Bigger rear sprocket: yay or nay?

[fyarl666]

I have an 81 GS 400L, and I'm going to replace the chain and drive sprockets, both front and rear. I went to the local bike parts store just to check prices and availability of items so I would know if I have to buy online or not.

The he guy told me he is not able to get a 41 tooth rear sprocket, which is what my bike is running with right now. He said the next smallest sprocket is a 43 tooth, but suggested increasing the size of the front sprocket as well so as not to knock the gear ratio too far out of whack.

Is is this acceptable? Or is this information total BS? I've tried to do a bit of research, and from what I've discovered, it seems like his suggestion is logical but I figured I'd ask the experts here first.

 

[Steve]

We did not have a 400L in '81, so the only information I have to go on is what was available here.

The '78 400 had 16F/45R sprockets
The '79 425 had 16F/45R sprockets
The '80 450 had 16F/41R sprockets

Moving to a 43 on the rear (from your current 41) will raise your engine RPM ever so slightly at any given road speed, but should not be a problem unless you do high-speed riding on the highway all the time.

.

 

[fyarl666]

The 400L was only available in Canada. Usually when I'm searching for parts, I have to look for 81 450L.

 

[tkent02]

How do you use the bike?

Which type of performance do you want?

 

[fyarl666]

How do you use the bike?

Which type of performance do you want?

Mostly just city driving, not more than 50 to 60 kph. Occasionally I'll ride to work which is a quick highway trip, ten minutes at 100 to 110 kph.

I want the bike to run adequately without causing damage to itself that will cost me $$$ to fix every two months. After that, as long as I'm pretty good.

 

[chuck hahn]

Given your driving style would leave it stock. Going to bigger sprockets also means a chain with more links`also.

 

[Guest]

Put a fifty on it and ride on one wheel

 

[Gorminrider]

I wouldn't worry too much but I wouldn't want to lose top end speed on my 400. Torque is not an issue. They will launch two people and some luggage uphill from a stop as they are.......43/41 is 5%.. one 1/20th....You are in Saskatoon and not challenged overmuch with hills except at the river? I would overshoot 5% for a faster bike rather than gain torque versus speed....
You have to change both sprockets anyways if there's wear on the ones you have. Yes Chain will be a tad longer but they come needing to be cut anyways in my experience.

 

[fyarl666]

I'm doing both sprockets as well as the chain.

Yes, I'm in Saskatoon, so hills are not much of an issue round here. I did some math and figured that the new sprockets will give me a small percentage loss of top speed, but obviously will gain a bit more torque.

Thanks for for the info!

 

[Jedz123]

+3 in the rear is equal to about -1 in the front. You'll notice an acceleration change (as in the bike will go 0-60 quicker). The revs will increase 300 rpm (dependent on gearing) in 6th gear at 50 mph. I go shorter gearing on all my bikes when it's time for sprocket change. Usually go -1 up front for its cheaper. The FZ1 is -2 in the front +5 in the rear. Bandit -1 in the front. The GR is stock for now for its geared really short with only a 5 Speed. The B-King is fine. Very tall gearing but the HP backs it up.

You'll enjoy the new gearing. More fun, little less in gas but worth it IMO.

My 2 cents.

 

[fyarl666]

Yeah you weren't kidding, way more fun. Makes a huge difference starting from first gear, bike definitely has a set of balls to it!

 

[tkent02]

Yeah you weren't kidding, way more fun. Makes a huge difference starting from first gear, bike definitely has a set of balls to it!

What ratio did you change to?

That's the next thing I'm changing on my 450, it's geared to do 125 or so mph at the redline, no way in Hell it has the power to pull it.
Better sprocket ratios and it will be a lot better to ride.