honda bike mod

April 27, 2009 4:08 PM

So I picked up a 1981 honda cm400 custom and I love it so much - but Im ready to start altering it. have a few questions about finding parts.

[I realize there are motorcycle forums which might be more suited to these sorts of questions, but i already have an account @ mefi and would like to avoid a useless sign up if i can.]

I don't have access or the money for custom fabricated parts and I can't find many aftermarket parts *specifically* for this bike so Im wondering which would be compatible.

say the first thing id like to replace is the seat, tank and bars.

is there a CB model that id could look for which would fit my bike? I see TONS of CB parts. I was told the CB550 would probably work, but I would want to be sure before i start placing orders.

say I got all crazy and wanted to put an entirely new engine on the frame, how large could I go?

suggestions or general comments on modifying these sorts of bikes are welcome.

posted by nihlton to sports, hobbies, & recreation (5 comments total)

Nothing not CB/CM400 will 100% fit.

However; with an angle grinder and a welder anything is possible.

Simple.
posted by BadMiker at 5:30 PM on April 27

Yes, you're unlikely to find 100& compatibility outside parts made for the bike model itself. Handlebars in particular, though, are fairly universal, whether you go with uprights or clipons.
If you got all crazy and switched the engine, you might find that your registration authority might get a bit crazy on you in return---I'd check your local rules about vehicle licencing first. In any case with a bike that old, a well-running engine is something to cherish.
posted by Fiasco da Gama at 6:24 PM on April 27

Thirding the above answers. I've been a Honda parts guy for too many years, and I can say that only CB/CM parts will bolt straight on.

I've never seen model specific accessories for your bike, although there are a ton of generic aftermarket bits about, indicators, handlebars (make sure you get the correct diameter, Harleys and late model Jap cruisers use larger tube), headlights etc. I doubt you would find a tank/seat that would bolt straight on without modification.

An engine swap, well I'd steer clear of that. A lot of work fabricating engine mounts, aligning engine/wheel sprockets plus most likely grief from DMV over mismatched engine/frame numbers.

Also, if you think about modifying the original engine for more power, your getting into painful territory. These bike run best standard.
posted by Duke999R at 6:48 PM on April 27

Some interesting links from a blogger who seems to be a fan of the idea.
posted by GeckoDundee at 3:12 AM on April 28

Things you can easily do:-
Seat- Corbin are one of the big aftermarket seat manufacturers, they might make something bolt on-able. Actually, modding your seat is very easy; the seat cover is just stappled onto the underside of the plastic seat base. You can take it off, cut the foam and stretch a new sheet of vinyl over it. Probably best using a spare base for your first try; you'll be suprised how much a little change to the seat changes the feel of the bike!

Tank. Except for re-spraying it, dont bother. It fits to the frame, and to the seat, and there's the fuel tap to think about and, and. Unless you have a welder, grinder, garage, time etc it's best left alone.

Bars; seconding Duke99R (not a Honda man now from the sound of things?!). You can get a huge range of different bars. Make sure
-the new handlebar position wont hit the tank on full lock
-the cables will still reach
-you have good circulation (having your hands up in the air, holding onto vibrating bars does give you white-finger.

I dont know what the score is in the states (I presume you are American) but in the UK you can get the M&P catalogue which is a couple of hundred pages of all sorts of replacement parts, quality accessories, performance parts and tassled shit.

CM/CB400 is a great motor. Reponds well to a pair of cone filters, a dynojet kit and a fruitier exhaust. Absolutely bulletproof if you keep on top of oil changes.
posted by BadMiker at 5:00 AM on April 28 [1 favorite]