1980 CB250RS Project.

[AshimotoK0]

Managed to get the swinging arm bolt out today (turns out collars had corroded to swinging arm long bolt). Lots of heat from two Mapp gas torches and plenty of release fluid and welly. Had to angle grind off one collar. Also main-stand pin is corroded in the pivot tube, so I chopped it out of the frame and I will drill it out (done loads like this).

Cleaned up and blasted the alloy brake parts and etch primed them with PJ1 satin paint. I will bake when I am in at work Thursday. Just need to zinc plate the bolts. I guess they would have been olive-drab passivated originally but I still need to find the chemicals to do this as lots of parts on this bike olive-drab passivated.

Stripped the engine completely apart from removing the generator rotor, which needs a puller tool. Bought a lorry wheel bolt M22 x 1.5 and hoping this does the job (arrived today and pictured in box). The crank and gearbox didn't look at all bad for a high mileage engine but I already have replacements from a low mileage import bike, so I will be replacing. Looked like the bottom end has never been apart before and absolutely caked in oil, mud and grime.

Didn't get a headlamp unit and rim with the bike as it had a fairing fitted, which I haven't got yet and unsure of the type.. So tonight I bought locally (near Beverley)  a headlamp complete plus air filter housing, front indicator frame, brackets  and indicators plus a spare main wiring loom off FB marketplace all for £25    Seller was asking £35 but I made a cheeky offer and he accepted without any quibbling. Nice bloke .. has a 400/4 and CB360G5 and probably more and only looked 30 odd, which goes to show that younger guys are still into our bikes     Says he misses his CB250RS and wishes he hadn't sold it.

Good old TEC shocks are back so I grabbed a pair whilst they are still available !

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[Laverda Dave]

Fantastic progress Ash👍. I know how the guy feels about wishing he never sold his RSA, been there, done that😐.

[AshimotoK0]

Cleaned tons of muck and oil off crankcases side cases, cleaned in paraffin parts washer at work,scrubbed with Scotchbrite pads and degreased in Acetone. Then PJ1 satin black finished. Still need to bake everything. Original Honda coating/ paint very durable, so just treated small areas before paint.

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Rear guard metal centre section (other two are plastic) corrodes really badly on this model. Mine was OK apart from rotted through one side around double-skinned mounting area so had to cut out rot, braze in new metal sections after blasted clean. Then painted in etch primer, then epoxy 2k primer then coat of dark olive drab paint. Original Laverda Dave tells me was that this metal part of the mudguard was zinc plated olive drab passivated. Bit of a labour of love job but nice and solid now and chances of finding a decent one pretty slim.

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[AshimotoK0]

Guard in dark olive drab colour paint. (doesn't look as greeny in this photo though)

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Bolts stripped of plating ready for further cleaning and zinc plating (many are olive drab green passivated). I just received my 2l of of Olive-drab passivate solution ... man did I have to jump through hoops to get hold of it, as it's banned for sale to Joe-public.


Fuel tank was rotted out as shown but rest of it inside was rust free. I was going to braze new metal, until I grabbed this lovely condition, powder coated, one off eBay for £45 (most people charging well over £100 for dodgy looking ones). Tank will be pearl blue (as it was when the bike was new) ... eventually... Same seller sold me a LH bar switch £20 and almost NOS condition gear lever and link bar. £15

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[Johnny4428]

Some nice work there Ash on you restoration. Good to see before and after. Think you’ve got a knack of picking up a bargain too!

[andy120t]

Some nice work going on there.

Locking petrol cap looks the same as my old cb900f - I wonder if it is the same part (and yes, I could look at a parts list, but it's a pain on a phone!).🙂

[AshimotoK0]

When I was learning how to spray paint during this year,  I joined a 'Pro' closed group on Facebook with main contributors being in the automotive refinishing trade.
Lots of useful tips, invaluable to a novice like me in all honesty  but they don't suffer fools gladly.  Also a very male oriented group with crude comments that even make my eyes water and I wouldn't call myself a prude.

Anyway, asked them about wet painting a powder coated motorcycle fuel tank and this is what I got back.

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[McCabe-Thiele (Ted)]

Thats very interesting information about painting over PC Ash - another info gem.

[AshimotoK0]

Thats very interesting information about painting over PC Ash - another info gem.

Yes Ted varying opinions on the way to deal with the PC. The powder coating on the tank I bought is very were adhered and I am tempted to flat it like they say and wet paint on top of the PC. I wouldn't do this if I was getting somebody else to paint it but seeing as I am painting myself it's not £££ down the swanee if it goes t*ts up.


I got a CB250JDM headlamp bowl from Japan which had been  powder coated. With that I just put a torch to it and burned it off.

That group has trade info that you would normally never learn as a novice so worth looking at. I often hear them banging on about that lovely candy looking red you get on modern Mazda cars ( and similarly on some Renaults but doesn't pop so well IMHO). Evidently it's a 4 stage process and an absolute b*stard to do repairs on. One guy on there said he cocked a job up painting it on a Mazda and lost his job over it. 

[Oddjob]

I've got a Mazda 3 in that colour red Ash, it's called Soul Red IIRC. It's a lovely colour, very similar to the red on my CB1300, which is called Arcadian Red.

[AshimotoK0]

I've got a Mazda 3 in that colour red Ash, it's called Soul Red IIRC. It's a lovely colour, very similar to the red on my CB1300, which is called Arcadian Red.

Yes they refer to it as Mazda 46v Soul Red Ken.. First time I saw a car painted in  it on the motorway, in the sunshine I,  went WOW! ... what a brilliant colour.

[Laverda Dave]

Some great repair work on the rear guard Ash, a known rot point on these. Have you sprayed the PJ1 directly over the original Honda engine finish on the cases and then baked, did you have to use etch primer first or wilk rhe PJ1 stick to anything?

We had a Mazda MX5 in that red colour, lovely car, fantastic to drive and the only car I enjoyed working on . We had to sell it when the O/H suffered with a prolapsed disc in her back and found it really painful to use the clutch.

[AshimotoK0]

Some great repair work on the rear guard Ash, a known rot point on these. Have you sprayed the PJ1 directly over the original Honda engine finish on the cases and then baked, did you have to use etch primer first or wilk rhe PJ1 stick to anything?

It was s b@gger to get clean Dave ... loads of oily grime but degreased it pretty well using various methods and when I washed it finally in acetone, the original finish softened very slightly so I rubbed all over with Scotchbrite pads and then put the PJ1 on top. Seems to have adhered pretty well but need to bake over Christmas at work , as they have a lab type oven.

[AshimotoK0]

Found that one of the RS fork stanchions is bent so going to have to check the frame out too, plus source new stanchions or rechrome some straight but pitted ones, which is a bit of a bummer. Need to quiz  the PO in pub to see if he has ever seriously dropped the bike (he owned it from new) or perhaps forks were off the donor bike he had. Not settled up with him yet anyway he doesn't seem that bothered ... just keen to see it restored. I bought some pitted but supposedly straight forks off eBay for £40, so will get those rechromed at this place (I can drop off and pick up as I usually go to Leeds a couple of times/month).
 
https://www.brooksuspension.co.uk/motorcycle-fork-rechroming-service-for-stanchions-both-legs


 There are a few bits I can sell on to fund it all ..like 3 wheels, seat, barrels/piston x2  and head covers x2 . All of the 3 heads I got with it look dodgy to me as two have at least one valve seat removed. They all have decent cam bearing surfaces though. I think one head may be off an XL or something as it doesn't have the valve decompressor assembly and is not bored for one either. Obviously, I have the NOS top end so going to fit all of those anyway. Just need to source a genuine NOS standard piston (already have the genuine rings set).

To be honest, the bottom end, despite the bike having done 50k looks pretty decent but I already have the  low mileage bottom end internals that I got from DK so I am using those for the engine rebuild..  The tank I got for £45 was an absolute steal ... really nice condition. I was told it had been powder coated but when I  rubbed it down you get white dust so I think it's not PC and the white dust is from clear coat.

I now have the two 1 litre bottles of 'unobtainium-to-Joe-public'  olive drab passivate chemical concoction, so had a go at plating a bolt and it turned out pretty good.
 
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I stripped the bar switches and painted the casings with etch primer then PJ1 and baked at 150 C on Friday and blasted and painted the handlebars with etch primer/PJ1 satin. Not sure if I should satin 2K the handlebars too. What do you reckon? Also need to find the correct paint for the green letter indents. May have to source a replacement kill switch knob too. I repainted the tacho drive too in PJ1 satin black  and cleaned  and painted the plastic sprocket cover ... took ages as absolutely caked in chain grease.

[Seabeowner]

No comments from me except how do you propose checking the frame out? Just close inspection or bar through the headstock.
Keep the info coming as all is very interesting as usual.