Automotive Manual PDF

The basis of these notes have come from a series of website printouts I obtained over the last couple of years in my effort to understand how the Mikuni BDSR39 carburetors work on my Suzuki SV650. From these printouts, I’ve produced this document aimed at rejetting the SV carburetors yourself rather than taking your bike to a dyno shop and getting it done for you. While a dyno shop will probably produce a more accurate torque/power curve, the DIY wrench monkey will be satisfied in the knowledge that he/she has done it themselves and in doing so, has learned more about their bike as a result. Be aware that rejetting your bike on a dyno normally takes 1 – 2 days, however, doing it yourself is going to take much longer due to the number of times you have to strip down and rebuild your bike for the road tests. To makes things simpler and help you get it right, I’ve divided the rejetting procedure into steps which need to be completed in sequence or you’ll simply compound any problems that you may come across in a later process.

Throttle Position
Remember, jetting is all about the throttle position, not the engine speed (although they are somewhat related). Also be aware that carburetion is effected by altitude, temperature, humidity and air density so try to complete the rejetting under similar conditions. If you can’t, allow some latitude when comparing some of your end results.
Carburetor Parts Effected by Throttle Postion
Marking the throttle will make tuning easier and your on-road tests a whole lot safer (less time being distracted by the “small” stuff). It also helps to take most of the guess work out of the tests and makes your results much more consistent.
Use a felt tip pen to mark the following positions on some white/coloured tape wrapped around the throttle grip: Closed, 1/8, 1/4, 1/2, 3/4, 7/8, Full

Get pdf Suzuki SV650 Carburetor Rejetting DIY