Struggling with MK11 carbs

What carbs are they?

Mikuni 32 MM TM flat slide...I have experience with TM's on my Triumph race bikes..They are not expensive and have fantastic throttle response when set up correctly.But they are not everyone's cup of tea..MK2's are a good carburetor but on my bike the off idle rich stumble and a hesitation when oclosing then opening the throttle at higher speeds was frustrating...

Interesting.

Could you share your settings, or if possible, thoughts on settings for a standard-ish motor?

I run the FCR flatsides on my Commando and they’re grrrrrreat! So I’m certainly not averse to flatslides on my other Brits.

Personally, I think folk overreact with this stuff. Sure, I’d hate to see fuel injection stuck on a ‘29 Brough Superior SS1000 Pendine ! But let’s be honest, mk2 Amal’s are not sexy looking, so there’s nothing lost by replacing them on a T140, especially if it’s for something that works as well as those FCRs do on my Commando...

Fast Eddie said:

Interesting.

Could you share your settings, or if possible, thoughts on settings for a standard-ish motor?

I run the FCR flatsides on my Commando and they’re grrrrrreat! So I’m certainly not averse to flatslides on my other Brits.

Personally, I think folk overreact with this stuff. Sure, I’d hate to see fuel injection stuck on a ‘29 Brough Superior SS1000 Pendine ! But let’s be honest, mk2 Amal’s are not sexy looking, so there’s nothing lost by replacing them on a T140, especially if it’s for something that works as well as those FCRs do on my Commando...

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.The engine is a 79 TI40D with the parallel port head.Intake cam timed at 100 degrees lobe center,1971 650 exhaust cam timed at 103,internal modification for tight piston squish, 9.2 static compression and the stock T140 2-1 pipes with a straight through muffler...On the 32mm Mikuni TM's...#4 slide, the only one offered, 22.5 pilot jet,P6 needle jet,6DH2 needle ,clip in middle groove, #175 main jet.The stock TM jetting is way to rich..I had mounted an air fuel meter and welded in an exhaust bung for the O2 sensor not for absolute readings but to get an idea of what was going on...This set might be slightly lean in the mid range for some riders ...
In the USA these carbs are about $140 each on Ebay, they will accept the stock cables and rubber inlet connectors. Air filters can be an issue on any OIF Triumph...I used TSS manifold rubber connectors that have about a 10 degree bend, and the somewhat small filters, but they do not affect performance.The stock air box will work ok , the TM's are about 3/4 inch shorter tham MK2's..Reaching the right side choke is a bit fussy with the stock Mikuni arrangement...It can be changed

That’s great info, thanks.

Well, I didn’t write it on the calendar or anything so I’m not 100% sure, but I think the T140 has sat in the shed, untouched, for 4 months now.

I thought I’d fire it up today as the missus and kids we’re off out at some event or another.

It fired first kick but died, nothing second kick, roared into life on the third and settled down to a nice tick-over after a brief warming up.

It’s not been on a battery tender. No wet dumping. No fancy additives in the fuel.

Can’t argue with that now can yer !?

Triton Thrasher said:

I had a pair of Mk 1.5 Amals, which have Mk 2 type chokes.

There was no cold start jet size which was good for very cold mornings and less cold mornings.

I blocked the whole cold start circuit up too, with cork and drilled down into the float chambers to fit ticklers made from welding rod and ballpoint pen springs.

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I thought of doing that myself but never got around to it.