70s GS750 really this undergeared?

[ZacharyB]

I ordered from my parts place a stock chain, front and rear sprocket and put them all on. I noticed the rear sprocket had fewer teeth than the sprocket that was on there. "Oh, the sprocket I had wasn't stock... now I'll be able to turn even lower RPMs," I thought (or didn't; I'm 24). Turns out it's the other way around, I'm now turning really high RPMs in my opinion--I'm shifting into 5th by 35 mph (I live in the city) and doing 50 MPH at 4000. My MPG dropped by 5 points!! I'm so disappointed. The only upside that I can't use is that my acceleration has gone through the roof. Fat lot of good that does me in the city, where I'm lucky to get to 55 mph on off-hours. This was supposed to be my interstate bike.

My whining is done--my question is, that I ordered everything stock, did the GS really come this undergeared from the factory?

I've got 40 miles on the chains and sprockets, would it be too late to switch out the rear sprocket for one that has more teeth? Yeah, in effect, it is too late, because I already put the new one on...

[robinjo]

Re: 70s GS750 really this undergeared?

I ordered from my parts place a stock chain, front and rear sprocket and put them all on. I noticed the rear sprocket had fewer teeth than the sprocket that was on there. "Oh, the sprocket I had wasn't stock... now I'll be able to turn even lower RPMs," I thought (or didn't; I'm 24). Turns out it's the other way around, I'm now turning really high RPMs in my opinion--I'm shifting into 5th by 35 mph (I live in the city) and doing 50 MPH at 4000. My MPG dropped by 5 points!! I'm so disappointed. The only upside that I can't use is that my acceleration has gone through the roof. Fat lot of good that does me in the city, where I'm lucky to get to 55 mph on off-hours. This was supposed to be my interstate bike.

My whining is done--my question is, that I ordered everything stock, did the GS really come this undergeared from the factory?

I've got 40 miles on the chains and sprockets, would it be too late to switch out the rear sprocket for one that has more teeth? Yeah, in effect, it is too late, because I already put the new one on...

Lesser teeth on the rear sprocket lowers the RPM at a certain speed, your old countershaft sprocket was also different I think (or not I'm 30 )
I haven't ridden a GS750 for a while, must have been 3 or 4 years back I think but it revved higher then my 1000S. I would exchange the front sprocket for one with a tooth more and see how you like. What number of teeth do you have now? You can also exchange your rear sprocket with aonther one with less teeth but your chain would have to be shortened, 1 tooth in front is about 2,5 in the rear.

[jimcor]

The only explanation for your 'reverse' performance is the new stock front sprocket has to have two possibly three teeth fewer than the old one you took off.
You can change it out if your new chain is long enough to accomadate the extra teeth. You'll be out the $ for a new sprocket, but you'll make it back in mpg and less engine wear.

Not 'undergeared', low geared. Yes, some the of models had some very low gearing, and they screamed. The 80 550L had some ridiculously low gearing...and you could go aftermarket and get even lower!

Call and get a free Dennis Kirk Catalog, 800-328-9280. I don't give a hoot wether you buy anything from them or not. It is the greatest parts cross reference guide you can get for nothing. Chain, sprockets, suspension, turn signals...yada, yada.

[ZacharyB]

Call and get a free Dennis Kirk Catalog, 800-328-9280. I don't give a hoot wether you buy anything from them or not. It is the greatest parts cross reference guide you can get for nothing. Chain, sprockets, suspension, turn signals...yada, yada.

I should have never thrown mine out. Damn housekeeping tendencies.

Thanks for the info guys!

I didn't check the number of teeth on the new sprockets, because I thought stock gearing would be as Suzuki intended it to be, and All Would Be Good.

The teeth on the old sprockets were:

Front: 15
Rear: 41

[frosty5011]

Call and get a free Dennis Kirk Catalog, 800-328-9280. I don't give a hoot wether you buy anything from them or not. It is the greatest parts cross reference guide you can get for nothing. Chain, sprockets, suspension, turn signals...yada, yada.

I should have never thrown mine out. Damn housekeeping tendencies.

Thanks for the info guys!

I didn't check the number of teeth on the new sprockets, because I thought stock gearing would be as Suzuki intended it to be, and All Would Be Good.

The teeth on the old sprockets were:

Front: 15
Rear: 41

I thought that 15 front and 41 rear was stock on the 750? (that and 96 links) 8O 8O

What number do the new ones have?

I was surprised when I first read this, because the '78 750E I did up a few years ago was geared much better than my 80 850L. You could take it a nice 'low' rpm on the highway in 5th....whereas the 850 was quite a bit higher in rpm's.

[jonr]

Stock is indeed 15/41 on a 78 GS750 according to my parts fiche.

I'm running tan plugs with plenty of punch and I have always got between 35 and 38 MPG. If I remember correctly, I run about 5000 RPM at 65 MPH or so.

J

[jimcor]

Yep, something funny going on around here. 15/41 is what my DK catalogue states...hmmm.

Brake isn't dragging? Nothing binding on reassembly?

Don't think you can go smaller than 14 teeth on the front sprocket.

Any chance the dealer gave you a 14 tooth front sprocket?

[ZacharyB]

I should have compared them. I don't know the size of the sprocket I got. Well, this will make sure I always check in the future (and order my own parts!). Yeah, I got a 96-link chain. I'm going to take the sprocket cover off and check come morning.

I remember the rear sprocket had a "40" stamped on the face so I assume it was 40 teeth. This was when I hadn't checked for stock sprocket size, so I didn't catch it not being stock... what did the guy give me? 8O Son of a B!

The only bright side to this is that now I will have a spare sprocket set that makes the bike a screamer, which could be a selling point...

Edit: I just sifted through the trash for the front sprocket casing. This a-hole had ordered me a 13T front sprocket!!!! Arrrgh!!

I have one more question--what's the difference between the two front sprockets on this page? (Aside from price)

http://tinyurl.com/cdt5h

[jimcor]

I see what you mean about that DK sprocket. I'd call to order that one, rather than order on line.

If you're going to use that bike on the highway, I'd keep the 40T rear and go with the stock size 15 tooth front! This will keeps the revs down a bit and shouldn't really cut in to your stock acceleration.

13! No wonder that thing was a screamer! 8O 8O

[frosty5011]

I have one more question--what's the difference between the two front sprockets on this page? (Aside from price)

The 8008115 is for a 82-83 GS750T

If going with Sunstar, you want the 8006915

[ZacharyB]

Thanks Frosty! And everyone, for your help.