81 gs400L first run out of storage

[MekaniX]

Hi everyone , i'm new to the board.

After sitting for 2 years I got it cleaned up and running.
Took it for a test ride, only to notice a lack of power throughout the gears.

In first gear the power is weak up to 5000 rpm and each gear after that feels weaker,

I'm not sure how much power these 8 valve 400's are suposed to have but it seems like there should be more getup and go.

any suggestions would be apreciated


1981 GS400L
22,000kms

thanks

steve

[rgierer]

first confirm that you are running on both cylinders

[Nessism]

Take the carbs apart and clean out the passages. Also, I'm not familar with your particular bike but I thought all '81's were 450's no? Twin cylinder, two valves per, for a total of four valves.

[MekaniX]

Its running on both for sure , carbs where apart and cleaned

In 1981 suzuki put out the gs 250 and 400 twins, which both had 4 vlaves per cylinder.

I beleive there is a 4 and 8 valve version of the 450 and 400. 1979 -1980...

So far this is the second 81 GS400L i've owned and only the second one i've ever know to exist.

Its a little stuborn to start, and will not start on choke,, I know that with full choke It should fire right up and climb to about 3000 + and stay there.

However, starting it on choke will only make it rev to about 2000 slowly and then die.

the only way i have to warm it up is to baby the throttle untill its warm, at that point it will idle perfectly and have no problem pulling itself along.


Throttle response is pathetic compared to my last 400L.

any ideas ?

One last thing , i havn't had it out for a long ride yet , it could just be in need of a run in...

[nabrams]

Could be running way too rich.
That would explain inability to start with choke applied. It would also explain low power.
Did you check the plugs after a ride? If they are black then you're too rich.

Have adjusted the mixture screws properly?
Have you changed any carb components to non-stock?
Is there a stock air filter element in the airbox? Is it properly installed and not over-oiled?
Is the exhaust sytem stock? (back pressure from the exhaust system must be proper - if not, it will prevent full power).
Are there any obstructions to air flow in the airbox or exhaust system? (even though everything is stock).

Any of the above could cause a too-rich mixture.

[MekaniX]

Had it out for a long ride.,

took the plugs out and the left side is tan/white
right side is black

Everything is stock
air/fuel mixture is set right on
air filter is brand new and looks oiled just right,

took the exhaust off and didn't see any obstructions,

Seems like the #2 cylinder is driving while the other is just barely keeping up,

there is a flat spot at 4500 and its gone at 5000, if it gets over that spot that is.

Looks like i'm going to tear the carbs apart again just to see whats going on ,
thanks