wrist pin running clearance

Reed · Nov 19, 2014

I have a 93 fe501. Im doing a top end due to a blown head gasket.
While im in there Im taking a good look at the condition of all parts.
I have .005 in/.13mm clareance on the wrist pin. seems loose to me. As I do not have a table of limits for this engine what is the factory spec for this dimension.
This is the 20 mm small end bushing.

tourist · Nov 19, 2014

Hiya,
Just wanted to make sure you knew about the service manuals section here? Service Manuals - Husaberg Forum

There's a service manual for the '99 model there, it might be something? http://husaberg.org/service-manuals/19032-1999-fe-service-manual.html

Taffy · Nov 19, 2014

that is very loose. suggest that you get a new bush and try and find someone who will press it in nicely (as the metal is soft and burrs up quite a bit) and then reem it square to the rod and with the right clerance.

a lot of engineers can't do it because they can't gauranteee that their work is 'square' to the rod etc. it should be done with the rod off the crank ideally.

regards

Taffy

makazica · Nov 19, 2014

What Taffy said is quite right, the rod should be off the crank to do it properly and cheaply with modern machinery but it can be done by hand by old craftsmen with the right tools and experience.

M.

Reed · Nov 20, 2014

Hey Taffy, I assume that you are saying the bushing material is soft? Just to clarify. Rod does seem pretty thin in small end. I wouldn't want to damage it while attempting this repair.

I was thinking of making a press on the lathe w two dies and all thread. Press the old one out and then reverse the dies to squeeze the new one on and ream to fit.
Anyone done this successfully?

Taffy · Nov 20, 2014

I do a hardened little end bush.

regards

taffy

bushmechanic · Nov 21, 2014

Reed said:
I have a 93 fe501. Im doing a top end due to a blown head gasket.
While im in there Im taking a good look at the condition of all parts.
I have .005 in/.13mm clareance on the wrist pin. seems loose to me. As I do not have a table of limits for this engine what is the factory spec for this dimension.
This is the 20 mm small end bushing.

the oem clearence is about 0.8 thou on the 20mm berg pins.. generally most bikes run 1 thou per inch of pin diameter

1.5 thou per inch being upper wear limit usually.

ive pressed little ends with dies like you describe, it works well if the sides of the rod are square to the bore

Reed · Nov 23, 2014

Thanks bush mechanic.
Looks like Ill need to make a couple of dies and a fixture to hold the rod square. May take a little time but I don't feel like tearing into the bottom end at this time.
Thanks

bushmechanic · Nov 23, 2014

sounds good.. pls post an action picture !

Reed · Nov 25, 2014

Ive made the fixtures and dies.
Now just need to get my hands on a bushing, probably gonna use taffys little bush. I imagine a 20mm ream should handle sizing properly? I was gonna order a ball hone just in case it needs to go a little larger.
Should the taffy bush be honed looks to be a material other than bronze?
Ill post pictures when I change the parts.

Taffy · Nov 26, 2014

it's steel backed phospher bronze reedy.

regards

Taffy

Search

Search

wrist pin running clearance

Reed

tourist

Taffy

makazica

Reed

Taffy

bushmechanic

Reed

bushmechanic

Reed

Taffy

Similar threads

Register CTA

Recent Discussions