Topic: CB500 K1 – 1972 – Everyone’s building one, so I’ll give it a try !

[MRieck]

If you hard weld the cam, the rockers need to be hard welded too. The material hardness difference will eat the rocker faces very promptly.

Regarding painting/coating/not painting - Aluminum oxidizes immediately. It continues to oxidize forever and depending upon its exposure to moisture, your engine cases will turn a chalky, silvery grey. To prevent that, paint them or powder coat them. Else you will need very regular maintenance cleaning and buffing with some type of aluminum "wax". Not so hard to do if the motor is on the bench, no carbs, etc. A major pain in the arse assembled in the bike.

Paint or powder coat is perfectly fine for regular performance. The thermal coatings are typically applied to the head and jugs to assist in dissipating the heat internally and promoting cooling by the air flow around them.

Very, very true Cal. I have personally seen this on several engines that were built for dragracing......and they only go 1/4 mile at a time.

[cantarauk]

Thanks Cal, Mike,

Since there was not any concern with the cam lobes my understanding which may be wrong (again excuse the inexperience) was that the cam was going to be hard welded only on the sections that fit the journals. Would this not be the case and if so I may have to enquire about the rockers as mentioned.

Below show the scoring on the journals of the cam cover



and then the scoring to the cam itself



The lobes and rockers after cleaning up did not seem that bad for their age. I think it may be best to call them back to be sure I understand the exact work that is been done.

[cantarauk]

For the engine painting I will probably be going the power coating route but as a matter of interest how good are the VHT type solutions and what are the pitfalls? Also if I go for paint would that have to be hard baked ?

[SOHC4 Cafe Racer Fan]

That's pretty rough wear.

[RAFster122s]

Painting the fins can be challenging and yes you will have to bake the coating to prevent chips during reassembly.  You can do this in your oven...just clean the oven if any odors from the paint linger.  Powdercoating will be more durable and modern powders are applied thinner than previously. Powdercoated parts are sand blasted to give them better tooth.  The electrostatic application of the powder also helps you get the powder deep between the fins and on the cylinders.

As far as the cylinder head and rocker cover goes, I highly recommend you replace these parts with a cover from a '77-78 cylinder head/rocker cover.  You cannot really redo the bearing surface inexpensively or easily.  It is Not commonly done because the aluminum is tthe bearing surface.  How do they propose installing bearing shells for the cam where none existed previously and I have never heard of anyone attempying such a repair.  You also may have wear on the rocker arm shafts and those cannot be repaired either.

The 77-78 cover has a pinned rocker shaft design that eliminates any wear in the rocker shafts in the cover.  On the 550 from 74-76 they often wear eccentrically.  So, you have a cam destroyed as well as the rocker arms and the cover.  The rocker arms and cam can be hardwelded to create a useae items again.

[cantarauk]

Thank you for the replies regarding the wear on the cam and cam bearings.

When I spoke to SEP about options to repair cam bearings in the cylinder head I referred them to this response that I had from a post on the UK forum from AshimotoK0.

http://www.sohc.co.uk/index.php/topic,11161.msg82799.html#msg82799 Very interesting.

As mentioned I discussed this with the machine shop and they said there are other ways to repair these surfaces and the price was expensive but less than I expected. For now I am going to see what they come back with and as a backup plan I have a few heads/covers earmarked on a popular auction site that I may purchase as a backup. Am looking for 77-78 as you mentioned RAF122S.

[cantarauk]

The wheels have become a priority as my inexperience has caught me out.

I was working on the frame removing tabs and cleaning up where I can getting it ready so that it can be sent off to be powder coated. The next step was to figure out where all the electrics would be positioned and now most of this can be hidden in the spaces under the cowl and seat.

It was then pointed out by the guy who will be doing all the welding and fabrication that I had not worked out my clearances for the back wheel. By this time the tyres are already off and spokes cut so before I could do anymore frame/fabrication planning I had to get the wheels complete and shock dimensions worked out.

So some wheel hub polishing and wheel rims powder coated as mentioned earlier it was time to build these up. There is something to be said about lacing a wheel that is quite relaxing.









Wheel laced and then off to for truing and tensioning and also new set of rubber. I went with the Avon road-riders and rather than getting a wider rim stayed with the stock 18x1.85. Very pleased with the outcome.






Now that wheels are complete I have been speaking with the guys at Hagon to best advice what shock preferences I have based on the wheel clearances. They have advised 335mm with 20mm restriction giving me a 60mm travel. Shocks are as shown below accept with clevis option.



And now back to where I need to be working on the frame

[XC204]

Ha I've got you beat I started my cb500 in 2012 still not done. Almost though! Your project looks great 👍
Gary

[cantarauk]

Cheers Gary. Yours must be a labour of love taking that long.

Had a quick look at your project and it is looking great and you must be fairly close now ?

"Things" just get in the way sometimes and now that I have moved into new property and job is back to normal with less travelling I have found the time so thought best to take advantage of that.

[RAFster122s]

Would be far cheaper to source a useable good head and cover from eBay, you can ship to someone like Mike Rieck who could rebuild it and then send it to you. Or, HondaMan, etc.

[cantarauk]

Hi RAF122S

That was exactly what I thought and I looked at going that route but what I found was that it works out roughly similar when you take additional head cost and shipping costs into account.

I spoke to Mike a few years back and got all the costs to refurb the head and then discussed options with a motorcycle machine shop here in UK and as mentioned to hard weld and cut cam, rockers and then machine the head journals to match the cam came to roughly a similar price.  I was hoping to try and get the journals engineered to host shells which would then match the cam sizing as per this

https://www.classicbike.co.uk/ricks-fixes/grind-your-valves

Problem is these getting hold of these shells is as easy as obtaining rocking horse poo but if anyone could suggest an alternative I may consider this route.

[Stevecb500chop]

Very nice bike to start with.

[cantarauk]

Cheers Steve,

Some issues when it came to stripping it down but was not a seized rust bucket as you sometime see

[cantarauk]

Part are coming in thick and fast and I am now just waiting on the primary chain before I can make a start at re-building.

Digging through all the bags of nuts, bolts and screws this is the one thing that I left until last and could delay the build start. The engine was originally painted assembled so all the fastening hardware is black with scuff marks so not very good in appearance.

So I believe options are to clean up and plate the ones I have or replace with new. If I chose the plating option could anyone suggest the best way to go about this and also any useful contacts who could do this for me.

Researching the replace with new option I believe at a Class 8.8 (grade 5) or class 10.9 (grade 8 ) should suffice. There are sites that offer hardware in these strengths but my question firstly is if this is a requirement for the stronger bolts or just BS.

Probably not the right place to ask and I have asked on UK site but If stronger is better then where in the UK would the best place be to get hold of SS Hex head or 12PT bolts as shown below. Also the places I have found so far do break the bank so interested in best financially viable options

allensfasteners.com is already on the cards if I cannot get these in the UK for same price

I do like the hex head with hollow on the head

[cantarauk]

Still no closer to getting fastening hardware as I am now waiting on pricing for made 10.9 bolts/screws as per the second option spec. Also waiting on plater quotes to come back as this may be the route I go down unless advised otherwise.

I did a quick costing up of the 12-PT option from the US which is going to work out close to $550 for all I need shipped. The other race SS option as pictured did not have the longer bolts required for the CB500 and even without those was around £300 which does not include the cover screws. 

Taking the final bits out from the cases I struggled with the plastic oil guide which took so serious persuading and gentle hit with a compact driver. The reason for removing this was it looked mangled as shown in the pictures but again if told otherwise I would not replace as I am struggling to find these and when I do again £50 for a piece of plastic is taking the piss.

[cantarauk]

For the plastic oil guide I may go the route of getting this 3d printed at least that way I should be able to help others when they get stuck looking for one of these.

[cantarauk]

Some more updates I never got round to posting.

The forks sanction have been hard chromed and ground down to size and look great ready to be rebuilt.





considering that this is what they looked like before

[cantarauk]

Most of the components required for the engine assemble have arrived so I will be making a start at building the motor. Since this is the first time I have undertaken such a task I will be taking it slow documenting everything so that hopefully the community can correct me where I go wrong.

The engine cases have been cleaned and sprayed using Simoniz Engine Enamel SIMVHT31D

[wolf550]

Still no closer to getting fastening hardware as I am now waiting on pricing for made 10.9 bolts/screws as per the second option spec. Also waiting on plater quotes to come back as this may be the route I go down unless advised otherwise.

I did a quick costing up of the 12-PT option from the US which is going to work out close to $550 for all I need shipped. The other race SS option as pictured did not have the longer bolts required for the CB500 and even without those was around £300 which does not include the cover screws. 

Taking the final bits out from the cases I struggled with the plastic oil guide which took so serious persuading and gentle hit with a compact driver. The reason for removing this was it looked mangled as shown in the pictures but again if told otherwise I would not replace as I am struggling to find these and when I do again £50 for a piece of plastic is taking the piss.

50 seems high for that plastic piece. had a couple laying around. they look similar to your condition. if you want they are yours. let me know and we can find out how much to ship overseas.

[cantarauk]

There seem to be different ways to do this but I have opted to start with the top half of the case seated on a homemade made frame to keep it steady.

Gear shift and drum inserted first with each part well lubricated with assembly lube.



Looking at the top half of the case with the crackshaft to be positioned at the top. Drum lubricated and inserted from the left side of the case with the left gear shift fork assembled with the pin and circlip side facing the left.



Next gear shift fork B assembled with the pin hole and circlip side facing the right hand side of case.



The right gear shift fork assembled again with the pin hole and circlip facing the right



New oil seal inserted and the drum pushed completely in

[cantarauk]

Starter gear and shaft cleaned lubricated and installed with the M6 retaining hex bolt torqued down to 1.0 Kg-Meter

[cantarauk]

Posted this on the UK site but though it best to ask for some help here also

Need three things checking please as I hope some of these are correct but could do with a Jedi/Expert opinion to validate.

For the Countershaft assembly No 19 and No 20 on the image is the way I put these washer back correct



The way I put these back below but I am more interest in washer 20 to see if the turned pieces went in the correct way. No 19 I assumed is the flat washer and No No 20 the washer that has bent ears for the I/D piece.






The second thing I need checking is with the Mainshaft when I stripped it down there were 2 washers where No 18 is.



I started putting this back without the second washer. Below is what I found when I stripped the Main shaft down for cleaning.





The 3rd query is reading the Haynes manual when inserting the second drive it says - " Ensure that a new oil seal has been fitted to the secondary drive sprocket end of the layshaft and that a new O ring positioned behind the oil spacer" From the parts images above I can't see this O ring only the one that fits between the bearing and the fixed positioner on the mainshaft No 3.

I did not remove the bearing No 22 all the way to No 7 only No 19 to No 24 for cleaning. So assume O ring No 27 is still there
 

[cantarauk]

From the previous post there was one thing that was bothering me in that No 7 (second gear) was not moving an stuck to the shaft so I decided to inspect further and get that off with whatever means possible. I gave it quite a few taps and eventually got it off the shaft and that is when I discovered more damage which could be same as to what caused the cam and top end bearing damage.

Image of the shaft where the second gear came off. And I am right in assuming this means it needs replacing ?





Then the gear itself -




From another post it is suggested that this is either something that has gone round or run dry that has caused the damage.

 To get the gear and the washers off I had to Dremel down parts of the shaft


 

[cantarauk]

Parts arrived to replace the damaged ones with one of them not the correct part which was causing me a headache while trying to assemble and then once I figured it out I had to return and wait for replacement gear before I started build again.





New on the left, right one was the headache one






With the new parts that arrived and over the Xmas period to escape the insanity of been cooped up I braved the cold in the  garage to get some more work done.

Mainshaft assembly

All parts cleaned and checked 


Forth gear


Thurst washer and circlip


2nd and third mainshaft gear


mainshaft top gear


thrust washer


roller bearing and then all painted with some assembly lube


Drop the mainshaft into the top case aligning the middle gear shifter fork to sit between second and third gear. Align pin with the roller bearing and give a spin.

[cantarauk]

Countrshaft cleaned and checked ready for assembly


replacement countershaft


Tope gear and circlip




Thrust washer and second gear




Thurst washer and lock washer which now fit since another replacement gear received


Third gear thrust washer and circlip





Forth gear


Lower gear with bush inserted with the flange side sitting against the forth gear


Needle bearing to top it off


Drop the countershaft in aligning the outer gear shifter forks to be positioned on forth and top gears