P&G on a bike? How?

[PaulB2]

I'm new at this. If I understand correctly, pulse & glide means accelerating to a certain speed, turning off the engine, putting the gearbox in neutral and coasting down to a lower speed, then going into gear again and bumpstarting the engine.

Also there are other things like coasting down hills with the engine off.

How is that done with a bike, with the sequential gearbox? People aren't really getting into neutral are they? But if they are just pulling the clutch in, leaving it in gear, isn't there a lot of drag with the wet clutch and engaged gears?

[dcb]

I just use the clutch. I tried clanging down to neutral and there isn't much difference in coasting. You might be able to add more neutral detents if you are so inclined. The tranny doesn't like going through the lower gears at higher speeds, and there is less relative motion if you leave it in a higher gear.

Be aware that your tranny might not be getting full lubrication though. I haven't had a problem so far, but some guy with a high powered bike on a dyno apparently locked up his tranny on coasting engine off. He was able to fix it with minimal expense (another nice thing about bikes) but FYI.

[PaulB2]

Woops, that's right! No oil pumping with the engine off. Well that kills it for me; I will leave my engine on for sure. Even idling, the oil pressure might not be high enough to protect the tranny bearings.

[alvaro84]

I mostly coast just using the clutch, I only shift into N when I plan to slow down very much, because our bikes hate to get out of N over a certain (low) speed.

I turn off the engine if I plan to stop at the end of the coast, or O predict I can coast for long enough to be better off with using the starter than letting it idle. It's very hard to smoothly bumpstart Teresa, so I seldom do it.

I had no problem with engine off coasting so far, even though I've even done it downhills for more than 4km (2.5 miles) without starting.

My normal P&G routine doesn't include turning the engine off, though: motorcycles are very light compared to a car, and the aero drag is much worse, so my typical glide on a flat road is no longer than like 10 seconds.

[PaulB2]

I was looking at a couple of other threads on this subject, and it appears experienced mechanics think the clutch-disengaged coasting is OK. One thing I am wondering about is transmission bearings - are they pressurized by the oil pump or does the transmission simply run in an oil bath? If the latter then there can be no worries about them under coasting.

[redyaris]

Originally Posted by PaulB2

I was looking at a couple of other threads on this subject, and it appears experienced mechanics think the clutch-disengaged coasting is OK. One thing I am wondering about is transmission bearings - are they pressurized by the oil pump or does the transmission simply run in an oil bath? If the latter then there can be no worries about them under coasting.

On a Suzuki GS500 the Parts of the transmission that are pressure lubricated are through a pressure reduction orfice > counter shaft bearing > drive shaft bearing, transmission gears, Primery driven gear bushing, clutch thrust bearing. The other transmission parts are splash lubricated.

[slowmover]

Shoot, you said bike . . . just quit pedaling when going downhill.