Compatibility question

[jedan71]

I have a compatibility question, and I am trying to get the right balance.

I have a series 1 Li125 block, also a SIL 150 block, i am probably going to build a 175 stage 4 kit on it. Which block is best to use? I have two large engine mounts to use on the chosen one.

The compatibilty i need to find out is that i have two gearbox end plates, one from a GP and one earlier model (no kick start extra bit on it) which one is best to use? I can't guarantee that the older model is the original one for the series 1.

I have only one crankcase cover, i don’t know what bike it came off? but it has Innocenti stamp on it.

Can i use a GP clutch setup (pressure plate(no nipple version)) in this setup of the series 1 block and just renew the clutch cam and arm to GP version, even though the crankcase might not been originally from a GP? I am aware that i might have to buy the pressure plate, cam, pull arm etc.

I am aware that i will have to use a GP mag flange to cater for the bearing that is used for GP crank that is going into it.

I am trying to plan the build prior to purchasing parts as it can be even more costly being out here in New Zealand.

[rosscla]

In the case of the Indian GP case / end plate these always come as a matched pair because the end plate and casing are machined at the same time, it's not guaranteed that any combination of end plate and casing will be compatible unless they've been kept together, you need to check them and see if they fit. I've replaced the GP style end plate in my Indian casing with a Li style one, as the one that was in there was an Italian one so wasn't the original anyway. The theory being that the LI one places less strain on the end plate and the kickstart mechanism has a degree of adjustment due to the ramp being attached to the side case.

In respect of the side case itself, if you wish to use a GP clutch you have to use a GP side case as there is a cast recess for the phosphor bronze bush, you can see this from the outside buy the presence of a raised semicircular area to the rear of the bump at the bottom of the clutch actuating arm rod. See here -

[jedan71]

The gearbox end plates both fit snugly on to the studs and visually look flush in my S1 case, so i will probably use the Li Style for your reason you stated.
As for the crankcase, i will double check when i finish work but i think it doesnt have the raised casing as shown in the above picture, If that is the case, i will either have to buy a GP crankcase or fit a Li clutch.
Are the Li clutches any good as all you see and hear is that everyone uses GP as the performance on Li are poor? What would you recommend?

[rosscla]

I'm not sure that there's that much difference between the two clutch centre types. Most aftermarket performance clutch flanges are the GP type, and these are probably to be preferred, but some, like the MB one, offer interchangeable centres to cope with either side case set up. If you do settle for the GP style then you'll need to drill and tap the chain case to fit the ramp.

Back on the end plates the machining mentioned is related to the holes for the gear cluster bearing location and layshaft in both the end plate and the casing. If these are not aligned this will lead to issues of bearing wear and possibly gearbox misalignment. Now, most of the discussion in relation to this relates to Indian manufacture but I'm not sure if this might also apply to Italian casings and endplates.

[Muttley McLadd]

I am trying to plan the build prior to purchasing parts as it can be even more costly being out here in New Zealand.

Whereabouts are you? There's bound to be someone near you that could offer 'eyes on' advice.

[nelson pk]

Regarding the endplates. In my opinion your not going to know about the endplates until you build up your gearbox, fit the endplate, put the clutch spider on and do up the clutch nut on the spider to pull your gearbox input shaft into the correct position. if the gearbox turns freely it should be ok. If not check your gearbox shim on the layshaft has enough clearance via a feeler gauge. If thats ok and it still doesn't turn freely without tight spots, forget that endplate.
Also make sure your gearbox dowels are not loose. There are a lot of casings out there with enlarged gearbox dowel holes where the endplate bolts/nuts have come loose. If they are loose get them repaired before trying the endplate.
It is always best to use the endplate thats matched with engine but if you can't because you don't have it, try the above.

[RICSPEED]

also be aware if you have the series one mag flange they are different to later 2 and 3 type ,also you would need to modifiy the starter lever if fitting to a series 1 or two with a gp side case

[jedan71]

Thanks rosscla,

After i did a double check on the casing, i have a case with the raised semi circular mound as in the photo you posted. So from that it would indicate a GP crankcase cover.
But in saying that, i do have 3 * 6mm threads where a kick start ramp would be, i thought GP didn't need this ramp as built into the gearbox end plate?

Is that right for GP Innocenti stamped case or could it be an previous owner who tapped in the 3 threads?

FAO Muttley i live in Wellington...

[coaster]

In respect of the side case itself, if you wish to use a GP clutch you have to use a GP side case as there is a cast recess for the phosphor bronze bush, you can see this from the outside buy the presence of a raised semicircular area to the rear of the bump at the bottom of the clutch actuating arm rod. See here -

That's not correct, both side cases are identical from the outside, they both use the same clutch arm/spindle/cam but the GP has a raised part on the inside where the bronze operatin piston fits. I know this is true as I have just been and checked my two, one has a GP side and the one I'm currently building has an Li type. I would therefore say that jedan71 had the Li type.

If it was me, I would use the indian case as it will have the larger 7mm exhaust studs and will also have the recess for an oil thrower on the driveside of the crankcase. Regarding Li and GP clutches, the GP ones are regarded as better due to the use of a brass piston with a wide base to push on the clutch bell. This ensires that the clutch seperates squarely. With the Li type, the little operating cam bears directly onto a fairly narrow nipple on the clutch bell. Early Li clutches had a spindle on the underside of the bell which slid into a hole drilled into the gear cluster. This prevented any tilting of the clutch plates during operation. However, at some point in the Li production Innocenti dropped the spindle so tilting during operation is a possibility although my Li Special has this type and I've covered thousands of trouble free miles with it. The TS1 I'm working on will also have this type of clutch.

God luck

colin

[byron]

no, the side casings are different externally as said
and the exhaust studs on anything but series Is and early IIs are M8
You could always cut the ramp off the GP endplate and use that