Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Rear sprocket on BSA 441 Victor 69

I am new to this site but have been wanting to join for years, finally did.

I am thinking about buying a 47 tooth sprocket for the rear instead of the 49. Has anyone had any issues with this as far as riding?

What CS sprocket and what kind of riding are you planning on doing?

Hi and welcome to the forum.
I notice you are in Crestline CA, a mountain community. If anything, you might want slightly lower gearing due to decreased power at high elevations. This is especially true if you fancy doing any trail riding in those mountains.

Personally, I've done the trail from Big Bear down to Pioneer town and back up several times on a B44 or a B50, both with lowered gearing. It has worked out fine for me.

My B44R has a 47 tooth sprocket and it rides just fine as long as you keep below 50 mph. Above 50 my ass and hands get numb.

A B44 I had years ago would shake your feet off the pegs and shut the petcock if you revved it too hard!

A proper balance job fixes that really well. B44's have a substantial built in rocking couple imbalance that just makes things worse.

where does the rocking couple come in on a single cylinder?

The crank flywheels are different widths on a B44 so one side is heavier than the other at the centre line, B50 went back to identical width flywheels, my B44 will cruise at 70 mph with little vibration all day long but I run a 19T gearbox sprocket and a 49 rear for high overall gearing.

Back to the rocking couple, if the weight difference is close to the centre then its effect per gram is less than the same weight at the crank ends.

And what's more, the web area around the crankpin is approximately the same thickness on each side. It would have been much better if BSA had made that web thicker to match the thicker counterweight on the drive side flywheel.

So, what I do when balancing one is to first machine the drive side counterweight to approximately the same thickness as the timing side but leave the flywheel rim the standard thickness. That hugely reduces the number of holes to be drilled.

I will have to look into that once this bike is done. I will stay with the 49 for now but will buy the 47 just to have it. Keep riding and keep it up on two wheels.

The stock 17 tooth is what I am running, but just thought since I am in the mountains I would probably benefit with a 47 tooth on the rear.

A couple of more question please........

What size tires are you running. Front and rear? ( I used to think it doesn't matter but now I not so sure)

What kind of riding are you planning on doing?

I've never claimed to be a mechanic......(I do know some though) I have no way to quantify any of my "worked better" other than seat of the pants. But when trying to figure out what gearing was best for my bikes they usually got several hundred miles of testing. 250 miles one way or a 200 mile weekend, never just around the block.

Here's what I came up with



My riding is pretty much the same no matter which bike. Two lane highway, 50-60 miles per hour. I live in the foothills of North Western North Carolina and a lot of my miles are in the mountains. One of my favorite rides is to go over and meet my friends (Ga and NC) in the North Georgia Mountains. My route takes me along Hwy 64 through some beautiful mountain roads in NC.

EVERY one of my bikes is different....the C25 likes it's stock gearing. I geared it lower thinking it'd help for Giro work but it made it a pig on the highway......you could tell it was in a bind. My B50.....I had a 19/47 set up on it for a few years and absolutely hated it...and so did the bike.
The road going B44 with 19/47 is a dream......but it came with larger tires than I usually run so when I swapped them I kept those sizes.......not sure how much difference they actually make but.

To get where I am now........I have LOTS of sprockets and CHAINS. I'd try something out and if I didn't like it I swapped until I did. Keep in mind you usually have to adjust the chain if your changing sprockets......easy enough if you're shortening one.

I honestly don't think anyone could tell you what gearing your bike needs. Your stock set up was 17/49 The same year's SS was 17/47. The Shooting Star was considered a road bike.....the VS was dual purpose. So.....you really couldn't go "wrong" gearing higher.....but you're going to probably have to try it to have your own opinion.

OH........there are two other sprockets in the engine. (4 total) These bikes have been around a long time now......anything could have been done to them.

Sorry to have carried on so.........I've been down this road (pun intended) before.

Could you elaborate on the "larger tires"? If it is a dream, you prolly orta share... (most of mine end up in cold sweats)

What happened with your 18t countersprocket? The one I tried worked pretty well I thought...

First off I haven't ridden a VS is a LONG time.........B50, B44R and C25.

You know my first B44R......I got it for DC. I ran stock tires on it....3.25 Front and 3.50 Rear........put thousands of miles on it. had stock gearing but I went to 18/47 and loved it. Then I changed it to a sidecar tug.......had to down size the 18 to a 16. Worked great.

C25.....is a 1967 and has the same tire sizes as the B44R stock gearing works the best for my riding.....tried three different set ups....went back to stock

THEN I picked up another B44R from richrd. Instead of stock tire sizes he went with 110/90 rear, 100/90 front. (4.50 4.25?) I know that's not a big difference but the darn thing handles so well I didn't want to mess that up (I can be my worst enemy). I was surprised to find the sprockets were 19/47. I had tried that combo on the B50 and hated it.

I have no clue how much difference the tires make but I've ridden a few unit singles and this one.....(for some reason) is absolutely the smoothest road going unit single I've owned/ridden. that 19/47 combo works great........even in a parking lot or starting off on an uphill grade.

WHY........I'm not sure. Damn thing came with out of date tires....(richrd loved them (?)) also had a 530 chain on 520 sprockets.....good ole BSA didn't complain one bit. I upgraded those but didn't try to outsmart myself and change things. Best riding unit single I've owned......or maybe I spent too much time on those other 67's and I've forgotten how the others ride????

BUT if you ask me tomorrow......I'll say 19/47 and 110/90R 100/90F is the set up for a 1967 B44R for (speed limit) two lane highway use.

You have to watch comparing just the rear sprocket ratio. The 250/350's came with a 23T engine sprocket (except for Trials where there was an even smaller one) and the 441's and 500's came with a 28T engine sprocket. I tuned a B40 in the 80's and it was just too revy so I fitted a 28T engine sprocket which dropped the revs a lot.

Yes sir… that’s why I mentioned there are actually 4 sprockets involved. I’ve never run across a different clutch chain wheel (a sprocket) but that doesn’t mean there couldn’t be one out there. When I built my B25 trials bike I did the common mod of installing an early (I forget the tooth count) C15 engine sprocket (w/seal).

Without opening up the primary side and checking those three sprockets you can access from that side…..you really won’t know what you have.

4.0 18 K70 on the rear.

If I remember my ratio's on a Motorcycle the smaller sprocket on the rear and larger sprocket on the front (drive) the higher the ratio. This said I should get better top end with less RPM's. Or am I just sucking water threw a straw? The Rear tire size would also make a difference.

BSA according to the manual says 17 tooth and 49 tooth is standard but I am thinking this 30 HP bike at 307lbs. would really like the 19 tooth and 47 tooth to keep the rpms down and still have plenty of torque.

The caveat to this is roller big ends do not like being laboured and the slower the speed the clutch revolves at the more it is prone to slip .

I used to think the 18/47 was the trick…..dropped the RPMs maybe 500 or so at highway speeds. Back 20 years ago I thought the 18 was as big as it got…..and they were hard to find…..to a point where folks were machining 530 sprockets.

I hated the 19/47 on my B50 but love it on my latest B44R. IMO if you’re going to stay on the road higher (you are correct) gearing helps keep the bike from being so buzzy.

I’ve collected sprockets from 14-19 and 47-60…….and have tried all sorts of combinations.

Programmable advance curves would fix the labouring of the big end at low revs as you could retard the spark at low revs but keep the fully advanced timing, twin plugging where less advance overall would also work. Or go back to points and play around with the advance springs preload and strength.

Might happen this coming week but I’m not known for going fast…..done literally thousands of miles on a BSA unit single in pretty much every road condition and I’ve never holed a piston and so far (fingers crossed) don’t think I’ve had any big end issues.

I can’t help but think about it when I’m climbing one of the many long uphill grades around here….” Have I just been lucky?”

LOL, no just been in the right gear !!!

I’m always aware of what Mr Healy recommended. If you twist the throttle and you can’t increase speed……down shift!!!!