The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: RoyC on 26.11. 2017 11:56
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I am gearing down for the sidecar and have two questions.
1. How do I get the split pin out that is inside the recessed locknut (see picture)
2. My existing engine sprocket is 19 teeth.
I have got a 17 T and a 16T , which one would be best ?
Thanks, Roy.
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1. How do I get the split pin out that is inside the recessed locknut (see picture)
*conf2* ....(1) straighten the legs and pull it out by its head, or (2) Cut the head off and pull each of the legs out...
2. My existing engine sprocket is 19 teeth.
I have got a 17 T and a 16T , which one would be best ?
A. Depends on the terrain around where you plan to ride. If it's super hilly, the 16T would haul easier but rev more. Personally I think best to go bigger on the wheel sprocket, but the downside of that is a wheel sprocket may be hard to find, and it will affect the speedo/odometer reading, but that's easy to compensate for by don't look at it, just calculate the % of inaccuracy for mileage/fuel consumption/range
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1. How do I get the split pin out that is inside the recessed locknut (see picture)
I don't think you should have a problem with that split-pin. Bend the legs straight. Use long-nose pliers to pull the pin out. If that doesn't work, bend the head up and grip it with a mole wrench then tap the wrench with a hammer to pull the pin out.
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I will do what you both suggest and rip it out, problem will be getting the new one back in.
Pretty flat around here so will go with the 17T to retain a little top end speed and MPG.
Thanks for the replies.
Roy
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Hi Roy,
Have you tried the bike on the existing gearing?
Back when the bikes were built the traffic speeds were much lower,
To keep up with modern traffic with "low" gearing the engine will be revving its nuts off *eek*
On the BSA twins that I have rebuilt for solo use I have geared up from standard and the results are
good for today's road speeds
John
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Roy,
My gearbox is a scrambler type, so, lower gearing for 1-3 to start with. Maybe this is why I found my existing 19T sprocket too.low. Changed to a 22T for solo and was much happier. I don't really know about sidecars, but I would have thought the 19T was low enough. I think John hit it in suggesting trying it as is. If it's good you don't have to go through the sprocket change and potential chain modifications, twice.
Regarding replacing the cush nut pin, problem solved if you get an SRM cush nut. Use a regular socket on a torque wrench and tighten to 65 ft-lb. Locking up the clutch while tightening is another question. Some use a clutch-locking plate, some stand on the brake with the bike in gear. I use a piece of aircraft cable laced in the primary chain and anchored to the frame. I'm sure there are more methods.
Richard L.
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I have geared up from standard and the results are good for today's road speeds
Me too. I agree.
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It is easy to overgear an outfit so that it is faster in third than in top. And flexibiity suffers.
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Julian,
For my understanding, are you saying that a lower drive ratio, say 19T instead of 17T can cause the condition you mention, and why is this?
Richard L.
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19 tooth on either engine or gearbox will give higher overall gearing than 17 tooth sprockets.
Factory recommended sprockets for A7 sidecar were 18 (solo 18) engine and 17 (solo 19) gearbox.
overall ratios with STD box;
1st =13.62 (solo) 15.2 (sidecar)
2nd= 9,28 (solo) 10.35 (sidecar)
3rd=6.38 (solo) and 7.02 (sidecar)
Top = 5.28 (solo) and 5.9 (sidecar)
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Got the engine sprocket changed to a 17T but now the chain is too long.
The book states that the engine sprocket should be 18T, but someone in the past had changed it to a 19T and the roller coaster parts were not a good match, but on the 17T that I have just fitted they are a perfect match.
Looks like the chain wants shortening by about 1 to 1½ links (Renold's chain).
The book states Primary chain ½ x .305, is that the same as ½ x 5/16 ?
Will a chain splitter fit both primary and rear chains ?
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1/2 inch is the pitch and 0.305 inch the diameter of the roller.
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The reason for lowering the gearing when fitting a sidecar is to lower the stress on the engine, you can get away with increasing the gearing on a solo but you do run the risk of going faster in third than you will in top. Years ago a friend of mine had a Norton 99 he increased the gearing via the engine sprocket and his bike would do about 95mph in third but when he went into top gear it did not go any faster it just reduced the revs. Also about 50 years ago my brother fitted a sports sidecar to his 1957 Gold Flash and did not change the gearing most of the time he had a mate in the sidecar the bike lasted about a month when the crankshaft snapped through the big end journal. Now at that time the Gold Flash still had the small journal crank shaft but would the same have happened to the larger journal crankshaft I would not be prepared to take that chance and would always lower the gearing if fitting a sidecar. Too expensive to take the risk of not changing.
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I had to go to the book so I could put my comments in context. My bike is a '55 A10, which is listed as having a 21T engine sprocket stock versus 18T for a stock '58 A7SS. So, my going up from 19T to 22T seems OK for a scrambler gearbox on the street and Roy's going down one tooth to a 17 for the sidecar also now makes sense to me.
Sorry if I confused the issue, not to mention, myself.
Richard L.
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Hi ALL,
While reducing stress on the engine is a good thing, over revving or continuous high revs at a lower road speed
cannot be too healthy for the innards *????*
My brothers SR on "standard" gearing feels very harsh at 60-70 MPH compared to mine that has a 23 tooth engine sprocket
I ran on a 22 tooth for a while and felt as though I needed a 5th gear *ex*
It will rev out on the 23 tooth without a problem, and runs nicely at 4000rpm at 70MPH
(I know all this is getting away from Roy's A7 sidecar issues *red*)
John
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If you want to keep up with modern traffic then ride solo, with a sidecar attached forget about keeping up with today's traffic by keeping solo gearing. The gearing does not affect the stability of the bike but speed does, going round a corner either left or right on a solo machine makes no difference the stability does not change. On a bike with a sidecar you can go round a right hand corner much faster than a left hand corner, take a left hand corner too fast and the sidecar will come up off the ground losing you control of the bike this happens easier with sports sidecars simply because they are lighter. Back in the day it was not uncommon to put a bag of sand in the sidecar to help stability when not having a person in the sidecar. I know all this from experience when in my youth I used to borrow my fathers Gold Flash which had a child adult Canterbury sidecar fitted, I also rode a neighbours Ariel twin with a Steib sidecar fitted. As a family years ago we would travel all over the country on more than one occaision travelling from NE England down to the South Coast me and my brother on my Norton 88 solo and dad and the rest of the family with the sidecar outfit dad would criuse at about 50mph top speed I would belt on ahead for a while then stop and wait for them to catch up even then 50mph was quite slow for me, now even on my A7 or A65 I rarely go above 55mph. I,m showing my age now.
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Hi Roy, I'm late here but in the mid 60s I put a Canterbury Double Adult on my Golden Flash (the one in the picture). Had it on for about a year to transport my girl friend (now my wife) around in absolute luxury - so it must have worked. I never changed the sprocket from the 21 toothed solo sprocket and never found it was a problem. Then easy to take the chair off and go back to solo - which I did a couple of times.
When you fit your chair don't forget to tighten the steering damper down or you'll drive up the road doing tank slappers. Beware going around left corners too fast as you can lift the sidecar wheel off the ground and steering is more of a push and pull on the handlebars,
Great fun though, I loved it.
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My A10 had a sidecar chassis when I bought it. I made a body for the sidecar; tried it; hated it; took the sidecar off.
In olden times when folks couldn't afford a car a sidecar outfit for the family, or even a girlfriend must have seemed like a great idea, however if you've already been a car driver and a solo motorbike rider a combo seems to be the worst of both worlds, at least in colder climates; you can no longer zip about among the traffic and you, the driver, have to sit in the pouring rain for hours. That's exactly what made me give up the sidecar: my wife and I went to visit parents one rainy Saturday in the winter. We got stuck in traffic on Londons South Circular road. Janet was ok in the sidecar, (although probably freezing her wottsits off) while I just got soaked to the skin! I swore never to do that again! The chair was off and put in Exchange & Mart in double quick time.
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Keep solo gearing results in poor acceleration and flexibility - ok if you are riding a nice long straight road maybe. But not much fun on country roads or on an organised run.
The sidecar will add about 200 lbs weight or almost half the bikes weight.
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Going from memory riding solo and driving an outfit you need a totally different outlook and handling technique but I quite enjoyed it. I have fond memories of poodling along with my left elbow resting on the top of the sidecar.
My only experience was with the Canterbury Double Adult, and it was a very big sidecar but I don't ever remember my Golden Flash struggling with it and here in the south west it's very, very hilly. I would imagine a light single seater would be a doddle. The Canterbury had windows front and back with three on the sides and one seat behind the other. It had a canvass press studded top which could be rolled up and secured with straps, so a nice sun roof and you could easily chat with your passenger. I do remember on more than one occasion having to retrace my journey to look for the perspex windows that blew out . . . so I must have been able to go r-e-a-l-l-y fast!
There were other benefits that I remember, and not being a car driver in those days, that I liked, such never having to pull my bike onto the main stand - just leave it in gear. Get on it like you would a horse, easy position to kick start it, somewhere to keep your waterproofs and anything else you want to carry.
My best friend was a motorcycle salesman for Kings of Oxford and he got it for me for a knock down price and helped me fit it to my GF. The one thing we forgot was to firm up the steering with the damper and on my first test ride, being used to riding solo, I opened the throttle and nearly hit the wall. I remember you had to fit it with a certain amount of lean out and tow in for stability.
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you can no longer zip about among the traffic and you, the driver, have to sit in the pouring rain for hours. That's exactly what made me give up the sidecar:
I don't intend going out in the rain.
1968. It was going down the outside of stationary traffic that made me end up in hospital for 6 months and 7 months convalescence after that.
I was in a traffic jam, so I overtook on the outside, only 5 to 10 mph, a Austin A35 van came out of a side road and that was it.
I still suffer with a stiff / painful left ankle, that is why, if I want to ride my BSA I have to have a sidecar.
Roy.
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you can no longer zip about among the traffic and you, the driver, have to sit in the pouring rain for hours. That's exactly what made me give up the sidecar:
I don't intend going out in the rain.
No one intends going out in the rain; it just happens! ;)
1968. It was going down the outside of stationary traffic that made me end up in hospital for 6 months and 7 months convalescence after that.
I was in a traffic jam, so I overtook on the outside, only 5 to 10 mph, a Austin A35 van came out of a side road and that was it.
I still suffer with a stiff / painful left ankle, that is why, if I want to ride my BSA I have to have a sidecar.
Fairy Nuff. Sorry to hear you were unlucky. *countdown*
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No one intends going out in the rain; it just happens! ;)
But some (one) is silly enough to do it 3 times in as many days.... *bash*
But at least it isn't cold