Obselete G5 Discs

My G5 failed its MOT on drake judder.
The bike had been laid up for 4 years - unintentionally.
In that time the discs rusted quite a bit.

Ive cleaned them ub with a wire brush and Emery (after they failed). But I can still feel pulsing through the lever.

I have measured the discs and there is a 0.1mm “bulge” where the pads were whilst it was laid up. I assume that the rest of the discs rusted more than the bit under the pads.

So new discs - but I cant get any. Motomecca, Gutsibits, Reeboot have all told me they are now obselete. Neither do they have any usable second hand ones.

I have tried car garages to get them reground, but they tell me that car discs are so cheap they dont bother.

I have tried eningeering firms, but they wont grind cast Iron on a lathe, as the grit gets in the lathe bits…

Anyone come across this before and sorted it ???

Des

Are the G5’s front discs the same as a T3?
I have a spare T3 front wheel I would like to sell.

Any engineering firm should be able to skim the discs. They use a carbide tipped cutting tool not a grinding wheel.

G5 discs same as T3/4, Convert and Spada, LM2 will fit. Some early T3 ones are cast rather than punched mild steel. As Bikeralw mentioned skimming is eminently feasible.G.

Go with skimming then.

Apparantly, from the enigneering frims i have contacted, using a cutting tool causes “ringing” where the disks resonnate due to their large diameter (rather like a violin bow). This causes the cut to be very rough and Grooved they end up a bit like a record. The correct way is to grind.

However if they are mild steel rather than cast iron (as I thought) it might be worth trying again.

Ian - how much do you want for your discs?
Are they in good nick?

If they are definatly scrap and you want to give it a try let me have them and i will
either skim them
or
surface grind them
have skimed them in the past its hard work stopping the vibration but is possible the first cut is the worst as its got a hard skin on it

Surface grind is the best but its a matter of getting them fixed secured square

Ex smokingbiker2012-04-20 18:19:49

[QUOTE=bigdes] Apparantly, from the enigneering frims i have contacted, using a cutting tool causes “ringing” where the disks resonnate due to their large diameter (rather like a violin bow). This causes the cut to be very rough and Grooved they end up a bit like a record. The correct way is to grind.
Â
However if they are mild steel rather than cast iron (as I thought) it might be worth trying again.
Â
Ian - how much do you want for your discs?
Are they in good nick?[/QUOTE]

I have some experience in machineing cast discs .I have machined both front and rear T3 discs along with new and used car cast discs. It’s not easy, sometimes it works and sometimes it dosent.I would go with exsmokingbiker and get them surface ground.

They are probably DUCKED!

How about trying another MOT station, possibly one that uses an old fashioned winch system or similar, one that does not use a rolling road.Once the bike is in use the slight bump might wear off or it will give you time to look for some 2nd hand discs.Where abouts are you, someone on here may know a suitable MOT station.


Don-Spada2012-04-21 14:49:38

If you fail to cure them and Ian can’t help you, give me a buzz.

what about a good long ride to the MOT station to bed them in??

Are both front discs pulsing or just the front right hand one ? If just the front r/h one then why not swop discs over but remove the duff one and it’s caliper and brake hose . All you need is 1 front and rear brake.Then put the other back on after the mot.Just put up with the pulseing until you get the duff one ground or replaced.



OR go with exsmokingbiker.ralph2012-04-23 08:19:15

got a pair of a suzuki in the post to me to grind
so will be setting up the grinder to do them, so if you want to send the guzzi ones can get them done

New ones still listed by Stein Dinse.The last ones I tried to get skimmed couldn’t be done.

I had all 3 discs off the Convert skimmed/ground last year at a place in Stoke for very reasonable money. Worked a treat, cured the pulsing brake problems. I’ll see if I can find his details if you are still in need of assistance. He does do a postal service I think.Steve







\

Our Gas Turbines use cast iron casings and quite a few companies won’t machine them because it c*&ps up their machine

Did the discs get sorted ?
offers there if needed

Y know Ray they never listen…Peeps Ray is a local Branch Member ad is a real good engineer top bloke and all round good guy ( psst that’ll be a fiver Ray )

I try my best