rejetting after piston swap

[biglaaa]

whatsup everyone ! had some help the other day from you guys so i hope i can figure this out .. i recently had to change pistons for compression issues and a busted up ring. went up from stock size to superstock Vitos 65mm and also had put a fresh bored set of cylinders ( over .040) .. starts right up now , but was running real lean for some reason. do i need to rejet due to the change in pistons ? was told i didnt have to by a shop owner around my way but when i jumped on the banshee today she was revving real high after half to 3/4 throttle, and was spitting out coolant out the over flow hoses . i previously have 300 main and 30 pilot, along with needle 2nd from top ... stock carbs, k&n stock air box no lid and pro circuits . should i change the needle and see ? or rejet completely ? thanks in advance guys !!!

[Larry's Shee]

Did you do a leakdown test? SS pistons are almost like porting. Anytime you change how the air goes in or out, you have to change the jetting, or at least do a plug chop/read.

 

Spitting coolant is another issue, unless it's from being super lean due to air leak and SS pistons.

[biglaaa]

My guy did a leak test yesterday said no leaks .. I will just ordered a kit now .. Possibly a needle change as well with the main change ?

[trickedcarbine]

Something like that will probably need a 30 pilot needle all the way rich or one clip from it, and maybe a 320 pilot. The super stocks act like port work so the jetting needs to accomidate.

[biglaaa]

Yea I have a 30 in there now , gonna start with 340 and work my way down .. And needle 2nd from bottom @tricked ?

[trickedcarbine]

Yep

[biglaaa]

Thank you tricked ! Will report back after rejet

[sleeper06]

I didn't know you were putting in the super stock pistons , so my original thought was just pistons should be close on jetting, secondly I said no two motors are the same give it what it wants thank god you were smart enouph to realize it was lean now before killing , also you should be close last one I jetted with super stocks plug chopped perfect at 310 main but that's not gospel by far , every bike likes what it likes

[biglaaa]

Yea I started her up she sounded fine . Warmed up , took her up the block and she started spitting coolant as if the thing was boiling .. High rev even off the throttle I knew she was too hott . Shut her down and ordered the kit Vito offers with the super stock .. Gonna start at 340 sleeper , run down from there .. I should be good with the 30s so I'll leave those in . Thanks a lot guys big help from both of you !!!

[trickedcarbine]

You should make sure the head is sealed up and that it's not causing the coolant gurgle.

[sleeper06]

Np if your bud did pressure test correctly 6lbs for 6 min head should be sealed fine def start rich any other issues I'm rite by jones beAch prob 45 min from you keep Intouch an let me know where your riding might have to meet up and go

[biglaaa]

Cool def will keep in touch .. Thanks again guys .. Yea head is sealed fine I double checked that big help guys appriciaite it .. And I usually go riding up exit 64 gsp in nj . Lookin for trails upstate near villa roma area

[sheerider11]

Cool def will keep in touch .. Thanks again guys .. Yea head is sealed fine I double checked that big help guys appriciaite it .. And I usually go riding up exit 64 gsp in nj . Lookin for trails upstate near villa roma area

Then your in my neck of the woods. Come out and see what my bike can do. Then you'll be driving to Carl's house handing him your motor. He's done a few local bikes.

[biglaaa]

[sheerider11]