Please, I need pilot jet info.

[Eliseo Monteverde]

Hello folks,

My bike (Kat 650) has stock air box, home made exaust system, and stock jets.
Temperature here (South America), is falling down; and this winter I do not want problems starting in the cold any more. [-o<
Some weeks ago, it was discussed in another thread, something like going up one size on the pilot jets, well, stock pilot jet for my bike is #42.5.
The question is, which is the next pilot jet size? :roll:
In my Country is dificult to find jets, but a bike shop has offered me a # 40 pilot jet :? ,as I am interested in a bigger size than #42.5 this one,must be re-drilled with a precision drill, but has someone any idea wich drill diameter do I need in this case?

Thanks in advance and have a happy weekend.

Eliseo.

[SqDancerLynn1]

They come in steps of 2.5 40 42.5 45 so on. Drilling them is only asking for tuning problems

[KEITH KRAUSE]

With your only mod a home made pipe, it depends on how much freer flowing it is than stock.
I would first try adjusting your mixture screws out a little more. That's what they're for. Your pipe mod may still be within the mixture screws range.
Generally, with mixture screws on the CV carbs, you can adjust them out to about 4 full turns. If you don't get the results you like by then, THEN go up on the pilot jets.
Be sure your hard cold starts are not for some other reason. Carbs synched? Carbs clean? Air filter clean? Etc.

[tfb]

I reckon Keith's on the right track there; try the pilot mixture screws before you try upping the size of the pilot jets. Recently I tried putting richer pilot jets in my Kat1100 (from 47.5 to 50) and just that one small size increase went and gave me a rich flat-spot at around 2,500 rpm. So put the standard pilot jets back in, wound the pilot screws out to 2 1/4 turns, and all is well!

Mike.