JAP 750 MT

[john.k]

JAP 750 MT......got another one to rebuild .........rods and pistons are missing ,which isnt a big loss,as the rods are crap.......Anyhoo,Im thinking of using WLA Harley bits all thru........anyone her done this?....The WLA bigend is about .10" wider ,which isnt a problem as I see it........the only difficulty is a crankpin.......there is a new pin with the bits,but JAP in their wisdom used a 25.2mm size for crankpins,not 1"......In fact all the shafts are hokey metric sizes......Ideas,anyone......and dont say Alpha..........I wont live long enough to get a custom made pin from them.

[cardan]

I assume the Harley rods are setup for a 1" pin with standard rollers?

25.2 mm leaves the pin about 0.2 mm or 0.008" undersize. Maybe someone has +0.002" rollers? Typically expensive...

Leon

[chaterlea25]

Hi All,
My reading of 25,2 vs 25.4 is 0.2mm = 8 thou so +004 rollers needed

It depends on whether you buy a complete HD assembly or the individual components (I believe)
The rod bearing inserts come with an undersize bore the needs to be honed round and to size once fitted
It maybe worth checking out how much under size they are ?

Eastern HD parts list up to +003in rollers
which might work depending on rod finished size

Peters bearings in Germany list , 6.35, 6.4, 6.45 and 6.5mm rollers in various imperial length equivalents
I know HD use 0.490in. long rollers instead of 0.500in
http://www.peters-bearing.de/produkte_neu.php?klasse=8&#data

John

[john.k]

Thanks for the info,especially the rollers ...........my preference for the HD bits is price......as you all know ,there are any number of NOS piston kits for US$10 upward,other parts similar..........I havent measured the pin yet ,but from a cursory glance its not new ,just unworn......i have used the 003 os bearings before in JAP re builds.......quite cheap as opposed to some euro sources wanting 1 euro each ,up to one crowd wanted 3 euros each for 6.5 rollers.........I can get chinese ,but then its how many kilos do you want.............believe it or not,this guy paid $3000 for a motor from an autotruck ,in pieces.

[chaterlea25]

Hi John K
V twin mania 

John

[john.k]

V twin insanity ,more like........I suggested that a WLA Harley is ten times the motor any JAP is likely to be,shock horror......anyhoo ,Ive splurged on bits at bargain basement prices,and just have to wait to see it all arrive.