Pitted cam lobes

**FlyingDutchMan** · 11th February 2006, 12:52

I recently got a new engine for my cibby, and I decided to bench test it before throwing it in the bike. Anyway was going to do all the normal maintance things (valves clearances, spark plugs (super rich running/or oil fouled), oil (about 1 litre too much), float levels etc), but after I took the head cover off I noticed a couple of the cam lobes were pitted. I'm pretty sure this isn't a good thing.

So whats the best course of action? Leave them as is and pretend that I never took the cover off, change the cams for the ones out of my other engine, or use shelleys moldable steel to fill them? I'm thinking the best option is to swap the cams over, but I suspect that I'll have to get new bearings. And Mr Honda loves to seriously fleece you of your money for new parts.

Does anyone know what causes pitted cam lobes?

**WINJA** · 11th February 2006, 13:25

can csl hard face them then grind them back . the sellys stuff wont work . if it was me id prolly ignore it

**Sketchy_Racer** · 11th February 2006, 14:40

the cams dont run bearings?? well on the MC19 they dont.

oh and whats wrong with your other engine??

**FlyingDutchMan** · 11th February 2006, 15:52

Originally Posted by RG100!!

the cams dont run bearings?? well on the MC19 they dont.

oh and whats wrong with your other engine??

Well I've just checked the manual... seems that there are no bearings.

The other engine has definetly blown a head gaskett. There is also a nasty vibration that starts at 11,000rpm. Not sure what yet. Plan is to have one engine working fine, and the other as a spare - can just dump it when if the other ever shits itself.

**Bonez** · 11th February 2006, 16:01

Originally Posted by FlyingDutchMan

I recently got a new engine for my cibby, and I decided to bench test it before throwing it in the bike. Anyway was going to do all the normal maintance things (valves clearances, spark plugs (super rich running/or oil fouled), oil (about 1 litre too much), float levels etc), but after I took the head cover off I noticed a couple of the cam lobes were pitted. I'm pretty sure this isn't a good thing.

So whats the best course of action? Leave them as is and pretend that I never took the cover off, change the cams for the ones out of my other engine, or use shelleys moldable steel to fill them? I'm thinking the best option is to swap the cams over, but I suspect that I'll have to get new bearings. And Mr Honda loves to seriously fleece you of your money for new parts.

Does anyone know what causes pitted cam lobes?

How bad is the pitting? They could have been there since the cams where manufactured.
They may be fine as is. Read an artical in a mag about an FJ1200 servicing with this. As long a the edges of the "pits" are'nt protuding should be ok. Pull of the rocker cover off every 3,000-4,000kms to make sure they haven't gotten worse.

If you are really worried get a regrind as suggested or swap out the cams. Don't fill them with Selly's anything!!!!

The extra litre may explain the fouled plugs.

**Motu** · 11th February 2006, 16:34

If it was me I'd put the cams from the other engine in...at least compare them - but I'm not scared of doing major engine surgery.Otherwise.just ignore.

But don't ignore your oil changes from now on,early Honda's destroyed cams...use synth oil and change often.

**Bonez** · 11th February 2006, 17:01

Originally Posted by Motu

If it was me I'd put the cams from the other engine in...at least compare them - but I'm not scared of doing major engine surgery.Otherwise.just ignore.

But don't ignore your oil changes from now on,early Honda's destroyed cams...use synth oil and change often.

the '76 550 has 140,000ks up and hasn't touched a drop of syth

**FlyingDutchMan** · 11th February 2006, 17:46

Originally Posted by Motu

If it was me I'd put the cams from the other engine in...at least compare them - but I'm not scared of doing major engine surgery.Otherwise.just ignore.

But don't ignore your oil changes from now on,early Honda's destroyed cams...use synth oil and change often.

Up till now I've been using semi-synth and changing it every 3000km. I checked the valve clearance before taking the cams off - they were all way too big for the ex. ie. in the range of 0.3 - 0.33 mm instead of 0.2 - 0.26 mm. For the in, they're all on the upper limit (0.19mm). The pitting is on the ex lobe rise too - takes up about 1/3 of the width at the worst spots. Me thinks it might have to do with an excessively large clearance and the lobes smaking into the covers harder than they're meant to.

Major engine surgery is on the cards - the cams are out already. I'd have the head off too, but I don't have a 7mm dodecahedral socket. Damn Honda and their weird bolts! I think I'll be checking the valve seating too, make sure that they're all sealing properly. Maybe between the two engines, I'll manage to get one very nicely running one. Hmm... might even do some porting if the mood fancies me.

Then get my EFI project onto the cards with my own ignition timing... maybe I'll be able to get a few extra horsies out of it.

**The Stranger:Me** · 11th February 2006, 18:10

Um ok then how do you hold (secure it in place at least) a rotating shaft if there are no bearings?

**TwoSeven** · 11th February 2006, 18:27

If its like the 600 I suspect the cams are clamped in place.

**FlyingDutchMan** · 11th February 2006, 19:03

Originally Posted by CaN

Um ok then how do you hold (secure it in place at least) a rotating shaft if there are no bearings?

You have the head with a journal housing, the cam journal and top half of the journal housing bolted in place with two bolts. With the oil feed via the cam shaft, the cam should stay in there without friction or wear. I would have expected just some plain sleeve bearings in there, but there aren't any.

**Bonez** · 11th February 2006, 21:04

Originally Posted by FlyingDutchMan

You have the head with a journal housing, the cam journal and top half of the journal housing bolted in place with two bolts. With the oil feed via the cam shaft, the cam should stay in there without friction or wear. I would have expected just some plain sleeve bearings in there, but there aren't any.

Japs have been doing this for years on m/c engines, the crafty little swines.

**Ixion** · 11th February 2006, 21:15

Well, if you will have bikes with these silly, unnecessary and irrelevant bits, you must expect these things. Leave 'em out altogether (and those silly valves, too). My bikes go fine without 'em (well, two of them do anyway)

Me, I'd ignore it. If your old ones are nice, swap 'em out, it's not too big a job. But the pitted ones will probably outlast you.

**Motu** · 11th February 2006, 21:26

Yamaha used to know how to do camshafts....before the bean counters counted the beans and said ''you use too much metal''. The XS 650 camshaft ran in 4 ball bearings,the TT/SR 500 ran in ball bearings too,and even the rockershafts were needle roller bearings.