Honda-Forums.com
Home » General » Restores, Rebuilds and Tart ups. » Honda CJ250T restoration project (Advice/help)
Honda CJ250T restoration project [message #302460] Mon, 22 June 2020 13:08 Go to next message
Dezza is currently offline  Dezza   United Kingdom
Messages: 4
Registered: June 2020
Karma: 0
(1) Club Racer
Hi All,

I've had an old 70s Honda CJ250T that I adopted about 6 years ago sat in my garage that I'm just getting around to attempting to restore, preferably in a café racer style.

The bike was last taxed in 1980 and was sat in a garage since then before I adopted it approximately 6 years ago and it has sat in my garage since.

So far I've removed the battery that looks like it's knackered with one cell about half full and the rest completely dry, so I'm guessing it'll need replacing and cannot be refurbished.

I pulled the carbs off and they look amazingly clean considering, the fuel tank is empty and no jelly inside so I'm hoping it's recoverable.

The engine won't turn over but I think it's just seized from sitting there so once I get the plugs off I'm gonna try some lubrication and see if that loosens it up ?!?

As you can see from the photo's there's plenty of surface rust and it's certainly seen better days.

It has no registration according to DVLA but as it was given to me by a friend after his Dad passed away the paperwork's been lost so I'll need to register it if I ever get it going.

As far as my mate knows there where no issues with it before his Dad stopped using it, so hopefully with a bit of tlc and some help I can at the least get it running.

I've found a shop manual online and have a limited mechanical knowledge from tinkering with bikes as a kid and have had motorbikes in the last ten years although not right now.

Any advice or directions to any websites etc would be greatly appreciated.

Thanks,

Dezza

/forum/index.php?t=getfile&id=22577&private=0
/forum/index.php?t=getfile&id=22578&private=0
  • Attachment: 1.jpg
    (Size: 31.45KB, Downloaded 224 times)
  • Attachment: 2.jpg
    (Size: 29.95KB, Downloaded 226 times)
Re: Honda CJ250T restoration project [message #302461 is a reply to message #302460] Mon, 22 June 2020 14:34 Go to previous messageGo to next message
Kermit is currently offline  Kermit   United Kingdom
Messages: 24136
Registered: June 2003
Location: Yorkshire
Karma: 44
(22) Giacomo Agostini
Hi Dezza and welcome to honda-forums.....although not just Honda's anymore but the name sticks Laugh

Restoration is one of those things that its difficult to suggest where to start but it depends on how much free time you have and whether you committed to keeping going till its 99% done. My philosophy is one of getting a bike, check it runs, then tear it down into boxes (box for wheel related bits, a box of electrics, a box of engine bits etc) then there's nothing for it but having to start putting it back together BUT only once your happy the part your going to back on the frame/bike is as clean/painted/new as you want it to be. A bench grinder with wire wheel attachment is one tool I now couldn't do without as they're ace for cleaning rust and other shit off rusty parts either pre-cleaning for painting or just to make something rusty like bolts shiney again.

The other essential imo, is replacing as many nuts/bolts with stainless steel bolts/nuts/washer as there not much worse than nice shiny parts on a clean bike bolted back on with the old rusty fastners although I tend to stay away from using stainless steel bolts on critical items like brake calipers, brake disc etc as they don't quite have the tensile strength of the original rusty items....best maybe buy new oem for those or use a wirewheel to clean them up. Stainless M5/M6/M8 bolts, washer and nuts can be had on ebay for not much...perhaps £25 or so if you buy the right lengths/Mx sizes will replace most bolts/nuts/washers on a bike with nice ones that won't fur or rust up.

So that'd be how I'd start after the basics your going to do like getting it running just to check the engine doesn't need an overhaul which is one area I tend to stay away from as breaking an engine = lots more parts and complexity.

Good luck getting it going, then if you decide to go for it, check one of my restoration threads so how I start off with full strip down, then decide if main parts (frame etc) are getting powder coating/sprayed etc, consider spraying some parts yourself and take it from there and of course pics as and when progress is made and ask along the way for any specific help required although in my experience, the stripping down to engine, frame + other component parts tends not to need much help but its good to take pictures along the way of any slightly complex parts (electrical connections, wire/cable routing to refer to later when reassembling
Re: Honda CJ250T restoration project [message #302462 is a reply to message #302461] Tue, 23 June 2020 08:43 Go to previous messageGo to next message
Gearbox is currently offline  Gearbox   United Kingdom
Messages: 5823
Registered: January 2004
Location: Beds (UK)
Karma: 19
(15) Kenny Roberts
Adding to Kermit's comments,
David Silver will be able to supply most of the parts needed.
If you are stripping down, take pleanty of photographs as some bits do not always fit as you would expect.
Doen not look horribly rusty to be honest, so would asume most parts are salvagable. Exhausts, mudguards and fork stanchions may be more difficult to get, Stanchions can be ground and rechromed back to standard diameter.
Take your time, its not as if you need it for work the next day. Enjoy the challenge, they all put up a bit of a fight
Re: Honda CJ250T restoration project [message #302463 is a reply to message #302460] Tue, 23 June 2020 14:06 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
Messages: 8121
Registered: August 2003
Location: Throne of Disgrace
Karma: 45
(19) John Surtees
If I remember correctly those Keihin carburetors have a rubber membrane in them (Honda calls it "vacuum piston or something like that) that will crack with use and age. They generally last about 20 years so if they have never been replaced there's a high chance they need to go and while they are still easily available they are bloody expensive.
Another thing I have learned about carburetors is that even if they look good they generally aren't, especially if they have been left sitting for any time with fuel in them. The good news is these days an ultrasonic cleaner can take care of all the nozzles and jets while you do something else. You can use a tea strainer like this for the jets and other tiny bits: https:// www.ebay.co.uk/itm/Cooking-Seasoning-Filter-Stainless-Steel- Tea-Ball-Mesh-Strainer-Infuser-Tea-E7Q5/202998414817?hash=it em2f43a5fde1:g:eusAAOSwo71ex3kw

If you have a cheap endoscope (about ten bobs on eBay) you can examine the tank with that to see if it's still sound. More than gummy deposits I would worry about rust (pretty common on 70's bikes) and leaks: Honda has always had a few problems with leaky welds.

I think you should really get a manual for it. It will really come in handy down the road, especially when you are setting up the carburetors after rebuild. Your best option is the Clymer manual called Honda 250 & 360 CC Twins 1974-1977, which covers all those now rare "export Honda twins" such as the CJ250T and the CL360.
Re: Honda CJ250T restoration project [message #302464 is a reply to message #302460] Tue, 23 June 2020 16:31 Go to previous messageGo to next message
Dezza is currently offline  Dezza   United Kingdom
Messages: 4
Registered: June 2020
Karma: 0
(1) Club Racer
So I started taking it apart to get a better idea of what's going on under the hood so to speak.

I've removed the seat, tail light, rear storage box, and mud guard, most of which wont go back on if I convert to a café racer.

I also removed the battery compartment and rectifier, carbs, fuel tank and mirrors, so I have some room to work around the bike. I had a good look in the tank in the clear light of day and it does look pretty rusty so will need to do something about that and pressure test it I guess at some point ?

I wanted to get the spark plugs out next which proved to be harder than expected. the left came off with a bit of brute force but the right just wouldn't budge and eventually snapped leaving the thread inside.

So looks like I'll need to try and drill and tap that unless anyone has any better ideas ?!?

So with the gearbox in neutral the wheel spins nicely but if I put it in gear and try and rotate there is no movement apart from the expected slack in the chain. Obviously I cant see the piston head on the right as the plug is still in but on the left its visible and not moving in the slightest, same with the kick start although I'm not jumping up and down on it as I don't want to bend a con rod or do any other damage. Looks like the engine is well and truly seized though.

I'm gonna start just cleaning it up a bit next and I suppose then I'll need to start stripping the engine down to find where the issue lies.

I've never stripped an engine other than when I bored up my Kawasaki AR50 to an 80 as a kid so fairly dubious about it, but nothing to lose. Not sure if I should remove the engine from the frame to do it although the manual I have seems to do it all in situ, any advice ?

Thanks for the encouragement and info, I had already bookmarked David silvers and the manual I have seems to be of a slightly older model and a PDF but looks very comprehensive although a pain to reference as I don't have a pc in my garage and oily hands etc.




/forum/index.php?t=getfile&id=22579&private=0/forum/index.php?t=getfile&id=22580&private=0
  • Attachment: 3.jpg
    (Size: 35.94KB, Downloaded 180 times)
  • Attachment: 4.jpg
    (Size: 34.68KB, Downloaded 183 times)
Re: Honda CJ250T restoration project [message #302467 is a reply to message #302464] Wed, 24 June 2020 08:24 Go to previous messageGo to next message
Gearbox is currently offline  Gearbox   United Kingdom
Messages: 5823
Registered: January 2004
Location: Beds (UK)
Karma: 19
(15) Kenny Roberts
Can get a Honda manual from here. You will probably have to register, but would be worth it
Re: Honda CJ250T restoration project [message #302468 is a reply to message #302460] Wed, 24 June 2020 09:09 Go to previous messageGo to next message
Kakugo is currently offline  Kakugo   Italy
Messages: 8121
Registered: August 2003
Location: Throne of Disgrace
Karma: 45
(19) John Surtees
My advice is if possible to remove the cylinder head and take it to a local machine shop or ship it to one. They probably do a dozen or so classic car/bike heads every year and they have the tooling and expertise to get the thread out without drilling and, if need be, they can drill perfectly straight and insert a Timesert or whatever they use. They tend to have flat tariffs for this sort of thing.
When you are installing the spark plugs once again do yourself a favor and put some liquid graphite on the threads. It's an old trick I have picked from aircraft maintenance to avoid... well, what you are dealing with now.

If you meet frozen bolts try using temperature differentials to your advantage: put an ice pack on the offending part (or a rag filled with crushed ice), then a few minutes of heat gun, repeat and then tap a few times with a rubber mallet. A manual impact driver can help as well. A chemical approach is to use a solution of 80% acetone and 20% ATF (in volume) and let the offending part soak in it overnight. Sawdust and brake cleaner are mandatory as this stuff really does get everywhere.
When reinstalling bolts a dab of ordinary multipurpose grease will make wonders to prevent future seizures. Wink

Now the tank. There are all sorts of products out there that will both re-coat the tank and seal any tiny leaks there may be. Stuff such as this: https:// www.rust.co.uk/product/cat/fuel-ethanol-proof-tank-sealers-1
Mind tank cleaners are generally very caustic stuff so they need to be handled with care.

To be honest with you I have no idea what might have happened to that engine: start by taking the head off and take a look at the valvetrain and pistons/rings. Those 70's Japanese engines could and did indeed seize like two strokes but I have seen at least one valve/piston strike completely seizing an engine.
If you decide to fully take the engine apart know those crankcases are held together with a billion bolts of at least three different lengths (!) so make a note of where they go, use color markers... everything that works. Also the crankshaft is in at least six pieces (plus bearings) so again take notes and keep parts separated.

Now I am off to try and see if my body can still take replacing the shocks on a BMW. I know for sure my wallet is getting tired of it. Laugh
Re: Honda CJ250T restoration project [message #302469 is a reply to message #302467] Wed, 24 June 2020 10:21 Go to previous messageGo to next message
Dezza is currently offline  Dezza   United Kingdom
Messages: 4
Registered: June 2020
Karma: 0
(1) Club Racer
That link sent me to the manual I have so I guess that one will do.

Thanks
Re: Honda CJ250T restoration project [message #302470 is a reply to message #302469] Thu, 25 June 2020 08:24 Go to previous messageGo to next message
Gearbox is currently offline  Gearbox   United Kingdom
Messages: 5823
Registered: January 2004
Location: Beds (UK)
Karma: 19
(15) Kenny Roberts
Rust inside a tank can be removed by electrolysis. Lots of articles on the method. Have a google.
Re: Honda CJ250T restoration project [message #302479 is a reply to message #302460] Mon, 29 June 2020 13:27 Go to previous messageGo to next message
Dezza is currently offline  Dezza   United Kingdom
Messages: 4
Registered: June 2020
Karma: 0
(1) Club Racer
Well what an absolute joy this bike is proving be to dismantle NOT.

It's taken 2 days to get both exhaust joints of the engine using a combination of WD40, a blow torch and brute force, but the exhaust still won't budge as I can't remove the collar from the left side, grrr.

The sump plug is proving to be just as stubborn and has started to round so I'll be putting a nut remover on that soon enough I guess Sad

On the plus side I've managed to remove all the electrics and handlebars etc with little effort.

I will not give up, I will not give up, is my mantra.

/forum/index.php?t=getfile&id=22582&private=0
/forum/index.php?t=getfile&id=22583&private=0
  • Attachment: 6.jpg
    (Size: 52.15KB, Downloaded 133 times)
  • Attachment: 7.jpg
    (Size: 45.75KB, Downloaded 134 times)
Re: Honda CJ250T restoration project [message #302480 is a reply to message #302479] Mon, 29 June 2020 15:57 Go to previous message
Yorkie is currently offline  Yorkie   United Kingdom
Messages: 2583
Registered: August 2003
Location: North Yorkshire
Karma: 13
(8) Moto2 GP Racer
Perseverence will get you there eventually Grin

PS, like the steel toe caps Laugh
Previous Topic: Honda FES 125 S -wing
Next Topic: Cb250 Charging issue. Who can solve the puzzle!?
Goto Forum:
  

[ PDF ]

Current Time: Tue Oct 04 17:12:57 BST 2022

Total time taken to generate the page: 0.03028 seconds