I'm having trouble 1982 gs1100

[Guest]

My bike is peaking out at 7k rpm after I changed my sprocket back down to stock from 48 to 42 any reason why this is happening

[Redman]

one thing to ponder: now with the 42 rear sprocket, at the 7k rpm is now faster MPH than it used to be so more wind resistance and more horsepower required than7k rpm before .
Could be about the same top MPH as before (would have been something more like 8.2k rpm).
I dont have any expereince doing any such thing, but am just thinking of the physics of the situation.

[posplayr]

Minor detail you are leaving out if op means in 5th gear.

[Btr]

Every 1 2 3 and 4

[Btr]

Yes it is a faster mph I was just wondering why it loses power after 7 thousand

[Buffalo Bill]

Yes it is a faster mph I was just wondering why it loses power after 7 thousand

Duh, is this a 36 year old engine?
Have you engineered the intake and exhaust for high RPM service?
Have you rebuilt the cylinder head for high RPM?
These are rhetorical questions, I just want to give you an idea what it takes to build power in any engine.

[posplayr]

Duh, is this a 36 year old engine?
Have you engineered the intake and exhaust for high RPM service?
Have you rebuilt the cylinder head for high RPM?
These are rhetorical questions, I just want to give you an idea what it takes to build power in any engine.

Despite all those factors, something is wrong if you can't get a GS to rev past 7K in 1st gear whether 42 or 48 tooth.

[Redman]

Every 1 2 3 and 4

Oh.....

Well, if not go over 7k, in any gear.... then I dont see how that can be related to changing the rear sprocket.
Since it was said this happend after changing the rear sprocket, I assumed you meant in top gear.
Disregard my previous statements.

[Btr]

Ahhh that's my point I know some things wrong it wasnt doing this before the sprocket change

[posplayr]

Ahhh that's my point I know some things wrong it wasnt doing this before the sprocket change

Well when I refer to something, it is not the gearing which means it has nothing to do with the sprocket unless you threaded the chain through the wheel.


No idea what the problem is, but I would put the bike on a center stand in neutral and see if you can turn the wheel freely.

BTW is this is an 82 GS1100EZ? You should easily be able to go over 10K redline in lower gears

[Btr]

Ok thanks I appreciate the help

[posplayr]

Ok thanks I appreciate the help

Another thing to do (although it is ludicrous to think of) is to put the old sprocket back on and see if you get your horsepower back.

[Btr]

I'm at stock now with 42 the 48 was working fine

[mmattockx]

Duh, is this a 36 year old engine?
Have you engineered the intake and exhaust for high RPM service?
Have you rebuilt the cylinder head for high RPM?
These are rhetorical questions, I just want to give you an idea what it takes to build power in any engine.

Stock redline on an 82 1100E is 9000 and mine pulls hard well past that point with only a pipe and pods. Something is wrong with OP's bike if it won't scream past 7000rpm, especially in the lower gears.


Mark

[rapidray]

Check all of the wires that go behind the countershaft sprocket cover to make sure you didn't pinch any when you put the cover back on.
Ray.