Topic: 500 bigend nuts

[Kevnz]

Hi All,
I am pulling down my 500 engine. The bigend nuts are 12mm, but none of my sockets will fit as there is not enough clearance around the bigend cap. Do you normally require special thinwall sockets for this job, or has my engine got the wrong size nuts on it?
Thanks,
Kevin.

[dave500]

i use six sided 1/8 drive sockets.

[Kevnz]

Thanks Dave
I have 2 sets of 1\8 drive, but they both go from 11mm to 13mm for some reason. But thinwall sockets required? Tight clearance normal?

[dave500]

yeah mine fit ok,just a cheap little set.

[jaytee-nz]

Kev - If I remember correctly I had to shave down a 12mm socket to get to fit when I restored my (now ex) CB500.

[dave500]

also look close at the nuts when you refit them,they have a shoulder on one side a bit hard to spot.

[Kevnz]

Got it apart, two spun bigends, bummer. Rods probably toast, crank may be ok. Wierd, bike ran fine when cold, but started knocking when warm, but still smooth as, no blurring of mirrors, in fact probably the smoothest of the 6 I have owned. no flickering oil light either. Sigh!
Thanks for the advice Guys.

[dave500]

spun big ends?original motor?loading when cold and or too high rpm when down shifting heavy?

[Kevnz]

Don't know much about it Dave. I bought it as a project, pulled the pan and it was clean as a whistle before I started it so I was hopeful. PO is a whizz at engine building, and I painted 4 sets of tinware for him gratus, so I expect we can work things out amicably. These things tend to work out.

[bryanj]

If the shells spun the rods are toast and due to tight tolerances probably the crank as well, good news is all 500 and 550 crank/rod assemblies are thesame.
While you are in there fit a new primary chain, the Kawasaki equivalent is less than half the price of a Honda one, good idea to change the primary damper rubbers as well but they are Honda only and have gone up in price recently

[Kevnz]

Thanks Bryan,
Yes the rods are definitely stuffed; you can feel a ridge. Crank looks ok, but the PO is a whizz engine builder, so I will leave it to him to ascertain what needs to be done. He has plenty of spare cranks. Possibly take it out to 550. Just not likely to have it going for this summer, unfortunately.

[bryanj]

Maximum bore on 500 barrels is 550 plus 0.5mm but if you go that far chain and dampers is a must.
If you get crank and rods as assembly at least you only need to source main shells

[RAFster122s]

Main shells aren't cheap anymore and are only going to go up as availability drops.