M600 wet to dry clutch conversion MK2

Ok there is no particular advantage to doing this but we all like a challenge. LOL

At the beginning of 2010 I undertook a wet to dry clutch conversion on my 620 DD bike. I had great success with the exception of creating a leak free seal between the output shaft and the clutch push rod. Although I raced all year with the conversion it was prone to regular oil/leak seal changes.

I decided the time had come to have another go at a MK2 version.
I picked up a later 600 motor off steeevooo (one of the forum users) as Louise’s M600 is the earlier wet clutch version and cannot be converted.

The conversion is (reasonably) straight forward as regards parts,

1. Matched pair of dry clutch and crank gears (and the oil pump gear if yours does not match the crank gear)
2. OE dry clutch casing
3. 1mm thick spacer for behind the clutch gear
4. OE dry clutch spacer for behind the clutch drum
5. OE dry clutch basket
6. OE dry clutch plates (stacked accordingly)
7. OE or after market dry clutch pressure plate
8. Dry clutch alloy racing or after market drum. This needs to be so as the original multi part dry clutch drum will not fit the wet clutch output shaft. You ca use the wet clutch drum and pressure plate however, the pcd of the wet clutch basket spring mounting points are different to the dry clutch which prevents the use of an after market pressure plate. The drum centre also needs to be turned down to a depth of 15mm allowing the retaining nut and locking washer to fit.
9. New longer push rod (had to make this)
10. The oil seal. Now some of the 620 motors have an Allen bolt behind the sprocket which enables you to block off the oil gallery to the clutch by fabricating a blank. The alternative (in my case) was to create a better designed seal around the push rod. This seal would also have to support the push rod when the clutch is open (the OE dry clutch has a small bearing and seal in the end of the output shaft). I was able to purchase a 12x8x3 Viton oil seal for £3. I machined an aluminium plug which retains the oil seal and is an interference fit into the end of the output shaft thus giving support to the push rod when the clutch is open.
Finally there is a small oil gallery in the output shaft which I blocked off with plastic metal
Unfortunately I did not take any pictures on assembly. However, the basic drawing gives you the general idea and after the bikes first outing next year I will be dismantling the clutch to inspect it and take some pictures then.

Hopefully the new seal design will be more robust than the one I used last year.

I've spent my life in engineering design so enjoy reading about projects like this - nice job.

This is the main thing I would love done with mine

How has it effected the clutch if at all has it made it alot heavier then wet clutch on the newer M600 engine.

Originally Posted by zhango

I've spent my life in engineering design so enjoy reading about projects like this - nice job.

Thanks. It's a pleasure.

Originally Posted by He11cat

How has it effected the clutch if at all has it made it alot heavier then wet clutch on the newer M600 engine.

Mel, it's made the clutch a tad lighter but more important it's a lot easier to get into neutral.

i have a several questions...

year of your M600 engine? i had one of the early models, y96, is possible the conversion???





my last update was a oilcooler system, but the sound of a dry clutch put me crazy!!!


i want it!!!

I suppose anything is possible. However, the problem with the early engine like yours is that the slave cylinder is in the casing and subsequently the clutch shaft is to short to accommodate the conversion. You need the later engine with the external slave cylinder.

i saw this pics before and i believe is possible...



is the same kind of mine

I think this is one of the really early dry clutch ss models that had a similar slave cylinder set up as yours. This model will still have a different clutch shaft to yours though.

Still wanting this mod done .
Having bad neutral issues now and after my spine op the giant go kart incident I've been
Left with weak side .
Currently having physio and more scans .
So yes this will be a case of have to be done .
Not just for a whim
How's it holding up ?
Im now classed as disabled due to this year but intend to keep riding and strengthening myself but it really suddenly impacted me .

I planned it this year but it's just been total hell .
Starting to get frustrated lol
How many hours and cost for bits did the M600 engine take ( pm me in you'd rather ).

[Dirty]

Originally Posted by He11cat

How many hours and cost for bits did the M600 engine take ( pm me in you'd rather ).

I'd be massively interested in the answer to that as well!

All the parts where off fleabay. Alas no idea on the time it took, sorry.

Why not buy my already done bike and swop all the good bits onto your bike and sell the remaining bike.



£2200 will buy the bike and spares or £2000 for the bike.

and nice to hear from you Mel.

[Dirty]

Excellent idea!

Sadly not an option to buy a new bike .
I've spent so much on mine since I've owned it and all the little mods and lowering .
I've got to stick with the devil I know.
And also my bike is so me Id get very little money for it
Looked at this for Scrapps 900 but the sums don't tally up.
I'd not get a huge amount of money for mine so the mod is the cheapest way right now.