Bonneville America Forums Forums Technical Forums General Tech Shift Speed Too Low?

Howdy all. According to my user manual, for the '07 America, shift speed for 5th is at 40 mph. Now, for fun I'll shift into 5th around that speed and be able to hold my own on level ground. However, if I attempt to accelerate, I get a little bucking for about the next 5-10 mph then she's smooth as silk. NOTE: The carbs are synced. Is this bucking due to only pulling 2300 RPMs, when I try to accelerate, or is there an adjustment I should make?

40 is too low for 5th

No adjustment needed... you are lugging the engine at 40 mph in 5th. When you feel it is when you put the engine under load, such as trying to accelerate.

Ok, John, what's so funny?

The only reason I ask is because I've always felt this speed for 5th was too low, but the manual says it!

Yeah, I wanna know too.

I don't know why the manual says that, it's ridiculous. Yota and Keith pegged it. That's what's known as "lugging" the engine. That's why the bike bucks when you try to accelerate. It's not a problem with your bike. Try ignoring the user manual and trust your gut.

Well, I personally don't think Matt's inquiry is all THAT funny, but yeah, I can kinda see a little humor in one feigning not knowing that lugging one's engine(ANY engine in any vehicle they may own) puts a strain on it and can cause unnecessary wear and tear to it.

Basically, one should be able to "feel" when an engine is lugging, and should then immediately downshift to a lower gear if they're then going to attempt to quickly accelerate...and no matter at what speed an owners manual might say this attempt at sudden acceleration would be "okay".

And thus, I have a feelin' here that John might've thought that this is such a basic principle of operating any internal combustion vehicle that maybe Matt was putting us on about not knowing this.

(...am I right, John?)

Well, I see you beat me to it, John!

Lugging puts and extreme force on the crank and mains . At a higher RPM all the rotating mass tends to "float".

Lugging is bad , but there is a brand of shoes called "Lugz" and they're OK I 'spose .

D'oh, open mouth, insert foot. I am well aware what lugging is. I used the term "bucking" as to not lead you to the conclusion of "lugging" but to hear your opinions, unaltered, creating an open-ended question.

I just find it disconcerting that the manual says 40 for 5th when any minor acceleration or slight incline, under that condition, causes the engine to lug. Therefore, I was drawn to the conclusion that I may have to adjust something to eliminate the lugging.

So, let me ask a riding style question. (To which "ride it like you stole it" is not an acceptable answer.) What's the lowest RPM you can accelerate from, without detecting engine lug? For me, it's about 3300. At those RPMs+, I just twist and go.

Yep, Matt. 3300RPM is right about in the rev range where these Triumph twins will start into the "sweet spot" of their torque curve.

Agreed.

Well, for the EFI bikes the sweet spot is 3500 to 4500 but there is plenty of torque for accellerating (without lugging) from about 2500rpm - which I think was the question Matt was asking.

I feel it really starting into the power at around 4000 rpm, and it stays there all the way to the rev limiter at 7900.

Why worry about the lowest you can accelerate from without lugging?
Just learn which gear you need to be in at what speed to accelerate from 3500-4000 rpm.

Agreed.

Don't know about others, but I'm starting to thinking of 4th gear only when above 40 mph. Sometimes, just for fun, I'll break 40 mph while still in 2nd (especially if there's some rattling H-D trying to pull away from me - and he's already well into 3rd!).

I usually think about 5th only if I know I will be cruising above 50 mph.

Like everyone has already said, forget what the manual says about speed and gears. Go with what feels rights. Years ago, someone posted here about how these bikes like high revs, unlike V-twins. Go with what feels right, especially since we all don't have the same weight.

Manual? Manual! Why would you believe a manual for a bike that has a speedo that indicates your bike will go 120 MPH. Unbelievable huh ? Well my Thruxton speedo goes to 140MPH...maybe picked up by a tornado.

I have a favorite spot to hammer it to highway speeds, routinely hitting 70 before I finally shift to fourth. Then quickly to fifth and chop the throttle since the cops around here tend to be not so nice. Lol and I tend to highway ride usually between 70 and 75, because any more and it just seems like the motor is really screaming. Maybe that will change with the new clutch springs, but I've always felt this bike could use a 6th gear for really long trips.

I shift like you do Steve. Didn't even know the manual said 40 mph for 5th. That's just ridiculous.