On the road again...

[clanger9]

After 35 years off the road, the li'l CSR is back! Passed its MOT first time.

It was slightly terrifying taking it through traffic, as this is the first time I've ever ridden a bike with the gear change on the "wrong" side. Only managed to stall it once.
I've still got a bit of work to do (the sharp-eyed will have already spotted the oil drips in the photo...), but hopefully I'll be able to get to a Cheshire meet-up over the Summer.

I've got a question about the Amal carb, as it's running very fluffy. Symptoms are:
- Idle speed is extremely sensitivity to lean angle. Slightly to the left, it'll speed up to 2000rpm. Slightly to the right, it'll stall. I know monoblocs have some sensitivity to lean angle, but surely not this much!
- Seems to pull OK on open throttle, but is very fluffy/missy on light throttle and overrun.

The float level is good, the carb is clean and the jets are new.

What have I missed?

[cbranni]

"They all do that Sir".........lean to the left mixture gets weak, lean to the right it gets rich, most of mine do anyway.

Colin

PS......the smile says it all, good looking bike too.

[Rob Harknett]

Never noticed a carb sensitive to lean. Are you sure the throttle cable is not being pulled.

[clanger9]

@cbranni thanks! I think the smile is more relief at getting there and back without it breaking down. I haven't had the engine bottom end to bits, so its state is completely unknown. I nursed it all the way there & back, just glad it didn't seize or throw a rod!! No smoke and the gearbox & new clutch work great, so that's a good start.

@Rob definitely not the throttle cable - the route is clear. Just leaning the bike ever so slightly produces a huge change in idle, so something is wrong somewhere.

I suspect the fluffy running and unstable idle have the same cause. I'll take the carb off and have a closer look...

[Rob Harknett]

Very odd, I never noticed and difference in running when leaned over. Surely the throttle would have to open a bit . Fluffy & unstable may have to be lived with. It's over 65 years old. When it was new it must had been great, compared to a circa 1905, 65 year old bike.

[SPRIDDLER]

I suspect the fluffy running and unstable idle have the same cause. I'll take the carb off and have a closer look...

Most likely the Pilot jet's constricted or blocked. Been off the road a while........ but even if you've checked it 'recently' it can easily become blocked with gribbidge from the tank or gummy deposit from the ethanol.
You need to examine the jet very closely to see if the tiny end and side holes are clear. Even then, silt/muck can be dislodged to the sides of the jet when poking it about and it will appear clear, but as soon as petrol flows through it the muck will wash into the hole(s) when you're not looking.

[Rob Harknett]

Or a bit of fluff from a rag that cleaned the carb. Times I have found that out, you see through the jet hole OK, but if not clear, hole a bit misty, could be a tiny strand of fibre. A few runs and inspections should eventually discover if there's muck loose in the tank. Even a water bubble. Undo the bottom of the mixing chamber, check for muck, flood carb so petrol flows through. Then replace the bits.

[clanger9]

Thanks, guys!

Had a quick look: noticeable gum deposits on the needle and elsewhere. Probably from being stood over winter, so another strip & clean is probably needed.

Also, there seems to be quite a bit of clearance between the throttle slider and bore - about 5 thou. Is that too much?
I remember reading somewhere else that you can get Amals re-sleeved and this makes a big difference to tickover. Any thoughts?

[ajscomboman]

5 thou is big, Surrey Cycles stock 3 thou oversize slides which you can fettle to get a snug fit without the need to re-bore. It doesn't always work but so far I've used 3 to great success as the bikes don't cover 1000's of miles every year.

[clanger9]

It's fixed now. The bike was running stupidly rich (as evidenced by a very sooty plug).

• I got a new #3 slider and replaced the jets with what I think are the correct ones: 200 main and 25 pilot. Oddly these are one size up on what was fitted.
• The carb body took a little bit of gentle fettling to get the new slider to move smoothly, but now that it's fitted it has taken up almost all of the slack.
• Replaced the inlet manifold gasket (which had a tear in it)
• Checked and re-checked the jet block gasket inside the carb. It looked fine, but I used a bit of Wellseal on it to make sure.
• Checked and re-set the float level (which was slightly high)

Result is that the bike now ticks over beautifully, with no sensitivity at all when leaning it side to side.
Thanks all for your suggestions!