Re-jetting

[jestercinti]

Cancelled DirecTV last December.  Amazing how much extra tme I have now.

[iclrag]

Thanks for the wiki link, i guess that's what i get for being lazy 

[Daytona_Kid]

This one is for Adidas Guy asking for info as to why you need to re-jet when changing exhaust. Here is a technical explanation I found on the interwebs.

http://blog.jpcycles.com/2010/07/will-i-need-to-rejet-when-i-change-my-pipes/

[jestercinti]

Zombie thread pictures in 5...4....3....

[BockinBboy]

This one is for Adidas Guy asking for info as to why you need to re-jet when changing exhaust. Here is a technical explanation I found on the interwebs.

http://blog.jpcycles.com/2010/07/will-i-need-to-rejet-when-i-change-my-pipes/

That is a good article and one I have read before; however, rejet is more pertinent when you change the diameter and/or length of the pipes which will change the physics and performance.  I haven't seen anyone argue that aspect.  Changing the can has an effect no doubt, but one that is cause for a rejet?  Depends on the case... most people who change only the cans, are just looking for the 'cool' factor and sound, and probably aren't concerned with maximizing performance efficiency.  Yes, it may change the power rpm a little, but enough to crack the carbs for the average user?

- Bboy

[Daytona_Kid]

Bboy, I guess it depends if the exhaust (slip on or full system) they put on is going to lean the engine out anymore that what it comes from the factory. Only way to know is to use an AFR meter or use the other simpler methods like spark plug inspections. If it does lean it out further, then I would say it would be enough to crack the carbs even for the average user. Why risk potential engine damage?

jestercinti, I look at this forum like an encyclopedia on this bike, the information is here, you just have to flick through the pages to find it. I didnt think it was necessary to create another thread to simply help out another forum user when the information in this thread will always be current and useful. Even if it does get brought up from 6 months ago.

[adidasguy]

This one is for Adidas Guy asking for info as to why you need to re-jet when changing exhaust. Here is a technical explanation I found on the interwebs.

http://blog.jpcycles.com/2010/07/will-i-need-to-rejet-when-i-change-my-pipes/

That is a good article and one I have read before; however, rejet is more pertinent when you change the diameter and/or length of the pipes which will change the physics and performance.  I haven't seen anyone argue that aspect.  Changing the can has an effect no doubt, but one that is cause for a rejet?  Depends on the case... most people who change only the cans, are just looking for the 'cool' factor and sound, and probably aren't concerned with maximizing performance efficiency.  Yes, it may change the power rpm a little, but enough to crack the carbs for the average user?

- Bboy

The start of that article speaks of 2 stroke engines. I believe it is more intended for a 2 stroke engine than a 4 stroke.
"Exhaust technology is the reason two-stroke engines work."
It continues on with vague references to 4 strokes while I believe most of the article really speaks of 2 stroke engines. It seems to speak more about tuning an exhaust - critical for operation of a 2 stroke - and doesn't say much about rejetting.