Thanks for sharing. Yeah, I've had the tank off many times, and it is indeed (especially if you're in a bit of haste) very easy to get something pinched in there.

 

I just started my Bonnie first time in months yesterday morning. It must have started and stopped at least 5 or 6 times before it stayed running. It was in the mid 30s when I started it and I was afraid that the battery was going to run down before it stayed running. I will take a look at that tube when I get home. Thanks,

 

"stabiler" = more stable glad you got that sorted!

 

That little vent hose was giving me trouble recently too, but of a different kind. I was getting a slight surge at steady throttle (highway speeds), and was getting quite frustrated chasing gremlins. Now I'm fairly certain it was a wind issue at the tip of the vent hose, creating a vacuum. I cut the end at a 45 and routed the opening facing away from the blast (toward the rear of the bike) and it was cured. It's been 4k miles since without a hint of the trouble.

I guess that little vent, just like the fuel tank vent, is important too

 

That's what happens sometimes when manufacturers (or customers) fix something that isn't broken. My '03 never had that vent hose--just the open "T". I don't know what year they decided to fix what wasn't broken, and don't really care.

 

Hmm.. Mines an 03 also...

 

Never any problem with my '03.

The vent hose pictured above carries crankcase vapors to the carbs for burning. When next you service your air cleaner, you should notice just a little evidence of oil at the bottom of the filter seal. Can't imagine that a kink in this hose would have caused difficult starting.

 

I think the OP means the carb vent hose. This provides atmospheric pressure to both the float chamber and one side of the diaphragm and should be terminated in some relatively calm area under the tank or behind the engine, but not poking out underneath the bike where it can melt on the exhausts, or clog up with dirt and water, or be exposed to wind turbulence.

 

Is this vent usually up under tank or down towards rear??


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Cold starting

Hi I bought my 2001 Bonnie in January and have had the same issues with starting cold. Checked pipe , no kinks and was loosing power when first ridden today. Felt like fuel probs but everything looked ok. Stopped it then started no problem and was ridden for 130 miles with no issues. Bike had stood for about 5 years just started occassionally. Has had a new battery, plugs oil and fuel. Could the carbs be the problem? Thanks

 

Bike had stood for about 5 years just started occassionally.

Standing for 5 years with occassional starts seems to hint at carb jets being gummed up. Everytime it was started the carbs were filled up with fuel that then evaporated over the idle period leaving behind residues that gradually choke the jets, float chamber needle valves, etc.

Just in case it's kinked or trapped somewhere, first of all check the fuel tank breather hose and see that it's clear. It's just by the top of the cam cover, right hand side, attached to a spigot welded to the tank, it goes to a tip-over valve just behind the engine and in front of the airbox and terminates under the engine by the swingarm pivot area.

Also make sure the tip-over valve is fitted vertically. (it has the word "UP" moulded on it to indicate position).

More about the tank breather system here:

http://www.triumphrat.net/twins-technical-talk/155943-gas-tank-breather-hints-and-tips.html

 

Yes, I meant "vent hose". as I stated in my opening post "There is a vent line running from the carbs down the left side of the engine."

 

Ive posted this before, seems stupid, but the only thing that
prevents me from having to crank my bonnie 6 times
on a cold morning is a small space heater blowing hot
air on the carbs. Ive tried just about everything suggested
on these forums. I have an 02. Weird.
I am going to check out this vent though.

 

Isn't it great when the solution to a problem is so simple.....

 

Cheers Forchetto
(Just in case it's kinked or trapped somewhere, first of all check the fuel tank breather hose and see that it's clear.)
Hose wasnt connected tried it and fired 1st time and better off the choke.

Now it's snowing so I ain't getting out to play !!!

 

Cold starting

Since moving my T-100 back into the garage and switching to non ethanol gas, my baby fires right up! I will look for that vent hose also.

 

If that "vent hose" on your '03 is from the "tee" between the carbs, it shouldn't be there--the "tee" should be open and pointed down. This is the vent for atmospheric pressure for the carb bowls as Forchetto said. Putting a hose on this "tee" has only caused problems. Plug it up and the carbs will flood. Hope this helps, but do what suits you.

Larry

 

I'm a little confused as to what hose you guys are talking about here. I have a little short hose that connects to a T in between the carbs that bends back in front of the frame about 3 inches long. The other hose is a vent from the fuel tank that goes down under the bike. Then a vent hose from the crank case and I vented that (bad me) to above my chain. Are ou guys talking about that little 3 inch tube that is connected to that T????

 

Sonicboom,
Yes that 3" hose you are referring to is the one I am referring to. Apparently Triumph made changes to this carb vent. Depending on the year they seem to have done different things. Evidently even during the same model year run they weren't exactly the same either.


And for the record. That hose/line which was running down the left side of the engine and pinched between the swing arm. It IS connected to the "T" connecting between the carbs. I DID NOT add this hose/line. I am VERY sure it was a factory installed hose/line. I have good reason to believe it was not added after the bike was manufactured. This bike was not taken care of at all before The Francis brothers (Ozark RAT Raid family) purchased it for the Ozark RAT Raid raffle.(Yes, I won it) The told me everything that they did to it. Mainly, Paint and clean up. They said it was the ugliest shade of faded maroon you ever seen. They said it looked like it had sat outside its entire life. This hose/line is as old as anything on this bike. In fact, it was not the easiest cutting hose/line.

 

I removed that stupid hose from that "T" and position the tee down so junk will not get in that sucker. I noticed it was pressed up against the frame and bent a bit. I've also had trouble with cold starts. It looks to me like it was partially or fully cutting air flow for vacuum.

Good call on this one.

 

I put nology wires on my Ducati for about a week . It started harder and only liked to run on one cylinder til warm. I called nology and they sold me more resistors or some such that you put on each wire, supposedly mine might have failed or some such. I paid for them as I couldn't find my purchase slip. Installed them, same problem, no better. Pulled the hot wires and put the ones I had made back on. Starts and runs great. Not a nology fan.

 

When I pulled the vent tube it smelled strongly of fuel and was wet to the touch.


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My vent tube was the same way. Strong smell of fuel and the tip was wet with fuel.

 

Any of you guys notice this issue with an '08 carbed t100? I have also noticed my bonnie is not idling very smoothly and when I start with the choke it revs high for a moment and then bogs down. I have put on the Preds, removed the airbox, and re-jetted, but this did not start right away. It actually started sans choke no problem for a while. I am looking forward to checking this when I get home. Thanks for the info.

 

Spraying carb cleaner or seafoam thru the vent lines every so often can cure a lot of ills. By the way, do you think Seafoam might ever come in a spray can?