Gear ratios key to low speed

[haga41cat]

Got it at last, as i mentioned before in another thread my gearing is way off, but i found out i was even more off than i realised.
Standard is 15 43 ratio of 2.867
I thought i had 17 45 ratio of 2.647
Just found out the 45 stamped was a part ref or something and under some crud found a 38 so im running 17 38 ratio of 2.235!!!!!! Way out.
So when i fit the 49 it'll be a ratio of 2.882 alot closer.

The old ratio would be like running a standard 15 and having a 33 or 34 on the back, crazy maybe i shouldn't of just used the sprocket that was on the suzuki GS sprocket carrier then

 

[haga41cat]

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[Lou Ranger]

Just curious if you are dissatisfied with the way it rides - i.e., does it rev to high in top gear or too low? Isn't the sprocket ratio kind of a meaningless number without knowing what the final drive ratio of the transmission is?
The reason I ask, is that my Maxim had a 16T/35T combo and a 5 spd. The 6 spd Seca has, I think a 16T/38T combo, yet the revs at speed are the same. Don't you have a 250 cc. engine and tranny which will have a whole different set of drive ratios?

 

[haga41cat]

No in 5th and 6th it rolls off and won't continue with the rev range, so im dropping back to 4th to get it back up and the cycle begins again. Whan i fitted the gs500 wheels it had a sprocket on there in good nick, so i thought id see how it faired and its turned out that the ratio is beyond the ability of the engine to rev out full in the top two gears hence the correction.

 

[Lou Ranger]

... its turned out that the ratio is beyond the ability of the engine to rev out full in the top two gears hence the correction.

Thanks, that totally makes sense. I may turn into a motorcyclist yet.
So in layman's terms, it was too much of a good thing (though I recognize not every rider would enjoy losing 400 rpm at 90 kph as I). While, I might never need to have it top out in high gear, even I wouldn't want to need to drop down 2 gears to go up a hill.

It must have been interesting starting out up-hill from a dead stop too.
Glad you had enough spare bikes sitting around that you could get it back into its range.

 

[haga41cat]

Im talking about dropping two gears on a flat road lol its that bad

 

[Lou Ranger]

Im talking about dropping two gears on a flat road lol its that bad

Wow. Sounds almost like "gas-saver mode" where you run on only one cylinder. The transmission gearings must really vary a lot. My sproket ratio for 17/35 is 2.059 - way lower than yours, yet at 90 kph it runs at 5100 rpm. Mind you, my bike has only the 5-spd transmission. Interesting.

 

[haga41cat]

Mines a 250cc btw, i've been pissing about with jetting to no end cos of my homemade exhaust pipes and open filters, it seemed like the problem obviously was jetting as i'd mucked about with fueling. I originally thought i wasn't far off with gearing and it would be fine as it said 45 but didn't see it actually said p45 (a part or make stamp o think) and it was a 38 tooth!
Yeah the DOHC had a different gear box and engine completely.

 

[haga41cat]

Woohoo!! Full revs in every gear. Finally its running lovely and the weathers taken a turn for the worse

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[drewpy]

Woohoo!! Full revs in every gear. Finally its running lovely and the weathers taken a turn for the worse

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I know, typical. my battery has still not arrived.

 

[Scorpio1963]

View attachment 9086

View attachment 9087

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I suppose theres a lever to shift the chain from 1 sprocket to another?