LCGB Forums

Hi all, I have just stripped a 150 casing, I'm fitting a 198 mugello, my question is. The crown wheel is in excellent condition, so I wondered if I grind the lugs down with a dremel to take a 5 plate clutch (which I have already) is there any measurements or do I just grind them flat with the outer, or will that be to deep and need a 6 plate.. probably not making myself clear here. Basically I dont want to buy a new 5 or 6 plate set up when I can hopefully achieve the same results from grinding down the current crown wheel.

Thanks in advance for any assistance

Trevor.

Before you do the work are you sure that crown wheel and your front cog will give you the correct final drive ratio? Plus not sure what you're planning to grind, as most modern 5 plate conversion clutches work with a std crown wheel and clutch basket

Thanks for the reply, youve solved my problem.. yes the final set up will be as I have in my others, so no issues there, the fact a standard will take the 5 plate etc. Perfect, I can just fit the 5 plate set up I already have. Thanks again for your advice, greatly appreciated.

As a modification, regardless of the total number of clutch plates, increasing the depth of the slots can do no harm whilst making provision for an increase in the number of plates & also the room available for full disengagement.

The easiest 46'T sprockets to modify are the two part items, once separated. To do a neat job on a solid one piece sprocket is very fiddly & ideally suited to modification on a vertical milling machine IMO.

The last that I did takes a CamLam six plater even with a standard OEM centre. It copes with a tuned TS (70 x 60 with additional ports) & does not drag in the slightest. Mind you, I fitted the stronger springs that were the last to get coilbound when I checked through my many sets

 Warkton Tornado, thanks for the reply, that was the answer I was hoping for, didnt want to go too far and destroy a perfectly good crown, so although I should be able to go to 5 with the standard, if I need more I can make a 6 which would be sufficient for a 198.

I ran my mugelo 186 on a 4 plate clutch with strong springs with no issues so in my opinion 6 would be overkill

missing lynx wrote:I ran my mugelo 186 on a 4 plate clutch with strong springs with no issues so in my opinion 6 would be overkill

You are probably correct that four plates can be made to cope.

However, chances are that the more plates, the weaker the springs need be.

Having owned Lambrettas since 1973, mostly tuned, I am now considering how to graft a rack & pinion from a 'bike into a crankcase cover. Almost certainly the set I bought can be made to function, but it would be easier with a GP item. Currently all of mine have been modified for racing. The prices of secondhand stuff has really got ridiculous right now.....

There's a video on YT that describes how to do one similar to what Chiselspeed offer

Edit : this -

https://youtu.be/XLjP0AXPXUk

rossclark wrote:There's a video on YT that describes how to do one similar to what Chiselspeed offer

Edit : this -

https://youtu.be/XLjP0AXPXUk

I was unaware of the guy or his videos, so thanks for that

The clutch rack & pinion that I intend to fit are hardened steel & appear to be the same centre distance as Lambretta. The rack part is smaller in diameter, so a GP cover would require bushing down. So that part of the job is easy. Non GP's would require a rack housing to be made & fixed in place either by welding or a through fastening.

The pinion element will require the existing holes to be enlarged for bushes to suit the journals, but they are smaller. It's the pinion part that is bigger than the existing holes. That's not a bad thing because eccentrically drilled/reamed holes mean the operating arm can be moved outboard a nat's which gives additional running clearance to a clutch, should it be required, say in the instance of a DIY clutch using alloy 'bike parts. I have done that modification on race scooters when old school six plate clutches meant thinning the actuating spindle down & they would bend!