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CBX 250 Cafe

Discussion in 'Modifications and Projects' started by perko, Jan 7, 2013.

  1. Drove out west on sunday and bought a pair of CBX 250's[​IMG]

    Got home and found that they both run, i had checked they had compression and turned them over out there but the connection with the battery i borrowed wasn't great so we didn't get either of them started before I bought them.

    The red one is missing the front brake master and the white one has a snapped chain master link but otherwise reasonable condition.

    The white one had leaked a bit of oil in the trailer, seemed like it was coming from the airbox, odd...

    So I pulled the filter out and found a huge puddle of oil where the crankcase breather leads into the airbox, getting odder...

    Next step was to pull the dipstick so see how much oil was in the engine itself, unscrewed it and oil came gushing out everywhere so I pulled the sump plug and have left it to drain, I'll have a look at it properly at a later date.

    In the meantime the fairings have come off and ideas are slowly forming, most likely involving keeping the stock front fairing and belly pan and making up a nice cowled single seat, dropping the bars (they're clip ons from the factory so I can hopefully just mount them under the triple rather than above) and making some rearsets (once again the stock controls are already on rose jointed pushrods so I should be able to make new rods and weld the pegs further up the frame)


    If anyone here has owned one and has tips on tuning, mods or just general info that would be great, I'm fairly sure the engine is essentially the same as that in the xr250 but can't find much else about them.
  2. In case you didn't already figure it out the reason why there was so much oil in your air box is cause someone filled the crankcase up to stop it from corroding. That or it badly needs new rings.
  3. ill have a sift thru my hard drives...i think i MAY have tracked down a manual awhile back
  4. didn't think of that, though that would make sense, hopefully it's not the rings, ill have a look at how much oil came out, but that could well be the case

    epic if you have one, had a quick search last night on google and couldn't turn up anything, i shall continue looking anyway

    Todays effort, removed the airbox (forgot about the oil in the bottom until i pulled the breather hose and spilt it all over the floor), the rear wheel and did a quick mock up of a possible idea for the new seat and cowl arrangement


    The bit of board will be the seat and the black outline will be the edge of the cowl, pretty rough but I'm fairly happy with the idea.

    Tomorrows jobs are to get the carb off and possibly start on the front end, going to leave the engine till the weekend when there's someone round to help me juggle things to get it out.
  5. pity you're not in vic
  6. any particular reason or just because it's a nice place?
  7. mate it's a shit place, at least in the city, but if you were in vic I'd come over to give you a hand
  8. Check out dotheton dot com mate, may well be some good technical info over there for the bikes. All I know about them is that they've got a quoted punch of around 30hp up around the 10,000rpm mark - not bad at all for a small single!

    Cheers - boingk
  9. well if you're ever in sydney you're welcome to drop round and have a look

    they do have a bit of a kick, took the other one for a quick burn round the yard last night and it got up and went pretty damn well for a 250, going to be fun once I've taken some weight out of it

    Todays update - everything's now off except the motor, swingarm and front end

    Had a peek in the intake port and everything seems to be nice and clean, probably going to leave everything as it is for the moment, head work is going to be out of the budget for the next little while so it'll just go together with some clean oil for the moment.

    Pulled the carb apart to find that I needn't have bothered, tiny amount of gunk on the front intake but nothing else to worry about so stuck it back together.

    Next job is to decide on a seating position, thinking of moving the pegs back a bit and dropping the bars to under the triple, had a quick squiz on the other bike and I'll lose a tiny bit of steering movement but the turning circle on these is super tight anyway so not too worried about that.

    Rearsets are going to be more of a hassle, the brackets are welded on so I need to grind them off and re weld if I'm going down that route, gearshift is already on a pushrod so getting a longer one there will be fairly simple and there's plenty of adjustment in the brake lever as well.

    Had a mate round yesterday who is a shipwright, tossing up between doing fibreglass or aluminium for the rear cowl, now thinking a slightly square aluminium one will be easier, making moulds for the fibreglass will be a major chore, plus the aluminium will be lighter.

    So my mate came over this evening and was super keen to help out, motor, swingarm and front end are completely gone, only things left on the frame are the pegs and brake switch, time to start prepping the frame for a new coat of paint

  10. Good stuff mate, very nice progress.

    I'd perhaps do a conical section for the rear and cap it front and back with flat ends... like a half cone shape with the pointy top cut off. I've tried fibreglass and it was a total pain.

    Cheers - boingk
  11. oh yeah the white guy...the one your working on i can vouch for being a 88 model for the record...and sincerely - thankyou...as much it would've been nice to see the white guy restored it's still good to see that it's being turned into a actual bike again as opposed to gathering cobwebs - apologies bout the oil overflow you spoke about...i had known about it but it honestly slipped my mind...didn't know about any in the airbox tho....glad to hear other parts of the bike are in better condition and causing you less hassle tho.

    will be aiming to track that manual down later today hopefully i've just been either bogged down with stuff or locked into that goddam say something about the person above thread....

    overall good work mate (Y)
  12. That's what I was originally thinking but with the squarer lines on the rest of the bike plus the fact I want to try and squeeze the battery in there I might go for flat sides with the top curving down, might fit better with the front fairing and the whole 70's racer feel I'm aiming for. Doing the fibreglassing shouldn't be too much of an issue, I have a good mate who is a shipwright and he's really excited about helping make some stuff so I'm not much worried about that.

    thanks for that man, if I have time and funds a restore of the red one might be on the cards, I'm going to use the red tank for the current project so the full white set of externals will be together minus the front fairing which is aftermarket as far as I can tell anyway, looks like a well done fibreglass replica. The oil in the airbox is most likely cause the damn thing almost tipped over just after I picked them up, should have had them on the centre stands from the get go...

    As for progress today, grabbed the bars, top triple and a fork to see if the bars would lock in if I mount them under the triple and they do :).
    Held one up at the same level on the other bike and it seems like the bar controls might just bump the tank at full lock, since it has a huge amount of steering angle already that shouldn't matter too much, might add some meat to the steering stops so stop myself denting the tank but that should be pretty easy.

    A design for the rearsets is starting to come together, should be able to use the stock bracket (slightly modified) to mount them up, means minimal welding and cutting and the ability to easily move them round later on.
  13. Don't forget that you need clearance for your fingers too.
  14. Yeah, good point, jamming fingers on the tank in a stack would really hurt.

    In other news, busted out the angle grinder and chopped off the pillion pegs, airbox/battery box hangers and a couple of other tabs I don't need anymore. My mate did a couple and cut into the frame itself a little on a particularly tricky one so need to get the welder out and fill it up before I clean up the frame.

    Got the welder out today and patched up the hole in the frame today, took a while since the frame was so thin it was tricky not to burn straight through.

    Also degreased and started sanding, should hopefully have it ready for paint tomorrow and can prime and spray when the weather clears up. Finally have a pic of it in the sun, I have a couple from when we were chopping on a hard drive somewhere, might have to have a look for them.

    • Like Like x 1
  15. Nice work...what colour is the frame going to be?

    Also those rims look quite unconventional....I reckon they'd look the part if you decide to polish them.
  16. Quick worker :). Looking good.

    Any particular reason you're leaving the pillion peg hangers there? Its not looking like you'll need them.

    Seen many 80s Hondas?
  17. I'm thinking machinery gray for the frame, not a huge fan of metallic colours on frames but I'm keeping it semi stock looking.

    The exhaust hangs off one of them and it's going to be easier to leave them there as I'm going to re use the main peg mounts and welding with steel this thin is a massive effort.

    Speaking of rims, the design is sort of growing on me, and seeing as I don't currently have the funds to buy new ones I'll probably polish them up and see how they go, later on a set of nice wires might be in order though

    Quite a productive weekend. Since it was raining painting the frame wasn't an option so started cleaning up some other things instead.


    The front fairing all nicely sanded. Will get the bog out and smooth the joins when I am doing the rear cowl/seat.


    The top triple. Going to leave this in straight aluminium, I'm kinda liking the gritty look from the dirt and muck on it, although there are a few scratches.


    And the tank. Decided to use the tank from the red bike since the white one still had the original logos and the paint was in pretty good condition. This was an absolute biatch to clean. Pic is after 3 goes with paint stripper, the rattlecan paint just goes globby instead of peeling off nicely.


    Did a quick sand with the oribital. Pulled most of the paint off the top but the sides proved more difficult. Did a few more coats with the stripper today and then did a final wet sand to get it smooth and ready for primer, didn't take any pics though so they will come later.

    Tomorrow should be a good paint day, try and get the etch primer on at least just to stop it getting rusty and get a coat or 2 on the frame. I'm realising that now it's really time to get things going back together, I need to see stuff on the bike to get the looks sorted for the rest of it.
  18. Damn if you were in melbourne I'd have helped you polish the top triple tree if you wanted...they seriously look the goods that way.
  19. You LIKE polishing?

    Damn, I got some work for you - and I am in Melbourne...

  20. Hahah I actually enjoy doing it believe it or not...seeing something transform into beauty is like awesome.

    Currently I've used up my felt and cotton polishing wheels on the spada, but if you spot me these, I'd be happy to work some parts for you!