Scooterotica

I have just built a crank with 110mm yamaha rod on a set of AF webs !!!!!!!!!!after i had finished i realised there was no cuts/holes in the big end of the rod,Now i have always been aware this is a necessity or is it whats your veiws .........do i split the crank and try drilling?
any info much appreciated .

looks like its got lube bits to me already. check the indentations on the rod big end.

So do you think the indentations are adequate I can only think Yamaha use this method for strength, what do yous think its just innocent didn't choose this method they went for slots but its possible all the indentations leave as much open area as a slot.

is it an rd rod?

I thought all the proper yamaha rods had oil slots in them. The ones I buy do. Many (all?) vespa ones don't, but then the carb intake (lube) is directly on the crank.

I wouldn't recommend trying to make slots. I admit I've never tried, but I read in one of the tuning books somewhere that carefully opening the slots can be ok, but never touch where the actual bearing runs. Any burr or mistake there will quickly wear the rollers and lead to failure.

Muppet wrote:is it an rd rod?

as far as i,m aware its an rd 250.

any more thoughts on this anyone?????????

I'd ask myself the question what a repair to your top end would cost.if your running a cheap piston in an iron barrel give it a go...if your running a racetour piston in a ts1..why take the chance,I must add what end float have you got...looks tight to me...and you haven't used shims?

camel wrote:I'd ask myself the question what a repair to your top end would cost.if your running a cheap piston in an iron barrel give it a go...if your running a racetour piston in a ts1..why take the chance,I must add what end float have you got...looks tight to me...and you haven't used shims?

My very thoughts..........it was for my new gt186 build and at 500 quid its a bit of a risk, I,m going to do a home tune sr 175 engine so maybe that's were it would end up and will be interesting to see if it works out ok!!!!!! I just cant get over Yamaha are happy to spin these conrods up to 10000 rpm
thanx for the input Camel.

looks like no one else has run these around here?

i recently had a crank built using SIL webs and a pattern RD400 rod and that was slotted