Honda-SOHC
SOHC.co.uk Forums => SOHC Singles & Twins => Topic started by: AshimotoK0 on November 26, 2023, 09:20:36 PM
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Picked up a 1980 CB250RS Single this week. Always fancied one since I saw the restored one in Classic Mechanics a few years back. Been off the road since 1991 and spent the last few months under a tarp outside. Taken off the road because it had burned out a valve and done 50k miles. A bit of a change for me as my latest year model bike is a '75 CB400F .. But I had to save it! ::)
Like most of my bikes I got the silencers before getting the bike and had these made directly by Brituro, rather than from David Silvers. We literally chucked the bike in the back of my mates van on Thursday and I won't have chance to fully asses it until I go to my mates warehouse (where I do my painting) on Wednesday. Even though the bike comes with a spare head, in unknown condition, I bit the bullet and bought a NOS head with valves inlet rubber etc, plus a NOS cover with the rockers etc. fitted and NOS cylinder barrel. This should hopefully save me a load of grief. I picked up these bits today near Easingwold York and the seller included a surprise freebie pair of wheels and a spare seat. The bike comes with a spare set of wheels (and CDi) but I suspect that these freebie wheels are in better nick and the spokes with replate fine at home. I bought a lovely crank and gearbox/selector parts from DK but the b*ggers have lost one parcel with the gearbox bits in it >:( It is shown as being in transit via DHL but oddly no tracking given. They refuse to discuss this over the phone and will only communicate via eBay messaging. I wanted them to ship everything together but they refused, saying one part may possibly damage the other in transit.
The great thing about this model is that there is hardly any chrome on it and I now feel confident enough to paint it myself in pearl blue original colour. Piki on here is kindly supplying the decals although I am going to paint the stripes myself.
Laverda Dave has been a fantastic source of help to me on this model and has some spares to trade. Thanks Dave ! If anyone else has decent parts then I will pay a decent price.
I bought a late version of the parts book for £20 in fantastic condition and I hope to scan it sometime and share with others in my Dropbox links. It covers the early and later e-start models.
Feast yer eyes on these NOS top end parts ... they don't come along every day of the week ! Cost ££££ but it's only money. Pics of the bike to follow but be warned it's not at all pretty :-[
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Congratulations Ash on a very wise purchase. Those NOS parts are gold dust especially the head and rocker cover. Where did you get them, it couldn't have been eBay?
I'm looking forward to reading about the rebuild with plenty of photos👍
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Sounds a great project Ash - good luck
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Congratulations Ash on a very wise purchase. Those NOS parts are gold dust especially the head and rocker cover. Where did you get them, it couldn't have been eBay?
I'm looking forward to reading about the rebuild with plenty of photos👍
Facebook Marketplace .. they were amongst a load of other used RS parts as a job lot but other parts sold quickly. Nobody apart from muggins here would offer a decent price for the NOS parts. I just gave him my top figure ..deal or no deal and he accepted. Cos I didn't muck him about, I think he included the wheels and seat for free ... which was a real bonus.
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Interesting project Ash, and bit of a find to get those nos bits.
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Nice bike Ash, at the Station where I worked a young PW used to commute on her learner motor cycle.
She turned up after passing her test on this single cylinder Honda it was a 250 RS aside from splashing out on a new bike she would wax lyrical about how nippy & economical it was compared to my 750GS. It had a good turn of speed in traffic iirc methinks it had a disc brake being a strangely skinny bike for a 250 - multi valve possibly as well - it was a long time ago!
Just looked at your photo 4 valves in one cylinder. Have you taken a before photo or was it in too many parts?
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I met the guy I got the RS from in the pub Monday night and he gave me three bags of spare parts. Evidently, he had a donor bike at one time. Some useful stuff including three cylinder heads and cam covers, CDi etc etc. They don't look bad in terms of the camshaft bearing surfaces and the rockers look OK too but two heads have one valve seat insert removed. Not sure how you would obtain and replace a valve seat but my mate Graham Curtis is bound to know. I have NOS head and covers complete anyway and that's what I will be using along with the NOS barrel. There is also a spare cylinder barrel plus the one on the bike. Among the spares were a couple of the cam chain tensioner main assemblies (evidently rare unobtainium NOS) and one looks to be in great condition and I reckon I will be using it plus a few cam-chains, one of which I suspect may be unused but I need to investigate this further to be sure. Also a set of clocks, which are much better than the ones on the bike.
We unloaded the bike at my mate Rogers warehouse today, photo'd it along side it's temporary mate .... a Beezer C15 and then completely stripped it, apart from removing the swinging arm from the frame. Removal of the swinging arm is going to cause me problems I suspect because I think the bushes are seized...certainly the long bolt won't turn, although I haven't put too much welly on it yet, as I didn't have a full hex impact-gun type socket where I was working today. Surprisingly none of the fasteners both on the bike and already taken off by the P.O. were chewed up and should replate fine .... It has the hex type screws instead of crosshead JIS screws an the case covers (as favoured by Oddjob on here).
There was no air filter fitted but Mickey and his mates had attempted to make one ;D.
One surprise was the state of the fork stanchions.. a quick rub and they look pretty good .. I was budgeting for a rechrome but I don't think it will be needed now.
Overall, the frame looks fairly solid as the rear end was caked in grease as was the swinging arm ... I believe these can rot quite badly.
Not sure what happened to the headlamp unit ... it's probably still with the fairing in the pub blokes garage that I still need to pick up (has broken screen ... not sure what type of fairing it is ), I won't be refitting the fairing anyway or the engine protection bars. I did get the headlamp frame though, in the bags of spares and the indicators too.
One bit of damage is a crack in one of the front alloy footrest hangers, so I need to find one or get it welded.
I got a super condition crankshaft assembly and gearbox etc from DK but they lost the gearbox and decided to refund me after 10 days. However, it was bought on my wife Cathy's eBay account and she pleaded with them for me and it mysteriously turned up the day after they were going to issue a refund.
I only found one camshaft in the spares ... One lobe has a pit and the the flanks look a bit worn but the journals look to be OK. Maybe a job for Newman cams or find a decent replacement. IMD sell a new one for just under £100, made in Japan but its for the XL250 and pretty sure that the profile will be wrong for the RS.
The bike didn't have any exhausts (he may find some once he searches harder but bound to be grotty I reckon so not too bothered if he finds or not ) but my new replacement silencers, which Brituro made me have arrived at work and look to be excellent quality and faithful repro's of the originals. I think I will get him to make me a set of downpipes, as they already make those as well.
I got a spare front wheel c/w disc (and a front wheel from a BSA Bantam ? ) with the parts but the pair of wheels I got with the NOS cyl.head etc., as freebies, look really nice and the spokes will replate great I reckon so I will be using those. They have nice tyres too that look like they have never been used. I was about to cut them off and bin them both until I looked at the date codes, which are late 2019.
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It will be interesting to see the project progress.👍👍👍
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I think the seat has been recovered at some point Ash as it should be quilted with a heat welded pattern but overall it sounds and looks like you have a really decent basis of a bike there especially with the spares you have gathered. The alloy wheel rims were known to rot from inside out so maybe worth taking the tires off to check the rim. I had stainless spokes fitted to my original rims after getting them vapour blasted and the hubs blasted and powder coated gloss black. I tried to rebuild the master cylinder but it never worked properly and it proved impossible to separate the white plastic reservoir from the base so I bought a reproduction reservoir without the white plastic part. Piki makes the vinyl insert for the cast footrest hangers.
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I stripped the master cyl last night Dave and managed to get the clear reservoir part separated and the bore on the alloy body doesn't look bad on it. It has an O-ring that retains it and pretty tough to separate. I also got a spare pattern one without the clear plastic section in it, which looks fairly new apart from on the outside brake fluid has leaked and stripped some of the paint.
Yes the seat cover is not original. I have another seat with about half of the original cover fitted so i know what the cover should be like.
Thanks once more for all of your help. !980's bikes are new territory for me :)
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Good luck with the build, Ash. I’ll be logging in occasionally by satellite to check on progress….something for me to look forward to.👍
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When they were new and i worked at Meads we had an insurance job where some scroat undid the 2 headlamp mounting bolts a cut EVERY wire going into the headlamp.
Damn near wrote the bike off with what we had to get new plus had to make the two earth wire nuts inside as Honda couldnt supply
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The left hand alloy footrest hanger plate is broken on this project ... lots of RH on eBay but LH hard to find.
My mate bid on one in Japan and won for 200 Yen = £1.07 :)
Also the air filter holder thingy is absent. Laverda Dave put me onto one on Ebay UK at £39 but before buying that one, I needed to see the P.O. in the pub on Monday to check if he still has it, as he had the bike from new. Anyway,I found one in Japan and got my Man-in-Japan to bid on it and won it for 1,000 Yen = £5.40 :). His mate is coming back from Japan in a months time and is fetching my stuff back in his luggage.
I stripped the original style Master cyl. and brake caliper and the alloy parts look serviceable so order repair kits for both and S.S caliper which have arrived already as well as two cans of PJ1 satin black paint. Mater cyl white plastic part was a bugger to remove ... retained with a rather expensive (£6) O-ring .... I also have a spare caliper with a bloomin big allen cap screw tapped into the front face ... presumably to extract the piston. Neat job but just doesn't look right. Pretty sure I saw another one on somebody's post on here recently on a caliper piston body. I also gota pattern M/cyl with the bike in good shape (needs re-painting) but not the standard CB250RS design
I wondered how DK have parts for this model but the Japanese writing on the label on the alloy hanger they have (wrong side for me) gave away that they must also import bikes to break from Japan.
Pics of parts my Man-in_Japan got.
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Japan is the place to get the bits Ash if you have the contacts. They had the CB250RZ over there, the tank and side panels were pin stripped and gave it a real classic image.
There was a CB250RSA on sale at Kempton Park yesterday, 18k showing but the top end was covered in oil, looked like it had a blown head gasket, leaking rocker cover gasket and the classic oil weep from the ends of the rocker spindles. He wanted £650 for it but it was rough, full of rust below the paintwork (the paint is very thin on the tank, built to a price). As you have a complete, brand new rocker cover the spindle ends shouldn't leak but if decide to refurbish the spare be careful putting the rocker spindles back in as it’s very easy to tear the very thin O-ring on the end. Triumph unit twins had the same issue and you can use a special tool for those to seat the O-Ring without damage, probably worth making one up for the 250 as its only a bit of hollow and tapered tube.
Did you get the main stand spindle out in the end? I used heat on mine and it eventually relented. From memory I don’t think Honda fitted a grease nipple on the tube (cost cutting again) so probably worth doing when you put it back together.
The front brake calipers come up often on ebay, I dont know if it was used on another model, I think it was made by Tockio and not the usual Honda Nissin. Are the four rubber boots intact and not split, if they are you can get them in an overhaul kit.
You are making a lot of progress very quickly, it could be on the road by Christmas Day :)
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The kit for the Tokico caliper came with all of the seals/dust seals/bleed nipple Dave. I just intend to use all of the NOS top end parts .... somebody has gone to a lot of trouble and expense to fit everything to the head and rocker cover even a NOS inlet rubber and valve decompressior mechanism. I noticed there were quite a few of the Hondastyle nose fairings for sale on Yahoo Japan .. even a NOS in bag one. Mine had a fairing (not sure what style) but the PO said the screen got broken .. he still has it and said he will dig it out for mebut TBH I probably wont fit the fairing. Thanks again for your kind help with this bike!
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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 :D 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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Fantastic progress Ash👍. I know how the guy feels about wishing he never sold his RSA, been there, done that😐.
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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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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... ;D Same seller sold me a LH bar switch £20 and almost NOS condition gear lever and link bar. £15
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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!
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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!).🙂
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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. ;D 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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Thats very interesting information about painting over PC Ash - another info gem.
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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. :(
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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.
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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.
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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.
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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.
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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.
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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.
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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.
Going to make a jig up initially and use a high accuracy digital inclinometer to check various points. If I detect anything untoward I will cart it off to someone to check out/realign with the correct gear. Or perhaps get another frame.
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The handlebars on my RS were gloss black Ash. I used to think how terrible they looked all scratched where the PO obviously kept other keys on the ignition key and they rattled about on the handlebars taking the paint off! When I restored the bike I had a leather key fob with the ignition key to prevent the same thing happening again.