Struggling with MK11 carbs

Joined
Oct 18, 2018
Messages
69
Country flag
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...
 

Fast Eddie

VIP MEMBER
Joined
Oct 4, 2013
Messages
11,712
Country flag
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...
 
Joined
Oct 18, 2018
Messages
69
Country flag
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...
.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
 

Fast Eddie

VIP MEMBER
Joined
Oct 4, 2013
Messages
11,712
Country flag
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 !?
 
Top