High speed question

Howardr · Post by **Howardr** » Sat Apr 10, 2010 7:14 pm

I have this rather interesting problem. When I go down long hills (think mountain) the Buddy acts as if it going to die every time I get off the throttle. This is most noticeable after 60mph or so. If I roll off the throttle for a corner, the motor "coughs" (not quite backfire) and acts like it will die. Once I get back on the gas, it fires back up again.

This did not seem to be dependent on elevation. It happened at 6000 feet, but also less than 2000.

The only other time is does anyting like this is when I coast into a stop light and/or set at idle for a while. Then when I hammer the throttle, it "coughs" stutters and then takes off. I have mentioned this to my local mechanic and he hasn't been able to duplicate the problem.

This is a Buddy 150, 15k miles, Prima pipe, NCV variator and clutch kit and #100 main jet.

Ideas?

Howard

Lostmycage · Post by **Lostmycage** » Sat Apr 10, 2010 7:23 pm

What's your spark plug look like?

Post by **ericalm** » Sat Apr 10, 2010 9:43 pm

And when was your last roller change?

Howardr · Post by **Howardr** » Sat Apr 10, 2010 10:44 pm

I'm using 14 gram sliders and they have 2-3k miles on them.
Spark plug is new. Color was good when I changed it.

Howard

Lostmycage · Post by **Lostmycage** » Sat Apr 10, 2010 11:38 pm

If the plug looks OK and the sliders are still basically new, I'm at a loss. Your exhaust was fixed and you're absolutely certain that there are no leaks in it anymore, right?

The only other thing that could think of is maybe the 14g sliders are too heavy. I'm not sure how that would cause it to "cough" though. Actually, I'm not entirely sure I fully understand that.

When it does that, does it do it more frequently at lower altitudes than higher ones?

jijifer · Post by **jijifer** » Sat Apr 10, 2010 11:44 pm

consistently or is this all on the same tank of gas? The only time my buddy did that was with bad gas (is my guess) when you're way out in the boonies, it's best to go with low grade fuel (imo) because it's probably been awhile that premium fuel has been sitting in the tank way out in the middle of now where. My bad premium was in Mammoth. boy was that an unfun tank of gas!

Howardr · Post by **Howardr** » Sat Apr 10, 2010 11:59 pm

Many different tanks of gas. I noticed 3-4 months ago, but I was over 6000 feet elevation and attributed it to that. yesterday, on my 500 mile jaunt, it happened several times, at very different altitudes.
Since I stopped for gas 10 separate times, I don't think it was bad gas. It's a mystery. I was hoping that some other rider who lives near some monster hills may have experienced this.

Howard

Cheshire · Post by **Cheshire** » Sun Apr 11, 2010 3:15 am

How long's this been going on, and have you ever had your stator replaced?

Another thing is are you WOT? I had a few hiccups last summer that seemed to be linked to going WOT for long-ish time periods. I've gotten into the habit of letting off every now and then when I'm holding high speeds (over 60)...the idea in my head is to keep the throttle from "sticking" at WOT.

Kaos · Post by **Kaos** » Sun Apr 11, 2010 5:44 am

Yeah, I'm not really sure what to suggest here. LMC and Ericalm's suggestions would have been my first two guesses. I can hold WOT till I run the take dry with no issues at all.

jmkjr72 · Post by **jmkjr72** » Sun Apr 11, 2010 1:48 pm

i would take a guess at your torque/contra spring why do i say this you say its when you get off the throttle if the spring is binding or worn and not returning all the way to unsprung you are keeping the clutch engaged when you let off the throttle

LisaLisa · Post by **LisaLisa** » Sun Apr 11, 2010 6:15 pm

check the valves, including exhaust?
You could be talking a loss of compression at high rpm's.
But of course it could be other things too.