JETTING... Once again(sorry guys)

[Tonyklem]

well im going to be jetting my bike probably this weekend. i was wondering if i wanted to get a larger or smaller jet. there is some spooge coming out the exhaust and my plug will foul every 30 minutes when im ripping around in my field.

what do you guys think. oh, and is it bad or ok if i sand blast my plugs when they foul? they seem to work fine after i blast them, but they just keep fouling. i have tried putting brand new plugs in and it doesnt seem to help much more than just blasting the others.

Thanks for the help guys

 

[TimberPig]

Jetting

 

[Tonyklem]

??? are you saying its the jetting? i kno its the jetting, im asking what you guys think, if i should go bigger or smaller jets. and is it ok to sand blas the plugs?

 

[ellandoh]

that is a link to some jetting tips, and if i was you , i would follow them , learn how to jet, and never worry about sandblasting spark plugs again . however if you insist then just make positive theres no sand in the crevices of the plug.

smaller jets, which one , cant tell ya without more info , possibly move needle or air screw also .

 

[Tonyklem]

well im not at home right now ill get the sizes of whats on there this weekend.

if it helps at all, it usually only fouls when I'm really reving up high. my friend was riding my bike around the yard for about 45 minutes and didnt have one problem. and now that i think of it i cant remember a time that it happened when i was just cruising(not pinning it)

 

[oldfrt613]

Uh.... what bike are you trying to jet....what temp and what elevation. In general, fouled plug + spooge = rich jetting ( or leaking transmission side crank seal ). To lean main and pilot jetting, get smaller jets. To lean mid carb setting raise clip ( lower needle ) or get a bigger needle. To lean very bottom of carb circuit, turn air screw out.

 

[ellandoh]

that is some more useful info , jetting is throttle position sensitive, not rpm sensitive. sounds to me like you need to move the needle down 1 clip position and try from there

 

[Tonyklem]

hey, i tore my carb apart today and cleaned it all. Theres a 172 Main jet and a 58 Pilot jet in there. the air screw is only turned out slightly over one half turn.
so, my bike has been fouling plugs, seemingly only when i keep on it for a while. which jet is for full throtle? also theres quite a bit of spooge coming out the exhaust. what do you guys think. im going to the dealer tomorrow and i am probably going to pick up a couple jets and some oil. Is maximium good oil? thats what ive been using. So since im going tomorrow if you guys can get me ideas by tomorrow before like 2-3pm that would be great.

Thanks in advance guys.

 

[TimberPig]

Go to my last post, click on the link I left you, and read the material found there on carb jetting. You'll find all the answers to your jetting questions, and how to solve them.

 

[ellandoh]

turn the air screw out to 1.5 turns out from full seat. then move the needle down 1 clip position, make sure your float is set and you most likely will be all set

 

[Tonyklem]

well iirc the needle is on the very top clip.

edit**
i was reading about adjusting the float. it said to make it parrallel to the carb's mating surface. does that mean to make the actual float level with the mating surface?

 

[ellandoh]

go through spankies jetting guide in this link

pay close attention to the part about diagnosing the pilot

 

[Micahdawg]

I would find out what the factory jetting is for the main and pilot + needle clip position. It'll be in your manual...otherwise you can call your local dealer and ask. The hop on fmf's website and go to their jetting guide. They will recommend jetting for a bike with filter + pipe/silencer. Their recommendations are usually a little leaner as most bikes come from the factory fat.

Then you can compare their specs to what you already found. That would be a good start.

Spanks has a good procedure for adjusting your air screw with the bike running which also gives insight into whether your pilot is too small or too large.

Throughout this process, you really should pick up a few brand new plugs too. They are only a few bucks each and it would be nice to know that it's not a plug issue.

Once you have everything set...do a plug chop and then inspect your plug to see how it looks. That will tell you if you need to adjust your main jet any further.

I wouldn't try doing any meaningful jetting without some brand new plugs, good gas that is mixxed at a KNOWN ratio, and also a basic inspection of the bike to make sure your vent lines are free and clear, filter is good and your crank seals, cylinder base and head gaskets + reed and carb boots are not leaking.

Micah