Rattle in disc conversion

Sorry cant help on the disc as I survive on a std + RGM 13mm conversion.

Also have iridiums for last 3000 miles with black unsuppressed NGK caps, copper leads and Pazon Surefire. Coils are PVL 6v. Not had any issues but have not noticed any improvement in running or starting either. I think the std BPE7 and suppresssed caps work fine as do the BE7 non projected plugs.

My cure would be to throw the disc away and fit a Mick Hemmings 'Norvil' disc as designed by Peter Williams. Approx. 6,000 miles since fitting, no rattles and works very well.

As you sit in the hospital bed you'll have plenty of time to work out what went wrong with the disc. It's not worth the risk taking chances with brakes.

Happy New Year All:

What is it with all this jap plug business? Never had a problem with a Champion yet. People will be changing their Amal's for Jap stuff next. Stop it!

Boyer Mk 3 is sound and reliable, just make sure you have a good battery or it won't go.

I have an RGM fully floating disc, fitted in 1989. It rattles like mad but stops well, It was given 3 advisories at the last MOT so not sure what to do at this stage. Maybe put the original back on but I got an advisory on the rear one of my Mk 3 and it is stock, less the stainless hose.

Another tester might be the answer?

Previously neil_wyatt wrote:

Happy New Year All:

What is it with all this jap plug business? Never had a problem with a Champion yet. People will be changing their Amal's for Jap stuff next. Stop it!

Boyer Mk 3 is sound and reliable, just make sure you have a good battery or it won't go.

I have an RGM fully floating disc, fitted in 1989. It rattles like mad but stops well, It was given 3 advisories at the last MOT so not sure what to do at this stage. Maybe put the original back on but I got an advisory on the rear one of my Mk 3 and it is stock, less the stainless hose.

Another tester might be the answer?

Find testers vary considerably - have got three bikes requring MOTs and use three different testers mostly as a sampling of all bike test stations within comfortable distance. Got an advisory on a front brake issue withmy BSA RGS (varying lever pressure required to maintain brake force - drum needs skimming) so next year took it toa differenttest station and told him during the process about the front brake drum so after passing MOT the guy said he wouldn't bother with the advisory since I already knew about the front brake issue.

For my Mk1A 850 it was the third year I'd been to the same station ,also with same tester , and each year the test gets quicker and easier as he clearly remembers me and the bike ! No substitute for a thorough testing but there are easier andhardertest stationswhile familiarityas a repeat customerprobably also works in your favour.

With regards to the disc brake problem I think you'll find the alloy carrier is worn allowing the spools to rattle in it. If so then a new alloy carrier and spools will be the only answer - unfortunately.

The new carrier will last no longer than the first, an alternative disc from MH would be a more long term fix.

Back to the plugs. Back in 1970, I had problems with Champion plugs lasting only tens of miles on my 99. I fitted NGKs and had no further problems. However, just to be fair to Champion, every few years I would try some N4s but they were never as good as NGK B7ES plugs. More recently, my friendly local mechanic fitted my elderly Land Rover with Champions instead of the NGKs I had fitted - 10 miles later it went on to 3 cylinders. Out came theChampions, back went the NGKs and it had been perfect ever since. So 40 plus years of trial and error tells me that NGK make better plugs Neil.Happy New Year y'all.

I find NGK plugs better than Champion. And if I did want to put a Mikuni carb on my Commando the fact that it was made in Japan wouldnt bother me. After all my frame was made (badly) in Italy, and the Veglia speedo made in France.

I have iridian NGKs non suppressed caps and a 30 plus year old Boyer and coils an it starts first kick hot or cold an runs fine. I think the new Premiers have had the most noticeable an useful effect on that though not the plugs.

I and my friends between us have had many modern machines with massive floating dice the power of which many classic bikes would not get no matter what upgrade was. None of these discs ever came loose despite stopping heavier machine form higher speed and in shorter distances. There discs where held tight to the carrier by pressed bobbins which where more like large rivets.

The disc is allowed to heat an expend but can't move there may be a tiny flex in the carrier but its main reason for being alloy is weight reduction. As the disc can freely expand it is less prone to warp than those one piece none floating disc which would be held by its centre which is ridge an cooler than the working area leading to heat induced stress over repeated use.

If as you say the brake felt wooden this should not be a fault of the disc as it is solid an can't be compressed. The feel of the disc is down to hydraulic system an pads. Perhaps the disc was slightly offset by the extra washers or pistons sticking.

I to have a loose 13inch Norvil disc so am very interested in what others have to say on this matter.