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Discussion Starter #1
hey guys, just reading up a bit on my 79 Gs550e. some info on a website said this bikes top speed is 114mph. however, my bike screams at 70mph, 5500rpm in 6th gear... is this right?
 

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114 was when new.....
What gears are you running?
is your bike running 100%
whats redline?

If you are just trying to "do the ton" you should just get internet slapped
 

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114mph = 8957 rpm using your numbers

your bike makes max power @9000 rpm stock, doubt it will pull much more than that in to top gear, so sounds about right
 

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Discussion Starter #5
It definitely says 114MPH. the bike is running well, not 100% tuned. also, as far as I know the gears are stock (not actually sure what sizes those are). and no, I'm not just trying to hit 100. the guys I usually ride with are all on v-twins, so it's hard to keep up with them on the freeway. I'm thinking about putting a smaller sprocket on, maybe 1-2 teeth smaller. I know that'll screw with my acceleration a bit, so do you guys think that's worth it?
 

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Ok i just physically bit my tongue not to want to curse around my GF's parents......

So you claim yourself that the bike is not 100% but want to mess with gears to maybe get a better top speed?
Wild guess here but pods and cut exhaust?
Well lets hold off on talkinng about why 100+mph is needed or the fact that over time some of the horses that it had might have left the barn....

As Ken said it sounds like you are getting the speed that the bike should or at least in a range of it..
 

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I did some quicky research to find that peak HP number(like a minute).

You're not the only guy that thinks his 550 is geared too low stock for highway use.

Without knowing the internal transmission ratios and riding it I'm not even going to venture a guess as to how bad it'd hurt acceleration.

Do you really need first gear now? A couple teeth's typically going to be like starting in second or first and a half.
 

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1 tooth up on the countershaft sprocket makes a detectable difference, 1 or 2 teeth down on the rear not so much, moot point if you can't pull redline in top gear as Ken indicated 5500 is a long way short of the 9k you should be seeing.
...now how much do you say you weigh again?
 

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Just to be clear; I'm assuming you're cruising at 5500 and it's just buzzing more than you'd like.

If will surely go faster than that right?

If not something's terribly wrong.
 

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Discussion Starter #11
Like I said earlier jaguar, I have no desire to hit 100, I simply wanted to know if I should have an easier time keeping up with Panheads/Shovelheads that the majority of my buddies are cruising.
Trials, I weigh 180 give or take a few.
Ken, yes to everything in your last post.
 

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It's fairly simple math.

Just figure out how much rpm you'd like to loose at 70. Use that to figure new final drive ratio.

You can even work backwards from that and figure out your new first gear overall ratio will be. (need to find the trans internal ratios somewhere)

Then say your new final drive ratio makes first equivalent to second with your current final drive ratio. Ride around town taking off in second for a bit. See if that's liveable, then you'll know for yourself what it's going to be like.

But then you also get that a little Shovel's still like 1200cc? Even though the HD's ancient design your 550's going to work to keep up.
 

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In what way can you not keep up with them?

2nd, remove the little airbox cover and go up 17.5% (could be 15, could be 20 depending on your bike and location) in size for stock main jets.

Profit.

Your redline is 9k or 9.5k or whatever. If you are trying to keep up with you HD buddies by keeping the same RPM as theirs, you are doing it wrong.

I shift at 10k on the 550's.
 

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OP you keep saying yes but not answering....

You claim 70mph=5500rpm right?
and the math was done to say that its correct that at that speed you should be turning that RPM.
In top gear will it pull to 10,000RPM or 115mph?

Are you just trying to make 70mph=like 3500rpm?
in that case those HD you are trying to keep up with are going to get away from you alot faster in gear....

The question just isnt clear enough to help with
 

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I built a 'production racer' GS550 around 1980. (forget if it 618cc or full on 720?)
It would do well over 150mph but speedo was faulty so it never read anything over 90mph.
Never bothered to get a new clock
If you can see rev counter (still have it?) there is a red 'wedge' on left side of clock, make sure needle is somewhere near it and you HD buddies will probably complain you ride too fast (even at 30+ yrs old it should still make more power than an iron head sporty)
 

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PJ, what is the red 'wedge' you speak of???
 
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