Cheap air filters suck

[wordslinger]

I can only get you in the correct direction and the rest is in the ears of the tuner or an AF meter and dyno...


..ahhh...well said lankee....

[wordslinger]

Drilling and soldering was not my first choice. It works though

..the first time i tried that, i wound up dropping the jet into the burner tray and got solder all over the threads...

..i own four jets, two 4t and two 2t...and a "kit" that i put together for soldering and drilling...

..i have one jet running and one already soldered and drilled for the next anticipated relative temperature change...

[Peters]

Is the general rule of thumb smaller jets in the winter or do I have it backwards???

[wordslinger]

Is the general rule of thumb smaller jets in the winter or do I have it backwards???

..there are a cpl of different lines of thought here..

..i've found that yes, my scoot requires larger jets in colder weather...

..however, art, who resides in the portland or area, generally decreases main jet size during the winter season...

..the difference in the setups has everything to do with relative humidity...

..itsa lot "wetter" in portland than in NC...we suffer a semi-drought condition for 6-9 months every year...

[lankeeyankee]

Usually in the winter the use of a larger main jet will compensate for the higher air pressure in the winter time.
Yes, jetting will vary depending on altitude in relevance with  sea level, due to the air pressure is a little higher at sea level allowing the air molecules to be compressed. Thats why bikes tend to run more at a peak level. More compressed air allows more fuel which = bigger boom!!
Water moisture droplets increases combustion. Ever hear of methanol water injection kits. Which basically sprays a very fine mist usually at 2.5GPH in with the fuel and air to increase the combustion.
Another is cold air intakes. The colder the air the more fuel you can add to the equation.
Bottom line is you should increase the main jet in cooler air tempatures. this is IF your bike is already tuned properly.

[lankeeyankee]

I guess I really should take it to some of the bike shops around here and see if I can find some with the right thread size.
Thanks for the reply lankeeyankee, very helpful.

If you goto jetsrus.com and another member mentioned another great site that sells jets which I cant remember may post it again.
Forget the bike shop, those places were handy before the internet, most likely they will say "We can get them but we have to order them" I dont care to goto the Stealers unless there is no other option. I like ordering and coming home to a brown box on my porch over driving, parking and dealing with others at a bike shop.
IMO drilling a main jet isnt as precise as a machined fuel jet. Just how the jet is designed and tapered and designed to work with the needle. I am not saying it doesnt work and its been proven by others that use this method here. When it comes to these small carbs metering fuel and air through the jets is very precise and jets dont cost but a few bucks. Hmmm adding up all the jets I have around here... LOL yeah they do add up.

[ianmac]

Provoscooter.com is a great site for jets too.
Almost as good of a selection of Keihin jets as jetsrus and cheaper shipping to the US.