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General GS500 Discussion / Re: thinking about gearing down...
« Last post by user11235813 on Today at 06:32:46 AM »
...Currently in top gear I turn about 4K rpm at 60mph....

That seems a low rpm! I thought it was closer to 5K at that speed. I'll have to go out and check.

btw, I presume you've seen the https://www.gearingcommander.com site but I'll put it here anyway.



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General GS500 Discussion / Re: thinking about gearing down...
« Last post by Watcher on Today at 04:42:54 AM »
Basically, no one outside a lab will have evidence.

Which means to me "you won't notice a difference."
I'm sure things like chain lubrication schedule and sprocket alignment have far bigger impacts on chain life than the sprocket size.

I can.....it's down to a phenomena known as chordal action or chordal effect. {Snip}

Interesting.
Thanks for the info.
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General GS500 Discussion / Re: Sticking shim bucket left exhaust.
« Last post by Numewsm on January 19, 2019, 07:38:48 PM »
I would avoid using pliers if at all possible, it's inevitable the serated jaws will damage the finished surfaces. try and find some that have plain jaws. I would also avoid using a naked flame and instead use a hot air gun for the same reason..........But in saying that your options are very limited

You will probably find some scoring between the walls of the follower and the chamber, polish it out with 240 or higher wetndry and light oil or WD40. When you reassemble ensure everything is 100% clean and that there is plenty of oil in the chamber.

I have used this method several times with mixed results. In a couple of cases the buckets again seized after a short period of time.
Thanks for the advice. I'll see how it goes and report back!
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General GS500 Discussion / Re: Sticking shim bucket left exhaust.
« Last post by sledge on January 19, 2019, 05:54:24 PM »
I would avoid using pliers if at all possible, it's inevitable the serated jaws will damage the finished surfaces. try and find some that have plain jaws. I would also avoid using a naked flame and instead use a hot air gun for the same reason..........But in saying that your options are very limited

You will probably find some scoring between the walls of the follower and the chamber, polish it out with 240 or higher wetndry and light oil or WD40. When you reassemble ensure everything is 100% clean and that there is plenty of oil in the chamber.

I have used this method several times with mixed results. In a couple of cases the buckets again seized after a short period of time.
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General GS500 Discussion / Re: Sticking shim bucket left exhaust.
« Last post by Numewsm on January 19, 2019, 04:31:39 PM »
Right, I've ended up taking both cams off.
Li was at 0.00 but bucket moves and comes out
Ri was at 0.01 but bucket tight. Won't come out. Moves under duress!
Re was at 0.01 and bucket tight. Won't come out. Moves under duress!
Le gap unknown. Bucket stuck down at rim won't move.
Ri shim 2.58 go for 2.50 shim?
Li shim 2.58 go for 2.50 shim
Re shim 2.65 go for 2.55 shim?
Le shim put in the wrong way and number rubbed off. 😮 I'll get it measured to get its width.
To remove these buckets, currently sitting in snow foam for the next 24 hrs, should I then heat up the surrounding area around the bucket with a heat source, i.e blow torch etc, and work the bucket up with pliers?
The worse problem bucket would pop up to its full hight after a few cranks of the cam.
Or do I put the cams back on and work the bucket up and remove the cams again?
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General GS500 Discussion / Re: thinking about gearing down...
« Last post by mr72 on January 19, 2019, 01:13:03 PM »
Have you tried to find +3 or +6 rears?  I ask because going down on the front increases chain wear because it's going around a smaller radius.  While other setups have smaller fronts on higher output engines, I prefer to reduce the effects on the existing maintenance schedule.

I also ask because comparing a GS and a Triumph, two down may not be enough.

Yes I considered it. But not for the reason you mentioned, which I also did in fact consider as well. :) Too many years mountain biking, I'm fully aware of the wear factor. It's not only the chain but the sprocket itself will wear more quickly with fewer teeth.

I considered going up a couple of teeth on the rear in conjunction with going down in the front in order to keep the overall chain length the same. I haven't gone out and measured how much slack I can take up with the chain adjusters but I don't want to have to cut the chain when switching;

This brings up other options of perhaps going down to 15t in front and up to 40t in rear, which will give me something slightly between my previous two options.

Regarding the difference with the Triumph, well it has 70% more torque than the GS, but the gearing on that bike is very different and the torque curve is a lot wider. I did a (not-so) quick and (pretty much) useless set of calculations to compare. Counting the primary drive and final drive ratios, I calculate that stock, the bike is traveling about 10% slower across the board in each gear 1-5 on the GS when the engine reaches the torque peak than the Triumph is, but also this gives about a 1.1x torque multiplier. So to get the GS to have a similar torque feel I would have to increase the gear ratio by about 50%, which is not possible. So there simply is no way to get the GS to "feel" like it has as much torque off the line as the Triumph by gearing changes.

One funny thing is that if I go with a 14t front sprocket on the GS then when calculating the primary drive and final drive along with the transmission gear ratios, 6th gear in the GS will be almost exactly the same as 3rd gear on the Triumph. That's nuts! But maybe that's acceptable. I'd be turning nearly 5K rpm at 55mph on the GS with a 14t front sprocket and my current rear tire (140/70). The good news I guess is that would be an indicated 65+ mph.

And... I'm ok with all of that. So now I'm even thinking I might as well go totally nuts and get a 14t front sprocket and a 41t rear and swap the whole thing. I won't likely be doing long stretches at 60mph on the GS, I have a Triumph for that. With that gearing, at 45mph-50mph, which is really the more realistic top cruising speeds I get to on the GS, I would only be turning 4200-4500 rpm. That's not horrible. And I happen to know my GS is quite peppy at 4500 rpm, nothing wrong with that. If I have to take a stretch of 60-65mph it's well within the reasonable cruise range of the GS, it'd just be loud and probably get crappy mpg and make me want to get back on the back roads ASAP. But that bike would be a back-road monster with that gearing.

I think I'm going to do it. That should inject a big chunk of extra character into the old GS.
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General GS500 Discussion / Re: Parasitic battery Drain
« Last post by mr72 on January 19, 2019, 12:10:15 PM »
Are you locking the steering?

I didn't think about that. Good point! And the rest of FH's post, more good points  :thumb:
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General GS500 Discussion / Re: Parasitic battery Drain
« Last post by sledge on January 19, 2019, 10:04:31 AM »
Parasitic drain?

If you are 100% certain the battery is serviceable and holding charge it's probably one of the diodes in the reg/rect failing and causing a high resistance ground.

Unplug it when the bike is not in use, if the battery stays charged.......case closed!




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General GS500 Discussion / Re: thinking about gearing down...
« Last post by Falken Hawke on January 19, 2019, 09:58:00 AM »
No.  Parts are long discarded.  Besides, even if I did still have them, variables such as maintenance is inconsistent over time, weather conditions, etc., etc.  Basically, no one outside a lab will have evidence.

Individual experiences will vary based on what was tried and experienced.  Other common variables are the vehicle, its use, the rider, and the specific parts.  I'm not saying don't go two down but rather that there may be results that are otherwise not desirable.
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General GS500 Discussion / Re: thinking about gearing down...
« Last post by sledge on January 19, 2019, 09:41:13 AM »
I can.....it's down to a phenomena known as chordal action or chordal effect. In simple terms the lower the number of teeth on a sprocket the More the chain will vibrate as it passes over it and obviously the More the chain vibrates the shorter it's lifespan.

http://chain-guide.com/basics/2-2-1-chordal-action.html

And of course you have to consider what effect the increase in vibration will have on other components and the ride quality.

I am with Falken on this, far better to alter the larger rear sprocket, at least from an engineering point of view.
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