Skorpion handling issues

[Butters]

Hi folks,

Now the good weather has finally arrived I have had chance to to give the rebuilt Skorp some proper beans. Everything is fine apart from a tendency to "wallow" on high speed bends i.e. 80mph plus. It feels like it is flexing at the head stock. Starts at the turn in and occilates regularly at about 2 "wallows" a second. Bike holds it line ok & does'nt feel like it is going to pitch you off. Just disconcerting.

Tyres are Pirelli super corsas in good nick & correct pressures. No detectable play in headstock or swingarm. Forks have fresh oil to correct level(15w). Rear shock seems to operate fine with adequate damping.

Anything else I should check?

[Bill Jurgenson]

unless the frame is damaged, you can forget any headstock issues; the design simply does not have them.
I can testify that even in a head-on accident I had myself, that bent the fork beyond any hope, the frame was unscathed. Multiple spills on the track did not crease anything but me.

And that is with my own prototype frame that was rejected by the engineers at MZ as being too weak. So weak in fact, that I subsequently removed the cross tube above the engine to get rid of that nuisance and finally be able work unobstructed and not have to remove or at least tilt the engine for even the smallest tasks.

With NO noticable effects whatsoever.

Likewise, I have never had any issues with head or swingarm bearings on any of the three Skorpions I have owned. That said, high pressure and steam cleaners do wreak havoc with bearings. Otherwise, they do not require any particular attention.
Foot pegs? back placement? Nice old-fashioned, stretched out, 50ies position, ideal for knee clinching the tank but anything but good for the design and hopeless. Even the front hole of the Sport is too far back. Puts too much weight on the wrists (unless you are 7ft tall) and far too little on the pegs, especially the outside peg of a turn. Could be part of the problem.

That leaves me with the Super Corsas which I used extensively myself, both on the street and above all on the track. What do you term correct pressure? They are very critical to pressure and the "correct pressure" in the MZ handbook is way too high. 1.9-2.0 (28-29pis) bar front and 1.7 (25pis) rear proved best for me and was what the Pirelli technicians recommended. Definitely not more than 30pis anywhere.
And the the SC also reacts badly to a flat center stripe on the rear, typical of street riding.

Likewise, the handbook "correct pressure" is too low for Bridgestone BT090 or BT45 which need at least 2.6bar (38pis) or they wallow like pigs.

[Butters]

Thanks for the reply Bill. As there is no evidence of crash damage, the finger of blame must point to tyre pressures. I have, as you suggest, been running at MZ handbook pressures. I myself thought these were rather high as I've used Corsas on other machines but nowhere near those values and found them suberb.

Regarding riding position, I find it very painful on the wrists at much below 70mph so the pegs & bars are on the bin list when finances permit. ( along with carbs, fork springs, shock, pipe, clocks etc !!)

When the roads get quieter ( it's TT race time here) I shall run pressures as you suggest & report.

Cheers

[Butters]

Well, went into the garage to drop the tyre pressures and found I did'nt have to. The rear has dropped from 35psi to 19 on it's own. No wonder it handled like lump of lard. No leak from the valve & nothing stuck in the tyre so I can only assume the bead is not seated correctly.
This bike had stood for a long, long time in poor storage conditions and a flat tyre. I'm wondering if the rim is corroded on the bead seat.
I coul'dnt check while the tyres were changed at the shop. Off they come I suppose.

That said, I set pressures as suggested by Bill J and she ran great. Rock steady.

[DAVID THOMPSON]

DO CLEAN the RIMS
my 10 year old RT125 has alloy rims and has corroded badly
the front is bad about loosing air if i do not ride it daily
and i check the air every other day as it has been a problem now for a couple years
dave

[radiograf]

I have the same problem with a kaswasaki er5, so I now use innertubes in the tyres.

[djsbriscoe]

DO CLEAN the RIMS
my 10 year old RT125 has alloy rims and has corroded badly
the front is bad about loosing air if i do not ride it daily
and i check the air every other day as it has been a problem now for a couple years
dave

Get it checked then shot blasted and powder coated. Not worth risking a blowout.

David.