Acceleration in first gear

[larsenpedersen]

When I start accelerating in first gear from a complete stop, it isn't a smooth experience - If I don't give a bit of throttle it's about to die, and if I give too much throttle it is the same thing. It is very fiddly, and I can't do fast accelerations.

I recently had my carbs cleaned and adjusted - and the idle jets too.

My mechanic says the acceleration problem could be fixed by getting new clutch springs - I would like to hear if you think he is right, or if you have some other suggestions?

CB650 (RC03) from 1979

[tario]

It sounds like you just need to release the clutch more carefully. Clutch springs stop slipping in the clutch. If it's grabbing then they should be fine. Your clutch is just a stack of disc brakes that are squeezed together by the springs. When you pull the lever it lets the discs spin independently. Disc 1,3,5 etc is attached to the engine. Disc 2,4,6 are attached to the wheel.

I know I had a lot of trouble getting the hang of it the first week or two and I still stall a bit now that I'm better. I have been driving standard for 12 years now. Actually automatics seem strange to drive since I rarely use them.

If you open up the throttle too much it tends to bog down. I'm not sure if the engine floods a bit or if it screws up the airflow but I've seen it happen. You need to be within a certain range of throttle to have the engine pull hard.


Besides that my best guess would be timing. If your timing is off you will lose torque throughout the range of rpms. The engine peaks around 5000-7000 off the top of my head. Starting at 1500 rpm there wouldn't be all that much power compared to the peak.

You can take off the round cover on the right side and get a hold of a timing light to see how bad/good it is. I'm not sure how the lights hook in but any instructions from a cb650, cb900 or cb1300 should be the same I think. Early 80's 750's might have the same ignition system as well, not sure.

[larsenpedersen]

It sounds like you just need to release the clutch more carefully. Clutch springs stop slipping in the clutch. If it's grabbing then they should be fine. Your clutch is just a stack of disc brakes that are squeezed together by the springs. When you pull the lever it lets the discs spin independently. Disc 1,3,5 etc is attached to the engine. Disc 2,4,6 are attached to the wheel.

I know I had a lot of trouble getting the hang of it the first week or two and I still stall a bit now that I'm better. I have been driving standard for 12 years now. Actually automatics seem strange to drive since I rarely use them.

If you open up the throttle too much it tends to bog down. I'm not sure if the engine floods a bit or if it screws up the airflow but I've seen it happen. You need to be within a certain range of throttle to have the engine pull hard.


Besides that my best guess would be timing. If your timing is off you will lose torque throughout the range of rpms. The engine peaks around 5000-7000 off the top of my head. Starting at 1500 rpm there wouldn't be all that much power compared to the peak.

You can take off the round cover on the right side and get a hold of a timing light to see how bad/good it is. I'm not sure how the lights hook in but any instructions from a cb650, cb900 or cb1300 should be the same I think. Early 80's 750's might have the same ignition system as well, not sure.

Thank you for the reply, tario.

I haven't been riding my CB650 for that long - I'm more used to a Yamaha MT-07, which is way different!

I'll try to release the clutch more carefully and try to get my timing checked