Freestyle Looking for 62t 760 freestyle specifics 64x Decking Porting

[Sasquachcrap]

Well I closed the plug gap down to .020 and still the same. Since my jets haven't gotten here yet I thought I would try a couple of 140s just to be sure I was running to rich and sure enough the larger jets made the stumbling worse and harder for the motor to recover from.

 

[CARBONX2]

Now you know for sure jetting down is the right thing, eliminate possibilities and what you are left with is the answer.

 

[kevbo]

Well I closed the plug gap down to .020 and still the same. Since my jets haven't gotten here yet I thought I would try a couple of 140s just to be sure I was running to rich and sure enough the larger jets made the stumbling worse and harder for the motor to recover from.

The top screws supplement the main circuit. Are they closed?

 

[Sasquachcrap]

I closed them with the 135s in there and it got slightly better. To prove it wasn't in my head I went with the 140s. I always started with a base of one turn out.

 

[waxhead]

125 low
110 high
2.3 ns
20 psi pop off

.......

 

[Sasquachcrap]

Jets ordered.

 

[CARBONX2]

Stock manifold? Crossover blocked/open?
Looking back through my notes, totally jetting should be 230-240.

 

[Sasquachcrap]

Blocked.

 

[CARBONX2]

Total jetting definitely below 240 then. 120p/120m/20psi is a good starting point. I used to run 120p/115m/20psi on full mod 701 with RIVA manifold.

 

[Sasquachcrap]

@waxhead I'm running an msd enhancer. I have read you need a little more timing for reverse jetting. I was going to try your suggestion but wandered if you could advise on timing using the enhancer.

 

[waxhead]

That will be fine with the jets I have given you. If you had a digital ignition you could put more timing in it and then you would need bigger jets.
However the set up you have is quite basic in the overall scheme of things and the jets I have given you will be close

 

[DirtKurt]

Not trying to de-rail this thread at all, just curious if you might have any jetting suggestions for my very similar setup. I have a ported and decked 62t/64x .060 squish 200psi comp. running dual sbn 46's on a php manifold, ported factory pipe with a C4 chamber and flame total loss.

 

[waxhead]

do you have any idea what curve is in your ignition.
Do you know what your port heights are.

 

[DirtKurt]

Havent programmed the ignition yet, still in the box. Cylinder was lowered .020 and porting was done by cpt

 

[mxr181]

Any update? I have a very clean 64X 760 I am considering sending to CPT to port and deck the cylinders and then run in my new ski...I would be running a bpipe but Im just curious to see what your jetting ended up at and the overall power delivery. I want a strong low end power / response for the surf but also want smooth linear power across the board that will be easy to ride at all speeds at the lake and river...would you say yours runs like that?

 

[Sasquachcrap]

Any update? I have a very clean 64X 760 I am considering sending to CPT to port and deck the cylinders and then run in my new ski...I would be running a bpipe but Im just curious to see what your jetting ended up at and the overall power delivery. I want a strong low end power / response for the surf but also want smooth linear power across the board that will be easy to ride at all speeds at the lake and river...would you say yours runs like that?

Update. Wax knows his stuff. I got it in the water finally this afternoon and think its all in the screws now. The original 115l 135h I was running were not what was causing the bog condition. It was from the fuel selector switch. So now I have no reserve but duel pickups and filters. Ran it one day on the 135 /115s and it was really rich. It hit HARD on the bottom but was so fat on top by the end of the ride it was acting like the plugs were about fouled and gurgling at me pretty good. Dropped down the reverse jetting 125L 110h with 20psi popoff and it ran much better. Hits hard and has lots of top end, even though I think I am spinning my prop a bit. Maybe it's not hitting quite as violently but I didn't have much time to play with the screws. @waxhead What could I do to get the back while keeping the reverse jetting?

 

[Half flip95]

7 months later and its still not dialed in.

Bet it wasn't really all that "done on the cheap" either.

Hope you learned a lot.

 

[Sasquachcrap]

I have learned a lot. And I don't ride a lot in the winter so I would say its been a good 7 months. I learned a lot in my new powder coating hobby. Got some case and cylinder porting practice. I know that my motor is fresh and rebuilt properly. I know this thing will stomp all over any limited modified 701 I have ever ridden. And since I already had the 760 motor I didn't have to factor in that cost. I know I spent on the new girdled ada head with domes cut an shipped from CPT 340$. I spent 50 on decking the cylinders and around 40 on jets for my carbs. 40-50dollars on a complete gasket set and crank seals. I know I couldn't have bought a motor for less then 500$. All in all it rips and after a couple of more rides I'm sure It will only get better.

 

[naticen]

Don't forget the carbide bits and all that little stuff that ends up costing more than the motor. I built a Kawi 650 once from the ground up like this and it definitely ripped harder than most 701's and 750's. I learned porting is not for me though and am glad to pay someone these days. Wouldn't trade the experience in for nothing along with that feeling of riding something you truly built yourself. A lot of people will never know that joy

 

[mxr181]

What's with the negativity...an ADA head is pretty standard on any built motor (or even limited setup) and he's in a "big bore" ported motor for less than $500. I'm very tempted to do the same thing but let CPT deck and port the cylinder. I think it was a cool build and something different. Wish I could ride the ski to feel how / where the motor hits for myself