collapse

www.cognitomoto.com

www.dimecitycycles.com

https://www.townmoto.com/collections/vanson-leathers


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.lostapostlejewelry.com

www.sparckmoto.com

www.pistonsociety.com

www.steeltowngarage.com


Author Topic: CB250 RS - Project "Phoenix"  (Read 7856 times)

Offline paddyshepherd

  • Posts: 71
CB250 RS - Project "Phoenix"
« on: Feb 12, 2018, 13:08:17 »
Hi I'm Paddy & I'm from the North East, UK.
New member here and a new build too.

I'm currently building an old Honda into either a brat or a cafe racer, probably the latter, but since the base will be the same for both, I'm not stressing too much on it yet.

The base bike is a 1980 CB250 RS - this was the single-cylinder, 4 valve version that they did. I picked the bike up from a guy that works at my local MOT garage. He'd mentioned a few years ago that he had a few bikes that would be ideal for what I'm after. Fast forward a couple of years and I went to his house to have a look. It's been sat since around 2006, outside but with a cover over - so rust wise it's not the best but it's not too bad either. I gave the old bloke 300 and the result was he now only has 36 motorcycles.



First things first, we needed to see if that old engine ran. Quick check of the bores, some oil down them, some fresh fuel, carb cleaned and a battery - to our amazement it started on the 3rd kick! The best part was, it didn't just start but it ran - beautifully. No coughs, no splutters, it just ran.

Knowing that the engine was sound, the strip down began. The bike was completely stripped to a rolling chassis. Many parts will never see the bike again so a pile of bits now needs sorting through as to what's worth selling and what's straight to scrap.

This is the end result:



I decided that the stock 250RS fuel tank was too modern looking for what I was after, so a tank from a CB400/4 was sourced from good old eBay. Apologies, but it's not the best photo, lighting is difficult in our garage!



Next up, I decided that I wanted upside down forks, so I've decided to go with Aprilia RS125 units. After a bit of a cock up on eBay, I ended up winning two auctions, the first for a set of forks, yokes and wheels - the second for a job lot, which includes fairings, frames, swingarms, suspension, wheels and various other spares too. I now have a garage full of Aprilia parts. However, not all bad, as having paid only 58 for the job lot and 66 for the first set of bits, I'll easily be able to make more than my money back which can then go back into the build.

Next on my list is to drop the Aprilia front end in loosely so that I can begin to get an idea of my riding position before cutting the frame - being 6'3" this bit might take a bit of playing around with.

Offline The Limey

  • Posts: 416
  • Evil English Villain
Re: CB250 RS - Project "Phoenix"
« Reply #1 on: Feb 14, 2018, 15:36:26 »
Underatted bikes, and rare now too.  The XL500 motor of then same era is a virtual straight swap, but biazarrely doesn't make the bike much quicker.

I'm liking where this is going with that tank, so I'm in.

Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #2 on: Feb 15, 2018, 09:06:05 »
Underatted bikes, and rare now too.  The XL500 motor of then same era is a virtual straight swap, but biazarrely doesn't make the bike much quicker.

I'm liking where this is going with that tank, so I'm in.

Thanks mate - I've read quite a bit about the 500 swap. The plan is for now to build it back as a 250 but keep an eye out for a 500 to then do up and drop in.

Yesterday evening I dropped the Honda front end out and loosely dropped the aprilia one in, so that I can get a better idea of my riding position.

Before:



After:



(I really must get a remote flash for my camera so that garage photos turn out a lot better lit. Either that or actually fix our lighting system.....)

The front end sits really nice on the bike. It's also shown me that the original passenger peg mounts may work perfectly for my rearset mounts (shame they're pretty ugly looking). Unfortunately having a 34" inseam prevents me from having the pegs very high for ground clearance.
However, now that I know where a comfortable(ish) seating position is for me, I can now start marking the frame for cutting and de-tabbing.

My plan is kinda as follows:
Cut/loop the frame, get rid of any unnecessary tabs.
Weld in an under-seat electronics tray. This will house a slim battery, reg/rec unit, fusebox and any other electrics. Since the bike is kick-start only and will have minimal electrics anyway, I can get away with a tiny battery (I could probably run it batteryless, but I feel that is only asking for trouble).

I then need to make adapters/spacers for my front wheel and swap the stems from the bottom yokes of each front end. This will mean I can just buy off the shelf Honda bearings for the headstock.

I think I am more swaying towards a humped seat. The bike will never carry a passenger anyway (especially as I'd never get the Mrs on a bike!) so the seat options are purely down to styling. A hump will need to be fabricated such that it suits the line of the tank once that is in its final position. I envisage quite a low profile hump.

I think colour-wise I'm swayed towards a silver and metallic purple kind of thing. It'll quite possibly be a two-tone set up on the tank, with a Honda lettered logo bridging the two colours.

This will be a long old project and I don't expect it to see the road at any point in 2018 - early 2019 would be nice.
However - before anything else, I need to sell some of those aprilia parts before the old man kicks me out of his garage!

Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #3 on: Feb 16, 2018, 14:14:50 »
Today I bought an angle grinder so the more serious stuff could commence. We started de-tabbing the frame and cleaning up some of the rear triangle. The rearmost seat mount was left on for now because it's a reference point for where I need the frame cutting at the moment. 




Items like the helmet lock, bodywork mounts and lock stops were removed. A new lock stop will be welded on since the aprilia yokes have the stops at the back, compared to the honda which has them at the front.




Not a massive amount to show, but it's starting to take some shape now. The rear triangle needs the top bars cutting and new ones put in which will run horizontal, rather than running slightly downwards like the current ones do. I have now decided that I will definitely have a seat hump, though it will probably only be very low profile and may be made as a removable cover revealing a brat seat underneath.






Offline Coopacoopacoopa

  • Posts: 72
Re: CB250 RS - Project "Phoenix"
« Reply #4 on: Feb 16, 2018, 15:10:42 »
Great lines to it. That tank just works spot on.

Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #5 on: Feb 17, 2018, 09:28:13 »
Great lines to it. That tank just works spot on.

Thanks mate - appreciate the words and I think so too with the tank. Will be nice to see it painted!

Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #6 on: Feb 18, 2018, 17:51:39 »
Not done a lot today (well, not that was worth photographing!)
I cleaned up a few more tabs and took the swing arm off to cut some stuff off there too. Before I did so I laid a spirit level from the crest of the tank down to the back of the bike. Gives a nice idea of the lines and where my rear hump will go. I've now decided I'll run a battery eliminator instead of a battery, so the hump area should be completely empty - instead it'll be used to house a bit of storage space for whilst out on a ride. It probably won't be lockable so it'll have to be for low value items only. The only way I can see it working with a lock is if I had a hinged bit of metal or something with a swivel lock mounted in it, then the hump padding cut around it. To be honest though I may end up with just a fabric hinge in the seat with some clips so that it folds up against the hump and latches into place - a system I've seen on quite a few builds on Instagram and Pinterest.

I think next up I need to get my frame chopped and the seat loop and electronics tray welded into place. Then I can start mocking up for a hump and for a seat. Whilst the frame is with my fabricator I'll probably start to strip the engine down to replace some oil seals etc. The engine ran a charm so I don't see this being a big task.

I think realistically my biggest challenge will be getting the front end sorted out with bearings, stem replacement and wheel spacers etc. I really cannot wait to get some paint on that tank!


Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #7 on: Feb 19, 2018, 14:41:15 »
Had a quick mock up on paint on what I'm thinking of bodywork wise. Ignore the white bit!


Offline teazer

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 8773
Re: CB250 RS - Project "Phoenix"
« Reply #8 on: Feb 19, 2018, 14:52:29 »
That seat bump looks really small to my eyes.  I would make it longer and taller to better match the lines of the tank.  Then I have to admit that I really like the stock tank on those bikes - so slim and sexy shaped.  But it's your bike so you get to make it look how ever you want.

Offline paddyshepherd

  • Posts: 71
Re: CB250 RS - Project "Phoenix"
« Reply #9 on: Feb 19, 2018, 16:03:30 »
That seat bump looks really small to my eyes.  I would make it longer and taller to better match the lines of the tank.  Then I have to admit that I really like the stock tank on those bikes - so slim and sexy shaped.  But it's your bike so you get to make it look how ever you want.

Due to the length of the tank and the seat (I'm tall so need some shuffle room!), the hump was always going to be small - I don't want any bodywork past the centreline of the rear wheel to keep visual weight to a minimum. If anything it may get slightly taller and steeper. I hated the original tank - not because I actually dislike the shape, but more just because I thought it was too modern for what I was after. The hump I've sketched on follows a "swoop" from the tank, but I may modify the swoop line since it comes off the tank a little early at present. I need to download photoshop so I can do it properly - on paint if I try to erase anything it removes the background too, whereas PS I can do it on layers instead.

But thanks nontheless for your opinion - I do appreciate anything people have to say, regardless of whether or not they agree with me!