GB is not OK!

[edboy]

hi greybeard, i have plenty of conrods but you will need new small end bushes. post me your address.
i risk opening a can of worms. but..... i think your cam and followers have ran too hot and starved of oil. i file a thin slot in each follower to allow oil to run down into the trougth. it seems to work.

[Greybeard]

hi greybeard, i have plenty of conrods but you will need new small end bushes. post me your address.
i risk opening a can of worms. but..... i think your cam and followers have ran too hot and starved of oil. i file a thin slot in each follower to allow oil to run down into the trougth. it seems to work.

Thanks Edboy, I'll bear that offer in mind.

[kiwipom]

hi guys, GB glad you found the problem could have been a lot worst than a small end bush, good luck with the rebuild cheers,
nice pics.

[KiwiGF]

If I cannot get hold of a replacement small journal conrod, is it feasible to have the old one bored out and a new bush made up to fit?

Its almost standard procedure in NZ! Our bikes tend to have been used a lot during their lives (aside from those bikes imported from the US).

A machine shop may also be able to expand a standard bush to suit the rod, and still be able to ream the ID to fit the pin. The expander tool can be a piece of bar with a short raised section of the required diameter. You just push the bush over it using a small press or vice etc.

[chaterlea25]

Hi GB,
What state is the timing side bush in?
I see you have an iron bodied oil pump so that is good
Check the PRV and make sure its good
The usual cause of cam wear is bad oil pressure
Glad to see its not a major disaster though 

John

[Greybeard]

Hi GB,
What state is the timing side bush in?
I see you have an iron bodied oil pump so that is good
Check the PRV and make sure its good
The usual cause of cam wear is bad oil pressure
Glad to see its not a major disaster though 

John

I was knackered at the end of play yesterday so I just had a quick look at bearings. The timing side bush looks good. Before I split the cases I applied leverage to the shaft to see if it visibly lifted in the bush. All that was visible was a slight squeeze of oil. I also tried a pair of internal callipers, (see below) in the empty bush and did not feel any difference in contact as I spun the callipers around.

The PRV is a plunger type that came from SRM so should be good. That pump was described as high capacity and the return flow is very good.

The camshaft I bought had been reprofiled from an old one so was smaller than standard; my tappet adjusters had to be screwed right in to get correct clearances. The seller claimed the shaft had been rehardened, but who knows how good that hardening was? When I last adjusted the tappets I did set them a bit closer than recommended as the engine has always been rattly when hot. It's possible that I left them too tight.

[Triton Thrasher]

Check the relief valve plunger and bore for smooth movement and marks which might indicate that they have stuck together at any time.

[coater87]

I always figure a good press fit is .001 per inch of diameter.

 Under an inch is always. 001+ when I make something.

 Lee

[Greybeard]

I've stripped and cleaned the PRV. It looks good as new.

Timing side bush:
I set my internal callipers to lightly touch inside the timing side bush. As I said yesterday the bush feels consistent all around. I measured the callipers with my brand new 1 to 2" micrometer and found a measurement of 1.3750". The crankshaft journal measures 1.3732". I make the difference 1.8 Thou.
I did not detect any appreciable ovality in the crank journal.

Big end journals, measured North to South and West to East:
Timing side, N/S, 1.4495", W/E, 1.4492"
Drive side, N/S, 1.4498", W/E, 1.4498"

What do you think about all this?

[Greybeard]

I always figure a good press fit is .001 per inch of diameter.

 Under an inch is always. 001+ when I make something.

Is this referring to getting my Conrod rebushed?

[KiwiGF]

I've stripped and cleaned the PRV. It looks good as new.

Timing side bush:
I set my internal callipers to lightly touch inside the timing side bush. As I said yesterday the bush feels consistent all around. I measured the callipers with my brand new 1 to 2" micrometer and found a measurement of 1.3750". The crankshaft journal measures 1.3732". I make the difference 1.8 Thou.
I did not detect any appreciable ovality in the crank journal.

Big end journals, measured North to South and West to East:
Timing side, N/S, 1.4495", W/E, 1.4492"
Drive side, N/S, 1.4498", W/E, 1.4498"

What do you think about all this?

You are getting on quickly! Those crank measurements suggest new shells needed, at most to me, the main journal has slightly more clearance than I would like but I think it’s ok, given the engine is going back together as a part worn one anyway, just my opinion!

[terryg]

Good progress indeed GB. Very pleased to see you've caught things before more major damage. Well done.
Looks like it won't be long before you're riding again at the rate you're going.

[RichardL]

GB,

I meant to ask, were there any signs of gudgeon pins spinning in the pistons? I should add, "...leading to evident wear in the pistons?"

Richard L.

[Greybeard]

I meant to ask, were there any signs of gudgeon pins spinning in the pistons?

Hmm, haven't checked for that, yet. I think they are probably OK though as I had to use the hot air gun on the pistons to get the pins out.

[Greybeard]

...Those crank measurements suggest new shells needed...

I was planning to get new shells.