Stumped

Call from a mate today to ask if I'd have a quick look at his bike
before he takes it for a 350-ish mile weekend.

Long story short, N plate Triumph 3-cylinder thing been sat for a while.
Carb butterflies immobile, one slide stuck open, one choke thing jammed.

Carbs off, lots of WD40, lots of swearing, but everything on the carbs
now moves freely, then plugs changed and back together.

Spins nicely, but won't start.

Have checked that we have spark.

Have checked the carbs have fuel in.

Carb rubbers haven't seated particularly well (could they have shrunk
with age?) but seem to have sealed and are getting healthy draw of air
through the engine.

Any thoughts as I'm beat?

 

september.org:

Tried fresh fuel?

 

No, but it fired and ran yesterday yesterday; just when he opened the
throttle it wouldn't close again

 

Crap in the carbs?

Try some of this
http://www.startyabastard.com/

 

The airbox-to-carb rubbers can be a right bastard to fit, but it would
still fire a bit & probably start if one had got folded over.

I'd guess it's Mikunis at that age, & the rubber diaphragms in the top
shrink with age & are hard to seat properly if you have them apart, but
you don't mention stripping the carbs, so probably not that.

My '96 point blank refuses to start sometimes until I drain the float
bowls if it's been left with fuel in the carbs, so that's worth a try.
Also worth double checking the choke mechanism is definitly moving
properly with the carbs back on, as there's a hose that runs down the
back of the head that can snag it.

The middle coil & ignition pick-up are known weak points, but not
likely to be those if you've got a spark on all three plugs.

Make sure any airbox restrictors are fitted properly too - some models
have one side blanked off & a baffle thing in the inlet on t'other side.

--
Krusty

'03 Tiger 955i
'02 MV Senna (for sale) '96 Tiger (for sale)
'79 Fantic Hiro 250 (for sale) '81 Corvette (for sale)

 

Stale fuel, parafin (wd40) or water shit in the carbs.
Disassemble and clean them properly, blow through all jets and passages
with airgun.

 

Not knowing nuffink about Trumpet triples, I'm not sure if this is
possible or likely to cause the effect but...

Plug caps back on in the correct order?

 

....in an unequipped garage at midnight with nothing to see with except
an old petzl head torch...

By the time we'd finished there was a lot of WD40 about - would this
stop it starting?

 

Strangely that did come up in conversation, as well as "for those really
tricky engines, a can of Oh For Christs' Sake Come On!"

 

Take the plugs out and squirt easystart straight into the combustion
chamber then give it a go.

 

all went on but yes a bit of a bastard. The ones that look iffy are the
carb to head rubbers, but they are on

Took the centre one apart (stuck slide and immobile choke thing).
Diaphragm looked fine, though Paul put in back together rather than me
so I can't comment on the reseating.

We could have a go at draining, but the carbs were grained taking them
off and refilled before starting. The choke etc works beautifully at the
mo. Because every thing was so locked up before, there was a lot of
choke pulling and throttle twisting and saying "oooh"

I only checked one plug (#3), but that was mainly because the engine
wasn't even attempting to start. I was expecting at least a phut or two.
In the circumstances, I'm intrigued by Chris' comment about the WD40,
because when we'd finished there was a lot of it in the carbs. Hmmm

Didn't spot any restrictors, but from the woodcrews holding the airbox
together it's anybody's guess.

 

Checked.

Twice.

And checked that the caps were on well.

 

Owner is under instruction to collect some on the way home from work
today. We'll see how it goes

 

Ask him if he remembers refitting the tiny O-ring at the top where the
balance port is. Shouldn't stop it spluttering into life, but will make
it run like shite.

That would still be the first thing I'd do, given how quick & easy it
is (crosshead screw on the side of each floatbowl).

That's how they come from the factory. You're not meant to take them
apart, but replace the whole unit when the filter needs changing.

--
Krusty

'03 Tiger 955i
'02 MV Senna (for sale) '96 Tiger (for sale)
'79 Fantic Hiro 250 (for sale) '81 Corvette (for sale)

 

Didn't spot one when the carb top was off, I've got to admit.

Fisrt one easy, nect a bit tricky, third a complete bastard no doubt

They came from the factory held together with woodscrews? I must
appologise to the owner...

Spotted the whole replacement thing; not seen that before.

 

No, they're all dead easy with a longish crosshead screwdriver. At
least they are on pre-99 Tigers. You don't need to take the screws out,
just loosen them a few turns.

Yep - well little self-tappers.

Heh. Did you call him a ****?

You can take them apart & replace just the filter if you're very
careful, but they do crack really easily.

--
Krusty

'03 Tiger 955i
'02 MV Senna (for sale) '96 Tiger (for sale)
'79 Fantic Hiro 250 (for sale) '81 Corvette (for sale)

 

Deep ends where the WD40 ended up.
I would first try draining the float bowls then crank for a while wide
open to clear the shit through. Then try some startyoubastard. You may
need to keep it running on this for a few minutes to clear the last of
the WD40, it makes a really shite fuel substitute.

 

Yes, there's also woodscrews holding other bits of the bike together

I noticed that

 

Started first time on SYB

 

Told ya!