Airtail Breva 750

[GonzoB]

Hi all.

Last weekend I did my first long trip on my '07 Breva 750 with pillion and luggage. It was a sort of a shake-down trip to see what I liked and what I didn't. Well, I didn't like the shocks. Not because they didn't work, but because they were too long. I'm only 163cm (5'3"), and even with the factory low seat it was a stretch. Riding solo is OK because I could simply back off the preload to lower the ride height, and I wouldn't bottom out. But with pillion and luggage I had to jack up the preload and it meant that I was on tippy-toes and in danger of dropping the bike when stopped.

Now, in a previous era I had a HD Road King and I fitted Progressive Airtail shocks to it. I kept the shocks when I sold the bike. Interestingly, they are about 60mm shorter than the MG units but have about the same 70mm of shock travel (not wheel travel). So I came up with this:




I had to make some extension brackets for the bottom of each shock because I only wanted the ride height to reduce by about 25mm (1").

Right side bracket:


Left side bracket:


The air fittings you see coming out of the shocks are to fix a design problem with the Airtails. Progressive didn't allow enough room in the lower chamber, and as a result the spring rate went up exponentially as the shock got closer to the bottom. I fixed that by adding an external air chamber, which I mounted on the swing-arm like this:



I'd done all this fiddling when I had the Road King, so I knew what to expect.

The result is that I can reach the ground easily now, and all I have to do when taking pillion is pump up the air pressure in the shock (see the schrader valve and pressure gauge in the first photo).


Gonzo

[Pizza Guzzi]

Nice work 👍

[pete roper]

60mm is a big drop. I suggest you monitor both the rear tyre and underneath of the rear mudguard for signs of the tyre rubbing when the suspension in compressed. You should also drop the forks if you want to maintain any semblance of agility on the beastie.

[Huzo]

Good on you for applying some thought to addressing your issue.
Is the cornering clearance acceptable ?

[GonzoB]

60mm is a big drop. I suggest you monitor both the rear tyre and underneath of the rear mudguard for signs of the tyre rubbing when the suspension in compressed. You should also drop the forks if you want to maintain any semblance of agility on the beastie.

Pete, the shock is 60mm shorter, but I didn't bolt them in the original places on the swingarm, because if I had your comments would be what happened. I made adapter brackets which mean that the full-extension ride height is reduced by only 25mm.

Your comment about lowering the forks - how far can I slide them through the triple-clamps before the mudguard hits the engine?

Huzo, yes, the cornering is fine. 25mm isn't much, but it's enough to make a difference for we short people!

Gonzo

[Dharma Bum]

How did you mount the lower shock adapter to the bike on the left side?  I can see from your pics how it was done on the right but not enough detail visible on the left.

[pete roper]

Your comment about lowering the forks - how far can I slide them through the triple-clamps before the mudguard hits the engine?

No idea. Suck it and see but my guess is an inch would be easily doable.

[GonzoB]

How did you mount the lower shock adapter to the bike on the left side?  I can see from your pics how it was done on the right but not enough detail visible on the left.

The brackets are 6mm steel, and the spacers are appropriate numbers of 10mm washers.

Here's the left one:


and the right:


The problem was to stop the brackets twisting. On the right it was easy as the axle was close by. On the left there is only one bolt so I simply made the bracket so it sits on the flat of the swing-arm.


And thanks Pete. I'll give it a try.

Gonzo

[Muzz]

Very cunning gonzo.

Yeah, the rear shocks are crap.  Although my wife doesn't ride on the back any more I have been known to tour with an awful lot of gear.  Even when she did sit on the back the rear shocks were about right with the springs backed off as far as they can go, so I just leave them permanently in that position.

Bike handles a lot better loaded.

[Dharma Bum]

Thanks for the additional pics and explanation.  An elegant solution for adapting normal length shocks to this model.