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SOHC.co.uk Forums => Other Bikes => Topic started by: AshimotoK0 on November 10, 2017, 09:50:38 AM

Title: CX500 engine
Post by: AshimotoK0 on November 10, 2017, 09:50:38 AM
Stripped the heads from my 300 mile only 'shed find' yesterday and the bores absolutely looked fine after a quick clean up and pistons had almost zero carbon on them confirming the mileage yet again. Any advice on what to soak down the sides of the pistons just in case the rings are sticking, as it was stored in a damp shed for over 30-35 years unused ? Thank's Trigg for advice on stripping yesterday. That engine was very 'alien' to me  :D
Title: Re: CX500 engine
Post by: MarkCR750 on November 10, 2017, 10:23:24 AM
I would start with something very thin such as carb cleaner, then WD40 then add diesel and leave to soak.
PS then after soaking heat the piston crowns with a hot air gun and allow to cool a few times, then WD40 again before gently rocking with the bike in gear.
Title: Re: CX500 engine
Post by: AshimotoK0 on November 10, 2017, 10:34:16 AM
I would start with something very thin such as carb cleaner, then WD40 then add diesel and leave to soak.
PS then after soaking heat the piston crowns with a hot air gun and allow to cool a few times, then WD40 again before gently rocking with the bike in gear.

The rings are not seized in the bores ..the engine turns over fine .. just wondering if there is something that will seep into the piston grooves just to make sure everything is free ... I suppose a compression test will confirm but that's a way off as I am still rebuilding the CDi and there is loads of alloy corrosion to remove on the outside. 
Title: Re: CX500 engine
Post by: burchy75 on November 10, 2017, 10:51:53 AM
Interested to see this thread as I have to admit I quite fancy a CX500 at some point along the line.  How much did you pay for yours Ash (if you don't mind me asking) as prices for CX500s can be anything from a couple of hundred quid on eBay to well over a few grand.

Are there any definite things to look out for and check when buying on, other than the usual bike buying bits and pieces? Just thought I'd ask and put the info away somewhere for when (if ever) I decide to get one.

How easy are they to work on as well?
Title: Re: CX500 engine
Post by: AshimotoK0 on November 10, 2017, 11:15:55 AM
Well I kind of got it for 'nowt' as we say in Yorkshire .... the seller didn't even know it existed as it was buried in a rotted out shed and we had already had a 'done deal' on the stuff in his garden / shed  .....long story but see the picture. To be fair if I ever sell it, I will slip him a few quid as he was a lovely bloke ... a few hours later it would all have been skipped by the Council anyway. Actually the mirror was on a 2k mile CB250G5, which I have now sold but the CX500B was next to it totally buried in rotting stuff / junk. Henry Cole eat your heart out  ;D

Resident 'Guru' on CX's is our 'Trigger'... it seems fairly easy to work on although a bit weird compared with 'normal' twins and Honda Fours.

Title: Re: CX500 engine
Post by: burchy75 on November 10, 2017, 11:33:37 AM
That's a find then, it amazes me what people have buried away in sheds and garages.  you hear all sorts of things like thousands of pounds worth of paintings, engineering gear such as lathes etc. be interested to see how your CX comes out, you going for an original resto?
Title: Re: CX500 engine
Post by: AshimotoK0 on November 10, 2017, 12:29:49 PM
That's a find then, it amazes me what people have buried away in sheds and garages.  you hear all sorts of things like thousands of pounds worth of paintings, engineering gear such as lathes etc. be interested to see how your CX comes out, you going for an original resto?
Yes they are still out there ...Not sure what I am doing with it yet .. I offered it for sale to a few people when I got it  but no takers, so I bought some shiny bits from Germany for it and decided to keep it myself for the time being. I can't blame people for not wanting to take it on but so far, so good & no horrors and when it's done, where else are you going to find a 300 miler other than in a museum or the States? Luckily I got the original bill of sale, owners handbook  and old V5 and service book ???? with it   and it's on DVLA register (last taxed in 1982 and it's a 1982 reg'd bike !! ) ... so no registration nightmares. The original fitment  front tyre still has the little sprue mouldings even in the centre of the tread! Not sure how you would go on if you found one of these needing a rebore though ? Trigger will know. I gave the Service Manual to RGP750 as I decided that the Haynes manual I had for it looked a better bet .. that will get fur flying on here for sure   ;D ;D ;D.

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Title: Re: CX500 engine
Post by: Johnwebley on November 11, 2017, 01:28:02 AM
That's a find then, it amazes me what people have buried away in sheds and garages.  you hear all sorts of things like thousands of pounds worth of paintings, engineering gear such as lathes etc. be interested to see how your CX comes out, you going for an original resto?
Yes they are still out there ...Not sure what I am doing with it yet .. I offered it for sale to a few people when I got it  but no takers, so I bought some shiny bits from Germany for it and decided to keep it myself for the time being. I can't blame people for not wanting to take it on but so far, so good & no horrors and when it's done, where else are you going to find a 300 miler other than in a museum or the States? Luckily I got the original bill of sale, owners handbook  and old V5 and service book ???? with it   and it's on DVLA register (last taxed in 1982 and it's a 1982 reg'd bike !! ) ... so no registration nightmares. The original fitment  front tyre still has the little sprue mouldings even in the centre of the tread! Not sure how you would go on if you found one of these needing a rebore though ? Trigger will know. I gave the Service Manual to RGP750 as I decided that the Haynes manual I had for it looked a better bet .. that will get fur flying on here for sure   ;D ;D ;D.

(Attachment Link)
Going back to the freeing point. Try neat diesel

Sent from my SM-G361F using Tapatalk

Title: Re: CX500 engine
Post by: royhall on November 11, 2017, 08:31:56 AM
Ash. Has that Bomber tank that was on the shelf got undented chrome side panels?  If so, do you want to sell one?
Title: Re: CX500 engine
Post by: AshimotoK0 on November 11, 2017, 08:44:25 AM
Ash. Has that Bomber tank that was on the shelf got undented chrome side panels?  If so, do you want to sell one?

The tank on the shelf is the one that's going on my own Bomber ..sorry (panels on it had a couple of minor dings anyway). My Bomber is being made up totally of bits that I found in boxes in that garden. I though the ones on your bike were OK Roy?.. they would definitely re-chrome OK. A guy at Stafford quoted me £75->100 to get them rechromed. You need to strip your bike ASAP and determine what you need. I want to sell off a load of surplus, hoarded Honda stuff to fund my daughters house deposit (she lost her job and has only just recently got fixed up again & whilst she was out of work she had to dip into her house deposit savings) .. that's why you will see stuff on eBay recently being sold by my wife Cathy & myself and the odd NOS stuff on here.
Title: Re: CX500 engine
Post by: royhall on November 11, 2017, 09:53:04 AM
No problem Ash. Yes the panels on mine are useable but one has minor dents. Will get the details of your Stafford chrome offer for them if I can. Was he going to fix the dents in that price? Sorry it's taken me a while to get round to sorting the Bomber, we have had three family bereavements in a short space of time (wifes brother, my sisters husband, my dad, and now one of my best friends has Leukemia). :(  Just to cap off the shit three months my work van died and needed replacing. On a cheerier note, am intending to get the Bomber in the garage and stripped over the Christmas break, so expect a shopping list in the New Year. ;D ;D

Sorry about hijacking the thread, and did I really start with No Problem. :-[
Title: Re: CX500 engine
Post by: Trigger on November 11, 2017, 10:59:33 AM
You got there in the end Ash and now you know why we used to bin those rad cowlings  ;)
Title: Re: CX500 engine
Post by: AshimotoK0 on November 11, 2017, 12:28:25 PM
No problem Ash. Yes the panels on mine are useable but one has minor dents. Will get the details of your Stafford chrome offer for them if I can. Was he going to fix the dents in that price? Sorry it's taken me a while to get round to sorting the Bomber, we have had three family bereavements in a short space of time (wifes brother, my sisters husband, my dad, and now one of my best friends has Leukemia). :(  Just to cap off the shit three months my work van died and needed replacing. On a cheerier note, am intending to get the Bomber in the garage and stripped over the Christmas break, so expect a shopping list in the New Year. ;D ;D

Sorry about hijacking the thread, and did I really start with No Problem. :-[

Oh dear Roy sad to hear that, life can be a bummer sometimes. I think the top end of the guys quote for chroming the side panels  was for very minor repairs. I will probably get mine stripped in Hull (reverse plated in chrome bath), panel beat to get rid of most of ithe dings  and then fill with silver solder then give him them to polish & rechrome. Both guys I use in the Midlands  charge around the same , the one at Stafford was Aaron Walkinshaw in Coventry ..he chromed my CB750K0 front rim earlier this year and made a really nice job of it for £100 (paid him by Bank transfer and that was the total figure). I like him because he does everything including the polishing.  I kept back a decent rear hub for you but I only got one front hub for my bike with the spares. I will be selling a bare tank on eBay but it's no way as good as yours. Don't bid on a K0 oil pump if I list it, as they are crap ..you need a larger capacity one from a later bike (the later ones have alloy body..info thanks to kettle738 on here). I got a later one this week used from Govnor's Bridge for  £24. I could have had the old K0 type complete NOS for £40 last week  but as Mick put it...about as much use NOS  as a rare Dunlop Denovo tyre  :) BTW ..you won't believe this but I get rid of the little tiny  dints by gentle glancing blows with a re-shaped Blue-Bird Toffee hammer .. I watched an old pro doing it ..you tap, tap, tap for ages taking your time....Go on someone ...ridicule me!
Title: Re: CX500 engine
Post by: royhall on November 11, 2017, 01:13:52 PM
Cheers Ash. Managed to get hold of a good used 500 twin oil pump with the larger piston. Hoping I wont need the hubs, will find out fairly soon.

PS. When are we getting our dedicated Bomber section Steve. Did you forget. ;)
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