Crank balancing

[Jordan]

Thanks for the info, folks.
The Taiwanese XL500 rod assembly on ebay is cheap, and looks pretty good.
The width is different from Ducati though, 20 not 22mm. Need washers?
Does one of the standard Ducati big end pins/bearings work with it, in terms of diameter?

[machten]

Thanks guys. I can weigh the wiseco tomorrow and post. I don't know what a stock original bore piston weighs though. Also, the crank has been polished and so may have already been balanced earlier. Splitting the engine tomorrow night so I'll take some pics when it is apart.

Kev

[machten]

Oops!...Got confused with a set of pistons for a 900. The piston I have for the 450 is not a Wiseco, but an Omega 87.0. The previous fitting being replaced is an Omega 86.6 which weighs in at 465 grams with pin and rings. I'll check the 87.0 tonight.

You can see someone has put a bit of work in to polishing the crank in this pic...

IMG_0747 (1024x768).jpg

This engine had a top end failure and I think the bottom end is OK but I'm splitting it to make sure.

Kev

[Eldert]

Hi Kev

you have some real wide custum made strustwashers in there . could be a late type crankshaft fitted with a early type 18 mm wide rod . this is possible if you use a straight 32 mm pin . who knows .

Eldert

[machten]

Hi Eldert,

Yes that is non standard arrangement in there. Back in 2010 the big end let go on me on day 1 of the Motogiro d'Italia. This Mk3 is the latest I have personally come across and was fitted with the 32mm pin. The con rod and pin to suit I found to be made from unobtainium, so the choice I had at the time was either to source some earlier crank cheeks and fit an earlier rod and pin, or get the rod sleeved and a custom pin made up. I took the latter option (for better or worse). I'm not expecting there to be an issue down there and it feels fine from what I can tell, but I'd kick myself if I didn't check after a valve has been knocking on a piston and find an issue later.

The major driver is that failure has damaged the small end, so I need to get that re-bushed and to do that properly I want to pull the crank out.

Kev

[Jordan]

The major driver is that failure has damaged the small end, so I need to get that re-bushed and to do that properly I want to pull the crank out.

Kev

That's a lot of work, just to replace the small end bush.
I've had no problems, doing it without removing the crankshaft.

[machten]

Hi Jordan,

I could try and press it and ream it in situ, and I confess I considered it, but I'd have to hand ream (with the consequential risks) and a split and reassemble is a weekend's work with some outsourced engineering in between. Plus I want to check the big end. Probably anal, but it's probably the last time I'll need to see the insides of this one, so might as well get it done and dusted.

Besides which...It's not a chore, I enjoy it!

Kev

[graeme]

Hi Kev, very satisfying to build an engine and see it run with peace of mind.

Graeme

[Jordan]

Besides which...It's not a chore, I enjoy it!

Kev

Fair enough, Kev. That's a nice attitude.
By the way, I wouldn't ream the bush. There are other ways.

[machten]

...The 87.0 Omega piston...

IMG_1468 (1024x768).jpg

IMG_1469 (1024x768).jpg

Fair enough, Kev. That's a nice attitude.

As a change from what pays the bills, I have to say, I love messing around with these things! Very therapeutic and I find it often elegantly encapsulates some life lessons.

Kev