359/372 HD 12 Swap

[ZukiRyder440]

What I have so far… pretty run of the mill, nothing really special timing

 

[ZukiRyder440]

I also like to clean the carbon off of where my ring is ongaa meat the top of the piston. That way it wont vary my timing.

 

[ZukiRyder440]

This is why I always double even triple check my self… i did the ring method 4 times on each and got the same result. Im thinking I REALLY screwed up checking my timing when i got into this cylinder the last time… but its what ever. I have a little more wiggle room and some improvement to do.

 

[ZukiRyder440]

Ruff grinding/ port height setting starting now

 

[ZukiRyder440]

Caps all JB welded on, and a little more to give me some room to work and make those transitions as smooth as I can. That PTO side secondary is ugly….. the freaking plating chipped when i first ground on it and tried to save it.

 

[ZukiRyder440]

Port work done, hit my numbers almost ready to bolt this thing on and test run it. I have to grind a liitle of the jb weld on the flywheel side so it clears the flywheel. Its close, but I want a little more wiggle room. It ain’t pretty but pretty port work doesn’t mean crap if there is no attention to direction/aiming/ angles of the lowers through uppers. THATS what is important in my opinion.

 

[ZukiRyder440]

Update time. Got everything finished up just have to double check my timing and everything. More to come soon

 

[ZukiRyder440]

First fire and some pi$$ revving. Still PLENTY rich. Cookie video(s) coming possibly tomorrow.

 

[ZukiRyder440]

First video of it cutting.. this was a pretty bad chunk of wood but it was all I had at the moment. More tweaking to come but have to work out some more minor bugs, and add a couple things.. stay tuned

 

[cus_deluxe]

thats some speed wood right there .
sounds good tho man

 

[ZukiRyder440]

thats some speed wood right there .
sounds good tho man

Thanks and Yes it was….. lol! Dry aged and left out in the rain too.

 

[old guy]

Well, I put my last hd12b on the 357 with the pop up piston, this showed 199 on the comp gauge.
Carb is pouring fuel in, gonna have to pull it off & rebuild it.

 

[ZukiRyder440]

D

Well, I put my last hd12b on the 357 with the pop up piston, this showed 199 on the comp gauge.
Carb is pouring fuel in, gonna have to pull it off & rebuild it.

Dang……. But luckily you can still get the HD 12 carb kits though.. Finding carb kits for the zama c3ms’ is interesting. Spend 3/4 of the time sifting through aftermarket stuff just to find the certain sellers don't have them in stock… yay lol

 

[ZukiRyder440]

So…. Based on my experiences here is the notes I have for this particular set up/ cylinder (359s mainly)
- lower exhaust held it back… wasnt getting the revs I wanted with the HD12
- transfers on the 359 were not optimal for this carb, really small bellies on the caps and abrupt changes in direction didnt help it none. I could not get the direction and/or angles I really wanted. A little JB weld and some RA hand piece time fixed that.

- I am using the 359 boot, would it would be better if I used the 372 and/or 390 boot to compliment this setup, yes, but I am sticking with what I have at the moment.

Thats what I have at the moment, gents.. feel free to share your swaps here. If you have questions, ask em. I am glad to help..

 

[old guy]

Took the carb apart today, I imediatly saw the needle lever too high, bent it back to level withe the carb body.
Since every thing else looked good in there I put it back together & fired it up, no more richness! tuned on it abit to get it useable & went to the log.
I was not impressed with it yet, main jet down to about 3/4 open but still not turning the revs it should.
I think this carb has been worked on, both butterfly shafts have been milled flat & I saw more than normal red sealer inside.
I'm sure this one came off one of the 372s I put 390 carbs on, it ran fine before.

 

[ZukiRyder440]

Took the carb apart today, I imediatly saw the needle lever too high, bent it back to level withe the carb body.
Since every thing else looked good in there I put it back together & fired it up, no more richness! tuned on it abit to get it useable & went to the log.
I was not impressed with it yet, main jet down to about 3/4 open but still not turning the revs it should.
I think this carb has been worked on, both butterfly shafts have been milled flat & I saw more than normal red sealer inside.
I'm sure this one came off one of the 372s I put 390 carbs on, it ran fine before.

Red sealer?? Hmm.. have the jets been drilled out too? Just curious.

 

[old guy]

Sealer on those little round covers inside. Don't know about drilled jets, didn't look. real nice mill job on those shafts tho.

 

[ZukiRyder440]

View attachment 357734 Sealer on those little round covers inside. Don't know about drilled jets, didn't look. real nice mill job on those shafts tho.

Ahh. And yeah, that looks good. Way better than my first go at thinning out shafts in one of those carbs