Super Dio ZX AF28 and other Dio scooters

[sanjuro]

Originally, I was just using Honda GN2 oil for the break-in, and then switched to Motul 710. The one constant was I always used a 32:1 mix ratio.

[bakaracer]

the motul 710 is more for injector use and a bit too thin.the 800 is for premix use and thicker.much better for higher reving setup like yours.I think the pilot should be around a 25 or 30 at lease. if you were having a mushy throttle response on the lower part of the throttle than either the needle was in the wrong position or the needle was just the wrong needle for your setup.sometimes you have to change the needle to get the carb to run right if not it will make you think the pilot is wrong.

[sanjuro]

I'll put in a 30 slow jet to start next time, and then maybe down to a 25. Also, I'll switch to the Motul 800 while I'm at it. I'm thinking 25:1 for break-in, and then going to 50:1 for the period afterwards.

BTW, my needle was in the middle position, and I never adjusted it.

What do you think a good range is for setting the air fuel mixture screw at, 1 1/4 turns to 2 1/4? Mine was at 2 1/4.

Another thing I think contributed to the problems on the previous page was the threads where the spark plug went in was too large. When one of my friends sent the cylinder head to be milled to increase the compression, they screwed up the spark plug hole threads. I always had to put grease on the spark plug threads and crush washer to keep it airtight. I was getting a little slack about doing this the last 2 spark plugs when I was checking the plug color.

[bakaracer]

even after you did that,did it still leak oil/gas out the plug threads?

[bakaracer]

I'll put in a 30 slow jet to start next time, and then maybe down to a 25. Also, I'll switch to the Motul 800 while I'm at it. I'm thinking 25:1 for break-in, and then going to 50:1 for the period afterwards.

BTW, my needle was in the middle position, and I never adjusted it.

What do you think a good range is for setting the air fuel mixture screw at, 1 1/4 turns to 2 1/4? Mine was at 2 1/4.

Another thing I think contributed to the problems on the previous page was the threads where the spark plug went in was too large. When one of my friends sent the cylinder head to be milled to increase the compression, they screwed up the spark plug hole threads. I always had to put grease on the spark plug threads and crush washer to keep it airtight. I was getting a little slack about doing this the last 2 spark plugs when I was checking the plug color.

how high was the compression at?

[sanjuro]

even after you did that,did it still leak oil/gas out the plug threads?

I didn't see any evidence of that.

how high was the compression at?

I failed to do a compression test, which of course will be remedied next time around.

[Wheelman-111]

Greetings:

Y'know, if you buy my piston, the compression won't be too high...

I started premixing HP-2 Honda Synthetic with the BBK on Flash 3. I've used it in the oil tank since the beginning, too, although not specifically recommended by Honda-san for this purpose. So far, so good. (If I don't reach for the stars on compression...)

BP8 HS BPR8 HSA, and all the iterations of the #8 heat range should make little/no difference in combustion chamber heat. The R (methinks) is for resistor-type, which can make a difference depending on the coil spec, and the "A" refers to some long-forgotten feature of the plug tip. Mouse, didn't you drill this down once?

If an 8 is correct, it's not the problem. Maybe your build needs a "9" however. Repeat request for sources of these non-Honda-spec plugs, please.

[elite_dub]

Victor about how much miles do you think is on that cylinder??

[sanjuro]

Easily 400-500.

[burnt_toast]

def need B8HS short reach plug, long reach dangerous too close to piston, causes predetonation

And 20pilot is crazy small, and 165main is crazy big, dunno how you and wheelz are rockin these setups

Bumblebee (24oko, 48mm Ruima, YMS canister) likes 45pilot, 125main, needle 1clip leaned, with open UNI. I'm suprised a diff carb, but same size would require such drastic changes in jetting

[Wheelman-111]

Greetings:

Burnt, you're comparing your OKO 24 to the Mikuni TM24, which as Mousewheels so beautifully summarized in Tech Docs uses a completely different jet numbering system. The 165 Mikuni jet has a hole much smaller than the number suggests. I've come to believe that the flow patterns in the Venturis of differently-shaped carbs matters more than the jet size anyway.

OKO 28/30 using a 55 pilot now and a 138 main on Nikasil + Phongeer "Long".
The TM 24 seemed to like a 25/165 combination on that setup.

[burnt_toast]

Greetings:

Burnt, you're comparing your OKO 24 to the Mikuni TM24, which as Mousewheels so beautifully summarized in Tech Docs uses a completely different jet numbering system. The 165 Mikuni jet has a hole much smaller than the number suggests. I've come to believe that the flow patterns in the Venturis of differently-shaped carbs matters more than the jet size anyway.

OKO 28/30 using a 55 pilot now and a 138 main on Nikasil + Phongeer "Long".
The TM 24 seemed to like a 25/165 combination on that setup.

Got it, that makes sense, thanks for clarifying. I recall running into same "jet#" issue when jetting arreche vs. dellorto carbs on jog bikes

[evilone]

def need B8HS short reach plug, long reach dangerous too close to piston, causes predetonation

Wow, the B8HS is about 3mm shorter than the BR8HSA.

[elitedio]

I think it has been said, I don't think you over-emphasize the importance of oil viscosity in jetting. Get one oil that you can live with, like Motul 800 @32:1 (it doesn't mix that well so shake it well) for premix. I have seen people pour oil into the gas tank, makes me shudder. Thicker oil makes the fuel more viscous and will lean the mixture and has to be adjusted for.

I carry a 2 liter pop bottle under the seat. It has 2 oz of oil in it. Add some gas, shake then top up, shake again. It is surprisingly durable with fuel. I have another at home for chain saw.

[sanjuro]

I have seen people pour oil into the gas tank, makes me shudder.

Is it okay to add the oil first, and then blast the fuel in there at the pump?