96 WB1 jetting after rebuild w/ pipe & head & oil mix

[KPC]

1996 WB1

rebuilding the top end, carbs, crank seals, this week
replacing all fuel lines
it has a aftermarket head & pipe

It currently has 135 mainjets in the stock mikuni super bn dual carbs. I run only flat water, with a mix of just blip, blip the throttle, to occassionally some extended WOT runs to keep up with fellow couch riders when going a few miles down river. I plan to run Klotz Super Techniplate (supposed to be a good oil and love the smell of klotz)

A few questions. What ratio should I be mixing with running 92 octane. I know there are a ton of threads on this, as I have been reading them for over the past hour, so no need to tell me to 'search'.

Some questions I have, are if I run 32:1 that many people suggest for WOT running, that supposedly I need to not only jet for WOT running, but I need to jet even heavier due to the lean condition due to the less fuel from more oil. If 32:1 is the desirable ratio, what main jet is recommended for my setup.

On another hand, I've read that adding just a pipe & head isn't enough stress on the factory engine to justify 32:1 as some threads say go with 40:1 or 50:1 as 40-50:1 is already plenty oil rich, that some people run 100:1 on stock runabout skis without any issues so and there is no need for such a rich oil mixture of 32:1

So I ask for some advice with ratio & jet choice for this soon to be rebuilt 96 dual carb WB1. I don't want to sieze the motor right after rebuilding it due to lack of proper oil / tuning.

(see my other thread about dual cooling / flow control valve upgrading questions, I seperated the threads to keep cooling in the other thread and fuel / oil in this thread)

 

[dabeetereater]

i got a pretty ba setup in my ski and i run 3 oz oil for one gallon, forget to what it actually works out to be but its been working for me great for some time now, and i do a lot of wot runs, i have dual 46mm buckshots with 100 hi jets, and she runs great,

 

[KPC]

Thanks for the reply
I believe that 3oz to 128oz (gallon) = 42.6:1 mixture ratio
Can anyone else chime in about oil ratios & carb jetting

 

[KPC]

bump

 

[Dustin Mustangs]

You don't need to mix at 32:1 for extended wot use. I just had a relatively souped up motor spec'd by one of the more reputable builders on this board and he has me mixing at 50:1. He also doesn't care what oil I run as long as it is twc2 (or whatever) and not one of the bottom of the barrel offerings. I told him I wanted it to be able to hold wot indefinitely and it can. Just make sure your cooling and fuel system are set up properly and you'll be fine.

As far as jetting goes, there is a thread on here where people have been posting jetting specs they have found to work for different combos. There is also a set of instructions on the factory pipe website that has jetting recommendations. I had good luck with those on a similar combo (61x single carb, bpipe, head, 13/17 concord) by just lowering the popoff a bit. This was with 50:1. If have any doubts, start rich and tune down from there.

On a side note, run at least the first 10 gallons through the new motor with 40:1 or richer on the oil. There are other things you should do for a proper break in that you can find with a search.

 

[KPC]

I got another question. I rebuilt the engine, I went 1 size larger on the main jets (just to make sure that the reason it blew up in the first place wasn't a lean condition).
I ran the first tank thru it with the 1 size larger jet, but it is running too rich. So I went back to the jets that were in it previously. It runs great on top end.
But this ski never did want to idle (even when I first bought it 2 years ago)
It really loads up with fuel on idle. If I let it idle for 10 seconds, and then go straight to WOT, it won't even get itself up on plane. It just spits and sputters because it is loaded up with fuel.
I'm thinking that the low speed jets are too large. I pulled the carbs apart and they are size 70 mikuni low speed jets (dual carb 1996 blaster with head & pipe)

See, I have two other skis and they both start just with hitting the starter, I don't have to give them any throttle, I just hit the starter, they start up, and idle fine. And when I go from idle to WOT, they perk right up with very little hesitation (not loaded up with fuel).

So for this blaster, I need to tune it so that it will idle better (it has never wanted to idle, and it will not start unless opening the throttle). I'm wondering if I go a little smaller (leaner) on the idle jets, if that will help with the rough idle and also when I go from idle to wot if it won't be so loaded up with fuel.

 

[KPC]

bump for jetting help

 

[Lakeside518]

How many turns out are the low speed screws? Also what Needle/Seat & springs are you using. Curious what your pop-off is set at.

 

[KPC]

It is about 1-1/4 out on the low speed and 1-1/2 on the high speed

Right now I'm running a 70 pilot and 135 main

I called protec pipe company yesterday and the guy said to keep the 70 pilot but go down to a 130 jet with 2 turns out on the high speed. I didn't think to ask him if that was for a stock engine with just a pipe, or a stock engine with aftermarket head & pipe.

I will wait to call them back on Monday to double check the 130 jet was their recommendation for tuning with pipe AND aftermarket head.

Last week I installed a genuine Mikuni super bn rebuild kit in both carbs with the spring that comes in the kit (I looked up the specs and I believe the spring is a 95gram that comes in the kit). Last week when I purchased the genuine Mikuni rebuild kits, I didn't purchase a needle & seat as I thought that would have come in the rebuild kit.

So I now need to pick up a needle & seat to finish off the carb rebuild. The guy from Protec said to run a 1.5 needle & seat

I don't know what needle & seat are in the carbs right now.

When I call back to Protec on Monday, I'm going to double check the 1.5 needle & seat along with the 130 main jet.

I did notice today that it seems the needle & seat are leaking some fuel into the engine just from when the tank pressurized in the sun.

So I need to get the new needle & seat before I can do any futher tuning of the carb.

 

[4iflounder]

Not to resurrect an old post. Protec sent me a rejet kit for my carb. It was a 135 main. 70 pilot and 2.3 NS..

 

[KPC]

I finally figured out the problem.

The mikuni rebuild kits came with 2 different springs

1 was a 115gr
1 was a 65 gr

testing popoff showed a big difference in psi

By the way, I called protec and the guy said running the protect pipe, aftermarket head & flame arrestors to run carb settings:

130 main jet
70 pilot jet
95 gr spring
1.5 needle & seat
2 turns out on the high speed
1.25 turns out on the low speed

I went with their recommendation except that I ran black mikuni springs (80gr) because I had them laying around, and didn't have a set of 95gram

I first started with a 135 main, tuned to 1.25 turns out on the hi-speed screw, the ski ran good with strong hp and good throttle response but on the very top end it just didn't seem like it was reving out that last little bit

So I went down to a 130 main, tuned to 2.0 turns out on the hi-speed screw, and the ski still has great throttle response and now seems to be making every last drop of HP.

I checked plugs with the 130 main, and they seem to have a good color.

I'm running a 50:1 mix of 92-93 octane pump gas with klotz super techniplate.

I only put about 1/2 tank of gas thru the engine with these carb settings. I did several WOT up & down the river runs, and it is running strong.

I'm about 800ft above sea level

 

[KPC]

Not to resurrect an old post. Protec sent me a rejet kit for my carb. It was a 135 main. 70 pilot and 2.3 NS..

that seems like a fairly large needle & seat.

What spring are you running? Even with a 115gr spring, I still think you will be considerably low for the pop off.

I'm learning about this as I go, I don't know what the effects will be with considerably low popoff. But with a 2.3 NS, I don't know if you can even reach 20psi. That is a large surface area that will be pushing up on the needle.

As stated, I'm running a 1.5 NS with 80gr spring (protect recommended 95gr) but I see no problem running the 80gr as the ski runs fine.

If you do end up running the 2.3 NS, please post the spring you use, popoff pressure you attained with whatever combination of NS & spring and finally let us know how it runs.

 

[4iflounder]

In the kit was a 65 gram spring at 15 psi Pop off. I ran it, the bottom end is great it doesnt bog down. It could be better though. There is good throttle response. Protec sold me a complete set with instructions for a single carb B1 with their pipe.