N00B!!!!

[bi0phreak420]

yeah it is a 27mm carb!!!

[Weldangrind]

Upgrade time!

[bi0phreak420]

so where would be the best place to get 30mm jets ....And do i need to ask for anything specific

[TurboT]

Originally Posted by bi0phreak420

so where would be the best place to get 30mm jets ....And do i need to ask for anything specific

You don't need jets yet. You just need to buy a carb first. You can search ebay for a mikuni 30mm carb or you can get one from Giobikes.com on their auction, if you wanted to buy in Canada. I know there's some members here in the US who have bought them from vendors down there, hopefully they will chime in.

Once you have the carb and start doing exhaust work, then you might need standard Mikuni jets larger than what is installed in your new carb.. and that's when you talk nicely to forum member WayneV or do some searching for the carb threads here for the part numbers.

Doubt you'll need the jets until you decide on an exhaust though.

[bi0phreak420]

well there is other people on here that are telling me just to change the jets...That i dont have to buy whole new carb...

[waynev]

Originally Posted by bi0phreak420

well there is other people on here that are telling me just to change the jets...That i dont have to buy whole new carb...

Well first you have to see if you need new jets on your carb, does it idle fine and come off of idle with no hesitation?, if not adjust your air/fuel screw, if your more than 2 turns out them you need a bigger pilot jet, midrange can be cured by adusting the c-clip on the jet needle, move the clip down for richer and up for leaner, full throttle is controlled by the main jet, is it breaking up or backfiring when wide open, if so you probably need a bigger main jet. Not sure if you have done this yet, but if it has a china brand spark plug replace it with a new NGK spark plug and remember the plug will tell you what your engine is doing, you are looking for a nice light brown to tan color, if your white your too lean, if it's black your too rich.

[MICRider]

Originally Posted by bi0phreak420

so where would be the best place to get 30mm jets ....And do i need to ask for anything specific

The upgrade is to a 30mm carb, not a 30mm jet. GIO uses a Mikuni (knock off?) on their 250cc dirt bikes and sells it as a performance carb for the Beast ATV. Here is a link to one on auction... Link might go wonky after the auction expires though?
http://www.giobikes.com/Auction/1554...buretor-250cc/

As Wayne said though, your stock carb might just need tweaking to get it running right. My Beast wouldn't run right with the stock carb, so I upgraded to the 30mm Mikuni. I believe jets (if you need them) are much easier to find for the Mikuni vs whatever our stockers were.

[Weldangrind]

I agree with all of the above posts (lots of smart folks around here). I wouldn't hesistate in buying a 30mm Mikuni for your 250; like MICRider says, replacement jets are easy to find for the Mikuni.

[katoranger]

You can rejet your current carb. It would help, but if you want to upgrade going to the 30mm mikuni is the way to go. Better to start off with the carb you want and get it jetted right.

I would start with the exhaust though. Find one that you think will fit and then get a carb to match. You will most likely need to play with the jets to get it optimum.

[bi0phreak420]

Ok now i noticed something that i don't think is right..I took my exhaust off to do some tinkerin and i noticed that its a bit smaller than the opening on the exhaust is there suppose to be some kind of gasket in there it seems like im getting a leak where they go together

[bi0phreak420]

Sorry for all the questions but can anyone tell me how to adjust the fuel air mixture

[waynev]

Originally Posted by bi0phreak420

Sorry for all the questions but can anyone tell me how to adjust the fuel air mixture

This will help you in understanding the tuning of the mikuni type carb http://www.iwt.com.au/mikunicarb.htm

This is taken from that link and answers your question above

The pilot circuit can be adjusted while the bike is idling and then test run. If the engine is running poorly just off of idle, the pilot jet screw can be turned in or out to change the air-fuel mixture. If the screw is in the back of the carburetor, screwing it out will lean the mixture while screwing it in will richen it. If the adjustment screw is in the front of the carburetor, it will be the opposite. If turning the screw between one and two and a half doesn't have any affect, the pilot jet will have to be replaced with either a larger or smaller one. While adjusting the pilot screw, turn it 1/4 turn at a time and test run the bike between adjustments. Adjust the pilot circuit until the motorcycle runs cleanly off of idle with no hesitations or bogs.

[katoranger]

Originally Posted by bi0phreak420

Ok now i noticed something that i don't think is right..I took my exhaust off to do some tinkerin and i noticed that its a bit smaller than the opening on the exhaust is there suppose to be some kind of gasket in there it seems like im getting a leak where they go together

At the cylinder head or where the two pieces join in the middle?

At the head is uses a copper gasket. Really designed as a one time use. Ask for a honda xr200 1987 one at a dealer. Should only be a few dollars.

The joint in middle alot of times had a gasket like wrap material. Not really sure what to call it.

[Cal25]

I used hi temp RTV sealant at the middle joint. Has worked very well.

Like was said, replace the little gasket at the exhaust port if you remove the head pipe. Also if the headpipe is off, try to clean up the weld on the inside of the pipe for better flow. They are usually pretty sloppy.

[bi0phreak420]

http://www.youtube.com/user/geo8778?feature=mhum#p/u