MAP offset rocker buttons in a T140

Fast Eddie

Fast Eddie

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As I’m sure most folk here know, the T140 is well known for having a pretty aggressive ‘full race’ inlet cam and a very mild exhaust cam.

The inlet can is good if re timed. But it needs a bigger ex cam to really come alive.

So I got to wundrin… has anyone used offset rocker buttons (sold by MAP these days, Dresda and others used to back in the day) to ‘correct’ the offensively mild exhaust cam?

They give an additional .028” lift. This extra lift would put them somewhere between a E3134 and a Hyde half race cam in terms of lift (from what I understand).

So fitting some offset buttons to the exhaust and re timing the cams would seem a good hop up exercise to me, without necessitating a full strip down to fit new cams.

Am I missing something ?
 
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Hi Eddie,sorry can't help with the cams 😗, but yesterday I was working on a really low milage 1982 Triumph bonneville 750 es really mint, all original burgundy /candy red paint, and the frame and swingarm paint is perfect 2168 miles on the clock, he has all the factory fairing and saddle bags.
The brakes are hanging on, return port blockage or something, will look at replacing the front master for a 13mm one and hopefully rekiting the rear master, front caliper seals are done, and will do the rear caliper as well. Cheers
 
Shelby-Right said:
Hi Eddie,sorry can't help with the cams 😗, but yesterday I was working on a really low milage 1982 Triumph bonneville 750 es really mint, all original burgundy /candy red paint, and the frame and swingarm paint is perfect 2168 miles on the clock, he has all the factory fairing and saddle bags.
The brakes are hanging on, return port blockage or something, will look at replacing the front master for a 13mm one and hopefully rekiting the rear master, front caliper seals are done, and will do the rear caliper as well. Cheers
Click to expand...
Pictures ??
 
Fast Eddie said:
Pictures ??
Click to expand...
MAP offset rocker buttons in a T140
MAP offset rocker buttons in a T140
MAP offset rocker buttons in a T140
MAP offset rocker buttons in a T140
 
Wow that’s nice !

Glad you mentioned the mufflers, those turnout things are horrid. I had one on a Tiger Cub, but I was 17 !

Looks like it might have been an Executive (ie originally had a top box, panniers and bikini fairing) ?
 
Years ago I ran a Tribsa with pre unit 650 Triumph engine. I fitted T140 inlet cams to both inlet and exhaust, Timed at 100 deg lobe center, it went like a scalded cat.
In a unit engine you would need a crank triggered ignition or something inventive on the end of the exhaust cam
 
Pass, never looked at that, yeah 85 you'd think it should be 130mph. I've just fitted a kit to the front calipers, a new 13mm master cylinder, adjusted the rear pedal height and master cylinder. I put some nice Beston grips on it as well , I just need to check it over for a warrant. Cheers
Fast Eddie said:
what’s with the speedo only going up to 85mph? I’ve seen that before on bikes from your neck o’ the woods…
Click to expand...
 
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Andy Higham said:
Years ago I ran a Tribsa with pre unit 650 Triumph engine. I fitted T140 inlet cams to both inlet and exhaust, Timed at 100 deg lobe center, it went like a scalded cat.
In a unit engine you would need a crank triggered ignition or something inventive on the end of the exhaust cam
Click to expand...
You can buy exhaust cams with the inlet profile easily these days and achieve that scalded catness ! Or what they call half race (same lift with less duration) which give a little less on top and more in the middle.
 
As you know I had some in my box of trick parts for my Dresda Daytona. No info & only two? Is that the reason why I only had two? The Dresda engine was quick & I didnt need to go looking for every little bit, so never used them. Mind you I have a few bits like that 😂 The Piper cams that looked like house bricks. The Axtell engine had plenty of grunt big cams big domed pistons unfortunately unobtainable. Bonnie pistons with cut down skirts making it a 560cc? Keep pushing mate.👍
 
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