Jetting & Chain/Sprocket questions

[wyldechild71]

Whats up guys my name is Jim I have a 77 GS750. I bought it for $400 dumped probably $1000 into her and I absolutely love it.

I just put a 4 into 1 exhaust on it and it runs like 110% now (the stock baffles were destroyed so I think it horrible back pressure). I realize with a bike you must change out everything if you want performance so my first question is this: I have the exhaust, I purchased indiv. filters, do you guys recommend the stage 3 dynojet kit? From what I have read this would be the easiest and most efficent improvement for my bike.


Now my second question, Ive been on many forums and I realize that the same old questions get old but I did a search and I cant seem to find a straight answer. I want to add some more torque to my bike and from what I have heard and read changing out sprockets are a good answer for this. I realize gas mileage and cruising rpm's will be compromised but this doesn't really bother me. I dont want to totally kill my top end, but what do you guys suggest as a good combo or even just one or the other as far as sprockets? My other question is if I put new sprockets on do I need to change the chain in any way? Thanks in advance

 

[posplayr]

Check for 520 mod for your bike

Check for 520 mod for your bike

There are newer chains that are smaller but just as strong which significantly (10%) change your rotating inertia (say increased acceleration). If there is something that will fit then strongly consider that if you want to swap out gears as the 530 chain will give you increased accleration but without loss in top end unless you want more and change the ratio.

Some one else can do a recommendation but this has been very popular.
Posplayr

 

[trippivot]

change the chain and sprockets as a set they all wear together if you only change a piece or two it will wear out much faster.

go 1 tooth smaller in the front the change is good for more acceleration and the top end is only changed by a couple hundred rpms not a big change but you'll be quicker from a stand still start.

1 tooth change in front = 3 tooth change in the rear (just so you know)

stg 3 jetting is good and easy to change when the weather gets hotter, colder, wetter, dryer etc....
and you will change the settings because the bike gets more sensitive to atmospheric changes. get used to needle changes when the barometer changes

 

[lecroy]

1 tooth change in front = 3 tooth change in the rear (just so you know)

Just a couple of notes, depending on where you are with the front, going small may not be such a good idea. You can start to wear the chain with too small a front.

Say you have a 20 tooth in the front and 20 in the rear. So the ratio is 20:20 or 1:1 or even 1. If you removed one tooth in the front in this example, that would give a ratio of 19:20 or 0.95. Adding one to the rear in the same example would be 20:21 or 0.95. Bottom line, do the math.

 

[wyldechild71]

So as far as a chain goes you just use the stock size/length?

Thanks for the input guys

 

[Junkie]

If you are adding and subtracting 0 total or close to it (1 down/1 up, 1 down/2 up) you can just use the stock chain length.

 

[lecroy]

So as far as a chain goes you just use the stock size/length?

Thanks for the input guys

If you had a 44 in the rear and you made it a 50, no I doubt you could use a stock chain. If you are all the way and one end of the adjustment, and you change by a tooth that requires more adjustment, no stock size won't work. You can run two masters and use different lengths of chain to make up the difference.

I suggest you measure it.

 

[andrewclaycomb]

The jet kits aren't compatible on our older GSs last I checked. (76-79) Just have to jet them yourself and yes, once you put the pods on you will definitely need a rejet.

 

[wyldechild71]

Thanks for all the help guys truly appreciated