Exhaust threads + disc re-con

Morini Rich · Post by **Morini Rich** » 04 Mar 2007 21:26

I have two questions I hope someone can help with.

Can anyone recommend a company to recondition cylinder head exhaust threads? How much does it cost?

I have a front disc that would probably benefit from skimming down to the base metal (chrome has come off at one part making them a bit 'grabby'). Has anyone done this to these chromed Morini discs? If yes who did you use?

Regards

Richard

Ballacraine · Post by **Ballacraine** » 06 Mar 2007 20:20

As regards the exhaust threads I would suggest taking the heads to a trusted local light engineering shop and asking them to helicoil them. It is quite a substantial size helicoil and they would probably have to order them specially, but I would think it would be the preferred option.

TBH I would ask the same machine shop to skim the rest of the chrome off and use it like that...

It will be a better brake for it.

Any surface rust from damp or rain will soon polish off after the first couple of instances of light braking.

Nige

moriniuk · Post by **moriniuk** » 08 Mar 2007 09:08

The chrome shouldn't be skimmed off. It should be chemically removed. It will cost about Â£20 per disc. I have had some done at scooter shop in Stockport. The braking will be improved but the discs will rust and your brake pads won't last very long.
If I was using the bike on the road, I wouldn't recommend it. I'd bite the bullet and get a new standard disc.
I have never ridden my Morini on the road and have only used it on race tracks. I have now had a better disc specially made.

Ballacraine · Post by **Ballacraine** » 08 Mar 2007 20:41

If you have it chemically removed it is not going to true up any wear, and it may damage the surface which would lead to excessive wear..

moriniuk · Post by **moriniuk** » 09 Mar 2007 08:56

The problem is turning off the hard chrome plate in a lathe apparently. Ideally it should be ground off. By the time you've gone to all the trouble, expense and still ended up with a rusty disc. You might as well buy a new disc. I've got lots of these de-chromed discs.
In the end I had a disc made up specially. It's not exactly a straight swap as the caliper needs a bracket.
The new disc is 320mm diameter, fully floating with an alloy centre and ductile iron rotor.
I got two made for not much more than a standard Morini/Gimeca chrome disc.
I wouldn't have bothered for a road bike, but this one is only used on the track and the standard brakes were becoming dangerous.
Howard

Morini Rich · Post by **Morini Rich** » 09 Mar 2007 22:01

Thanks for all the input. Seems there is a similar thread going on in the 500 forum.

Anyway, following a recommendation, I spoke to Hagons in Essex and they seemed happy to skim the chrome off. They need the discs still attached to the wheel as this ensures that the discs end up true to the wheel. Cost is Â£40 each +VAT and I'll let you know how I get on (although this may be few weeks away as I have a few other jobs to do on the bike before being back on the road).

Cheers

Richard

PS They won't do drilled discs.

Ballacraine · Post by **Ballacraine** » 09 Mar 2007 22:53

Aye, I can see where you are coming from with that, Howard.

As chrome is such a hard material, I suppose grinding does make more sense.

As I am just using mine on the road, with current traffic levels I think I shall go the twin disc upgrade route myself.......

I have sourced an additional caliper & a smaller casting 500 speedo drive.
I just need to source a second disc now, if anyone has any suggestions or knows of any looking for a new home.

Nige.

Brubru · Post by **Brubru** » 14 Mar 2007 11:56

A few years ago NLM had a new batch of disks made by the original supplier. They might still have some in stock.

Ballacraine · Post by **Ballacraine** » 14 Mar 2007 19:50

Thanks for that info.

I got lucky the other day though. A fellah I was buying some Morini bits from off ebay found one for me.

Nige.