60mm stroke crank casing clearance

[cezeta]

i have a mec 60mm crank with a jap 110 rod that i want to fit to a jet200 casing. the big end of the rod prodtrudes by about 1mm.

will i get away with it or not without altering the casings?

the crank is from scooter centre, shame it wast ground flat like other jap rods but at 115 pound its good value

[soullad]

i have a mec 60mm crank with a jap 110 rod that i want to fit to a jet200 casing. the big end of the rod prodtrudes by about 1mm.

will i get away with it or not without altering the casings?

the crank is from scooter centre, shame it wast ground flat like other jap rods but at 115 pound its good value

good price, I assume its got thrust washers and a decent big end bearing?. I've had one 60mm that fitted no probs and another that needed the casing mouth relieved top and bottom a few mm. To be sure, its a dry run scenario again I'm afraid.

[red ghost]

I have a BGM 60/110 crank fitted to an Italian 150 case, no probs at all..







'bout the only thing I haven't had problems with....

[cezeta]

mmmmm

no big end shims and not very good finish after handling a mbd alpha crank.

so im thinking it will be re rodded at replay some time soon....so not vfm after all.

im suprised scooter centre sell them, the standard mec cranks have shims so its a bit of an odity

[CPH Lambretta]

The standard GP200 cranks don't have shims, the GP race cranks do have shims.
The 60/110 & 58/115 don't have them.
A few dealers sell the standard GP200 crank and call it a race crank, which causes some confusion.

[cezeta]

so what bearing is in it, i assumed it was a yam rod or copy. is it a mec rod or a scooter centre modification? is it a race type or not. seems daft not to have gone the whole hog and made it a "race" crank, a pair of shims cant be much more than five pounds?

bloody mind field scooter bits

[gaz_powell]

i`ve got a mec 60mm with a yam 110 rod done by jon betts at SES and a indian 58 with yam 115 rod done by a local well trusted m/c engineer - the 110 rod kit with shims and the 115 without having discussed it with him he was confident it didnt need the shims.
The 115 rod had a little bit of work done so no need to machine casing. Again I spoke at length to him and has done this on numerous rd engines

not used the 115 yet as its for an ongoing project

Hope this is of use

gary

[soullad]

so what bearing is in it, i assumed it was a yam rod or copy. is it a mec rod or a scooter centre modification? is it a race type or not. seems daft not to have gone the whole hog and made it a "race" crank, a pair of shims cant be much more than five pounds?

bloody mind field scooter bits

Couldn't agree more ...no reason why thrust washers shouldn't be fitted to all modern cranks as part of the build process. No-one would mind paying the extra few quid.
I suspect there could be a slight "width" compromise being made here, enabling the manufacturers to fit a big end bearing / rod without the cost of machining the webs or rods themselves. Again, I doubt no-one would mind any extra cost here too.

[dirtyhandslopez]

Takes more machining to put shims in an Indian crank with a RD rod. Have to take some off the rod and off the crank to get it to fit. Then, is it worth having the shims if you are losing some of the meat that the upgraded crank gives you?

[cezeta]

well chalky said to send it up and he ll take a look. ive given him the freedom to upgrade if he thinks fit but his initial thoughts were that as its going into a mugello to resolve the port time issues then its going to be very under stressed and mecs reputation is good so.....

but we ll see :smug:

the tone in chaulkys voice was saying " you ride like a girl and crash before any wear apears so why worry " but you cant be too carefull