Cylinder porting..How much does your tuning change?

[Quinc]

Start with the jetting I gave you and buy a couple bigger and smaller jets and springs. If the first jetting you try feels great keep going richer.

 

[Roseand]

I think easts setup is closer to what I'm running and holeshot said I'd probably only need to go up on the main so I'll probs start with easts setup first.

 

[yamijumpn]

I will be doing the same thing basically when i get the hull back to wisconsin and get it all together! hopefully i can make it down and ride with you since your offer like two summers ago. Been busy finishing my Mech engineering degree but only 5 weeks left now! Im going ot keep running my sbn46 but the differenc should be minimal. i found a seller on ebay who combined shipping and i got a ton of different sizes a few years back.

 

[CRJ]

Currently I'm running a 44mm carb, 61x/61x setup with a limited b pipe, 180 compression(yes I know it doesn't effect tuning but it does make it run hotter, correct?), dual cooling, etc.
Right now I'm sending my cylinders off to HPE for exhaust porting and the transfers to be cleaned up/matched. Yes, I have talked to him about tuning changes but he said he rarely does anything with 44mm carb setups and said if anything, I'd maybe have to go up a size on the main jet.
With my current setup, I'd say if anything it's a tad rich but rips pretty hard. 145 main 120 pilot stock n&s and 95g spring and only one screen on the spark arrestor.
On my new hull, I'll be swapping out to 33 domes and my hull will be 30-40 pounds lighter than my current hull and my new hull probably won't endup seeing a ton of WOT.
Where should I start? Does porting change your tuning drastically compared to the typical b pipe setup? Because from what I understand, the standard b pipe jets are actually a little rich to begin with. IDK how many turns my screws are out right now but if absolutely necessary I can check that later. I don't hear of alot of people running a 61x/61x single carb 44mm with freestyle porting so I thought i might as well ask around..

Thanks aheada time!

a tad rich indeed! I was running my ported 762 61x/61x with single 46 at 150m 125p. even it was rich for the setup.

 

[Twake]

let me know how HPE does on the 61x cylinder. I plan on doing his 819 one day, but for now (next couple months) i thought about sending him one of my 61x cylinders and FP mani to see what he can do. bigger bore and port.

let me know how it goes and post some pictures!

 

[Roseand]

let me know how HPE does on the 61x cylinder. I plan on doing his 819 one day, but for now (next couple months) i thought about sending him one of my 61x cylinders and FP mani to see what he can do. bigger bore and port.

let me know how it goes and post some pictures!

Will do man! I'm having him bore out my head pipe and mani too.

 

[Twake]

cool, thats exactly what i plan on doing for now. my ada head with 33s too. Gotta let me know how it goes, we'll have the exact same setup. single 44 and all.
Also, how long he is behind or how long it takes from shipped out to back home.

Thanks.

 

[Roseand]

cool, thats exactly what i plan on doing for now. my ada head with 33s too. Gotta let me know how it goes, we'll have the exact same setup. single 44 and all.
Also, how long he is behind or how long it takes from shipped out to back home.

Thanks.

Haha awesome dude! I will definitely let you know! Uhhh I think he's out almost two months, but we'll see if he gets to mine faster. I'm cutting it close for this season if he's that behind.

 

[Quinc]

let me know how HPE does on the 61x cylinder. I plan on doing his 819 one day, but for now (next couple months) i thought about sending him one of my 61x cylinders and FP mani to see what he can do. bigger bore and port.

let me know how it goes and post some pictures!

I had him open up two B-pipe manifolds and head pipes. They look awesome and he had them back to me in less than a week.

 

[senor]

Which carb do you have? Be sure to know there are two versions of these 44 carbs. Some have three bleed holes and some have four. Just be sure you know what you have before you start using some else's jetting. Usually the porting will actually fill the cylinder better causing a richer condition. I have used a single on alot of these 61x ported motors and they work fine. Always used the aftermarket carb. 2.5ns. 95 gram spring. 130low. 115high. Sea level

 

[Roseand]

I'm just using the oem44 that came on my 1995 superjet.

 

[kevbo]

The pilot and pop off are married and very sensitive around 1/3 open throttle. Small changes to either really show in this range. It needs to be sputtering some for best response. You must power tune the top screw to find the proper main jet. Start 2 turns out and do some acceleration runs, close it 1/2 turn at a time until it hesitates. Open it until pulls hard, at this point the mixture is set. Now note how far the top screw is open, if over 1.5 turns install a larger main and repeat the process. I would use a 160 main and 120-125 depending on pop off.

 

[Quinc]

Which carb do you have? Be sure to know there are two versions of these 44 carbs. Some have three bleed holes and some have four. Just be sure you know what you have before you start using some else's jetting. Usually the porting will actually fill the cylinder better causing a richer condition. I have used a single on alot of these 61x ported motors and they work fine. Always used the aftermarket carb. 2.5ns. 95 gram spring. 130low. 115high. Sea level

How can you tell if you have 3 or 4?

 

[eastcoastjumper]

How can you tell if you have 3 or 4?

look up the bottom of the carb and open the flap a little. you will see 3 or 4 holes

 

[VXSXH20]

For what it's worth, I just looked into a wetjet 46 setup. It has 4 holes. This is going on a ported 735 maniac/blue 61x top end kit. Yes, that is a SBT rebuild kit. I found them to work well. However, I don't use the needle arms or pins. I find most have too much slop in them causing tuning issues. I use Oem mikuni arms. The springs all vary in tension. So, as a few have stated before. Going by the books color chart is often misleading. I'm trying eastcoastjumpers setup above. I'm currently at 19-20 lbs on the pop off on a new 2.3 needle and seat. Along with some various jets up and down the range. I'll be using a tiny tach and plug visuals when the engine is back in my fx1. I also have to break in this top end so.. More to come when the time comes.

 

[kevbo]

Plug color is a lagging indicator and useless for freestyle tunes because we spend too much time at part throttle. A clean plug at part throttle is too lean for good response.