2002 Carb question

[eddyp]

Hello first post so be gentle with me.

I have a 2002 315r ,looking in the manual for the carb settings I see that there are 2 listed.

1) Needle 3 notches from top, 110 main jet and air/mixture screw 1 turn out

2) Needle 3 notches from top, 108 main jet and air/mixture screw 3-4 turns out

I have the 110 main, but most of the posts Ive read say set the screw at 3-4 turns out, mine was set at 1 3/4 turns out- when I put it to 3 out the bike smokes for England. Ive now set it to 1 turn out.

Anyone know what the correct setting is?

Thanks in advance

[woody937]

I May be wrong but i think the carbs changed around 2001, yours would have the later one where the mixture screw controls the air rather than the earlier one which controls fuel. Those are the two different settings for the different carbs, 1 turn out as a starting point is what you should be looking at.

[wherry]

I May be wrong but i think the carbs changed around 2001, yours would have the later one where the mixture screw controls the air rather than the earlier one which controls fuel. Those are the two different settings for the different carbs, 1 turn out as a starting point is what you should be looking at.

As someone else said recently. 'Ya gotta love internet forums'. The above is completely ar$e about face. The mixture / slow running screw on the earlier PHBH carb controls AIR and on the later PHBL controls FUEL.

Your carb should be the PHBL, with that slow running screw the engine side of the carb. The number of turns in or out of that screw is dependent on what jets you've got in the carb. If you've got a richer than standard pilot jet then that screw will be further in than 'standard settings'. Adjust it till the bike runs nicely, which is what you've done by the sound of it.

[woody937]

Hi, I did say i might be wrong! I was just going by this entry in the 2002 workshop manual:-

Slow Jet And Air Screw

The air screw meters air that is mixed with fuel metered by

the slow jet. .

Turning the air screw clockwise, enriches the mixture:

counterclockwise leans the mixture.

Turn the air screw in until it lightly seats, then back it out to

specified position.

Air screw opening: 1 turn out

I'm Confused!

[wherry]

I'm Confused!

Don't be!

The manual trys to be all things to all people and fails sometimes.

PHBH - Slow running / mixture screw is on airbox side of carb. With carb in bike it's at the rear of the carb. This adjusts AIR so out is weaker, in is richer.

PHBL - Slow running / mixture screw is on engine side of carb. With carb in bike it's at the front of the carb. This adjusts FUEL so out is richer, in is weaker.

Don't forget also that the settings in the manual are only for how the standard bike is manufactured. With different jetting, atmospheric conditions, ethanol rich petrol etc etc the actual settings required to make the thing run right may need to be different

[bikepilot]

The manual is wrong. My '01 Montesa manual shows my bike as having the old style carb (and secondary air filter for the carb). Seems they forgot to update that bit.

For what its worth my bike came to me setup for 10% ethonal fuel. Over the weekend I lucked out and found normal fuel. It took a full turn in on the fuel screw for it not to load up, but then ran really well. So fuel type does seem to make a big difference on mixture requirements.