Top end work, 1100 Sport

[raz]

Like Tom and Slavek I just removed my heads and barrels for some work. Cylinders look like new after 72,000 kms, pistons look good too as far as I can tell. But the followers doesn't look all that good. On both sides the exhaust follower showed pitting while intake side was better.

 

Here is left side pair, exhaust at the left.

 

Here is right side ones, again exhaust at the left.

 

Cam looks absolutely fine as far as I can tell without actually dismounting it.

 

Questions include: Should I replace some of them, all of them, none of them? What do I need to know if I replace them? Break-in measurements? Mineral oil with lots of zink? Moly? Or just pop new ones in and forget about it? And what's the price tag on these things anyway?

 

I'll find answers in older posts here and on other boards but anyone bored with the low activity here please speak up if you wish!

[gstallons]

Replace them! This pitting means something BAD was about to happen. Use a good cam assembly paste when you reassemble them.

[raz]

Will do, thanks. Price is about 20 Euro each. I wonder why the exhaust ones are worse but I recall reading about similar stories.

 

I've been digging deeper into the heads. Inner springs are 37.2-37.5 mm free length, they should be 37.9 mm.

Outer ones are 40.3 mm, right at the minimum spec. I'll replace all springs anyway, I already bought them.

 

Much to my surprise, all valves measure out just fine so they can probably be reused. But the valve guides are worn, and oval. I can only feel and estimate, there are essentially no play at all in the directions where the least force comes to play. On the other axis there are significant play on all guides. I'll see if I can get them K-lined or if I should order new guides (I'll supply the shop with everything they need including the Roper writeup and relevant pages from the WHB).

 

As I'm interested in what squish I'll end up with, I measured the old head gaskets. (pistons are almost level with cylinder top, better than I dared hoping for). It turned out the LH gasket was 1.6 mm while the RH one was 1.1 mm I bought them at the same time but they were not part of a set so I guess they were different batches or even different origin. I'll check new ones carefully from now on.

[luhbo]

.... But the followers doesn't look all that good. On both sides the exhaust follower showed pitting while intake side was better.

 

....

 

The rockers are looking equaly bad. It's possible to rework them DIY using a standard grinding stone. Just take care that you hold them properly. You could try the same with the followers (but at 20 Euros each it won't make very much sense probably). How are the valve ends looking?

 

Hubert

[raz]

Good point. Rockers are €107 each... I'll ask the head shop if they can resurface them. All valve ends are flawless.

[GuzziMoto]

Good point. Rockers are €107 each... I'll ask the head shop if they can resurface them. All valve ends are flawless.

We used to get the rockers for our Ducati's redone by Megacycle. They were much less expensive then replacing and usually they worked well. But the surface finish has to be right or it will fail.

[luhbo]

This is a luxury version of what I had in mind when I wrote "Standard Grinding Stone"

 

 

It's matter of max. 10min per rocker.

 

Hubert

[gstallons]

You need to consider this! All lifters (rockers) unless it is of a roller rocker design has a convex surface. This mates to an angled cam lobe surface. This is designed to "spin"the lifter and keep it from remaining in place.

If you do not believe this you should consult a racing camshaft company and ask them.If you want to f**k up your engine, go ahead and do as your advised.

Advice is FREE. Parts are not.

[Skeeve]

You need to consider this! All lifters (rockers) unless it is of a roller rocker design has a convex surface. This mates to an angled cam lobe surface. This is designed to "spin"the lifter and keep it from remaining in place.

 

I think you meant to write "spin the valve." (Kinda hard to spin the lifter, since it's rather firmly located by the lifter towers, etc. )

[Guest ratchethack]

I think you meant to write "spin the valve." (Kinda hard to spin the lifter, since it's rather firmly located by the lifter towers, etc. )

Nope. Gene is correct. The lifters need to spin to wear properly.

 

The lifter faces are ground convex and located off-center (and/or angled, depending) on the cam faces to ensure they do.

[luhbo]

You need to consider this! All lifters (rockers) unless it is of a roller rocker design has a convex surface. This mates to an angled cam lobe surface. ...

 

Gene,

just in case something is not 100% clear here - I was talking about the rockers, the brown thingies with the relatively small worn surfaces, in the below picture placed above the followers.

 

....

....

 

Why not bring those rockers to a shop and ask them to grind nice little convex surfaces on them If you tell them how important these are to keep the valves spinning they'll do their very best probably.

 

One can read every now and then of such convex surfaces, but all followers I've seen so far (mostly old stuff ) don't show this feature. FIAT ones neither, nor was it implemented on the ones I bought from Stucchi once (the long and light ones). I could see no avantage of such a shape, but the downsides are obvious: only a very small contact area between cam and follower, short line if not even point only.

 

They may exist, why not.

 

Hubert

[guzzigray]

Replace all the followers. Don't use Mobil 1 for cars. Mobil 1 20-50 V Twin is great stuff. Lot's of Zinc.

 

I have taken apart 2 Sport 1100i motors and they both had the pitted followers. Both also had alot of wear on the cam.

 

If you replace the cam the Megacycle X10 is a good one. The V11 cam might be a good replacement too. I had a Ballabio engine apart and the cam was in great condition, much nicer than the Sport cams.

 

Obviously this is only my experience, I'm not holding myself up as an expert and there may be a perfectly good reason the V11 cam was in better shape than the Sports but it seems to my untrained eye that the Sport cams have a different, more 'peaky' profile and maybe the metallurgy is different. Greg can you add to this, correct me??

 

Regards.

[Greg Field]

Like Tom and Slavek I just removed my heads and barrels for some work. Cylinders look like new after 72,000 kms, pistons look good too as far as I can tell. But the followers doesn't look all that good. On both sides the exhaust follower showed pitting while intake side was better.

 

Here is left side pair, exhaust at the left.

 

Here is right side ones, again exhaust at the left.

 

Cam looks absolutely fine as far as I can tell without actually dismounting it.

 

Questions include: Should I replace some of them, all of them, none of them? What do I need to know if I replace them? Break-in measurements? Mineral oil with lots of zink? Moly? Or just pop new ones in and forget about it? And what's the price tag on these things anyway?

 

I'll find answers in older posts here and on other boards but anyone bored with the low activity here please speak up if you wish!

 

Send a pic of the cam, particularly of the RH exhaust lobe. Show the lobe tip and also a side view of both sides of the lobe. I can tell you what to look for.

 

Tappets that look like that usually indicate a lot of water in the oil. They can run like that for tens of thousands of miles, so long as they keep spinning. One day, they will stop spinning and very soon wear out. Replace them with new or re-ground tappets. New are about $30 US each. Re-ground are half that.

[raz]

Send a pic of the cam, particularly of the RH exhaust lobe. Show the lobe tip and also a side view of both sides of the lobe. I can tell you what to look for.

Crappy camera and hard to get the light fall in right. I took a lot of pictures, all can be browsed here. Hopefully some of them are good enough.

In real life the light areas that almost look shiny here are actually dull grey, and the darker areas are shiny but with "discoloration". I really appreciate some help here, I have no idea if these traces are good or bad.

 

What I can tell is there's no pitting and all four lobes measure 35.0 mm to the opposite side with a vernier caliper.

 

Tappets that look like that usually indicate a lot of water in the oil.

That may have happened before I got the bike @ 35,000 kms, I have no idea. I change the oil properly and I don't ride short distances. What I do know is that some PO did some pretty stupid things with the bike, worst found so far being the oil pump sprocket nut replaced to wrong thread, stripped it and GLUED that stripped nut to the shaft. Fortunately I found that years ago and fixed it. Today I could also see evidence someone did something with the cam before me, apparently with a chinese monkey wrench instead of 10 mm sockets. Why, I do not know. The cam has KE stamped on it, I guess that means it's still the correct cam.

[raz]

One can read every now and then of such convex surfaces, but all followers I've seen so far (mostly old stuff ) don't show this feature. FIAT ones neither, nor was it implemented on the ones I bought from Stucchi once (the long and light ones). I could see no avantage of such a shape, but the downsides are obvious: only a very small contact area between cam and follower, short line if not even point only.

Holding my two least pitted followers against each other, they are definitely convex. Do you believe that is an urban myth?

 

I asked the head shop guy about the rockers and lifters. At €20 each, he suggested I should buy a full set of new lifters. As the rockers are surface hardened he could regrind them but I'd have to find another shop for hardening them. He also gave the same advice as you, I could grind them down myself.

 

Only one of my rockers have pitting (incidently the one you saw in the picture, it's the LH exhaust by the way), the others are worn with (soft) steps but otherwise look fine. I will probably replace the pitted one right now and postpone the others. They are easy to replace later whenever I want/afford/need to.