T140 progress and thoughts...

Not at all, it’s all good stuff. In fact, how about a photo of yours ?

Here it is then.

Lovely job !

The longer Koni shocks were nagging away at me still. I have another bike that has a pair of Maxton shocks on that are slightly longer than stock T140 but shorter than the Konis, they have softer springs too. Verdict, they’re a noticeable improvement. Looks like I’ll have to cough up for a pair!

I also re-richened things up a tad by putting the number 3 slides back in. I did this because there was a very short hesitation just off idle, and it was the slides as it’s now cured.

Last weekend I went for a good blast and thought it felt a bit weak in the mid range, I had previously lowered the needle one notch (chasing a nicer plug colour) but this wasn’t the right thing to do, putting the needle back in the middle groove has improved things.

Final recent fiddling was with the front brake. The 13mm master cylinder just caused too much lever travel for my liking. I’ve put the stock one back on which whilst still having that slightly wooden feel, at least has a better lever travel for me.

I’m still not totally happy with this front brake though (Hyde big stainless disc), I expected better to be honest.

The caliper is a cheapo AP copy. Could that be the reason, would a genuine AP caliper function any better? Or is it due to the stainless disc having less friction than iron? Or am I just expecting too much? Anyone know?

I’ll ponder further front brake ideas over the winter along with a few other thoughts I’ve got for some more fiddling.

The eagle eyed amongst you may have noticed I tried to sell this on eBay recently. That was a mistake. Fortunately I realised this and pulled it before anyone bought it!


Maxton shocks in situ. It’s bad news folks, the verdict is clear, these expensive shocks really are actually worth it:

Looks to me like you stuck a Triumph on those Norton silencers.

Reggie said:

Here it is then.

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That is one GORGEOUS Harris Bonneville for sure! *I would trade one of my KZ1000 for it even ;-)

Nigel,

Fitting my TR7 with a Nissin 1/2" master cylinder has been one of the best mods ever. The brake which consists of the standard iron caliper,
EBC orgasmic pads, & a modern 12" floating disc is now very good.
On your bike too much lever travel may be caused by the pattern AP caliper. I recently built a T160 for a friend & fitted a pair of these, but after bleeding the brake for the millionth time I realised that the excess lever travel was caused by the caiper pistons retracting too much. I believe I'm not the only one to have had this problem, as I have heard that changing the seals for a set of genuine AP ones helps. My mate hasn't brought the bike back yet so I haven't tried this out.

Martyn.

Martyn, yes there is an issue with the pistons being pulled back by the seals, I can see it.

What about outright braking power though, are these callipers ok in that regard?

I can't answer that as I don't have one on any of my bikes, but my friend with the T160 seems happy enough. As they are made to the same dimensions as the real thing, they should, in theory at least, work the same.

Thanks Martyn,

What 12” disc are you using and is it iron or stainless?

I put the clone AP caliper on my T150v. Same problem with travel of the lever and the same problem with the pistons. Took the caliper apart looked fine. Rebuilt the new 13mm master no joy. Rebuilt the standard master at least usable, sort of. All using the standard iron disk but one that was
freshly surfaced.
Winter coming I guess Ill have to retry the iron caliper.

Onder said:

I put the clone AP caliper on my T150v. Same problem with travel of the lever and the same problem with the pistons. Took the caliper apart looked fine. Rebuilt the new 13mm master no joy. Rebuilt the standard master at least usable, sort of. All using the standard iron caliper but one that was
freshly surfaced.
Winter coming I guess Ill have to retry the iron caliper.

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Iron no. Iron bad.

I don’t normally buy cheapo copy parts, partly out of principle and partly as I don’t trust ‘em. The price difference swayed me with these though... and now I’m bloody regretting it!

If I understand Martyn’s post above, changing the seals in the copy callipers for genuine AP seals cures the piston retraction / lever travel problem. I might look at that over winter.

But then again, I got to thinking, maybe the seals are designed to pull the pistons back in order to stop brake drag?

I’m thinking of sticking another Hyde disc on the other side. Anyone done that already ?

The seal groove in a brake caliper is not square, but has a slight angle on it's periphery. This is what causes the piston to retract slightly. This could be the problem, but as I haven't pulled one apart to measure I don't know for sure.
The disc on my bike is stainless & was from a chap called Paul Field who sadly died last year. His partner still has some available if you are interested.

Fast Eddie said:

But then again, I got to thinking, maybe the seals are designed to pull the pistons back in order to stop brake drag?

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That is correct.

Matchless said:

The seal groove in a brake caliper is not square, but has a slight angle on it's periphery. This is what causes the piston to retract slightly.

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The seals need to be oriented correctly.

The seals are normally square/rectangular in section, at least all the ones I've fitted (including Norton/Triumph Lockheed). It's the base of the groove that's angled.

http://mgaguru.com/mgtech/brakes/bt104.htm

On the Nissin ones I have dealt with the O-rings appeared to be angled.

oldbeezer said:

On the Nissin ones I have dealt with the O-rings appeared to be angled.

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That's a new one on me. Over the years I have stripped lots of different calipers from AP Lockheed, Girling, Nissin, Tokico, ATE, & Sumitomo to name a few, & they have all had square seals with angled grooves. Just goes to show that there is always something new to learn.

Matchless said:

The seal groove in a brake caliper is not square, but has a slight angle on it's periphery. This is what causes the piston to retract slightly. This could be the problem, but as I haven't pulled one apart to measure I don't know for sure.
The disc on my bike is stainless & was from a chap called Paul Field who sadly died last year. His partner still has some available if you are interested.

Click to expand...

As you know Martyn, Paul (Fields) was my mate.
I'm seeing his partner in a couple of weeks and can find out just how many brake components she has left, as I thought I'd got the last brake kit for my mate Kevin for his TR7RV.

My memory may fail me but I seem to remember small airplane calipers with O ring seals not square section ones.
On my clone AP caliper the pistons move too much back and forth making the amount of travel too much for the 13mm
master.

Now then boys, inspired by the really rather excellent Brembo / cNw brake on my Commando, I have hatched a cunning plan for the T140 front brake. I reckon the caliper below would match up wonderfully to the 13mm master cylinder body I already have.
I just gotta work out how to graft it on, it requires a stepped adapter plate knocking up...