Another Sloper question

[Paul.W]

Thanks for that.  It would be interesting to know what your gearing is, that does sound a bit slow for a 500cc flat out -  I wonder if it has lower gearing for the sidecar, and a sidecar is also going to add a lot of weight which won't help.

Bevan, I've had a look and the carb is an AMAL with a 150 main jet.  I think it's probably correct as the plug colour looks good so the mixture must be about right. 

I took it for a 20 mile trip out last weekend and it now seems to run OK.  If the app on my phone is to be believed it was managing to sit at 45 to 50 depending on terrain.  On the flat about 50 seems possible.  The good thing is it doesn't seem stressed at those speeds. To be honest, if it can do that comfortably that's probably fast enough considering the size/effectiveness of the brakes. If/when it ever stops raining I'll try another run.

What plug do you use?  Mine was fitted with an ancient KLG, but I was getting an occasional miss which I'm hoping might be the plug so I've tried an NGK A7.  It starts and runs with it OK, but I've not ridden it yet.

[Y13 Alan G]

Hi Paul, My sidecar sloper does have sidecar gearing. It needs first gear to get up Sunrising hill on the Banbury Run with a passenger in the sidecar.
I Run my sloper on NGK A6 plugs and my Y13 on NGK A7 plugs. MY Y13 has High Comp pistons and eats A6 plugs but the A7 are good. I do know that the J12, 500cc OHV twin is quite gutless compared to the 750cc Y13 so perhaps the 350 sloper is the same when compared to the 500cc. After all the weight is very similar as both use the same frame & cycle parts. I think I would be happy if a 350cc Sloper cruised at 45/50 mph. Regards
Alan

[Paul.W]

to resurrect a slightly old thread..................
now lockdown is easing and its possible to play with toys again I've been re-addressing the gutless-ness of my 350cc Sloper.  Earlier posts on this thread describe the trauma of sprocketry etc but after all attempts I still can't get it to do more than 50mph flat out which isn't enough- it simply lacks grunt. So,

Chatting to someone got me thinking about carbs.  The one on it came with the bike so I'd not really thought about it other than to check it opened fully and was in good order, but I've just had a closer look with a vernier.  The inlet track in my spare head is 1".  The inlet to the carb (I haven't taken it off yet) is 15/16".   I've looked on line and Amal did both sizes, so I'm thinking its got the wrong carb on it. It doesn't seem much, but dusting down my abacus I've calculated that the extra 1/16" equates to an increase of surface area of nearly 14%.  Two questions... 1) does the hive mind on this forum think that would be significant enough to strangle the engine and 2) if the answer is yes does anyone have a 1" Amal pre-monoblock carb surplus to requirements?

[morven21]

There is a thing called a Two Jet, fitted to British Seagull outboard motors, it looks just the same as them fitted to bikes; the seagull IS a two stroke, tho, of 102 c.c. I'll just check mine an report back. I'm saying this cos there's lots of these (amal) carbs about.

[scifi]

Hi, your original post says you start the engine on full retard, as it kicks back on advance.   You didn't say that you then reset to advanced for driving..?   You could even adjust the advance whilst in motion, and watch for any gains.
You also mentioned cam timing.  Most engines will have an equal overlap at TDC on the non compression stroke.  i.e. both valves will be about 1/16 inch open at that TDC.  with the exhaust closing and the inlet just opening.
I suppose if you want to be a ton-up on a 350 you need an RD350 rice burner, but BSAs are not about that..