1 Engine is missing / hesitating under load. Noticeable in 1,2,3 gears. Any ideas? Fri Sep 10, 2010 5:58 pm
1987k100rt
active member
Hello, This is my last resort for help on my bikes issue. I hope your experience as a group may come up with a solution.
I have a 1987 K100 RT 2 valve motor.
Bike had sat under cover on a trailer for at least 4 maybe 5 years with intermitent running.
I was given the bike by a really cool neighbor and spent 1 1/2 years restoring it to on road/ safe condition. I have been riding it for a few months now with the original owner riding by me on his Harley. The last few rides I have been having an issue with the engine running eradically at slow speeds under load. While in town I tried to maintain the 25MPH speed limit and the throtle could not keep constant. It acts like it cannot make up it mind on too much or too little. As soon as you pull the clutch in it it stops acting eradic. It does not stall but if you down shift or up shift it still does it in those three gears anywhere from 2000 to 3500 RPM. The bike still goes but it sounds like the metal trap door on the air inlet is going nuts slapping open and closed constantly. The bike seems to run great in 4th and 5th gear just fine, No problems downshifting either.
Things I have replaced or fixed:
Fuel filter ( BMW and in correct manner)
Fuel lines on the entire bike in tank and out (correct ones for each)
Air filter
Plugs NGK (the BMW Bosch plugs fouled early on and the bike would not even start) replaced with the correct NGK and the bike had run fine till now. By the way took the plugs out and they all look normal.
Crank case breather hose is new.
all the vacumn nipples and hose on the throttle body end is new.
New tires, brake pads/brake fluid
new engine oil
new trans oil
new final drive seal and oil
I just bought new plugs to try
I unplugged the Throttle position sensor last night and ran the bike on centerstand and held throttle at constant 3000RPM. It still had trouble keeping a constant RPM even in neutral so i think I eliminated that as an issue.
I have not replaced the spark plug wires or coils.
I have not replaced the fuel pressure regulator
I have not replaced the fuel injectors
I do not know but I speculate that this is a electrical or vacumn problem. I am hoping someone out there may have had a similar problem can may have a solution I can try. The bike is great and I enjoy riding it but I know it is not runnning correctly. I have put a lot of time and money in this bike and want to get it running as well as possible. Any ideas or help is greatly appreciated.
James
I have a 1987 K100 RT 2 valve motor.
Bike had sat under cover on a trailer for at least 4 maybe 5 years with intermitent running.
I was given the bike by a really cool neighbor and spent 1 1/2 years restoring it to on road/ safe condition. I have been riding it for a few months now with the original owner riding by me on his Harley. The last few rides I have been having an issue with the engine running eradically at slow speeds under load. While in town I tried to maintain the 25MPH speed limit and the throtle could not keep constant. It acts like it cannot make up it mind on too much or too little. As soon as you pull the clutch in it it stops acting eradic. It does not stall but if you down shift or up shift it still does it in those three gears anywhere from 2000 to 3500 RPM. The bike still goes but it sounds like the metal trap door on the air inlet is going nuts slapping open and closed constantly. The bike seems to run great in 4th and 5th gear just fine, No problems downshifting either.
Things I have replaced or fixed:
Fuel filter ( BMW and in correct manner)
Fuel lines on the entire bike in tank and out (correct ones for each)
Air filter
Plugs NGK (the BMW Bosch plugs fouled early on and the bike would not even start) replaced with the correct NGK and the bike had run fine till now. By the way took the plugs out and they all look normal.
Crank case breather hose is new.
all the vacumn nipples and hose on the throttle body end is new.
New tires, brake pads/brake fluid
new engine oil
new trans oil
new final drive seal and oil
I just bought new plugs to try
I unplugged the Throttle position sensor last night and ran the bike on centerstand and held throttle at constant 3000RPM. It still had trouble keeping a constant RPM even in neutral so i think I eliminated that as an issue.
I have not replaced the spark plug wires or coils.
I have not replaced the fuel pressure regulator
I have not replaced the fuel injectors
I do not know but I speculate that this is a electrical or vacumn problem. I am hoping someone out there may have had a similar problem can may have a solution I can try. The bike is great and I enjoy riding it but I know it is not runnning correctly. I have put a lot of time and money in this bike and want to get it running as well as possible. Any ideas or help is greatly appreciated.
James