Monster 900Sie 50000mile refresh.

[Mr Gazza]

Well. I don't think I could take anything meaningful off the gearbox, the bolt heads foul it everywhere.
The heads would have to be no higher than a thick washer. I pictured a flat head about 2mm thick at most with an Allen socket going down into the actual bolt. More or less like a grub screw with a head.
The other idea I had was to countersink the disc carrier and use countersunk screws, but not sure that's good practice on a disc? I've never seen countersunk ones before, but I'd only have to do one side.

Actually thinking about it, countersinking might have legs? Unless there is some engineering objection? I certainly wouldn't be able to grind slots to get them out if they were stuck. (milder locktite me thinks?)

[Nasher]

I'm not sure about countersinking them.

The loads on the heads of the bolts will be different.
Pulling them out rather than simply in shear.

When I put the ST lighter wheels in my 900SS I had to make the speedo drive narrower.
I took at least 4mm off the outside edge in my lathe.
If the same could be added to the inside edge of the inner sleeve, and the drive flange made wider, plus using the bolts I linked you'd probably have enough room.

[Nasher]

Does anyone have a spare, even knackered, 25mm spindle speedo drive they'd sell me and get to me quickly so I could have a play?

I'm convinced my 999 has the bolts that I linked to, so I'll measure them in the morning and see how much lower they are.

I'm sure we can sort this.

[Nasher]

Your other option could be some 748R/998R discs.

I'm told they are 6 hole 320mm diameter, but have a 15mm offset rather than 10mm.

Your discs would be 1/2mm offset in your calipers, but that's not going to matter.

I know somebody who has a pair, I'll get them to measure them. I'll also pop out to measure some stuff in my garage in a bit.

[Mr Gazza]

You're on fire Nasher!
I really don't think that altering the speedo drive will achieve anything, it's ludicrously tight in there.
I'll get a picture when I've done some chores and can get to it.

I had similar doubts about countersinks.

15mm offset discs sound like a much better solution all round as it's the spacers that are causing the problem. My discs have seen better days to be honest but I hadn't budgeted for new discs, they certainly don't need replacing just yet.

I think I can see the financial event horizon!

[Mr Gazza]

Just seen discs listed for 748/998 and they are stated as also fitting Monster 900 ect.
So I assume a 10mm offset?
Also seen them with 6 and 5 hole versions for 748 ect, so very I'm confused!

[Nasher]

Only the 748R and 998R had the 15mm offset discs, not the 'lesser' versions, the 'R' is key.

I think it's because they were fitted with Ohlins Forks(pre-Radial), and the caliper brackets put the Calipers further out.

I've just measured a spare set of Brembo discs that came off my M1000 and they are @10mm offset.
I need to make sure the 'R' discs are measured the same, but have popped off a message to the guy I know has some and asked him to measure them.

Some additional info.
Your disc carriers look quite chunky.
The Brembo ones on my 1000SS and M1000 are both only @4.5mm thick.

I also removed a disc bolt from my 999, which has the low profile domed heads bolts I linked.
The head is just 4.2mm high when fitted.
Your nice shiny ones look a lot higher than that.

On the 999 they are fitted inside deep pockets in the Disc carrier, and only protrude @2mm.
The 999 discs are still only @5mm thick, so at the bottom of the pockets are only @3.8mm thick.
I wonder if you could get your discs pocketed to around the same thickness.

Aaagghhhrrrrrr, why aren't you closer?
This is the sort of 5h1t that keeps me alive, I'd have the whole front end of your bike in my garage by now working a solution if I could.

[Mr Gazza]

Thanks for you dedication to this Nasher, I'm sure we would cook up some devious plots if we were closer neighbours!

Right. I've trawled the misty web and only found one reference to offset for "R" discs @ 11mm which just sounds wrong? maybe they have measured the offset to the inside face of the rotor? https://www.ebay.co.uk/itm/294292137...Bk9SR97W0PipYw

My Ti bolts miss the speedo by about a mil at most. (In the standard forks with no disc spacers.)






Original bolt heads are 7mm high.
Ti are 6.5
Some random button heads are 4.5 (could be 4.2?)
My carrier is 5mm thick.




Counterboring might be the way forward, but the carrier would go down to 3mm using button heads. That might be pushing it? What do you reckon?

[Mr Gazza]

These are the lowest head M8 bolts I can find at the moment, but would need the carrier holes taking out to 10mm and a bit of the spacer, to clear the shoulder and then a counter bore at least .5mm deep x 16.

https://www.raceti.com/product/suzuk...olt-m8-x-22mm/

It's sort of what I had in my head when I described a grub screw with a flat head.

[Darren69]

Those disc bolts appear to have a flange, if you get some without will it clear then?

[Darren69]

First dibs if you can't sort it and decide to sell it all? PM me, ta

[Nasher]

Lets work this out then.

With no spacers under the discs, and 6.5mm head height Ti bolts you've got 1mm clearance.

Adding the 4.5 spacers gives you 2mm to get a bolt head in there and maintain the 1mm gap.

I've had confirmation of the dimensions of 748 discs, but need to go and mock the gaps up on my M1000 before committing that they would definitely work.

The ones I know about are for sale, but I'd need to see them to access their condition.

[Dukedesmo]

You'll need the 15mm offset discs.

When I did the Ohlins forks conversion to my 916 they have the bigger offset and whilst spacers would have worked (as I don't have a mech speedo), they don't fit with the speedo drive also, I'm not convinced spacers are ideal as the discs will no longer sit in the wheel properly and so are not held by the 'lip' on the hub.

I've got Brembo HPK discs (6 hole 15mm offset) and when the ally carriers wore out but the rotors were still good I bought replacement carriers from Mode Performance, very helpful and much cheaper than new discs.

I've also got a pair of (unobtanium) 748R 15mm offset discs as spares (sorry not selling) if you need any measurements etc.

For the record the 15mm offset/6 hole discs are harder to find as they were only fitted to the 748R of certain years and, I think 998R? Later SBK models, although 15mm offset used a 5 hole disc which you could use if you bought a new wheel but then the speedo drive won't fit.

Brembo do (or did) make the 15mm offset/6 hole in the 'serie oro' discs but you need to double check before you buy as many sellers don't know the difference.

Luckily the radial brake setup on my Monster uses the 10mm offset discs as they were made for that vintage of bike, all the later models use 15mm offset for better disc cooling, I presume?

I would try Mode Performance first though as I'm sure he can help.

[slob]

IIRC GSXR1000 has discs that fit xx8R models

EDIT: Brembo website doesn't back this up, although I suspect bad data since it lists 748R as 10mm offset

[Nasher]

I've just measured 4 different sets of 6 bolt discs I have around the place.
All 8 discs come out at 9.5mm offset, on the unswept part not the worn parts.
With the 4.5mm spacers currently in place that gives 14mm offset either side.

My contact has confirmed the 748 discs are 15mm offset, measured the same way as I'm measuring the 9.5mm above.

That means of course that using the 15mm offset discs the discs will be 2mm further apart, or in other words 1mm further out, or offcentre to the radial calipers.
I've looked at the setup I've done on both my 1000ss and M1000, and both would easily accommodate this, but are slightly different.

Gaz, have a look to see if a mm either side would work for you and let me know.
I'm happy to buy the discs, which are available for a good price, and send them up to you.
You can pay me if they work, or send them back if they don't and I'll use them myself.