Hi guys, I was looking at a Shane Conley video working on an Evo and noticed the end of the pinion shaft....to my eyes it looks like mine, tapered right at the end. I've attached a screen grab from the video next to mine, not great quality. If that's right then I am perhaps a little happier or am i looking at the wrong section? Is the chamfer on the very end marked A, "normal", but the section inward from that, marked B, is "cigar" shaped...which it is I think? Which section are you guys referring to?

Thanks again. And 98hotrodfatboy, I'm just continuing on this post.

 

The pic to the left looks straight across and smooth all the way to the outboard machined taper. The pic to the right does not. The machined taper "A" is normal. The surface "B" on yours is worn and not normal. As described earlier, it looks cigar or egg shaped, even looks a little "wavy" .

Some very experienced forum members are calling it suspect, so your getting good advice. I don't doubt that it needs attention. You can see just about everything in that chest (based on your pics) has been excessively worn by metal bits circulating in/on all the surfaces.

Hold a straight edge to it with a flashlight shining light from behind. You will see the issue more clearly. Have you ever looked at/cleaned the tappet screen? What did you find in that? I know it sux, but it is what it is. YD

 

Thanks Yankee Dog, it was definitely my lack of knowledge that I misunderstood the comments so I'm glad its now clear for me which part people are talking about - thanks guys! I will put a straight edge on it but as everyone says its going to have to come out anyway. First time in a cam chest!

This weekend I'm going to sieve the oil I drained out of the pan and have a look at the tappet screen also to see what i find. I'm hoping I can get everything cleaned up in there and open up the cases to rebuild it (including the oil pump), my last obvious concern is milling the breather bore otherwise its a whole new case which i really need to avoid.

Also I know haven't checked the flywheel pin side yet!

 

I was looking at my photos and I noticed that at the end of the breather gear passage it looks like mine is pretty "torn". IS this a problem or perhaps where some metal shavings came from, I wouldnt have thought that had and real pressure there to do any damage? I'm having another look tonight or tomorrow so I'll take a better photo. I really hope this doesnt make my case unsalvageable!

 

Here's a couple of more shots of the end of the breather valve...it certainly looks like the back end is off-centre but perhaps this is a casting misalignment back in 1992? Also a shot of my tappet screen with shreds of metal, not magnetic. I'll be checking the oil from the pan later this weekend. Something definitely sheared, dont know what yet.

 

Nothing's sheared, it's just the edge of the casting and not being able to easily smooth it out.

 

Thanks Mattbastard, appreciate the comment....a little hope on being able to re-use the casings on the rebuild!!

 

We are in these all day, every day here.
From what I see, I believe that the oil quality used/service intervals may be the culprit, as we have witnessed engines with 80, 90, 100K on them not look like that.
What flavor oil has been used in that?
Scott

 

All that oil coke probably came from when it was low on oil pressure and ran way above normal running temperatures.
Do people sleeve the vent valve bore? Or can an oversized valve be obtained and just rebore it. I would think back in bikes younger day, that would require a new block.

 

Hi Scott, I'm using the regular HD 20w 50 oil but to be honest I haven't been riding her much this last year with the Covid restrictions and when i have its only been for around an hour. Maybe should have serviced it more on time rather than miles. I'm just hoping I can get it all cleaned out and start afresh.