Classic Triumph Bonneville

[JackyJoll]

You’re not wrong though.

They reduced the pipe diameter in the late 1950s sportier models, because it improved performance, because it mitigated reversion.

[Mr. Dazzle]

I'm guessing you know about exhaust reversion?

Set of spannies should fix it right up.

[David]

They are, and I would! It's not that unusual to require different carb settings on either cylinder. The only thing which 'connects' the two cylinders is the crank and the fuel pipe which connects to the two float bowls. Other than that, it's basically two singles in loose formation.

EDIT: Oh, and the ignition coils. There's one per cylinder, but they're in series and always fire together.

Do you not have an inlet balance hose on yours?

FTFY

[Mr. Dazzle]

I've got the day off today, so I've been for a ride trying to find a pub with a plant in the name for the challenge game. Failed spectacularly.

I did about 40 miles without incident though, touch wood. I'm still getting used to the engine, its not like a modern bike at all. You can't just do any throttle movement willy nilly, you have to feel your way up (probably no surprise to anyone who's ridden with slide carbs). Gear choice is also different, on an modern bike you can pretty much get away with top gear anywhere more than 30mph, on this bike you have to hang on to them a lot more....really likes revs.

The midrange is quite strong, but she is way happier with revs on. Means you hang on to gears way longer than you'd think. It feels super weird staying in first for so lon although TBF it's a close ratio box and 1st is basically what 2nd is on anything else.

[Le_Fromage_Grande]

I had a few two strokes that would stall if you cracked the throttle open

[David]

Has it blown up or is it too reliable to be worth reporting?

[Mr. Dazzle]

I've been too busy and too on Holiday.

[David]

Reasonable excuse!

[JackyJoll]

I've been too busy and too on Holiday.

Holiday time is for tearing your hair out in the shed, enjoying your expensive hobby.

[Mr. Dazzle]

Went out for a teeny tiny spin today to make sure it still works I'm planning on riding to work on it Friday, so I wanted to check there were no howlers.

I also stopped to get fuel - I've now learned that it makes way more sense to get fuel at the end of a ride when the engine's hot and she starts easily! t'was 'only' £1.85/litre for Shell's finest V Power too.

Nothing to report really, which is odd

[Mr. Dazzle]

Made it all the way to work today and all the way back! 100 miles all in. Shoulders and knees absolutely ruined

We had the CTO of the parent OEM visiting today, flew in by private jet then limo to our site. I saw him stop to have a look around the Bonnie parked up

Holds her own just fine in rush hour traffic, everyone was holding me up rather than vice versa.

[JackyJoll]

The highest speed limit I know about is 70 mph and I’ll happily hold a higher speed than that, so yeah- traffic is likely to hold you up.

[Mr. Dazzle]

So one thing I didn't mention!

I've got a funny noise. Maybe.

I sounds like a bottom end knock but that seems very unlikely on several counts. The shells are new, the crank's just been ground, she's got 60psi of oil pressure all day long and there's no commensurate knocky vibes.

Its half way between a thud-thud-thud and a clatter-clatter-clatter at exactly engine speed (or maybe half engine speed, my ears aren't that musical).

Thoughts:

Paranoia. This was the first ride where I was tootling along bored behind a lorry on a single carriagway. Maybe it's always made that noise and i just never homed in on it before!

Tappets. Doesn't sound all that tappety, cause it makes that noise separately!

Exhaust. Apparently a loose exhaust spigot can sound very knocky. Seems plausible, given that the sound gets louder when you give it some.

Engine bolts loose in the frame. Same as above.

Alternator loose inside the casing, ditto.

For now I'm not gonna worry about it. Probably not gonna ride again this year. She needs a whole front end rebuild and the brakes cleaning up, get on to that first.

Oh and the rear needs some attention too maybe. I went over a series of bumps/ripples on the A421 that I've done a million times before. The bike responded so violently my arse left the seat! Maybe they were spaced just right to set up some sort or resonance or something, but jt was both surprising and unpleasant.

[mangocrazy]

Is it a twin or single carb model? (CBA to read through 50 odd pages to find out...) If it has twin carbs, are they properly balanced? On the VFR and the LC if the carbs are out of balance you can almost hear a bottom end knock. especially at tick-over/low revs.

If it has a single carb, then just move along. Nothing to see here...

[Mr. Dazzle]

Twin crabs.

There're no vacuum ports or anything like that, to balance em you stick er....sticks...under the slides and eyeball em to see if they move in synch.

[JackyJoll]

Something that sounds like a bottom end knock is the alternator rotor coming loose from its core.

[Mr. Dazzle]

Bet those crabs I spoke of don't help either.

[Le_Fromage_Grande]

Twin crabs.

There're no vacuum ports or anything like that, to balance em you stick er....sticks...under the slides and eyeball em to see if they move in synch.

That's how you balance Mikuni Smoothbores, 4 of them, it doesn't work very well.

[mangocrazy]

Twin crabs.

There're no vacuum ports or anything like that, to balance em you stick er....sticks...under the slides and eyeball em to see if they move in synch.

That's how you balance Mikuni Smoothbores, 4 of them, it doesn't work very well.

Couldn't the old fag paper trick be employed here, in the manner of finding when contact breaker points open? Might be better than lollipop sticks. And crabs...

Alternatively (and this will probably be regarded as heresy) couldn't you drill and tap the carb bodies for vacuum take-offs?

[Mr. Dazzle]

I did actually consider that. I bet someone somewhere has done it.

If you're gonna bother with that sort of thing though you may as well get more modern carbs.