I would be real careful there, dude. What are the RPM's at that speed in 5th gear? What happens when you throttle up at that low speed & RPM's? Luggin' a Harley- Davidson motor is not good for it.

 

"Luggin' a Harley- Davidson motor is not good for it."



Mechanically speaking, why?

I don't make a habit of it, but if I am damaging my bike I will make every effort not to do it.

 

" Lugging an engine means putting the engine under an extremely stressful load. A common way to lug an engine is to operate it at an extremely low rpm while the transmission is in a higher gear (for instance, leaving the transmission in fourth gear when it should be in second or third where engine speed is better matched to transmission speed). Lugging causes extreme stress between the rear thrust faces of each piston and the cylinder walls. Small bits of piston skirt can break away causing the rear surface to scuff. The best prevention for lugging an engine (either old or new) is to downshift to a lower gear where the engine runs more freely, and the transmission assists the engine in delivering peak power to the rear wheel." ....not to mention the stress on the clutch, primary chain and tranny.

 

Oftentimes on my return home, I have to go over a mountain from the interstate into town. I am usually in 4th or 5th gear coming down the hill. By the time I get to town I either coasting down a slight grade or leveling out and doing only 30 -35 mph (usually for less than a mile). Are you saying that, if I am in fifth gear at that speed, I am hurting my engine? Where's the stress on the engine?

I'm not trying to be a butt. I just want to understand my bike better.

 

No , you,re not because the drive train s "loaded"..as soon as you level off, you need(should) be in about 3rd...but ,hey...its your scoot...ride like you want to...

 

Thanks for the heads up. I plan on keeping the scoot for a long time and don't want to do anything stupid to it.

Happy trails.

 

I shift into 5th around 73 mph if I'm going through the gearz. If I'm stuck in some god awful speed zone of 55 (which is rare), I'll lug along in 5th, however, there isn't too much power with that low of an RPM.

 

This is something that has plagued me for a long time. I have been riding a 1992 Sportster Hugger with a 1200 conversion for almost 15 years. I now live in a county where most of the roads, and all of the small, twisty, up and down, local roads, have 50 MPH speed limits. That is about the fourth to fifth shift speed for this Sportster so I did a lot of shifting. On the level, or a downgrade, it can carry fifth gear if I do not accelerate very much. On much of an upgrade, or in acceleration, it has to be shifted to fourth gear or it bogs down. And, I agree that lugging is hard on the engine, more for the lower end than for the top. I recently traded the Sportster for an 06 Street Bob. I am not yet really familiar with the Bob but it appears that it will have more torque so it will be able to carry fifth gear at a bit lower RPM, but not much, without lugging the engine. Both bikes seem a lot happier when they are are at a lower gear and a bit higher RPM.

As an aside, I tow a camping trailer with a GMC pickup that has a "Tow/Haul" mode that electronically governs the ability of the transmission to shift up. I have found that the automatic selector has a strong tendancy to go to a lower gear and higher RPM, and that I usually can let up on the throttle a bit and maintain the same speed at the lower gear and higher RPM. I hope this helps the mileage. To me, the lesson is to stay in a gear that allows the engine to spin freely and do not be in a hurry to shift up.

 

I don't shift into 5th until I hit at least 60 or so. That said, I don't shift based on speed, but based on feel. I let the engine tell me when it's time to shift.

Cheers!
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