Rejetting Required?????

2 replies to this topic
  • BRP-rider

Posted October 21, 2005 - 05:51 PM


1990 XR600R :lol:

If I was to install an aftermarket free flowing: air filter and muffler, (which would bring a lot more air into the carb/engine, correct?), would I need to rejet my carb and bring in more fuel to compensate for an increased amount of air going into the combustion chamber? :banghead:
I would think that I would have to rejet the carb otherwise the engine would run to lean and overheat, correct?

In order to rejet the carb on a 1990 XR600R, would you buy new jets and replace the old ones with them, or would you drill the current ones out to a larger size? :banghead:

If your engine is backfiring, that is a sign that it's running to rich, correct? Because un burnt fuel is exiting through the exhaust pipe and igniting in there. :busted:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • maddmickey

Posted October 21, 2005 - 07:02 PM


You will probably need to rejet. I would buy a jet kit, that way you can play around with different sizes. on my 650r it would pop on decel because it was lean.

  • J_Daniels

Posted October 21, 2005 - 09:48 PM


NEVER drill out jets. Guys do this, and it works (sometimes), but the problems is in the swirl marks that are left in the jet orifice bore (which affects fuel flow) as well as the fact that after it is drilled out, you no longer know what size it is. and since a very tiny difference in jet size makes a big difference in fuel volume, it's got a very low chance of being right. You do almost always have to rejet larger every time a gain in the engine's flowing efficiency is made, or the engine will run lean.

Related Content


Supercross Preview 2017 Part 1: Championship Contenders by Chris Cooksey

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  132 replies

2015 XR650L Squeaking noise by Crayjay

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 3 replies

93 xr650l Restoration Project by Zigster

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 17 replies

Wiseco 101MM Spark Knock Low Engine Temps by imandrewparks

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 7 replies

XR650L super moto wheels by greggkklee

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  28 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.