What is correct gap.

[epod]

G'day all.

Tuning the 138 up here at 1000 above see level has been a challange believe me. The carbie has a 97.5 main jet, with needle lowered all the way clip in top position it seems to run ok but still intermittently rich rich near full throttle to full throttle. With 95 main jet needle wants to be fully raised clip bottom and motor is slightly lean I think. Has anybody ever seen a 96 main jet. Could my spark plug gap also be affecting reving. I just read that I high compession motors want small gaps and you just have to experiment to find the perfect gap. What gap are you guys running in NGK plugs?
Ride on, epod.

 

[Dreadful]

Come on guys , we are starting a moto club down here and will be building a killer mini track .

Here is bushy on the piece of land we are after

http://i28.photobucket.com/albums/c248/punkfiction/DSC00728.jpg


So if you are coming down you will need to jet yours too , I have'nt had much experience with the 138 But yeah jetting up here has always been a bit of a mission .

 

[johnnie5]

you have a couple of choices,

i find that each of the jet steps is usually pretty good , but if you believe you want that 96 then get yourself some jet drills

i think you will find its more to do with a needle problem though

float height is also important

heres some info that may help

this is for CV carbs so is different but a lot of the theory is the same

http://www.factorypro.com/tech/carbtun.html

heres somemore reading
http://www.gareth.evans9.btinternet.co.uk/articles/carbtuning.htm

end of the day you might be better buying a decent carb

 

[Dreadful]

cheers mate.

 

[epod]

Problem solved

Horay, the ****** is finally flying. Thanks guys, turns out the 30ml carbie was ******. I pulled the 97.5 main jet out of it and put in 25ml japanese mikuni and now she rev's till the cows come home. Anybody with a pit pro or DHZ 138 I suggest you throw away the 30 chinese mikuni as there are complete rubish. The difference the 25ml carb has made is unbelievable. The thing does 100km+ for sure and rev's hard as.