Doms CB550F1 project

[Bryanj]

Nowt wrong with that cam

[DomP]

Nowt wrong with that cam

That's a relief Bryan,  I'm  not sure if I want to find any other issues that answer my problems or whether a clean bill of health would be good.  Either way I'll be fixing a head gasket leak so it's all positive!

[Oddjob]

Has some pitting on number 3 inlet lobe, the journals are a little tramlined as well, depends a lot on how the journals are underneath on the head TBH. Post a pic of the rocker arms and the camcover as well, but before you do anything remove the tacho drive, CAREFULLY. It's breaks for fun, right where it meets the top of the camcover, a lot of the time only the bolt is holding it together. Push from underneath rather than try to lever it out. If it's intact store it carefully. They are expensive to replace and VERY easy to break if left in the cover.

The cam can be re-profiled if there is more pitting on the lobes.

The dreaded instant gasket has made an appearance, haven't seen that stuff for a long while now. Very common in the 80s.

[Oddjob]

Ken, do you remember offering any more help I might need? 😉   I might be asking a few questions

Feel free, my favourite engine the 500/550.

[Bryanj]

Dont remember seeing where you are located apart from uk, which whilst smaller than us still covers a big area

[DomP]

Ken, do you remember offering any more help I might need? 😉   I might be asking a few questions

Feel free, my favourite engine the 500/550.

Thanks Ken! I'm enjoying it at the moment. The tacho drive that screws into the rocker cover? It came out easily

[DomP]

Dont remember seeing where you are located apart from uk, which whilst smaller than us still covers a big area

Good old Herefordshire, right on the Welsh border just outside a town called Kington.

[K2-K6]

Nowt wrong with that cam

That's a relief Bryan,  I'm  not sure if I want to find any other issues that answer my problems or whether a clean bill of health would be good.  Either way I'll be fixing a head gasket leak so it's all positive!

What about the holes / inclusion on the lobe nearest the sprocket flange in 3rd photo  ? Looks like a good cheddar on my screen   

[Oddjob]

Yeah, that's what I spotted, number 3 inlet lobe. Showing some pitting, you need to check the other lobes for the same type of damage Dom. Also check the rocker that runs on that lobe for damage that pitting may have transferred to it. You should have a 550F type rocker cover, we need to check that's the case as they can be swapped and sold and fitted with a 500 cover. The 550 is the better type of over as the rocker shafts were pegged to stop them rotating and ovaling the holes out in the cover body. However the pegged shafts are prone to premature wear so maybe think about removing those as well.

Don't hammer the cylinder head fins to get it unstuck BTW or you'll break them. 2 small bolts fitted front and rear of the cam tunnel as well, make sure they are out. Use a rubber mallet or better still what is called a Compothane hammer, which is like a plastic hammer but the head is filled with lead shot so it gives a real dead blow which tends to shock stuff loose but without breaking it.

Like this.

https://www.screwfix.com/p/magnusson-dead-blow-rubber-mallet-35oz-0-99kg-/3081V?kpid=3081V&cm_mmc=Google-_-Datafeed-_-Tools?kpid=KINASEKPID&cm_mmc=Google-_-TOKEN1-_-TOKEN2&gclid=Cj0KCQjwusunBhCYARIsAFBsUP8616XTHja4_0HC5RPXdGZ7TOykNRarRGVFWQZhGP1N4kUKdpvza2kaAu5FEALw_wcB&gclsrc=aw.ds

[DomP]

I'll get some photos of the rocker lobes tomorrow but they all looked really good to me, I did notice the blemishes on the one lobe.  I really appreciate everyone's help on this, proper like minded community spirit!

[Bryanj]

Yes its pitted but seen worse, if you are going balls outfull race needs replacing, if, like most of us, it will do maybe 2,000 a year it will last forever.
The followers are hardened the lobes are not

[Oddjob]

If worse comes to worse you can always get the cam redone at Newmans. Maybe have it re-profiled to suit the engine better, a few degrees more overlap, a few degrees more duration for example really wake this engine up midrange. Cost is the same as just having it done to standard. It's about £100-120 plus VAT plus P&P.

[K2-K6]

Interested to see what the rocker faces look like. Wear from these component will often be too small (sub 5 ~10 micron ) to be trapped by conventional oil filters, that's what makes the "tramlines" in plain bearing surfaces by getting trapped in soft part of those bearings next time round, crankshaft assembly too.

Originates in oil condition during previous running, too long interval and fuel dilution. Cam lobe and followers always show this first due to highest pressure exerted on oil film at this site location.

[DomP]

I quite like the idea of a bit of cam reprofiling, if I find everything else to be in good order I may go down that route.  In terms of top end gasket and o-ring kits, where is best to get them? 

[Oddjob]

Always try and source a genuine top end gasket kit. Quality is far superior. Not exactly an abundance of them these days though.