Triumphrat

ProudRAT · 04-20-2007

Hello all.

I was riding the bonnie yesterday, since it finally got nice here in Michigan, and while cruising down the highway (approx. 10 miles or so and level surface) at about 70-75 (4300 rpm approx. and between 1/3 to 1/2 throttle) the bike started hesitating, stumbling and pretty much cut out. She never stalled and would pick back up if I backed out of the throttle or cracked her open. She also did it again later in the day but I was not on the highway and not doing highway speeds. Thoughts?

Mods are: BC air box delete kit with K&N's, 42 pilots, 140 mains, stock setting on idle pilot, with BC predators and AI deleted. Carbs have been balanced as well.

Thanks, Chris. :???:

FattRat · 04-20-2007

Take yer seat off, look for a lock washer, find your thread locker goop, and secure that ground cable to the battery..... I think it might be loose.

ProudRAT · 04-20-2007

I will check but I put that stinker on there when I put the air box delete kit on and I used dielectric grease as well. Gosh I really hope that is it but alas my luck is never so "lucky?" :???:

lindsayt · 04-20-2007

That's how mine acts when it's about to run out of gas. Probably not the case in your situation, but that's the only time I get that behavior.

Iceseven · 04-20-2007

I always suspect the coil when I read about these problems, but having to walk home after a bike with 700 miles on it quit may make a person a little paranoid.

My Bonnie surged and stumbled like running out of fuel, but would get better with more throttle or choke then just refused to start, dealer diagnosed a bad coil.

monkeyboy · 04-20-2007

Judging from the "first ride of the season" beginning it sounds like bad gas.

Was the gas fresh? Did you turn the petcock off and let the bike run out of gas before you put it away last time? How long has it been sitting.

Gas in Ca turns to crud in about a month. It begins to gum up your carbs and will cause these problems. The only thing you can do to stop it is either run the carbs dry, or use StaBil.

ProudRAT · 04-20-2007

Most definitely fresh gas. Runs absolutely fine but for this little intermitant hickup. Runs like a scalded chicken when you really romp on it but this cutting out is confusing me. I suspect fuel (either too much or not enough) but I have no real evidence to support that.

As for bad coil, lets hope not, 200 miles on bike total. She is brand new.

Oh, not first ride of the season since picked the bike up on December 23, 2006, miles are all from this spring.

[ This message was edited by: ProudRAT on 2007-04-20 13:05 ]

Rip · 04-20-2007

Proudrat,
I have almost the same set up as you, but with 135 mains and Thruxton needles, and mine has the same symptoms.

I have two trains of thought as I surge along. Like you the surging happens at a constant throttle position (75-90mph)

I think it's a lean mixture at that point of carburation. One thing that confirms it is; as the fuel goes to reserve the symptoms are more pronounced.

Or due to my fitting the billet manifold I may have buggered up the fuel float levels (hav'nt checked them yet) but am convinced it could be either

At the moment I am not bothering to solve it as I hope to put my bike on a dyno in a few weeks time.
I hope I have helped
Phil

[ This message was edited by: Rip on 2007-04-20 13:19 ]

ProudRAT · 04-20-2007

Phil, thanks, I happen to agree about the lean issue.

Talked to BC and they recommended I make sure the idle mixture is 2 1/2 turns out and this should take care of the problem. I will check it and we will find out.

cb4017 · 04-20-2007

Chris,
I have an 06 Bonnie Black with the same mods. The only other thing I did was to remove the California charcoal canisters.
Anyway, my Bonnie did the same thing. Felt like it was running out of gas after riding for awhile. I believed it was a tank venting problem. For trouble shooting, I removed the tip-over valve in the tank vent line and replaced it with straight tubing. I've only had a chance to ride it once since doing so but the problem did not re-appear.