revtothelimit - motorbike forum

The red line is a teeny tiny fuel path that runs to downstream of the slide. Its got a screw (not shown in that pic) which you adjust to change how much fuel 'bypasses' the slide and hence adjusts the mixture when the throttle is shut.

JackyJoll wrote: Thu Jun 16, 2022 2:48 pm I see that the T120TT, with pistons like yours, used Champion N58R, which is an obsolete racing plug.

So if I'm reading this right...N58R would be equivalent to about 9.something in NGK world. Whereas I'm running 8s. So colder plugs might be an idea.

The needle jet size and the cutaway size operate at more or less the same throttle range: just off idle.

Needle clip position has a big influence on mixture at “normal” road riding throttle opening range.

I’m not going to go back through the thread, but I may already have mentioned fuel flow from the tank into the float bowls. It’s often an issue when you try to go fast on an old 650.

You increase main jet size and test at full throttle until you know it’s too big, then reduce to correct. Smarter people than us sorted that out before 1930. You can’t do these tests if flow from the tank is restricted.

It would not be surprising if you needed a colder plug than NGK 8.

The space between the needle and the needle jet is smaller than the main jet, until the needle is lifted out of the needle jet.

Le_Fromage_Grande wrote: Mon Jun 27, 2022 10:00 pm The red line is an air bleed isn't it, on a Mikuni that's controlled by an air jet in some carbs.

The picture is misleading. The air bleed (or compensation circuit) is a drilling from the bottom centre of the bellmouth, parallel to the pilot circuit drilling which is off to one side.

Ita got inline filters which it didn't have before, they probably knock the flow a little. I could try opening both fuel taps, if that doesn't fix it I doubt its flow?

Tickles pretty fast, maybe 2 or 3s.

It should flow nearly 200 ml/minute from the bottom of each float bowl, at the same time. You can measure (or you can guess or assume or hope for the best).

The handbook recommended opening both taps if you wanted to go fast.

You're not opening both taps?

I bet he doesn't even use the three seashells!

Rockburner wrote: Tue Jun 28, 2022 8:24 am You're not opening both taps?

One is the reserve. I don't have a fuel gauge or a working odometer, so....

I actually needed to use it the other day too! I thought I was breaking down, but no, just running out of fuel

Noggin wrote: Sat Jun 25, 2022 12:35 pm

mangocrazy wrote: Wed Jun 15, 2022 9:36 pm

Of course it's supposed to leak. It's a Triumph...

Ummmm - I was once told that Triumphs don't leak.. they just mark their territory

So did BSAs, Matchlesses, Nortons, Enfieds, et al.

I've already agreed with work that I can leave it in the bike parking outside the front door, but I need to put some of that spill kit mat underneath it

Mr. Dazzle wrote: Tue Jun 28, 2022 10:33 am I've already agreed with work that I can leave it in the bike parking outside the front door, but I need to put some of that spill kit mat underneath it

A redundant baking tray.

Cousin Jack wrote: Tue Jun 28, 2022 10:30 am

Noggin wrote: Sat Jun 25, 2022 12:35 pm

mangocrazy wrote: Wed Jun 15, 2022 9:36 pm

Of course it's supposed to leak. It's a Triumph...

Ummmm - I was once told that Triumphs don't leak.. they just mark their territory

So did BSAs, Matchlesses, Nortons, Enfieds, et al.

They dont leak oil, they sweat power

My little engined velo does not leak a drop.

The bsa ,on the other hand......

slowsider wrote: Tue Jun 28, 2022 11:59 am
They dont leak oil, they sweat power

My BSA allegedly had 12 horse power. 3 of the horses were dead, 2 were lame, and the remainder were severely asthmatic.

Sweat power ? Wishful thinking!

Use very expensive synthetic oil.

It gives you an incentive to fix the leaks.

Cousin Jack wrote: Tue Jun 28, 2022 7:51 pm

slowsider wrote: Tue Jun 28, 2022 11:59 am
They dont leak oil, they sweat power

My BSA allegedly had 12 horse power. 3 of the horses were dead, 2 were lame, and the remainder were severely asthmatic.

Sweat power ? Wishful thinking!

I actually went for an overtake yesterday! Didn't even stop to consider, just pulled out and cracked the throttle like I was on a modern bike

Did you complete the overtake?

Back when we were apprentices,matey and I used to commute two up on a CB125 long past it's best. On one notable occasion I moved to overtake a bus sitting at the bus stop. The bus began to move off when I was about halfway down it's length,but as the bus accelerated,the little 125 hadn't the zip to complete the manoeuvre,so I had to fall back behind and endure the schoolkids giving us the wanker sign and laughing their tits off.

Oh the shame,it lingers still.