vx 800 rear disc

Hi. My recently acquired VX 800 has scored rear disc, so been looking for a 2nd hand one in good nick. Seeing Barneys request for a good used one, and having noticed that some used ones offered are no better than mine, my question is are these a weak point on the VX 800? Are they prone to wear early? Weak metal? Is this where all those milk bottle tops I sent to Blue Peter ended up? I`ll buy a new one if I`m wasting time looking for a good `un.

The standard 'new' VX800 rear disc is 6.0mm thick +/- 0.2mm. The wear limit is 5.5mm.

The scoring on your disc may be a problem with the type of pads that have been used that has lead to the scoring, or pads have bee run down 'too low' at some stage.

I've never had an issue with my rear disc in general terms - but did once have a problem when a small road chipping got lodged in the rear brake pivot and held the rear brake partially on, This had occurred on a freshly chipped road, & the chance of it ever happening again would be slim. Clearly any form of brake binding has the potential to ruin the brakes performance, but that is through over-heating, which commonly leads to a distortion problem (though prolonged overheating and cooling could lead to the disc becoming susceptible to scoring - but only on a poorly maintained bike - i.e. one with sticking brakes).
Fortunately when the chipping incident occurred I was riding with a couple of mates and one of them asked me if I was having a problem with my rear brake as the brake light was staying illuminated. This was spotted quickly & there was no long term 'damage' to the rear brake.
As a precaution I did change the brake fluid as any excess temperature could have 'spoiled' it - this was despite the fact that I had changed the rear brake fluid around 6 months earlier.
Many people neglect to change their brake fluid, and this is not good as old fluid will contain some water moisture and this softens the feel of your brakes, plus having 'water' in the system can lead to internal corrosion of you braking components, leading to sticking callipers or cylinders etc. Brake fluid should be regarded as analogous to oil in an engine, and needs to be replaced at regular intervals (No longer than 2 years). 

So summarising - I'm not aware of a significant problem with the rear disc brake on the VX800.

If your disc is over 5.5mm thick it is classed as serviceable, and putting on a new set of pads might help - but if the scoring is excessive, then the pad life will of course be less than normal. That is your cheapest option.

If you are patient you might find a better second hand disc - but breakers seem to charge around £50 for them, and what they are asking for them is no guarantee of how 'good' the disc is. Some breakers charge OTT prices for worn parts - but will offer a refund if you are not happy with the part when you receive it (i.e. it is your decision to make up your mind how serviceable the part is - not theirs). You should fit new pads to any replacement disc.

If you are 'anal' about the condition of your rear disc (that doesn't sound right ), then the only way you will be satisfied (here we go again ) is to replace it with a new item. You could be lucky and find a genuine Suzuki part offered cheaply as 'old stock', or you could use a decent aftermarket one such as from EBC (You will be talking a 3 figure number for that).

Whichever option you chose - if you are not sure when it was last done - CHANGE THE BRAKE FLUID

Hope that might help !

    Yam

Thanks for the reply. I had noticed, with interest, the previous post you made about the road debris getting wedged in the brake mechanism. And yes you`re right the hassle of returning an unsuitable part that`s not much cheaper is hardly worth it. If I can find one handy by, in the next coupla weeks, that I can see before buying, good. If not an EBC off the shelf is the way to go.
 Your comments on brake fluid are noted and already taken on board. Another reason I`ve heard for changing fluid is as follows: as you say the fluid is hygroscopic, and if the brakes warm up excessively, the water in the fluid could turn to vapour; so the pedal/lever will become soft, as if there`s air in the system. I`ve no experience of this, but don`t wish to either! Not something likely on a Sunday morning bimble, but 2 up with luggage coming down a Spanish mountain in August...
 Few quids worth of fluid and half an hour is a good way of keeping one`s anus intact, agreed.

to that Brian ...... I once had a problem in a car that I also used for weekend motorsport at club level. It was a front wheel drive car & Id be experimenting with the left foot braking technique (Not to be tried on the road !). This caused the brake fluid to go off during the season & I'd 'got used' to the change in pedal feel ..... but when I took the car for an MOT the tester would not pass it because although the brake efficiency was right, he thought the pedal feel was wrong. I also had competition pads in - so first I changed the pads - still not right .... then I changed the fluid & all was restored to his satisfaction (& mine).
It is surprising - but as you say a few pounds of fluid can make a big difference. Since my 'experience' of deteriorated fluid I have always changed brake fluid on a frequent basis - both in my cars & on my bikes. 
Hope you get sorted - & enjoy your touring

     Yam