carb needles...........and the common prob of weak mixtures

[Special X]

Have you tried

52 idle
AV266 atomiser
X13 needle
118/120 main

That should be somewhere near if you haven't got an air leak or a problem with the choke plunger (very common) You need plenty of play in the cable and to ensure that the spring is pushing the plunger home.

[drunkmunkey6969]

what problems are you actually having?

[RBG]

Talking about 5000 rpm & Needles.
I was going to post my findings & pick your brains.
But there's a post going.


I fitted an EGT & Rev counter before setting off for Spain.
RB22 35mm Mikuni with filter, full panelled
320 main
22.5 pilot
57 needle 2nd clip.
18deg
AF close ratio gearbox & 19 x 46
Franspeed tourer.

My main concern was travelling at the 5000rpm mark
cased of constantly speeding up & slowing down & bringing the main jet on line.
This I found strange as the Scoot just ticks over fine & before fitting the EGT this is where I would sit as I plodded along.

The scoot will not rev much past 7000rpm & the EGT reads 475-500 at 6000+rpm
At 5000rpm it can get up to 650+C.
I can keep it below 600C.

What will at franspeed tourer rev out at & what's the ratio of this gear box.
I don't think my speedo is too far out for a Lambretta at 6000rpm it says I'm doing 70mph.
Flat out is off the clock & shockingly fast on 10' wheels.

Do you think dropping down to the 3rd clip on the needle will help any?

[DaveInPortland]

what problems are you actually having?

I have a dual EGT/CHT gauge installed as well as a rev counter (tachometer). My exhaust gas temps spike to 1200F in the 25%-50% throttle range, indicating it is leaning out.

The only atomizers I have tried are the 264 and 266 with the X4 and X7 needles.

Can these PHBH carbs be dialed in reliably or should I dump it for something else? I don't want to continually fight this thing.

[drunkmunkey6969]

I have a dual EGT/CHT gauge installed as well as a rev counter (tachometer). My exhaust gas temps spike to 1200F in the 25%-50% throttle range, indicating it is leaning out.

What pilot jet and what slide are you running?

[drunkmunkey6969]

RBG.....crikey.....one question at a time please mate!

So.....to clarify:

1) Your RB doesnt rev over 7000rpm?
2) At 5000rpm the heat spikes from 475 upto 650+ (what part of throttle are you on here?)
3) You want to know what a franspeed tourer will rev out to
4) What is the final drive ratio of and AF close ratio gearbox on 19/46
5) Will dropping down to the 3rd clip on the needle will help?

Am i correct on what you are saying and what you want to know?

[sean brady scooters]

just generalizing here of course..........
but if your EGT,CHT guages are telling you that your motor is overheating at a certain rev range....................
it does not always equate to the fact that it may be a carb prob and too lean..................
consider also that its just not cooling efficiently enough at those typically 4th gear low speeds.............
the choice of gearing can effect cooling..............

[RBG]

RBG.....crikey.....one question at a time please mate!

So.....to clarify:

1) Your RB doesnt rev over 7000rpm?
2) At 5000rpm the heat spikes from 475 upto 650+ (what part of throttle are you on here?)
3) You want to know what a franspeed tourer will rev out to
4) What is the final drive ratio of and AF close ratio gearbox on 19/46
5) Will dropping down to the 3rd clip on the needle will help?

Am i correct on what you are saying and what you want to know?

Yes mate.
1. yep 7K is about the lot. "I have a feeling that it could be the CDI" but not knowing the limit of the exhaust.
2. 1/3-1/2 throttle. Bliping the throttle brings the temp down.
3,
4. 4.8???
5. please
Other than the 5000rpm temp shocker she's running well.

Thanks.

[Bufficus]

Yes mate.
1. yep 7K is about the lot. "I have a feeling that it could be the CDI" but not knowing the limit of the exhaust.

My Franspped Tourer would rev to 8000rpm according to my Pitsch Krober rev counter.

[DaveInPortland]

I split my inquiry off to it's own topic. We have a few different conversations going on here and it's going to get confusing.
http://scooterotica.org/forum/viewtopic.php?f=7&t=2928