GK76A Sprokets

[jonhunt85]

any one no the Chain a sprocket set up on a GK76A as it was out the factory??

Did Cadwell Park Wed and 1st time i used the bike and found the gearing to Low only 2parts of the track i used 4th most of it was in 2nd.

Had a quick look and it has a 44t rear fitted 2moro going check the front might just slap 1t higher on the front.

also have a 45t rear sprocket spare but i no 1t is nothing.

any help??

[Jaicen]

I'd have a look at the front. From memory you should have a 44/15 combo on there, but i'll have a check later see if I can find out.
FWIW, if you have an SP, you can pull that to 60mph in first gear anyway, so that should tell you something about the gearing on these things. Just keep the revs around 10k and you'll be fine

[jonhunt85]

pop down the local garage. 14front and 44rear like ya said.

Dont have a speedo cable fitted but it def to low gearing. will check next week see if it has a 15 on the front if so i just slap a 14 = 3on the rear so that should be prob fixed.

also found out can get 44 to 47 rear if i liked.

thanks for the help

[Jaicen]

I ran a 48 /15 tooth sprocket on mine initially. It gave it monster acceleration, but it did run out if top speed, as it hit the limiter early. It also accelerated me into a citroën.
I am now running the standard 44/15 which is the best compromise for the riding I do.
Fwiw, you can use SV650 sprockets, they're readily available.

[Variablevalves suck]

Hi mate, i ran the bandit 4 at cadwell not so long ago and im sure we got the same 6th gear ratio.
I run a 160 76a rear wheel and 14/47 was spot on. I run 14/46 on the road or im doing 8000 rpm at 70 with the 14/47. 15 front may be a better way to go as you need a long chain to run the 47, i'd try 15/45 and then you have the 14 to go with it. If the bike is only ever on the track you could go over to 520 chain and sprockets as ivd done on the gk73a and i can recommend the talon stuff, well made and the guys are super helpful.

[Jaicen]

Just a word of warning, you can't use a 14/45 combo, because the chain won't fit. Seems to be a quirk of the swingarm geometry, but a 520 chain ends up being 1/2 a link too short, or 1&1/2 link too long, it just doesn't work. I tried for some time to make it work, but it really doesn't!

[Variablevalves suck]

Is that due to the slot in the swingarm not being long enough? Wont be due to the chain being 520 though, will it? arnt the 520 and 525 the same lenght just different thicknesses. Think i would be openning the hole up in the swinger, half a link should be easy.

[Jaicen]

The 520 is the one to use as far as I know. The problem seems to be that you can't have a chain with half a link in. As you say, the swingarm adjusters seem to be too limited. Don't forget that it will shorten the geometry if you wind it fully in.

Personally, I would just drop a tooth on the front sprocket and see how you get on with that first.

[jonhunt85]

Had a spare 10min at work and had a look. 16t on the front when it should be a 14t

I find 14t f and a 44t rear should be fine have a 45t spare.

Outlon Park on 16th the test it. i like it being high rev so i never have to use 1st gear on the track if i don't have to. i make up for lost speed on the bends easy.

thanks all for ya help. garage was saying i should think about next year getting a race chain less drag but as they said not cheep.

Jon

[Variablevalves suck]

Correct me if im wrong but dont a larger front higher the gears and a larger rear lower the gearing? if 14/44 is too high a 15 will make it even higher so you would need to increase the rear. The B4 with a 160 was spot on at cadders with 14/47 so i'd say you will need at least 14/46 + a longer chain. I think you divide the rear teeth by the front teeth so 15/45 would still be higher than stock, i think!!