Another restoration ready for the road

[H2Eric]

Hi folks
Here is my latest restoration, a 1972 CB350f imported from the USA. It's been a fairly straight forward job. Take it all to bits, powder coat and re-chrome as necessary and replace various parts with new ones from David Silver / CMSL adding to their already bulging bank accounts, but what would we do without them. A big thanks to both. Phil Denton also provided some lovely stainless components - Cylinder studs, axles and swinging arm pivot to name but a few. More of him in a moment.
The snags, well there had to be a few. On getting the bike I noticed a bent fin on the right side of the cylinder head, nothing that a gentle tap with a piece of wood and hammer wouldn't cure, but then I noticed some damage around the number 3 spark plug. A strange place to get broken fins and also the top of the cylinder stud in that area had taken a beating. Once the cylinder head was off it was easy to see why. It had obviously suffered a seized / broken spark plug at some stage and some clown had tried to drill it out going off center in the process. Part of the old spark plug was still there! Cost of repair, well north of 100 of your best pounds. Plenty of second hand cylinder heads on ebay, all in the USA of course and cheaper than repairing the damaged one except that the cost of shipping was stratospheric. Fortunately DK Spares came to my rescue with a spiffing example, 80 quid all in, result. On removing the original cylinder head I also noticed that the oil feed pipes that distribute the lubricant to the camshaft and rockers were missing. Probably omitted by the same miscreant that damaged the head in the first place. Ebay to the rescue.
The one thing that did cause a problem and delay to the restoration were the fork covers that sit on top of the bottom fork cases. They were a devil to remove, but thanks to those on here that came up with the solution and I got them off without damage. The snag of course is that these components are no longer available and are so thin that a re-chrome would probably finish them off completely. The odd second hand one appeared on ebay in a far worse state that the ones I'd got. Enter Phil Denton into the equation and a commission to make a pair out of stainless. Very nice chap Mr Denton and he likes a challenge. Slight drawback in that he is a very busy man so the components did take some time to appear from his emporium, but well worth the wait and they wont rust. Hurrah!
So there you are, it's all tickety-boo, tip top and ready for the road whenever the weather decides to improve. Hmm, could be a while.
A special thanks to;
Terry Chambers (Racepaint UK) for the paint job
Triple S for powder coating.
My good friend John Edge for the chrome work
Phil Denton (see above)
Steve Lomas (5-one Wheels) wheel building and tyres
David Silver, CMSL and J. T. Marks (USA) for various new parts and DK Spares for the second hand ones
plus my trusted friend Graham Wood for all the help with the spanner work.

Hope you like the end result
Cheers
Eric

[H2Eric]

Forgot to mention;
Steve Smethurst for cleaning and treating the crank cases, cylinder block and cylinder head etc.
Peter Bond for the speedometer and rev counter restoration.
Rob Davies-Evans of Kernow Shocks for restoration of the rear shocks.
CC's for the carb cleaning.
John Kenworthy (FAB Fastenings) - stainless screw kit
John Kemp (Inox Fasteners, Southampton) - stainless nuts, bolts, washers etc.

Cheers
Eric

[paul G]

That look sweet Eric, job well done

[Trigger]

Great looking bike Eric, still have not bumped into you as you only live round the corner, or maybe we have met and did not make the connection 

[Nurse Julie]

Very pretty bike Eric, I'm quite fancying one for myself. Just love that colour.

[andut]

That's a great looking bike Eric - well done on the rebuild, and I hope you enjoy using it !

Andy

[Integra99]

wow superb restoration.. looks stunning!

[philward]

Great restoration Eric (a little more straight forward than your superb CR build that inspired mine) - they're a lovely looking bike and wouldn't mind a 350Four for when my big bikes get to heavy for me! Maybe a few projects away though

[MrDavo]

Thats a thing of beauty, Eric, I bet it runs as sweet as it looks.

[K2-K6]

Very nice looking bike,  and restoration. The four pipes on these look so good.

Some time ago a friend ran a small engineering company,  principally bikes, he could almost leave a milling machine setup full time to work on those two centre plugs of these heads. Bike shops would run them to him to usually bore out the old plug body which if they hadn't been chewed and butchered,  could be machined until the thread was just about down to a helicoil like remains,  remove waste and clean up with a tap. 12x1.25 pitch. If I remember correctly.

[MrDavo]

What happens, do the plugs corrode in place and get stuck?

Thinking about it, it's very exposed to the weather, and that iffy mix of steel and alloy, coupled with not being disturbed for a long while if the bike isn't being used or maintained.

I've never had it happen, but I can see how it could. I don't want to contribute to sabotaging Eric's restoration thread, just interested in why this happens a lot.

[hairygit]

What happens, do the plugs corrode in place and get stuck?

Thinking about it, it's very exposed to the weather, and that iffy mix of steel and alloy, coupled with not being disturbed for a long while if the bike isn't being used or maintained.

I've never had it happen, but I can see how it could. I don't want to contribute to sabotaging Eric's restoration thread, just interested in why this happens a lot.

It's called Electrolytic corrosion Trig, get it a lot on old Landrovers where the alloy body panels bolt to the chassis. Dissimilar metals + water, over time the steel rusts and the alloy dissolves to white powder. Obviously similar is happening to the heads of some old bikes, as you said, lack of maintainence is a major contribution to it.

Sent from my X6pro using Tapatalk

[haynes66]

lovely job. nice to see another one back on the road

[Laverda Dave]

Well done Eric, great looking resto and paintwork is stunning as is the whole bike.  Summer is on its way 

[K2-K6]

What happens, do the plugs corrode in place and get stuck?

Thinking about it, it's very exposed to the weather, and that iffy mix of steel and alloy, coupled with not being disturbed for a long while if the bike isn't being used or maintained.

I've never had it happen, but I can see how it could. I don't want to contribute to sabotaging Eric's restoration thread, just interested in why this happens a lot.

It's called Electrolytic corrosion Trig, get it a lot on old Landrovers where the alloy body panels bolt to the chassis. Dissimilar metals + water, over time the steel rusts and the alloy dissolves to white powder. Obviously similar is happening to the heads of some old bikes, as you said, lack of maintainence is a major contribution to it.

Sent from my X6pro using Tapatalk

Galvanic corrosion is method by which the metals are partly dissolved. Each metal appears on the galvanic scale with a differential between them,  the greater the difference,  the more likely to corrode one component. Usually requires an electrolyte to get the reaction going. In most cases that's going to be salt water solution,  so road salt in the rain is the normal culprit.

Can be protected against with another metal as sacrificial anode (think that's correct) so use of copperslip or similar can prevent the main components migrating.

Front brake caliper also subjected to the same.