Topic: 1986 Honda MB-5 Project

[333]

If the tires are mounted and holding air, why put tubes in?  Yes, the bikes of the era that this forum is devoted have to make compromises on tires by using tubeless tires with tubes, but when I first started in the M/C business back in the day, there was a case of a tubeless tire and rim, and the owner put a tube in.  It pushed the tire off the bead at speed.

So I would ask why, and refer to my first sentence.

[ColinMc]

Well what i'm worried about, is that the tires do mount and hold air, but i'm not sure these rims are designed for anything at speed like that...isn't there a chance things could go bad once things are moving, especially at higher speeds say in a corner? The original Honda MB5 rims can have normal tires mounted without tubes and they'll hold air, but they most certainly are for tubed tires so I would never risk it.

So in the end, do I go with what they originally used? I know tubeless tires were available in 1986...so why would Honda use tubes in the tires if they didn't need them? So i wouldn't be worried about the tube pushing the tires off the rims, or Honda wouldn't have used them in the first place...

I'm not trying to be argumentative, just genuinely curious...

[bryanj]

Reason 4 not using tubless then was cost as they were a fair bit dearer and the MB5 was a budget bike for youngsters

[333]

It might say somewhere on the rim if it is tubeless or not.  The point of my last post was that it seems to me( and that experience related to me) was saying was that having tubeless tire and rim, and using a tube will increase the chance of the tire being pushed off the rim.

[ColinMc]

Ahhhh ok! I get your meaning now lol. Well i'm gonna go with no tubes for now anyways...I got in touch with a friend in Holland that races MB-5's, and he uses MBX wheels with no tubes on the track all the time with no issues.

Oh and I went nuts today...bought a complete Derbi GPR/Senda motor to put in. Using an 80cc MHR kit on that sucker and a nice pipe...reliable liquid cooled power and 6 speeds here I come! The Senda version has a kick start, so I can use the stock MB5 wiring and everything! Not sure how well the motor will fit without much mods...but it's an easy frame to modify. So we'll see lol. Either way..waiting until I get that before going further with the rearsets and whatnot. For now sorting out the suspension and brakes so support speeds Honda never planned for this little guy.

[Ecosse]

What are your plans for suspension improvements? I know nothing about these things.

When I see your username I thin Colin McRae (RIP)... I still can't believe he's gone.





Or is he? It's you isn't it? It's OK, your secret's safe with me.    

[ColinMc]

I'm going to use a nice set of dual shocks in the rear...not going crazy with money, but new ones from 50cc.nl for now that are 30mm longer than stock. The front end is going to be MBX125 forks, with Sonic Springs internals, MBX front disc and braking system. Not a lot out there for this bike...i'm contemplating adapting a Derbi GPR front end to fit this bike...USD forks, nice braking system...but using the MBX wheels might be troublesome...


Oh and my name is Colin McCarthy...hence the user name, although I do love rally racing, not to mention the Colin McRae rally games for PC. I know, I can't believe he's gone either...amazing driver.

[bryanj]

Colin, check out ebay item 230294356118.

He has several set up and workshop original Honda "blue Book" instructions including MBX 50;MTX 50; MTX125 etc

[SHANWHAN]

I have a swiss mb5 rubbish as standard restricted worse than a british on and 4 speed so only capable of 25mph BUT look at the benifits for a special

mbx80 wheels as standard
down tubes for extra big engine support

heres some easy mods to help you acheive 70 mph+
h100a engine fits straight in {h100s is a #$%* to fit stay away} and use an mb8 exhaust youll get one of these exhausts from europe model never sold in uk
carb use mb8 if you keep engine standard or mbx 125 if tuning and you need the inlet for either to if your gonna mega port use a mbx inlet with a KR1S sideslide carb

serious styling modding try nsr80 parts

ill post some pics of mine once its been sprayed

[pknopp]

 I just picked up a project 1982 MB5 and found this thread. Any further progress here?

[ColinMc]

Thread reborn! Lol, back to work on this along with my CB750. Still trying to get some MBX125 wheel parts and whatnot to make the swap complete. Got a set of forks for an MBX125 anyways...it's coming along. Just a matter of getting parts together. Already did some frame reinforcement and whatnot...so it's coming along anyways...this, my XS500 with a TS400 motor project, and my CB750 project are finally all kinda making progress at once. I'll get pics involved soon. For now i've been trying to sell of parts I don't need from all these projects.

[Ecosse]

Thread reborn!

[ColinMc]

Well should get the MBX125 forks any day now. Got the senda motor and put the MHR80 kit on it, blocked off the oil pump...all that good stuff. But I also put the 70cc Malossi kit on my stock MB5 motor...still on the fence about what motor to use. The H100 conversion is tempting but too much of a pain getting parts...this bike is bad enough as it is lol.

I need the MBX forks so I can get her in rolling chassis to mockup the motor/exhaust/footpegs...before I do any welding of brackets and stuff. A tank/seat decision is going to be made too...I might not go with stock at this point. We'll see how things go though. I have 3 spare tanks one of which is a disaster that I could cut up and see what I come up with. An extra gallon of capacity would be nice.