Resistance when in gear

Hey guys,

I bought a 1977 kz650b about a month ago and I noticed a strange problem with it that I can't seem to find anywhere.

When I am riding, whenever it gets over 2.5 - 3 thousand rpms, there is a ton of resistance. It's not so much that's it's unridable, but it's definitely more than any other bike I've ridden. When I pull the clutch in its fine, but it seems to never want to coast when in gear, even at like 30mph in 5th gear.

Anyways suggestions on what this might be? Also, I gave it an oil change so it not bad oil.

Thanks,
Michael

Mikechuck_ wrote: Hey guys,

I bought a 1977 kz650b about a month ago and I noticed a strange problem with it that I can't seem to find anywhere.

When I am riding, whenever it gets over 2.5 - 3 thousand rpms, there is a ton of resistance. It's not so much that's it's unridable, but it's definitely more than any other bike I've ridden. When I pull the clutch in its fine, but it seems to never want to coast when in gear, even at like 30mph in 5th gear.

Anyways suggestions on what this might be? Also, I gave it an oil change so it not bad oil.

Thanks,
Michael

coast when in gear :huh:

Good Fortune!

That is not a "strange problem" or any other kind of problem. I've never heard of any motorcycle being able to coast while in gear without the bike quickly slowing down. I guess if it was a full dresser that weighed well over 1,000 pounds with rider and passenger it might, but not a relatively light bike unless you're going down an extremely steep hill.

I've been riding bikes for more than 50 years and have never known anyone who coasted a motorcycle in gear; is there some reason you want to coast in gear?

Ed

Some clarification would help. Do you mean that closing the throttle at 3,000 rpm and above causes the bike to slow drastically, or that it is difficult to hold a steady speed, or something else?

Ok i am no expert, but I don't think this is right. I rode a kz 400 and when it had low rpms, like between 1 and 3 thousand there wasnt a ton a drag from the engine, and it coasted similarly to when the clutch is in. This is true for all bikes I've ridden. With my bike, it feels like the engine is engine breaking at low rpms, when it definitely should not be. Is the KZ650 different from all other bikes, or is this a problem?

When I'm going down a grade and let go of the throttle the bike slows down.
Steve

Mikechuck_ wrote: ........ With my bike, it feels like the engine is engine breaking at low rpms, when it definitely should not be. Is the KZ650 different from all other bikes, or is this a problem?

The engine IS braking if it is running at any rpm higher than idle rpm when you let off the throttle. This is true of every engine that is mated to a manual transmission. So if an engine's idle speed is set to 1000 rpm and you try to "coast" at 2000 rpm or any other rpm higher than 1000 rpm the rear tire will, through the transmission, pump the pistons up and down instead of the pistons driving the rear wheel. As those pistons are driven up by the rear wheel through the transmission there will be a considerable amount of resistance when each piston is pushed up during its compression stroke. There's no escaping this fact unless you disengage the engine from the transmission by pulling ion the clutch or putting the transmission in neutral. It simply how cars, trucks, bikes, and anything else with a manual transmission works. If you found the KZ400 to act differently either the idle speed was set too high or the clutch was slipping bigtime.

It sounds like you may be very new at using a manual transmission. Have you ever noticed signs on steep hills instructing trucks to use low gears when descending? This is so the engine will help serve as a brake mechanism and that can help prevent the brakes at the wheels from overheating. Using the engine as a means of reducing speed is not at all unusual for anyone driving a car with a manual transmission, and bikes work the same way. Ed

Check your brakes. Sometimes they can drag after they heat up if the pedal or lever is not returning to the proper position. Since it only acts up when heated, it may feel fine when cold. This may lead to the sensation that the engine is slowing the bike down, when in fact it's the brakes.

I had this exact problem once when I hastily adjusted the rear brake pedal.

Then why has every other bike, lighter and heavier, not felt like this, Ed? I'm not new to manual transmissions. You're on help forum. Get off your high horse and help. Think about what might make the bike feel like this. Patronizing other people trying to look for answers doesn't solve anything.

The engine should NOT have this much resistance in my top gear at 30 mph. I'm going to rebuild my carbs with my friend, maybe they're all gunked up and can't give the power they're supposed to. I'm also going to take a look at my brakes, like loudhvx said, maybe they have something to do with this.

Mikechuck_ wrote: Then why has every other bike, lighter and heavier, not felt like this, Ed? I'm not new to manual transmissions. You're on help forum. Get off your high horse and help.

No, we're on a discussion forum. Get off your own high horse, explain the problem clearly, answer the diagnostic questions asked of you (e.g. the one from TexasKZ), and generally try to be a little more polite to the people you want to help you.

For the record, I had a KZ400: it would not "coast" as you described. Rolling completely off the throttle resulted in engine/compression braking as described above.

Is the reported sensation more pronounced in 4th gear?

Good Fortune!