I have a motor really close to what you have. I too tried exactly what your trying, and it seemed like the thing had restrictor plate on it. It was fast but nothing like it should've been. ESR told me with the pwk that I have to start with 195mj. It wasnt even close, I ended up all the way down to a 165 or 170(cant remember for sure).
Shortly after I switched to 44mm Lectron, I had hell with it at first, but I got plenty of help from this forum. Now it screams.

 

Thats what Im anticipating, keihns will work but they need bored out alot. I just dont want a seizing issue due to the restriction..

 

81mm bore? how far can these 370 esr cylinders be bored out to thats a fair amount already isn't it, i wouldn't of thought you'd seize it with a slightly to small carb aslong as the jetting is rich enough.

 

On my 370 on gas I ran a 40.5 and I belive my main was a 165 or 168 I too went to a 44 lectron and then to a 48 lectron. What a diff on the big end once you go to a lectron. They pull like freight trains

 

lectrons are good for alcohol but not sure on gas? Do you still have the 44 and want to sell it? Anything over that for this motor seems like overkill, then again I havent tried it.

 

If you decide to go with a new 44mm Lectron, I would call Packard. Had I have done that it would saved me alot of money and time.

 

I was running a 40.5 on gas. Went to a 44 lectron and still on gas, picked up a couple hp on top. This is on a 363.

 

Yes they are easy to tune period. Gas or alky.

 

Lectron all the way. Give Packard a call and he will fix you up.

 

44 has been gone awhile I ran the 48 hv for 2 years then I upgraded to my puma

 

You really only can bore a Keihin to 40.50MM measured at the slide center line Jetting a 39MM to start: 182 to 188 Main, 52 to 55 Pilot, DGH, CEL or CEJ needle on 3rd clip, 1 1/2 turns out on AS. Plug Chops to determine fina jet sizes.

Go with a 44MM or 48MM Lectron if top end power is what you are looking for.

Carlos

 

Thanks guys,

I think Ill pick up a lectron after this trip. Not sure a 48 will fit in the frame though without cutting something..

 

I have a 48 for my sphinx drag build

 

I just picked up a 48HV. What size needle would be best for a 430 Puma?

 

so i noticed when I put the cylinder back on this bike the piston was significantly below the port floor. Im guessing esr screwed that up as well and I just didnt notice?

 

How much does it drop below the port bottoms? .020,.040.........?

 

oh no, much more lol... I know its messed up. Probably 10mm below the floor. Motor will be sent to Tapia racing soon. Im done with ESR.

Bike ran moderately but not well. Not sure what symptoms that would create though. Powerrange was at the botttom end with a non existant top end.

 

10MM...really? If 10MM below or close to 10MM at BDC, then you have 21 to 22 extra degrees of porting...not good at all. How thick is your spacer plate...?

Carlos

 

10mm

I could see it being 2.5mm since you have a 5mm stroked crank, it would be easy to send the wrong cylinder setup for a stock stroke.

sounds like a good idea to send it out and have the port timing dialed in.

 

yep I will... ESR porting sucks anyway.

Tapia racing all the way haha. Dude does mostly banshees but everything Ive ran from him runs phenomenal and is beating the competition

 

That piston coming up flat with the deck at TDC ??, or down in the bore some.
Neil

 

piston comes to the top as it should..

 

spacer was about 6mm I believe. plus gaskets would have been correct for the appropriate cylinder/porting. about 7.5mm. Not sure what they were thinking but they wont see me again.. The porting seems further off than what removing the spacer would have used. I still need to look closet at it though..