Not quite right

G-Man · Post by **G-Man** » Mon May 09, 2016 4:54 am

LM - That's the only pic I had of a rotor. That's my 1962 C72. Judging from tire wear I think the engine may have only done around 5k miles hence the nice condition of the stator. it had been in a damp shed ( like all British projects) fro 35 or more years when I got to it.

G

LOUD MOUSE wrote:Nice pic of a DREAM engine. ...........?. ..............lm

G-Man wrote:Modelman

Those jets and more likely the needles are often not the correct spec. For the strobe, just hook up and point at the rotor. F mark with the extra set of marks for full advance as the engine speeds up.

Probably the needle, main jet or fully-advanced timing is the problem if it doesn't pick up well.

G

LOUD MOUSE · Post by **LOUD MOUSE** » Mon May 09, 2016 5:36 am

Don't see many with the blue circle still there.
Sprocket doesn't show much wear for sure. ......................lm

G-Man wrote:LM - That's the only pic I had of a rotor. That's my 1962 C72. Judging from tire wear I think the engine may have only done around 5k miles hence the nice condition of the stator. it had been in a damp shed ( like all British projects) fro 35 or more years when I got to it.

G

LOUD MOUSE wrote:Nice pic of a DREAM engine. ...........?. ..............lm

G-Man wrote:Modelman

Those jets and more likely the needles are often not the correct spec. For the strobe, just hook up and point at the rotor. F mark with the extra set of marks for full advance as the engine speeds up.

Probably the needle, main jet or fully-advanced timing is the problem if it doesn't pick up well.

G

modelman · Post by **modelman** » Mon May 09, 2016 7:12 am

Raised the needle up a notch, (2nd from bottom) MUCH better, not quite there yet, a bit more 'tweaking' required!!
Thanks all.

mike in idaho · Post by **mike in idaho** » Mon May 09, 2016 7:17 pm

What rpms is it turning when you whack the throttle open? A 26mm carb throat is a pretty good size hole to feed a cylinder of just over 9 cubic inches. With the slide pulled suddenly wide open, under the load of high gear, it's possible that there just isn't enough air velocity to keep the fuel flowing. Later bikes have accelerator pumps and vacuum operated slides to cover that hole.

modelman · Post by **modelman** » Thu May 12, 2016 2:05 am

Thanks mike, but I don't think its an air problem, as it has NEW filters & air tubes.

I only 'whacked' open the throttle when on the stand, not riding!

I'll try & describe it another way, instant start, 1st gear & off we go, accelerating 'normally' through the gears, then as top is selected, there's an induction roar & the bike 'bogs-down' as its wound open & wont go any faster, liken it to having too high a gear & dropping it to 3rd is needed.

Its not as bad as that, it CAN be ridden it top, but its not right, & lifting the needle has made it better, so I'm inclined it to be carb related.

I'm beginning to agree with G-man, as it points to main & needle jets.

LOUD MOUSE · Post by **LOUD MOUSE** » Thu May 12, 2016 6:25 am

Have you opened the cap when this happens?. ..............lm

modelman wrote:Thanks mike, but I don't think its an air problem, as it has NEW filters & air tubes.

I only 'whacked' open the throttle when on the stand, not riding!

I'll try & describe it another way, instant start, 1st gear & off we go, accelerating 'normally' through the gears, then as top is selected, there's an induction roar & the bike 'bogs-down' as its wound open & wont go any faster, liken it to having too high a gear & dropping it to 3rd is needed.

Its not as bad as that, it CAN be ridden it top, but its not right, & lifting the needle has made it better, so I'm inclined it to be carb related.

I'm beginning to agree with G-man, as it points to main & needle jets.

modelman · Post by **modelman** » Thu May 12, 2016 8:01 am

lm, I assume the cap you refer to is the fuel tank cap, if so, then yes I have.