Faster on Flats than Downhill

[Howardr]

As the title says, my Buddy is actually faster on a nice flat straigh way than on a nice, long, steep downhill.

Here is AZ, we know how to do hills. Not far out of Tucson is a 10 mile long, 8% grade. It has wide lanes, gentle curse and long straights. Seem like the perfect place to open her up and see how fast a scoot will go, right?

Well, I don't know about other Buddies, but mine hates this kind of thing. Once I get past 55-60 bmph, if I keep it at WOT it starts to sputter and cough and backfire until I roll off the gas a bit. Needless to say, this is a difficult thing to reproduce in the shop for my mechanic.

My scooter has been doing this for years, so it has nothing to do with any recent mods or changes. However, we think may have figured it out. We think that once the scoots nose is at a certain down angle, the carburetor float cause the bike to flood.

Out on a flat, I can keep giving the bike gas until I'm wide open. Top speed is 65-70bmph.

Has anyone else ever noticed the same phenomenon?

Howard

[skully93]

Interesting hypothesis. I guess since we have large mountains that are more like 10-13% roads, I've never tried to go up or down at speed through switchbacks.

What say you, veterans?

[k1dude]

Top speed is 565-70bmph.

Holy Mercury!!! You need to get that thing out on the Bonneville Salt Flats!

I've ridden mine in the foothills and mountains both up and down without a problem. Mine prefers to go downhill much faster with no popping or sputtering.

[Keys]

I sorta suspect over-jetting...maybe only a step or so. Happened to me with my MadAss.

[Tocsik]

Yeah, Howard. You're kinda in a different bracket with that 183cc beast!

[Howardr]

Yeah, Howard. You're kinda in a different bracket with that 183cc beast!

Actually, it did this when it was stock. The first time I noticed it was when I was only about 50 miles in to my Iron Butt run. There is a long downhill stretch in to Benson, AZ. I thought I could pick up some time only to find the bike stuttering and popping all the way down.

It's not a circumstance that happens to frequently for most riders though. It requires a long, steep downhill, probably 8% or higher. Mountain roads with frequent curves won't usually get the same reaction because one tends to be on and off the throttle. Fortunately, it doesn't happen to me very often either, but it is frustrating when I want to "fly" down the hill and the bike doesn't want to.

I don't know that it is something fixable, either. We are pretty sure it's just the design of the carb and how the float is mounted. I suppose an entirely different carburetor might work though, hmmmmmm.

Something to investigate.

Howard