ATV Fuel and Exhaust Technical = How To Adjust A Carb = Off-Road.com - - ATV at Off-Road.com
ATV & UTV »
ATV Fuel and Exhaust Technical = How To Adjust A Carb = Off-Road.com
Publish date: Oct 1, 2005
By:  ORC STAFF
Source: ATV at Off-Road.com
Carburetors are the one thing that give most 2 stroke guys fits. I do have some information from a company in Cleveland called Carb Parts Warehouse. They are the importers for Mikuni and Keihin carbs. They are located at 7777 Wall street,Valley View,Ohio 44125 (ph) (216) 524-1599. The following is a guideline for jetting Keihin carburetors. I hope this info will help you understand exactly which area(s) of the carb to adjust for your particular situation. 1) IDLE....Set idle speed to proper r.p.m. by adjusting the IDLE SPEED SCREW. Next turn the IDLE MIXTURE SCREW to achieve highest speed and best response. Next reset IDLE SPEED SCREW to proper r.p.m. 2) OFF IDLE TO 1/4 THROTTLE.....The SLOW JET and SLOW AIR JET are the most effective in this range. When you want a richer mixture in this range use a larger SLOW JET or a smaller SLOW AIR JET. The opposite holds true for a leaner mixture. 3) 1/4 TO 3/4 THROTTLE.....The jet NEEDLE is the most effective in this range.Raising the NEEDLE (by lowering the clip) will richen the mixture. Lowering the NEEDLE will lean the mixture. 4) WIDE OPEN THROTTLE.....Changing the MAIN JET effects this range the most. Select the size which offers the best performance at wide open, then install a MAIN JET one size larger for engine durability. NOTE.. Please keep in mind when tuning any carburetor . When you jet a carb lean, you may increase your performance but you also increase your chance of over-heating the motor and seizing the piston. The cylinder relies on air (4 stroke) and water (2 stroke) to keep it cool, but the piston relies on the gasoline in the air fuel mixture to keep it cool.
carb
EXHAUST
Repack the exhaust at the mfgs recommended intervals.
This will keep the exhaust flowing and the bike running with optimal performance.
As the packing begins to deteriorate the exhaust will get louder. We DON'T want that to happen.
Repacking the exhaust is really quite simple.
Purchase exhaust packing at your local bike shop,
Start by disassembling the exhaust baffle.
Remove the old packing. Measure the length of it and cut a new piece of packing to match.
Wrap the new piece of packing around the baffle and reassemble.
SIMPLE
 

Please submit any technical questions to the bulletin board.
Follow us on Twitter at www.twitter.com/OffRoadDotCom
post a comment
Please complete the form below to post your comment.
Bold = Required
Email Address Your email address will NOT be published.
Display Name appears with your comment
City
State
Country
Remember me: YesNo
Comment read our privacy policy
Note: does not support HTML
All comments submitted are subject to review, and may be delayed before posting. We reserve the right not to post comments.
Untitled Document
Sponsored Links
Off-Road Videos -
Check out over ten years of extreme 4x4 action, product testing and the Off Road Nation at play. Baja racing to rock crawling, ATVs in the sand to motorcycles in the dirt, it's all here. Rate them, share them and upload your own.
ATV Reviews -
Honda, Suzuki, Yamaha, Polaris, Kawasaki, Can-Am. First rides to long-term tests, check out the latest in ATVs, UTVs and Side-by-Side vehicles of every make and model. Read expert opinions and follow custom project vehicles.
Axxxtion Sports.....
Axxxtion Sports is heating things up with their 2010 Winter Heat snowmobile calendar! Simply Sexy!

Enewsletters

Stay on Top of All the Action:
Sign up for Off-Road.com's Enewsletters

Source: ATV at Off-Road.com, 10/1/2005
Click here