G3 First ride

[Janet]

I'd be in top long before getting out of the 30 mph zone.

The corresponding low revs and reduced battery charging may be one possible reason why some people have problems with their headlamps fading at night.

[Heinz 57]

Bjorn / Ian, I did a very rough final drive ratio measurement which worked out about 6.75:1. I imagine that it could stand another couple of teeth on the engine or gearbox sprocket. Engine sprockets work out around £42 whereas gearbox sprockets can be had for around £25.

Rob, the 50's must have been one of the best times for motorcycling. I'm envious. I didn't start till 1970 but that was good too.

The lighting on my bike is quite good Janet. It's got a 120 watt alternator so should be OK but I know exactly what you mean for those with 6 volt dynamos. I remember well.

[dave16mct]

Thats low (is that in topgear?) Should be 5.80 to 1 according to the 57-64 workshop manual with standard 19 tooth engine sprocket and 16t gearbox sprocket.
Dave.

[saltbox alf]

Oh to be pedantic Just done some maths, or more to the point my missus has, (cos I run out of numbers after 21) well using Pi and working out revloutions of the wheel per mile and other stuff I don't understand---- Come to the result that an 18" wheel will be 5.56% slower than a 19" wheel over a mile, so , if your speedo is calibrated for a 19" wheel it will read a set speed but actually you will be going, yes ,5.56% slower.

Yes a change of gear box and or engine sprocket would make a difference, my G3ls has a one tooth extra gearbox sprocket and goes quite well.

Now for a glass of red and a rest of the grey cells

[Heinz 57]

That was in top gear Dave. I doubt that it was deadly accurate but it does look low.

Alf. The 18" wheels make a significant difference then. I will have to take the primary cover off and see what engine sprocket I've got and assume the gearbox is 16 tooth. Just need motivation now.

Thanks all for your input.

[Colin F]

No one has taken into account tyre sizes

When I changed my back wheel from 19 to 18 inch part of the reason was for a better choice of tyre which I changed from a 3.5 to 4.
This gave me almost the same circumference, so gear ratios and speedo was unaffected.

[rex.webb]

SAME HERE !
When Ernis built the Diesel Matchles`s machines .He allways put a 4.00X18 0n the rear .
This he had worked out did VERRY LITTLE to alter the Spedo which was for a 3.50X19 .
RIDE with CARE ( IN the FROSTY Snowey ) weather
And LIVE LONG to enjoy your
MOTORCYCLING and Scootering .

[saltbox alf]

No one has taken into account tyre sizes

Very true Colin , I was just working on an assumption it had a standard wall height. However the post of Heinz did say it seemed it was going a bit slow to what he perhaps expected. Of course there are other factors that could be a problem , timing , carb and 99 other things Hope Heinz gets to a section meet and lets us all know any results.
Any photos

[Heinz 57]

I'm going along to the Warwickshire meeting on Monday. I'll see what the experts think.

Thanks everyone. Here's looking forward to warmer weather.

I don't think I can post photos yet. I Need to pay my dues first.

[Ozmadman]

I don't think I can post photos yet. I Need to pay my dues first.

You do!! otherwise you won't be able to access the forum either after a fixed time... Digital membership is only £22 a year and well work the dough. Full acess to the forum and a digital Jampot mag every month plus all the help and experience you will ever need to keep your bike on the road..

Paul