Thread: My Bonnie went from running great to rubbish while I stopped for a coffee.

Originally Posted by JamesH

81 Triumph T140E. I'm a sucker for the gear you Poms make. Just love it, though God knows what I did in a previous life to deserve this curse.

dirt in the main jet,air line fix,hopefully

Originally Posted by cooper

BONNIE might be a clue G-rockSorry could not resist that one,

soz, I thought he was on about a bike, not Bonnie Tyler,cos she's not a bike(is she ?)

Originally Posted by spudboy

Has it got a On/Off/Reserve fuel petcock?

Does it run rough on On compared to Reserve, or no difference?

She has two taps either side and the Amyl II carbies are linked so you can in theory run with one tap off which gives you a reserve but I prefer to run with both taps on. I've only got about 200km range.

The taps are new and they are the first thing I checked.

I'm thinking crud in a main jet as you guys are thinking but I won't rule out the air-cleaner. That'll get looked at too

Originally Posted by cooper

Dont know,but her song could have been about a Triumph "Once upon a time i was falling in love,now it's only falling apart"

very good Coope,'Brit parts'off to you sir

fuel restriction? or spark?

do these bike have a fuel filter?
doubt the air cleaner as at high rmp on no load still needs air flow.

Don't know much about Bonnies, so take this with a dash of crap!

Twin cylinder twin carby?

Air/fuel mixture screw on one carby may have gone a miss.

I have had the same symptons when trying to match twin carbies, and sometimes it only takes a little change in one of the carby mixtures to start running rough and /or lose power at any speed.

Edit: If it is the air cleaner, just whip it out and see if it improves things.

Originally Posted by JamesH

81 Triumph T140E. I'm a sucker for the gear you Poms make. Just love it, though God knows what I did in a previous life to deserve this curse.

That's your curse right there, 80's bikes are notoriously bad, especially Brit ones. At any time something can go wrong. I have a Cagiva and always carry a toolkit with me just in case...it's always something simple but pops up unexpectedly and is an easy fix. Unless you've got a Euro bike 3yrs or younger, expect massive problems and more time off the road than on. Because you love the bike so much and they're so rare, you quickly learn to accept that this is a part of owning such a magnificent bike. When it gets too irritating, that's when you lower yourself to the soulless and mass-produced Japanese equivalent.

Personally, keep throwing the dollars and love the bike with all your heart and soul, no matter what. It's a labour of love, but you know you'll kick yourself should you part ways.

Triumphs are reliable bikes, I have owned pommy bikes for most of my life, have a a 74 Norton 850 that I have own sence new and have own 2 Triumphs
82 Thunderbird and a 79 Bonnie, with electronic ignition not much goes wrong so I say your problem will be carbies (dirt, lose carbie mount, ajuster screw gone lose) try spark plugs as well, I have always run Champion plugs in mine as thats what they were desinged to run, when ever I ran NGK or Bosh plugs with in a week or so the bikes played up run ruff, could also be bad fuel as well and it has to be 98 octain with lead replacement (unless you had harden seats put in) it will be somethink simple so just go through and check all the things other have said but don't give up as they are a good bike just look after it and run good oil...

Ashley