Hey i just got my motor bored 20 over stock and got it back today. wiseco pistons.

before i got it rebuilt it idled until it wouldnt start. now it doesn't idle? i have to keep on the gas or is bog out and stalls. Do you i just have to raise the idle or after i break it in will it fix itself?

thanks 95 banshee

 

Basically, just putt around for 5 mins, then let it cool down, retorque the head and cylinder, do that a couple times. half a tank or so, then 1/4 throttle for the rest of the tank (not more than). then the second tank not more than 1/2, you get the idea.

before you do any of this, change out your main jet one or two higher, so it will run cooler. then a few tanks later change it back to the original jet.

btw, there was another post, i think it was about a blaster asking the same question, very informative, the long version of this!

 

Your pilot jets control your idle. You now have a larger cylinder so you need larger jets. Wiseco pistons react differently than stock because they are made of different materials. You need to be more careful with your warmup and your jetting. Do not run a Wiseco piston lean, it will seize. Your cylinders should also have been bored with greater clearances to compensate for the extra expansion of the Wiseco piston.

 

I was told by harry at trinity that all you have to do for break in is start it up let it run for 15 minutes get hot, and then let it cool, do this a couple of times and then retorque everything to spec. the reason that the breeakin period is so long for NEW motors is that everything from crank bearings to the bearings in the gears is breaking in. for just a top end rebuild there is very little break-in needed. Also, just going up .20 shouldn't require a change in jetting. I would check to make sure that your carbs are synced if youre haveing idling problems.