Author Topic: 1986 Honda MB-5 Project (Read 19861 times)

ColinMc · « **on:** September 23, 2008, 01:22:55 PM »

Well, I know this thread is useless without pics, but I have one of the bike before I brought it back from Holland with me. I'm tearing it back apart again and going nuts. I miss my Derbi GPR50R and this is gonna fill that void lol.

I'll take pics of it's current state tonight along with all the other stuff I have to get pics of for the forum lol. It's my "in between" project. The thing I work on when i'm waiting on parts for the CB750K6 project heh.

I have a Malossi 70cc big bore kit and head. Jolly Moto pipe...still have to get a good carb and reeds. I have a chrome aluminum dutch hand made swingarm, Honda MBX wheels...and a few other goodies.

scunny · « **Reply #1 on:** September 23, 2008, 01:25:44 PM »

nice wee bikes, good for bucket racing

ColinMc · « **Reply #2 on:** September 23, 2008, 01:32:20 PM »

Actually the plan is just for a fun back roads bike, i'm going to modified the crap out of it, but the bottom end is gonna get upgraded too. Ditching the oil pump and running premix...all that good stuff. The plan is a fun street legal bike that won't ever go near a highway but still rips it up under 60mph lol.

Gregorymoto · « **Reply #3 on:** September 23, 2008, 02:23:28 PM »

Funny man, my dad had one he took to the track when he was racing and used it to get around the pits. I was a kid and I soooo wanted it.
Good luck

bryanj · « **Reply #4 on:** September 23, 2008, 04:26:24 PM »

WHOA there, not sure if premix is a good idea as those little swines had mega trouble with the mains in standard form and there were many bulletins from Honda about how to rebuild bottom ends and several special tools, one of which was a generator casing with what looked like an electric kettle element attached to heat the casing and remove bearing "Preload"

ColinMc · « **Reply #5 on:** September 23, 2008, 05:22:50 PM »

I had a different one in holland that I ran premix after the oil pump went with no problems...I won't be using the stock carb. The stock carb is what causes the issue with running premix since most people don't use a larger main to compensate for less fuel and less oil than would normally be injected. I'm going to be running a Keihin Flatslide racing carb I have left over from a Derbi GPR I used to own so it's a non issue.

Main point being, nothing on this bike is gonna be stock, it's going to be a complete motor build up to both compensate for the crapload more power, and the lack of an injection system.

Here's the frame after being blasted and primered for now since i'll be welding on some rearset brackets and other fun stuff:

The fancy shmancy Dutch hand made chrome reinforced swingarm:

Oh and my spare 2k mile donor motor that will be the candidate for mucho mods:

I have a bunch more goodies including all the hop up parts but I just took quick pics of this stuff...

ColinMc · « **Reply #6 on:** September 23, 2008, 07:30:27 PM »

Ok here's a question for my friends across the pond...I have wheels from a 1986 Honda MBX125 i'm going to be using on this bike. They are aluminum wheels, no where is it marked "tubed" or "tubeless". I mounted a set of new Pirelli Sport demons and they hold air fine with no tubes...but i'm worried things could go bad quickly. If anyone could find out whether the MBX125 had tubed tires from the factory or not please let me know. I got the wheels from the UK and they had tubes in the tires that came on them, but they were tires that were made to use tubes...

So all in all I either need to know if a 1986 honda mbx125 needs tubes, or if there is an easy way to tell what wheels can take what kind of tires?

Here's a pic of the back wheel so you can see the style...and that it's holding the pirelli sport demon with full pressure no problem....

bert96 · « **Reply #7 on:** September 24, 2008, 02:47:41 AM »

I thought they only made the MB5 between 1980 and '82?

I had a '82.

ColinMc · « **Reply #8 on:** September 24, 2008, 04:30:22 AM »

In Europe they made it for much longer and I brought this one back with me from Holland. They also made an MBX50, an MT50, MB80, MBX80, and an MBX125.

bryanj · « **Reply #9 on:** September 24, 2008, 08:48:55 AM »

A lot of that was for the UK market where you can ride a "moped" at 16 and a moped now is less than 50cc and not capable of exceeding 30 mph, whilst a 17 year old (and older) who is a "learner" is restricted to a 125cc max which has a restricted power to weight ratio of something i cant remember, usually done by restricting the exhaust, strangling the carb and sometimes timing mods

ColinMc · « **Reply #10 on:** September 24, 2008, 09:56:23 AM »

Yeah when I lived in Holland 50cc and under was for 16-18 and you couldn't drive a car until 18. Also at 18 you could take a test to bump up to 125's and then 250's...I could be slightly mistaken about that.

My Malaguti Phantom F12 50lc I had was limited to 50KMH I think it was but of course the first thing you do is take the restrictors out. The MB8 and MBX50 as well as their dirt bike variants were also available in Holland, not sure about the MBX125 though.

bert96 · « **Reply #11 on:** September 24, 2008, 10:21:20 AM »

Check this site,

http://www.mb5.co.uk/index.html

ColinMc · « **Reply #12 on:** September 24, 2008, 10:29:08 AM »

Thanks, I e-mailed him and a few people from some Dutch sites I still had bookmarked from High School lol. For now just trying to figure out the tube or no tube in the tires mystery lol. My dutch is still pretty good so being able to get info from those sites is great.

Ecosse · « **Reply #13 on:** September 24, 2008, 10:57:19 AM »

I'm watching this one.

bert96 · « **Reply #14 on:** September 24, 2008, 11:46:42 AM »

Quote from: ColinMc on September 24, 2008, 10:29:08 AM

Thanks, I e-mailed him and a few people from some Dutch sites I still had bookmarked from High School lol. For now just trying to figure out the tube or no tube in the tires mystery lol. My dutch is still pretty good so being able to get info from those sites is great.

I'm not sure but,just by the look of these wheels, i think they are tubeless.

rachet · « **Reply #15 on:** September 24, 2008, 12:59:57 PM »

Quote from: Ecosse on September 24, 2008, 10:57:19 AM

I'm watching this one.

+1

ColinMc · « **Reply #16 on:** September 24, 2008, 01:35:27 PM »

Lol, well i'm gonna do mockup tonight to see where the new footpeg brackets can go. I have a spare set from a FZ750 i'm gonna see if I can make work. I'll see if I can get some pics...and some other measurements for other stuff. Trying to make headway on a few things at once with a tight work schedule and classes doesn't work out so well.

I have new straight rate springs coming from Sonic Springs, new rear shocks coming from 50cc.nl that are longer than stock, and some other goodies. I have an original seat in great shape I could use...or an extra junk seat I might modify to look cooler lol.

333 · « **Reply #17 on:** September 24, 2008, 07:45:49 PM »

Story- I'm at the Vintage Japanese Motorcycle Show at The White Rose M/C club in Hanover PA about 5-6 years ago. 2 of our group were very competitive and both had MB5s. We were on the road, going to breakfast in a nearby town when they both took the lead of the pack. One of them was in a full "Rollie Free"(except not striped down), and when he passed me, he reached down with his left hand and shifted!

ColinMc · « **Reply #18 on:** September 25, 2008, 06:00:42 AM »

Lol, yeah wind is your enemy on a small two stroke. All 6'2" of me would go into full tuck mode on my Derbi GPR no matter how uncomfortable and id' get an extra 5mph on a looooong straightaway...

Anyways, so the e-mails I've gotten back from people are mixed. No one seems to remember if the MBX came with tubes in the tires from the factory. Most people that have new tires put on the shop puts tubes in anyways, then the next shop sees the tubes and puts tubes in again...but i'm stumped, there HAS to be some way to tell these are gonna be safe without tubes short of me driving down the road and seeing what happens. The tires mount fine and the beads popped into place, and they are still holding air fine. Bah...i might just go with tubes anyways just in case, but it'd be nice to not have them and know for sure it's ok lol.

bryanj · « **Reply #19 on:** September 25, 2008, 09:13:30 AM »

Try finding a parts list and see if it lists tubes

ColinMc · « **Reply #20 on:** September 25, 2008, 09:51:02 AM »

Good call, just e-mailed David Silver Spares

ColinMc · « **Reply #21 on:** September 26, 2008, 01:57:45 PM »

Well according to David Silver Spares, they need tubes $:-\$ that means the tires are coming back off and tubes are going back in...blah!

DarkRider · « **Reply #22 on:** September 26, 2008, 02:20:54 PM »

Better to be safe then to be sorry with things like tires..

rbmgf7 · « **Reply #23 on:** September 26, 2008, 02:38:32 PM »

lol, i just saw one of these in a campus lot today. said right there, Honda MB-5. looked real good except looks like someone dropped it on the muffler.

i'm starting to love the diversity of bikes I'm seeing on campus this year. I've already seen a CB500 and CB350. There's a nice older Suzuki one lunger, twin, and Kawa KZ CSR1000 that've floated around the past couple years.

ColinMc · « **Reply #24 on:** September 27, 2008, 08:18:22 AM »

Quote from: DarkRider on September 26, 2008, 02:20:54 PM

Better to be safe then to be sorry with things like tires..

Yup, just a pain because I got the tires all mounted and everything lol. Oh well, for first set backs this is minor compared to some other projects i've had. I have everything mocked up in the basement, next week i'm going to make some brackets to weld on to mount some FZ750 rearsets, they should fit and won't look too weird on there. Next step after that is the motor buildup, I think I have everything I need before I get started but i'm going to inventory the couple totes of stuff I have full that are labeled MB-5. Ever since my first car project where I didn't do a good job labeling or storing things I learned my lesson, plastic totes, ziploc bags, a sharpie marker, and a digital camera are you best friend for EVERYTHING!

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Author Topic: 1986 Honda MB-5 Project (Read 19861 times)