Power problem

OK Guys I am at the end of my rope now and need any suggestions. I have a 1982 KZ750-M1 CSR Twin with Mikuni BS34 Carbs everything is Factory on it. I just replaced the clutch because it was slipping, it had 5 broken friction plates and one of the in two pieces. My problem is when I take it on the interstate it will not go over 55 MPH and that is with the throttle wide open. When I adjust the clutch it does not seem to want to adjust correct or it may be me but, it seems like the clutch has to be let out all the way before the clutch kicks in but when you start out it will start to catch about half way out. I just cant figure out why it will not go over 55MPH. The carbs seem to be working correctly, But I have not checked the compression yet. Let me know what you think

Well check compression! But my post earlier today will help you with the clutch if you suspect the clutch. To tell it is the clutch, I would do a snap of the throtle and you will feel if the engine revs up and there is no change in speed, and you will know if the clutch is slipping. Do you have any play in your clutch lever? When was the last time you opened the carbs to clean them? Checked your spark plugs? Also ignition timing can be a cause of this. Read your plugs to see what the fuel mixture is like then you can possibly rule out the carbs.

Another question is does your bike struggle at higher RPM'S?

kzwolfsr wrote:

Well check compression! But my post earlier today will help you with the clutch if you suspect the clutch. To tell it is the clutch, I would do a snap of the throtle and you will feel if the engine revs up and there is no change in speed, and you will know if the clutch is slipping. Do you have any play in your clutch lever? When was the last time you opened the carbs to clean them? Checked your spark plugs? Also ignition timing can be a cause of this. Read your plugs to see what the fuel mixture is like then you can possibly rule out the carbs.

Just put a new clutch in it doesnt seem to be slipping there is about 2mm play at the clutch lever just like the manual tells me.I cleaned the carbs about 2 weeks ago. the plugs do get a black look to them like soot and the plugs are new also if you put new plugs in and run it for about 5 minutes you get the same look on the plugs. the timing is non adjustable on this model. and it does struggle at higher RPM in town it runs great it seems to have power but just not what I think it should. but after 50 MPH it struggles.

Post edited by: dadams7161, at: 2007/05/27 00:03

2 things...when you adjusted your clutch did you have full slack in the cable and at the handlebar lever and do you know that the 750CSR clutch adjusts backward from the B series?
From the M1 suppliment in the FSM:
"-turn out the adjusting screw until it becomes hard to turn. This is the point where the clutch is just starting to release
-turn in the adjusting screw 1/4 turn from that point, and tighten the locknut"

ronjones wrote:

2 things...when you adjusted your clutch did you have full slack in the cable and at the handlebar lever and do you know that the 750CSR clutch adjusts backward from the B series?
From the M1 suppliment in the FSM:
"-turn out the adjusting screw until it becomes hard to turn. This is the point where the clutch is just starting to release
-turn in the adjusting screw 1/4 turn from that point, and tighten the locknut"

Yes I had full slack and I have the M1 suppliment so I knew about the adjusting screw adjusting out. I did everything exactly as described.

Did you also check your air filter? I forgot they don't have points, which is a good thing! How is your idle? Any backfiring? Also check valve clearances.

kzwolfsr wrote:

Did you also check your air filter? I forgot they don't have points, which is a good thing! How is your idle? Any backfiring? Also check valve clearances.

air filter is good it is new. the idle is a little rough but not really bad. no backfiring but will pop sometimes when I turn it off. was hoping to stay away from valves but if I have to I have to LOL.

Take off the right hand timing cover and make sure the timing advancer moves freely. Rotate the rotor clockwise, then let go and see if it snaps back. If you can't rotate it, or if it fails to snap back to it's original position, then remove it and clean and lubricate it.
A timing advancer stuck at full retarded (where they normally stick) will kill top end power.

steell wrote:

Take off the right hand timing cover and make sure the timing advancer moves freely. Rotate the rotor clockwise, then let go and see if it snaps back. If you can't rotate it, or if it fails to snap back to it's original position, then remove it and clean and lubricate it.
A timing advancer stuck at full retarded (where they normally stick) will kill top end power.

the timing advancer seems to be working fine it was a little stiff but did go back in place when I opened it. I did lube it up and it is working freer now but didnt seem to solve the problem.

what is the rpm that the motor is turning?
are you sure the carbs are opening all the way, maybe a cable in a bind

just saw this in another post, check the gas tank vent see if its open