a 2 part question.

[godswrath]

ok i have an 89 zx7

the first question is about carbs.

the 89 has 36mm carbs and the 90 has 38mm carbs.

i have put a stage 2 jet kit in and wanted to know if after i put it in is it the same as the 38mm carbs or what would be the difference.

part 2

after putting in the carbs and after market exhaust i have heard that it is best to modify the airbox just double checking on that one.after they put the jet kit on and dyno they said it was running lean some of it i think is because they said they is a airleak and they didnt run it as long as they wanted to cause of the oil leak.

[godswrath]

there has to be someone that can answer my question

[ZX7RJoe]

Originally Posted by godswrath

there has to be someone that can answer my question

Well,there are guys on here that know better than I do but here's my 2 cents.

I've never heard of having to modify the air box after installing an aftermarket exhaust or jet kit.With a new exhaust you're moving more air through the motor than with stock exhaust,that's why you should have the jet kit,to have the ability to richen the fuel mixture now that there's more airflow.

Your lean condition could be due to carburetor settings or an air leak between your carbs and the intake (carb boots).

You can take your tank off and bungee tie it to your rear seat so that the fuel lines are still connected.Take your air box off and fire the bike up,spray carb cleaner around the base of each carb,one at a time,around the carb boot.If your rpm jump you have an air leak around the corresponding carb boot.They either need tightened or replaced (tightening it fixed mine).

If you don't have an intake leak then the lean condition is probably due to carburetor settings.Contact the manufacturer of your jet kit for recommended settings for your specific application.This should give you a good starting point.

Hope that helped.

[godswrath]

well they are already installed by a motorcycle shop and they tried to dyno it but there was an oil leak at the cam tensioner so i ordered a ape to replace it they where afraid to keep running it at those rpms because with the oil leak they where afraid it would catch on fire but i ordered the carb boots cause some where bad so i am replacing all of them. i read in here somewhere that they where talking about modifying the airbox that is what i was interested in but thanks for replying it was really good info.