[Marioyaller]

Hello everyone. My name is Mario and i am writting from Spain.

Couple of months ago I had an issue with my 2015 Classic 500's cranckshaft. I had to replace it and decided to fix everything by myself. Dismantled all the engine parts, and purchased a new cranckshaft assembly. I am sharing some pictures so you can understand better my questions. All the pictures i mention below, are in this link: https://drive.google.com/drive/folders/1YRBsDuDa9L9ddeN9ZZ5E5sYVl6dyhNKI?usp=sharing

Imagen 001.
This are the 2 cranckshafts assemblies I have. The old one I removed from the engine and the new one, which its inside the cranckcase.
https://drive.google.com/file/d/1K453g1NzK48dxmof6F-OAerEio4mhIPJ/view?usp=sharing

Image 002.
The old connecting rod small end comes with a sleeve, which i guess its function is friction reduction among the connecting rod and the piston wrist pin.
https://drive.google.com/file/d/1jL_s5CHaE9UZfWabs0xUnhuEF1hgFBzx/view?usp=sharing

Image 003.
Assembly of old connecting rod, sleeve and piston wrist pin. As you see, the diameters match perfectly and there is no play between the parts
https://drive.google.com/file/d/1heNGvYslJhIK15icg-PMUFcq5mhVVeGW/view?usp=sharing

Image 004.
Old connecting rod small end without the sleeve. You can see the gap/play existing with only the piston wrist pin. So sleeve is needed.
https://drive.google.com/file/d/1N6ZsOMTRkxte8xWi6f7zXWqVrnVCLifV/view?usp=sharing

Image 005.
This shows the new connecting rod. Its small end diameter is smaller than the old connecting rod one, so there is no space to fit the sleeve.
The piston wrist pin fits perfectly in that diameter without any need of a sleeve. My question is about it: do i need always to use a sleeve? or in this case, the new connecting rod, as it fits perfectly without any play, can be used without sleeve and won't it generate any incompatibility among materials, excessive frictions,...?
https://drive.google.com/file/d/1WA6ZozOvxOgKyreQpxDKmsco8dfqoJ0X/view?usp=sharing

Extra video.
I share this video to see everything i am traying to ask "in motion".
https://drive.google.com/file/d/19cLKfFIJbJMEBdlUd9guhcygCI-PCeOY/view?usp=sharing


So, summarizing... Is that sleeve needed to prevent issues, or is it perfectly acceptable to use a connecting rod without sleeve.

Thanks!

[Haggis]

Just fitted a replacement crank in one of my bikes, same engine as yours.
Both conrods have a bush in the little end.
I have seen cranks that run the little end straight into the rod, just not on any of my enfields.
Where did you source your replacement crank from?

[Adrian II]

The con-rod design was inherited from the AVL engines. The wrist/gudgeon pin ran in a bronze bush which was common practice on older steel con-rod design, and which continued in the early EFI/UCE engines, but at some stage the Chennai factory decided to run the pin directly in the steel rod. Cost saving? I gather there are no issues with this assuming sufficient oil finds its way in there, and I think we would have heard something by now if there had been large numbers of little end failures.

A.

[Marioyaller]

Just fitted a replacement crank in one of my bikes, same engine as yours.
Both conrods have a bush in the little end.
I have seen cranks that run the little end straight into the rod, just not on any of my enfields.
Where did you source your replacement crank from?

Thanks for the quick answer. Thats it... no bush in the small conrod end... I dont know about the conrond big end since cranckshaf came already mounted. The full cranckshaft was purchased via Ebay directly in India, in one of the shops I use to buy all the spares. Already contacted them to ask about this difference and they replied that both (old and new) cranckshafts have the same reference number and all the ones they have in stock are similar for that reference number...

Thanks!

[Marioyaller]

The con-rod design was inherited from the AVL engines. The wrist/gudgeon pin ran in a bronze bush which was common practice on older steel con-rod design, and which continued in the early EFI/UCE engines, but at some stage the Chennai factory decided to run the pin directly in the steel rod. Cost saving? I gather there are no issues with this assuming sufficient oil finds its way in there, and I think we would have heard something by now if there had been large numbers of little end failures.

A.

Thanks Adrian for your answer too. That what you say makes some sense to me regarding what i replied to the previous user. The seller told me that all the cranckshafts they are receiving are not coming with any sleeve/bush. A contact I have, who I asked too, told me that could be a different series of connecting rods, being in the case of the new one manufactured with "sintered steel", which creates a porous surface to "trap" the oil and lubricate the wrist pin. As you say, as long I searched on the web before posting here, I did not find any complains or post about this conrod differences in terms of short-medium-long term issues.... So i guess that the original wrist pin (which is the one i wil reuse) will not generate any interferences...

Thanks!!

[RobinV]

 When you put some oil on the pin, and slide it in to the small end, how is the fit? If tipped sideways the oiled pin should slowly slide through and fall to the table below. Have you checked the internet for small end bronze bushings? A competent machinist could clearance and install a bronze bushing, and then ream it to a perfect fit. I like the idea of a softer material in contact with my wrist pin. Just my humble opinion.

[RobinV]

Here is a new con rod from an auction site. It is fitted with the small end bushing. Will try to attach a pic.

[SteveThackery]

Here is a new con rod from an auction site. It is fitted with the small end bushing. Will try to attach a pic.

I would urge you to get one from Hitchcocks. That way you can be confident in the quality.

[AzCal Retred]

Honda and basically all of the Japanese machines run the conrod small end & wrist pin steel-on-steel with I daresay astounding success. "If the wrist pin fits, you must use it..."     Save bushings for the sloppy fit small ends.