Triumphrat

snatchpiece · 05-20-2009, 01:56 PM

Are all Triumphs as weird as mine?

I have stripped, cleaned and rebuilt the carb on my 59 5TA, replacing all gaskets and seals plus the filter. Upon refitting the carb the bike started OK, I tinkered about trying to set it up and seemed to be getting on fine, although the plugs are telling me it's a bit rich. Anyhow as it was idling away (the engine was fairly warm by now) it just stopped and no amount of trying would get it to start again. It's generating a healthy spark and fuel is getting through as depressing the tickler floods it as normal

I will try it again tomorrow when it's cooled down.

Any ideas?

jimmy bush · 05-20-2009, 02:04 PM

Fouled plugs? Out of gas?

Sunshine Jim · 05-20-2009, 04:57 PM

a bit of glop in the idle jet?

squirt a liittle gas past the slide and see if she fires?

unscrew the idle screw and tickle to see if any gas runs out that side of the passage? screw the idle screw in gently till it bottoms and back out again, flood again and see if you've cleared the passage?

squirt a little gas past the slide and when she fires up put your hand over the carb and see if the cylinder vacumn will suck the passage free?

heres where having a spare carb to bolt on helps. ding dang ornery amals.

snatchpiece · 06-17-2009, 12:13 PM

Thanks for the replies, I've been away and not had time to respond.

The day after the episode detailed above it started first kick from cold!

I've checked the carb components and all are as stated in my Triumph manual except the main jet which is 170 as opposed to the 160 stated.

Today I thought I'd try it with the air cleaner disconnected (it's a perforated metal box inside the bathtub). The bike started fine and ran fairly well although on sharp throttle openings it gasped a bit (certainly did not spit!). I tweaked the pilot air screw at idle to try to get an even tickover, all I could get was a fairly even tickover but every now and then it would respond like someone had opened the throttle very slightly then shut it quick. I allowed it to tickover for about five minutes and sure enough it just stopped again. Without doing anything else I removed the spark plugs, the left one was black and wet and the right was sooty, this is after idling with no air filter! I did what Sunshine Jim said and removed the pilot air screw and tickled the carb, some fuel appeared at the pilot hole but most trickled out of the venturi. I lightly blew the pilot hole with an air line re-assembled everything and I managed to start it, I stopped it and managed to start it again but it stopped once more and would not start again. I then ran out of time to try anything else.

I'm a bit concerned about the apparent richness of the mixture, do you think I should try a 160 main jet? although I undestand this should not affect idling.

Should I lower the needle?

Any ideas?

epynt1050 · 06-17-2009, 12:18 PM

Is the air bleed hole in the petrol cap clear? If not bike will run for a few minutes and just stop but will start again next day.

Richness at tickover -Main jet not the problem. More likely to be float and/or float valve.

Ton Up Pirate · 06-17-2009, 01:03 PM

I'm used to the concentric carb,I'm taking it your's is monobloc.Try this link,you may get something from it.
www.hitchcocksmotorcycles.com/amal/mono_ht.html

GrandPaulZ · 06-17-2009, 05:46 PM

A carb that old needs to be bored, sleeved and a new matched slide installed with a new needle and matching needle jet.

I'd go back to original jetting on the main jet as well.