How to tell what part needs jetted?

[Rider-trx_250ex]

Alright It's been a while and I can't remember how to tell what part of the carb needs jetted. I know what throttle position controls what in the carb, main jet-3/4 to full throttle, needle-1/8 to 3/4 throttle, and pilot jet-idle to 1/8 throttle, but what will the quad do to tell you that that certain part needs jetted?

where the throttle is at when you do the chop and the reading of the plug...for istance...if you chop power at half throttle and the plug reads lean, then theat circuit is lean...etc...

[blindsey]

the problem I am having with mine right now is that from about 1/2 to full it is back firing real bad and will not allow me to carry my quad up a steep hill. I pulled the plug and it is white, so obviously it is running lean, but I dont know where to start to fix the problem? Can anyone give me some place to start? Thanks

[Honda#4]

Up the main jet it's too lean. What do you have for mods?

[Rider-trx_250ex]

Originally posted by speedyquad
where the throttle is at when you do the chop and the reading of the plug...for istance...if you chop power at half throttle and the plug reads lean, then theat circuit is lean...etc...

The only thing mine is doing is backfiring when I let off the throttle, so what would that be?

[blindsey]

the only thing I have is a full alba exhaust. Its kinda of weird how this came about. I didnt have my hot start hooked and took to the guy that always works on it and he took my carb apart and cleaned it and hooked the hot start up and now for some reason it runs like ****. Before he did that it ran like champ, except for trying to kick start it once it got really hot. So now my problem is that it back fires real bad from 1/2 to full and the only thing I know to do is put a bigger main in, but what I dont understand is how this happened by him doing what he did???

[joshyz125]

A back fire when you come off the throttle is a lean idle circuit.
You need to go up a size or 2 on the Pilot Jet.

[400exrider707]

Originally posted by joshyz125
A back fire when you come off the throttle is a lean idle circuit.
You need to go up a size or 2 on the Pilot Jet.

I wouldn't even touch the pilot right now, try adjusting the air screw first. If you cant get it to work with the air screw, then you change the pilot jet.

[joshyz125]

The screw is a fine adjustment, if it's lean enough for it to pop, i would go up one jet size, but that's what i would do,