CB250RS café racer project

[CM2005]

hmmm, lol I'm still thinking about your VFR... dad doesn't want me to have it, but i want to build a "special"

[Bonez]

The 500 obviously has more power. But some prefer the 400, finding its handling better balanced. and the 400 reputedly avoids the cylinder head probems of the 500. But Mr Spankme is the man to ask about GB singles.

Shouldn't be any difference handling wise, as they share the same running gear. The 400s can mix it quite well on tight twisty roads and seem to go a grand less price wise than the 500s.

Specs here- http://www.amy.hi-ho.ne.jp/tachi/eng.../spec_eng.html

[xwhatsit]

Hi Xerxes, looking at the GB400 on tardme, what do you know about those? must be rather gutless compared to the 500 i guess? Its either that or a KLR600..

I really have no idea, mate -- CB250RS represents the bulk of my meagre motorcycling knowledge. I do, however, know a guy who has a beautifully caffeinated version of the 500. Everybody I've talked to or everything I've read has been very positive about the GB400/500; supposed to be very flickable, very good handlers in a `classical' sense (i.e., not knee-down ultra-twitchy like a GSXR, but throwable and nimble and good at roadholding). The engine is also supposed to be a nice torquey lump despite being a modern oversquare single.

Don't think there's a huge difference in power between the 400 and the 500. The 500 is not massively powerful anyway. If you really were upset with the lack of power, throw in a NX650 Dominator engine (bigger version of the same engine), it's been done. Like Bonez said, apart from the engine, there's very little difference between the 400 and 500, apart from they made a version of the 400 with a fairing (MkII).

[avgas]

The 500 obviously has more power. But some prefer the 400, finding its handling better balanced.

I actually found the 400 a better bike, not for the handling, but revy'r engine. What the 500 has in thumper torque the 400 seem to make up in quickness up through the gears.
Overall its pretty much of a muchness. You really have to cover at least a couple of thousand on each bike to make a good comparison.
I found that once the suspension was sorted the 400 was almost the perfect balance of bike.
But in saying that the 500 has the nicer sound the better low down (400 was best above 2.5K)

[xwhatsit]

Well, thanks to El Dopa I now have a whopping big chrome 8" (210mm) headlight -- and hopefully some indicators if he replies to my text I was initially concerned about the 8" headlight until I saw some photos of a black Yamaha four-cylinder café racer that looked fscking awesome. Link will follow presently. Curious look, but it may work.

Oh yeah and I also fitted a speedo (cheers BungBung for the speedo, Buster for the aluminium to make the bracket, and GiJoe1313 for actually making and fitting the things). It looks a bit funny perched up above the square headlight, especially as it's upright, as the speedo cable won't go that tight an angle. However I've been alerted to a company called Robinson's Instruments (or somesuch) who make little speedo cable `adapters' that fit underneath the speedo and let the cable come in on a different angle. Will call them up.

Just now I bought some headlight brackets from Mt Eden ($38.95! Christ!). They fit my spindly little 33mm forks, but they're for 7" headlights, so I may have to bend them to fit, which is not ideal. We'll see. Mark said I could bring them back so long as I didn't tear the packaging to bits lol.

Oh yeah -- on the way back to uni from Mt Eden I saw Big Dave at the lights -- so busy perving at his Trumpy and pissing myself laughing at his suggestion I pull a wheelie off the lights I failed to see the light was green and earned myself a toot from a flash Beemer

EDIT: Here's the Yamaha Seca (?) with the big-bastard headlight on it. http://www.xjbikes.com/Forums/viewto...el=-10000.html

[bimotabob]

Hi

Watch out with those GB type engines, many have exploded!
A few Honda's of that era are not known for lasting reliability.
I had a friend who blew up a GB400 and then his GB500.
Make sure you hear the engine running or at least inspect under the
cam cover.
A lot of it comes down to rider abuse and lack of oil changes.

Cheers
BB

[xwhatsit]

Hi

Watch out with those GB type engines, many have exploded!
A few Honda's of that era are not known for lasting reliability.
I had a friend who blew up a GB400 and then his GB500.
Make sure you hear the engine running or at least inspect under the
cam cover.
A lot of it comes down to rider abuse and lack of oil changes.

Cheers
BB

I think they have a plain-bearing head too like my CB/XR/XL, don't they? So yeah, oil changes very important. If you don't change the oil very regularly you'll end up with a bike that sounds like mine -- `tap tap tap tap'. Although mine was caused by the cam chain jumping off. I'm anal about oil changes.

At least they have an oil filter, unlike mine.

I always thought that apart from that, the XBR/GB lump was very solid. I know it's RFVC, but it's one of the later versions.

[xwhatsit]

Hallo kiddy-winks, check out my shiny pretty thing

I've had all the bits for a wee while, but decided to wait until I got my new forks so I only had to do it once.

The electrics were a fiddly pain in the arse to detach then re-attach. Indicators proved to be a pain in the neck, because the originals used a frame-ground through the headlight bracket, which these ones don't -- two wires, and the headlight brackets are rubber-mounted so no go there. Found a ground I could wire into in the mess inside the headlight.

The 8" headlight and 7" brackets didn't end up being a problem. The Bandit headlight has thick rubber `washers' where it bolts to the brackets, so these just squished down to allow the minor angle to bolt up. Even with the bolts tightened up fully its possible to adjust the height of the headlight, which isn't very good, but I'll sort it out with some spiky washers or something.

It also seems that my little old CB has much more wiring than the Bandit 400 -- I seem to recall the Bandit only had a few plugs to undo. It meant that it was an utter prick of a job to actually put the headlight insert in; the wiring behind it took up too much room. It took a lot of fiddling to get it right, and it's still tight, so I hope nothing is under force.

I'm pleased with the look. With the much cleaner mounting system there's now a large empty space between the speedo and the headlight. I need to work out a better way of mounting the speedo lower and more angled.

Here's some pics. All hail my messy garage.

[tommorth]

did you this out to piha today? saw a grey tank with a big light and clipons

[xwhatsit]

did you this out to piha today? saw a grey tank with a big light and clipons

Yeah I did Who were you? XR250? I saw a few motards blat past, very cool

[xwhatsit]

Attached new speedo. Made use of my boxes of CB250RS junk -- there's a little strip of metal with two threads at either end that attaches the toolkit to the bottom of the battery box. Stole that from my spares, bent it into shape, drilled a hole in the headlight and there we go. Trying to work out where the hell to attach the ignition barrel, until I realised that it was a perfect fit through the top wiring port in the headlight. Was going to glue it in place from the bottom, but the rubber boot for the headlight holds it in place so I might not bother.

As the new speedo is tiny, it uses a different lighting thing than the other speedos; the rubber plug with the bulb in the end is much smaller, and there's only one bulb (an LED, actually) instead of two bulb/plugs each. This meant I couldn't just plug in the old bulbs, and had to find somewhere to get 12V from. Poked around with my multimeter where the old dash lamp loom plugged in, found something suitable, soldered up the connectors. Worked well -- until I got 200m down the road and found that the speedo lighting goes on and off in time with the left indicator. Cracked up laughing inside my helmet. Shame it doesn't do the same with the right -- otherwise I'd have a good indicator idiot light system

Speedo bracket acts as a sort of a spring, and it's only attached in one place, so it bounces slightly over bumps. Might get some of that sticky shit you use to stick things up in your shower (does anybody know what I mean?) to hold it to the top triple clamp or something (there's only a few mm between speedo and top clamp).

Pretty happy.

[tominoz]

G'day xerxesdaphat,
How did you go with removing the battery? Where did you get the info for doing this? How does the headlight go without it? I've been thinking of putting a gel cell in the tail for the lighting to reduce weight etc.

[xwhatsit]

G'day xerxesdaphat,
How did you go with removing the battery? Where did you get the info for doing this? How does the headlight go without it? I've been thinking of putting a gel cell in the tail for the lighting to reduce weight etc.

It's still running very nicely with no battery -- not sure how much information I gave earlier in this thread, but I've got a meaty electrolytic cap in place of the battery. Headlight is fine, no worries there; the only problems are that the horn is pissweak at idle, and if the headlight blows, then all the other bulbs blow in quick succession if you use them. I get around that by carrying a spare headlight bulb and leaving the headlight on all the time. Such a nice thing not having to worry about batteries, going flat, trying to kick the thing back into life with a flat battery isn't fun.

A guy here who runs a few of them reckons he runs his with no battery or capacitor at all -- just the battery terminals joined together. Dunno about that.

[Wobbles]

Hey Xwhatsit,
Any update on how the old RS is getting along?

I just trawled the web and found this post as I've been working on and off for the past 12 years on my RS to make an old school caff racer.
It's always interesting to see what other guys approach their vision.
I've got it to more or less how I want it to be now and if you were interested, I can post up some pictures.....may be useful to compare notes?

Cheers, Hilton.

[xwhatsit]

I'd love to see it mate!

Mine's nowhere near done, I've got the front how I want it (bar the mudguard, need a nice chrome metal one) but I need to do a seat and tail for it. Mostly focused right now on building a new 330cc engine for it, as the poor old girl is coming up for 100,000kms and has run out of steam a bit.

I keep riding the thing instead of working on it -- but then again, I've only been at it for a few years, you've been going for 12!