G3 First ride

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G3 First ride

Postby Heinz 57 » Wed Feb 04, 2015 2:30 pm

Despite the cold weather, I couldn't wait any longer to try out my recently acquired G3.

First impressions are that it's easy to start. (It's got 12 volt electrics and Boyer ignition.) it accelerates better than I expected but seems to run out of steam at about 55 mph or maybe I'm worried about blowing it up.

It feels under geared to me. It's a 1959 and has 18" wheels. Would 18" wheels make enough difference to need another tooth or so on the engine sprocket? Either someone who knows these bikes better than me needs to ride it and tell me this is how it should be or I need to check sprocket sizes or the overall gearing somehow.

The brakes aren't bad either for cable operated SLS drums.

Anyway, just thought I'd share this.

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Re: G3 First ride

Postby Rob Harknett » Wed Feb 04, 2015 4:15 pm

Do you really need to go faster than 55 for a nice run in the countryside.
Back in the 50's I was quite happy riding about 50MPH. In fact there were very few long straight roads to have a burn up. Perhaps touching 75 once the bike got going. I put a hi comp piston in my 55G3LS that made it go like a Triumph speed twin, not for long, big end soon failed.

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Re: G3 First ride

Postby Janet » Wed Feb 04, 2015 6:19 pm

Heinz 57 wrote:It feels under geared to me. It's a 1959 and has 18" wheels. Would 18" wheels make enough difference to need another tooth or so on the engine sprocket? Either someone who knows these bikes better than me needs to ride it and tell me this is how it should be or I need to check sprocket sizes or the overall gearing somehow.
You may be in luck. There is a club section meeting at The Tiltyard, Leyes Lane, Kenilworth on the 2nd Monday of the month. I think that's somewhere near you. I suggest you ring the contact, Andrew Ross tel. 01788 815448 to confirm it's on first.
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Re: G3 First ride

Postby Heinz 57 » Wed Feb 04, 2015 7:31 pm

You're probably right Rob. It just seemed like it flew through the gears too quick and topped out. I thought that's fine for the lanes but if I was to do a couple of hundred miles to a rally it might be a bit tedious. I'll go for another run when I feel I can brave the weather again and see how it feels.

Janet, many thanks for the information. I know the Tiltyard and its only about five miles from me. I'll give Andrew a call and I can see what he thinks.

I do like the bike though. It's mechanically very quiet, smooth shifting and handles well.

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Re: G3 First ride

Postby saltbox alf » Wed Feb 04, 2015 8:34 pm

Well done, nice to get out and have a go. Realisticaly about 68mph is about tops if your lucky!! 50/55 a good cruising speed. I do think that the 18" wheels came in for 1963 and yours should have 19" for 1959!
Chaps at the local section should be able to help you.
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Re: G3 First ride

Postby Ozmadman » Wed Feb 04, 2015 8:44 pm

Many of our models seem under geared... I have a model 8 which has an 18tooth gearbox output sprocket as standard and 1st gear is almost redundant unless you live at the bottom of a 1:4 gradient.. i switched to a 19 tooth and that was better but now the bike is in bits I have gone for the max (20 tooth) which I am hoping will give a more relaxed cruising speed as the bike has enough torque to pull that I should think. i will come back on this once the bike is up and running again

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Re: G3 First ride

Postby Heinz 57 » Wed Feb 04, 2015 9:31 pm

It was quite pleasant in the winter sun Alf and not long enough to get too cold. From what you say, the gearing is probably about right then. That's fine, I just need to adjust my riding style. Relax and enjoy the ride. The 18" wheels surprised me although the bike is far from original. Definitely a bitsa.

Paul, like you, it feels under geared to me, as if it would pull a fifth gear. I'm reluctant to disturb the primary so if curiosity gets the better of me I might see if I can rotate the engine in top and see what the overall gearing is.

I'll go quietly now and just ride it.

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Re: G3 First ride

Postby bjork » Wed Feb 04, 2015 9:42 pm

Go quietly? On a G3? With low gearing? :lol: Ref the 18" wheels, they will lower the gearing so would account for some of what you're saying. These bikes often feel undergeared on modern roads as they were built for the roads when Rob were a lad. No motorways and even a dual carriageway was a novelty, for a few minutes till you noticed what the road testers meant about 'some vibration was apparent'.
I think you could easily add a tooth or two on the crank sprocket and one on the gearbox too. Some folk have added lots of teeth and reported it to be good. It must work for them but I know it wouldn't for my weight as soon as I got to the first proper hill. If your standard crank sprocket is 19t, try a 20 or 21. They are available secondhand at jumbles and on the jumble shelves at Kettering. Then just settle back and enjoy the ride!
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Re: G3 First ride

Postby Rob Harknett » Wed Feb 04, 2015 11:06 pm

Heinz 57 wrote:You're probably right Rob. It just seemed like it flew through the gears too quick and topped out. I thought that's fine for the lanes but if I was to do a couple of hundred miles to a rally it might be a bit tedious. I'll go for another run when I feel I can brave the weather again and see how it feels.

Janet, many thanks for the information. I know the Tiltyard and its only about five miles from me. I'll give Andrew a call and I can see what he thinks.

I do like the bike though. It's mechanically very quiet, smooth shifting and handles well.

Back in the 50's I did many a 1000 mile holiday break 2/3 days, driving to and from at night. Roads were different then and at night only long distance lorry drivers on the road. The 6v lights shone bright as bike light was the only light. Few street lights they went off at midnight. 50 mile 2up was a fair speed, it seemed faster as you could only see as far as your lights. I ran at night on side light and a spot lamp. I could thrash the bike at 70 easy enough between coffee bars, but never did on long runs with just me and the girl friend.

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Re: G3 First ride

Postby iansoady » Thu Feb 05, 2015 11:15 am

I felt my 57 G80S was very undergeared - I'd be in top long before getting out of the 30 mph zone.
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