air fuel mix. Lean or Rich. Have a read of this. Its 2 stroke but the principles are all the same. http://justkdx.dirtrider.net/printcarbtuning.html

[Ray LeCheminant]

Havent pulled the plug (probally should though and see how it looks)

Valves should be all good the engine has just gone back togeather with all the clearances done.

I have been using the choke, helps to bring it above the bogging point before reving through to full throttle.

I am by no means the most experienced , but from a previous life in TQ racing, we ran the same carbs (4) on a GSXR750
Excess fuel could be created by emulsion tube firing backwards, does it run better when you choke it with your hand over the inlet?

We would by rotating the emulsion tubes 90, then 180 degrees we could improve it.....

...but as I said not that much of an expert , and not REALLY sure your carb has the same style emulsion tube setup!

Ray

[Pumba]

Thanks Ray (just got your message to by the way). Yes it is the same carb and I suspect in a previous life that these carbs may have been on a TQ or purchased as spares.

I will have a look at the emulsion tubes, its not somthing I had considered and I have had the carb right apart so it wouldnt surprise me if I put the dam thing in backwards.

[Pumba]

Right to some progress tonight. I have concluded that the poilet jet is getting to much air, so I will need to go richer there. That will solve the hesitation problem at the the bottom.

The real issuew that I am still concerned about is the amount of fuel that is comming back out the carb mouth. Maybe I should just use damians theory and put the filter back on so I cant see it any more

[koba]

Right to some progress tonight. I have concluded that the poilet jet is getting to much air, so I will need to go richer there. That will solve the hesitation problem at the the bottom.

The real issuew that I am still concerned about is the amount of fuel that is comming back out the carb mouth. Maybe I should just use damians theory and put the filter back on so I cant see it any more

I know old Volkswagens run like shit unless you have a trumpet to contain the fuel fog that hangs out there. Maybe try an open bellmouth...

[Damien_Toman]

Is that because it's not doing it or because you can't see it through the airbox?

Mine didn't spit back much and I changed the jets so many times that I'm not sure if it happens much now with my current settings and the airbox on. Certainly the airbox is not dribbling fuel but I should check it out just after a ride to see if it is wet.

[Pumba]

Well I am a happy camper. Had a think about it all day at work, come home, covered up the pilot air jet with a bit of tape, threw on the factory velocity stacks that went into the air box that were sitting in the shed and away she went.

Stoked, just need to track test it now. Bit of a shame I cant get out there for testing on Saturday (free V8 tickets, with pit passes cant really be passed up), so will have to give it a go Sunday morning.

[Rick 52]

Good stuff see you Sunday

[timg]

Bit of a shame I cant get out there for testing on Saturday (free V8 tickets, with pit passes cant really be passed up), so will have to give it a go Sunday morning.

Not a problem - I'll take care of those V8 tickets for you Good to see u got it sorted.

[Dutchee]

Stoked, just need to track test it now. Bit of a shame I cant get out there for testing on Saturday (free V8 tickets, with pit passes cant really be passed up), so will have to give it a go Sunday morning.

So, there must be alcohol involved too, to make it worthwhile being bored watching things with 4 wheels go round/over streets? I'd be taking Rick up on the offer of looking after the tickets for me if I were you (but I ain't, so you have fun and try not to get too bored - take a book).

[Pumba]

Well the conclusion is that the carb has potential. But I really need to sort out the pilot circuit by the more conventinal means because just puting some tape over it only lasted a half doesn laps or so.

Or I just need sticker tape. Not sure what the answer is yet

[Henk]

Half a dozen laps is just fine.