Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!

1 - 12 of 12 Posts

·
Registered
Joined
·
157 Posts
Discussion Starter · #1 ·
I've been eyeing this Bonneville for a week or so, finally went to the guys house to see the bike in person, and test rode it.

The bike is bone stock, no mods, no accessories, nothing. It is pretty much in showroom condition (from the outside). Clean as a whistle, chain lubed, tires have plenty of tread. Only sign that it has been ridden are the blued headers.

The sellers story and paperwork matched his craigslist post. He brought it in for service (new battery, carb cleaning, etc.) because it wouldn't start after sitting for a year or so (inside). The dealership gave him the runaround because something "wasn't finished" when it was supposed to be ready for pickup. When he got it back it wasn't running properly.

I took it for a test drive, and noticed right away something was not right. In any gear, throttle response seems to be delayed. From about 1/2 throttle all the way to full, I was getting the same slow acceleration curve. I've never ridden a bonnie before this one, but if I had to guess, I'd say about 1/3 of the horsepower was getting to the wheels. On an open stretch of road, I put it to full throttle in 3rd gear, reached 50mph, and the bike would rock me forward and back, because the acceleration curve had leveled off and become intermittent. It also sounded alot more "whistle" like than my legend. It's hard to explain, I hope this gives a better idea of what's happening. If anyone has any insight that would be great, please let me know if I need to clarify anything.

Here's a pic, the headers look VERY blued to me, is it my imagination?

 

·
Registered
Joined
·
151 Posts
It sounds like you were bouncing off the rev limiter - it is not a great experience - you get a juddering. However, the bonnie has bags of torque and the trick is to change up earlier - if the bike is a good one it should keep on pulling up to the ton.

My old 790 had blue headers from very early on. No problem though.

If I were you I'd test another one to make a comparison.

Good luck

Steve
 

·
Registered
Joined
·
157 Posts
Discussion Starter · #3 ·
There's no way this was a rev limiter, unless it was malfunctioning. It was occurring at 1/2 throttle all the way to full, there was no tachometer, but I couldn't have been past 6k RPMs.

No one else has an idea what could be causing this?
 

·
Registered
Joined
·
64 Posts
you may want to try adjusting the Air/Fuel mixture...the problem is you have to get a D-Tool to adjust...

Mine did the same thing when it was deliverd from the dealer...
But it wasn't as bad as yours...

I did get the hesitation around 4500 rpm..

the guy at the dealer warned me about it...say that its okay, my first service would take care of it...

I bought the D Tool later on when I remove my snorkle and restirctor plate... because i know I have to play around with the A/F mixture bolt.. and I bought the A/F replacement bolt from NewBonneville for easy adjustments..

Playing around with the A/F mixture eliminiates the hesitation...
 

·
Registered
Joined
·
1,525 Posts
sounds almost too violent of a herkey jerkey to be just a/f screw out of whack. if it has been sitting and the fuel varnished up, there could be goop somewhere in a carb or both. full carb cleaning is probably best bet but one could dump old fuel from tank, clean out tank, add new fuel and a pretty stiff mix of sea-foam through for a batch and see if that'll get 'er right + dialing in the a/f screw and the rest of the jetting.
those pipes are WAY blue and blue quite a ways down. it is running lean which would certainly explain the herkey jerkey, the whistle and big lack of power. stock jetting is lean on these machines, mains typically are 110, 40 pilots, no shims under the needle and approx. 2 to 3 turns out on the a/f screw. did you double check to see if the snorkel is still in? if it is gone with stock jetting that would amplify a lean condition somewhat.
good luck and let us know what you find!
 

·
Registered
Joined
·
1,065 Posts
My pipes blued like that within 600 miles from dealer. AI and all the other restrictios caused it. In this case I just think it proves there is a major A/F mixture problem. It seems to me that "CDubya" is probably wright about a deteriated fuel Problem
Kleen the tank and the carburetors, new plugs, check the air gap on the ignition, then give it a try. If that's not fixing it tell the guy selling it that you want to talk to the dealer to get the whole story of why they screwed it up.
Something may com to light.
Good luck.
 

·
Registered
Joined
·
2,641 Posts
it sounds like something is wrong with the carbs, either a massive vacum leak or the diaphragm is off on one of the slides.

Take some money off your offer for the risk and hassle.

But its very likely its just something wrong with the carbs...which if you can wrench, its a free fix.
 

·
Registered
Joined
·
143 Posts
My last bike (Kwak Zephyr) had a very similar problem after being laid up over winter with the previous owner. The fuel had varnished in the carbs and a good strip and clean had it running like a champ again. Did it idle ok as mine wouldn't idle either?
 

·
Registered
Joined
·
740 Posts
Don't get caught up on the bluing. I bought my (blue 2005 790) bonneville demo-new in 2007 with ~600 miles on the clock, and it looked *just* like that picture when I got it. I mean, *just* like it - it's like that's a picture of my bike the day I brought it home. Anyway, my bike runs like a champ and has always done so, and its headers are now even bluer than those.

I think it sounds like gunked up carbs. Did you check to make sure both cylinders were actually firing? The jerkiness could be one cylinder cutting in and out, or it could just be one or both carbs hiccuping as they try to get a/f through a good coat of gum.

I'm betting the whole issue can be solved with some sea foam. Maybe some more nasty carb cleaner and a carb teardown.
 

·
Registered
Joined
·
157 Posts
Discussion Starter · #11 ·
Thanks so much for the info guys.

The bike did seem to idle just fine.

The problem is, I still don't own the bike, so I can't really mess with it yet. I'm going to give him a low offer and see what he says. I know he's not interested in fixing it himself, so hopefully I can get it for cheap, and fix it for cheap. I'll see what the owner says in the morning.
 

·
Registered
Joined
·
27 Posts
I'm not surprised it's bucking. If it sat with gas in the tank for a year, especially without stabilizer, I'm sure there is gunk/varnish in the carbs.I'm amazed that it runs at all. It might be worth draining The bowls, adding Seafoam or the like & running it through. If you're lucky, that might do it. More likely, the gunk is too solid (after a whole year) & a good carb teardown & cleaning is in order. Still not a biggie.
 
1 - 12 of 12 Posts
Top