Rejetting after intake and header upgrade

[tank0509]

Is it necessary to rejet after putting a stage 1 upgrade?

 

[buckeye]

More air in and out..needs more gas.

 

[trinik7597]

Yes ... You will need at least a 36 jet maybe even 37/38

 

[creia]

Is it necessary to rejet after putting a stage 1 upgrade?

It will run like crap if you don't. By definition, that is part of a "Stage 1 Upgrade". Where did you purchase your upgrade kit? The larger jet(s) should have come with it.
Michael

 

[tank0509]

Creia i havent purchased it yet. Was gonna buy the header first than the air intake kit which does come with the kit. If i do buy the header should i rejet with that or will it be ok until i can purchase the intake kit

 

[catfishman]

mine ran fine with header.

 

[trinik7597]

You are fine until you open up the air ... Header is not going to make a difference

 

[tank0509]

Thanks trinik!

 

[creia]

Creia i havent purchased it yet. Was gonna buy the header first than the air intake kit which does come with the kit. If i do buy the header should i rejet with that or will it be ok until i can purchase the intake kit

My answer was based on your ORIGINAL question where you asked about changing/installing BOTH the header and air filter.
Michael

 

[bikesisbikes]

Anytime you increase the air flow, into the intake, you should increase the main jet size in the carb. This applies to any gas engine of modern build. Due to EPA regs, the engines are tuned to run about as lean as possible. When you increase the volume of air entering the engine, the mixture is altered, (leaned out even more). Too lean can burn holes in pistons and fry the edges of valves.
Besides, putting a little more gas into the extra air just makes it a little more powerful.

 

[Slim Jim]

Hey I'm new to this but I need help trying to figure out why my predator 212 will only run with the the choke on half way. I've done some upgrades( cam, aluminum rod, flat top piston, fly wheel, 14cc head valves springs etc)

 

[OND]

Did you re-jet your carb to ? Sounds like you need a bigger jet....a good starting place is usually a 36 to 38 jet.

 

[Slim Jim]

No I didnt but I'm going to try that next

 

[OND]

Good luck Jim...:thumbsup:

 

[Slim Jim]

Do you think it will be better to just rejet the stock carb or go with a large bore carb..

 

[bikesisbikes]

Jets are cheaper than carbs. What air cleaner are you running?

 

[Phil1958]

you did all these modifications without considering the affects they would have on fuel/air delivery???

why would you install a new cam without considering air and fuel flow through the engine??? enquiring
minds want to know! :thumbsup:

phil