1992 Dyna FXDC 60,000miles on her.

Hi guys, I had 2 warnings on my bike from 2 different mechanics, one who previously worked on my bike (replaced pistons after an oil blockage had ruined them) saying that my Pinion shaft run out was pretty bad and another who heard a noise and said I should check my inner cam bearing.

So I opened my cam chest and this is what I found. The good news is the PO had replaced the inner cam bearing so we were good. The bad news is I do believe the pinion shaft run out is pretty bad.

Brief history, around 4 years ago a woodruff key on the oil pump mechanism got chewed up in the cam chest which ultimately messed up my pistons due to lack of oil etc. I had my pistons re-sleeved and new pistons put in. I couldn’t afford to upgrade to bigger, better pistons so this was the most economical idea. I don’t know if the pinion shaft run our issue also was an outcome of this mess but they put the bike back together and said to be gentle and she would be ok (I also couldn’t afford a rebuild at the time). I’ve ridden her fine and gentle these last 4 years (fortunately I don’t need the big power/speed at the time, just happy to be riding), no major long trips and she seemed absolutely fine…barring some noise, I guess from the pinon shaft issue.

More recently I started getting more worried as the second shop told me about the strange noise and the inner cam bearing so it was beginning to freak me out and getting a bit fed up being nervous every time I rode her so I figured I would bite the bullet and see just how bad the situation was. I cut the pushrods so will be buying some ezi ones to replace.









As I am no expert and I am trying to do this myself as much as possible I would really appreciate any input from you guys in terms of analysis on what I found in my cam chest. I have uploaded 8 photos.

1. I can see there is a lot of “hard oil stains” around the place. Don’t know how to describe this but it cleans up with a fingernail.

2. I found a lot of scoring on the plastic oem breather casing and on the aluminium where it sits. The teeth are fine so I know she’s spinning but not sure if this is a major problem or how that could have happened unless that was when the original woodruff key shavings might have got stuck.

3. Inner Cam bearing is ok, woop woop!

4. Cam bushing….some internal wearing…is this buggered?

5. Pinion Shaft seems ok but the bushing seems to have serious wear on one side of it.

6. The actual OEM Cam seems to be ok, there is some wear at the ends but she feels smooth and the lobes seem fine. Don’t have a pic of the lifters but they seem ok. I may replace Cam with EVO27 if money allows me and once the crank is fixed.

My next step is to work our whether I need to split open the crank case and send to a shop to straighten the shafts and rebuild the bottom end while I prepare to basically rebuild the engine after that. Sadly looking for cheap options and I don’t want to sell her to some unsuspecting buyer….bad karma!

Thanks for any input, insights and experienced observations... and your time.

 

Is that what all that dark crud is all over the place, oil staining? Looks like someone painted the inside of your cam chest.

If oil got that hot enough to harden and stick onto metal surfaces I'd wonder about that engine's history, IMO.

 

You really need to check the runout on the pinion shaft. .0045" is the service limit.. If it exceeds that the case will need to come apart to repair. At that time you will need the Breather to be bored to .030" over for a new .030" over metal S&S breather.. Looks to me like that motor is going to need machine shop expertise.. Why is the oil so Black?
Agree with Matt... Very hot...

 

Still your call but the motor needs to come apart, it's hurt, metal debris has taken it's toll. Your thrust washers on flywheel pin can't be in any better shape by the indicator of shown bushings. The breather bore will need machined because even the S&S reed valve can't cover the damage in the photo, engine needs to go to a machine shop to do that.

Those nylon breather gears get harder than a wedding dick plus get out of round from heat but since there isn't much metal in the bottom of the cam chest, this damage was done at the first failure, the damage cylinders/pistons metal contamination was present especially indicator of needing sleeved. Cry only once on this repair.

 

Hi guys, yes it does look like the oil has got too hot at some point - I'm hoping it's from the initial issues but like you say it must have got real hot to film over like that. I did want to check the run out but to be honest I think just by looking at the wear on the bushings I think it's going to need fixing so I'd prefer to now start spending any money I have on preparing to fix her. Shame the people who opened her up didn't tell me about the breather bore before closing her up again but I take onboard all your comments and for sure it looks like I'm going to have to do a tear down and rebuild.

Might look on ebay for a used bottom end but then again I wont know the history of that so maybe not. Damn! Thanks again guys for the inout and i do like the last comment about "cry only once" Seems fair.

 

What's with the o-ring in the cam photo? No place in the cam chest for that.

The breather gear is definitely done but the bore may not be as bad as it looks, needs to be measured.

The pinion end does look badly worn (cigar shaped) but checking with a straightedge or micrometer from a photo can't happen.

All the "black oil" isn't from over heating, quite the opposite. That's a sludge of moisture and carbon buildup caused by running it short periods, never allowing the oil to get hot enough to cook the moisture out and clean as intended.

 

I think the o-ring is the cam shim. The angle of the light makes it look like an o-ring.

 

Hi, yes it is a shim and not an o ring.

 

hi t150vej, ok so thats quite a different observation on the dark oil issue. You may be right in that for the last few months I've only been taking her out for an hours drive at the weekend, no long rides. Very interesting to get these experienced eyes on my case (pun intended). I've also moved house in November to a place with no garage so she's outside with a waterproof cover - not sure if that makes a difference to the moisture idea?

The pinion is definitely cigar shaped by I thought perhaps thats the way it came to fit into the bushing.

Great input, thanks guys

 

No definitely not.. Sometimes it's hard to tell by a pic but the end of that shaft definitely looks like it's out way too much..