Carby tune help!

[Milkle]

My 2007 model Pitpro 140cc pit bike wasnt quite running right. When i snap open the throttle it seems to choke and will die if i keep it open. But it if i open the throttle gradually it will overcome that early hisitation and can then ring it out as i please. The adivce i was given suggested that all i needed to do with put the clip on the pin in the carby down one position to richen the mixture. i got as far as pulling the pin out and adjusting the clip down one slot and now cant/dont know how to re-place the pin with the cable correctly. Any help would be greatly appreciated.
Mick

 

[mattbombers]

yep, what setting was the e-clip (the one you ajusted on the pin) on? theres normaly 5 settings

now re-installing is easy

click the clip back on the pin, place the pin in the throttle slide then put the larger clip into the slide so it pushes the pin in and holds it in place. now put the carby cap onto the throttle cable and push the spring up onto that aswell (squeezing the spring down) and pull the cable through the spring. now slot the cable into the groove in the throttle slide and wallahh your done

 

[Milkle]

it was on setting 4, and iv adjusted it to setting 5, which i know isnt really a good thing right? should be in one of the middle 3. as for reinstallation, i cant get to the bigger clip as the cable is holding me back, was i meant to undo the cable to get the pin out?

 

[mattbombers]

yeah, i allways take the cable out to swap clip positions.

and yeah, i normaly run at in the middle or second from the top :/

you may need to ajust the air mixture screw, which is right under the carby (need to take the carby off to do so) ajust that by screwing it all the way in, then 2.5 turns out

 

[Milkle]

oook this i can do.. bit of a dummy question i know, but how does the cable unclip? is it easy enough to re position too?
im keen as to learn, but only had the bike a week so im accepting i have a lot to learn

 

[mattbombers]

wev all been there mate, and im for ever scabbing info off anyone i can to try learn more lol

takin the cable off is pretty easy, the way i do it is compressing the spring up and out of the slide, then pull the cable to the side and down. then it should be out... if i make any sense :/ and just reverse these actions to put it back in

 

[Milkle]

yeah it truely was that easy!! haha, i love this site!
so my next question is.. i put the clip on the very bottom setting (5th setting) and it improved things, but as iv learnt its ideal to run it on a middle setting.. so i now need to take the carby off and do something with the air or fuel mix? which one? and will i know which is which when i take the carby off?

 

[mattbombers]

you should have a mikuni '30mm' (actuly 26mm) if its still stock and there is one screw in the center on the bottom just screw it all in, then two and a half out then put the carby back on, you will probly need to fiddle with the e-clip positioning again

 

[Milkle]

haha i should realy try this stuff before i hastle you, coz i keep working it out as i go.. so yeah this is all making perfect sense, one thing tho.. the gasket from the carby to the exhasut is chipped at the top and has a dodgy oring.. maybe this is the source of my problem.. deffinately worth replacing before i continue do you think?

 

[ando]

Welcome Milkle to MiniRiders.

Check out Carby & Tuning - Mini Dirt Bikes & Pit Bikes Forum for all your carby tuning needs, i would refer you mainly to the stickied threads at the top of the page.
here's just two that you'll get heaps of great info out of http://www.miniriders.com.au/carby-tuning/25033-carb-jetting-tuning-dummies.html and http://www.miniriders.com.au/carby-tuning/20778-carburettor-tuning-guide.html

these are all under the Tech section on the homepage in the tutorials and how to section Mini Tutorials & How To's - Mini Dirt Bikes & Pit Bikes Forum

there is a wealth of information and heaps you can learn just from spending a few days, maybe weeks lol, learning the in's and out's of mini's.

have fun

 

[Milkle]

thanks mate! i did have a look through those pages, and just thought id ask a little bit more specific questions. But i really appreciate all the help. thanks peeps!

 

[ando]

yeah i just thought this answers the most recent one about the gasket for ya

"This guide will only cover problems associated with carburetion; any other problems cannot be fixed by adjusting the jetting but may appear as carburetion problems. So before you start make sure there are no air leaks where the carb attaches to the manifold – run the bike and spray the area with wd40 or any other aerosol, if the idle speed drops or increases then there is a leak and this must be fixed before any other changes are made. Also check that there is a good spark (fat and blue) by holding the spark plug by the HT lead against the head and kicking the engine over. A further test is to ensure there is compression by checking for resistance as the engine is kicked over. "

 

[Milkle]

so lads, i did all this, i replaced the damaged gasket, played with the pin settings in the carby and the air mixture, and the bike still seems to be low on torque and response low down, and still wants to die if i snap on the throttle from idle.. any suggestions as to what it may be and what may help would be great! thanks

 

[DHZ_XR8cing]

do a search on here mate on setting your valve clearances. Its always a good place to start.read allk the tutorials carefully and take your time while doing it.