|
|
Post by birdman on Oct 7, 2019 23:57:32 GMT -5
I just acquired a 1982 (only year it was sold here in USA) Honda Mb5! It's rough but it was all there from what I could see. The kid who sold it to me was more interested in his honda hobbit and wanted to let this go. It was not running, mostly a pile of parts, but he had a title so I gave home the $700 he was asking for. He said it didn't run because it had no spark and needed a cdi (more on that later) but for now here's a couple pics  This is how it looked when I got it  Then before I even got it off the truck I had it looking like this with the help of the box o parts he gave me with the bike. More info coming soon. Stay tuned my friends. |
|
|
|
Post by aeroxbud on Oct 8, 2019 5:10:12 GMT -5
Lot you can do with these. The 80cc head bolts straight on. And if I remember correctly, the H100 bolts in too! Our version had lower handle bars. I think they suited the styling better.  Honda 1980 MB5. bs.07.18 |
|
|
|
Post by oldgeek on Oct 8, 2019 6:01:52 GMT -5
Nice find! I always wanted one of those but dont think it would be very comfortable for a big boy to ride  |
|
|
|
Post by Lucass2T on Oct 8, 2019 6:36:06 GMT -5
Man theres so many parts available for these bikes. You can fit a nsr 6 speed gearbox in there and mb-8 motors are plug and play. Theres are plug n play 125cc big bore kits available from malossi, athena, parmakit etc. Suzuki RM85 reeds fit right away in the mb8 cylinders, need a 1/2 inch spacer tho.
HPI makes inner rotor ignitions and Homoet even makes an exhaust for 50 the and the 125cc motor.
|
|
|
|
Post by birdman on Oct 8, 2019 11:00:04 GMT -5
Man theres so many parts available for these bikes. You can fit a nsr 6 speed gearbox in there and mb-8 motors are plug and play. Theres are plug n play 125cc big bore kits available from malossi, athena, parmakit etc. Suzuki RM85 reeds fit right away in the mb8 cylinders, need a 1/2 inch spacer tho. HPI makes inner rotor ignitions and Homoet even makes an exhaust for 50 the and the 125cc motor. Good info! I heard of the mb8 motor but we don't have that bike here in the states so its hard to find that motor here. I already have a malossi 70cc kit, hi compression head, hpi inner rotor ignition, and mlm pipe from treats. Also, I heard of swapping in a cr80 six speed and clutch assy into the mb5 cases, I haven't heard about the ysr so I will look into that further. |
|
|
|
Post by birdman on Oct 8, 2019 11:24:12 GMT -5
I won't be putting any performance parts on until I get it running as is. The kid who sold it to me was convinced the bike had no spark and the cdi was to blame. Before I tore into the bike a quick Google search revealed that a new cdi may be hard to find... Great.. So to get this thing going first I checked spark.. IT HAS SPARK!! So since it's been sitting for awhile I decided to pull the carb and see how it looks, it was clean as a whistle but I gave it some sprays anyway. The inside of the tank was previously lined and fuel flowed out of the pet cock nice and clean! Tried to kick it over and nothing, so I was scratching my head. I checked compression for shits and giggles, because surely the kid who had it before me wouldn't have let something that obvious stop him. It had 30psi! That just won't do! I pulled the head and the head bolts were loose and no gasket or sealer at all!! The bore looked great still could see cross hatch! So put some moto seal on the head tightened it all down and bam. This thing smoked my garage out in 30 seconds flat.  So the battery was dead I replaced that. Every bulb was blown. I got the tail and brake light working, I put fresh bulbs in the blinkers but they don't work so I have to figure that out. A headlight is on the way from treats along with some other odds n ends like an airbox coupler air filter, and a rectifier I will need once I go to the hpi ignition. I bled the front brake and it works great, the kid put a new master on but didn't bleed it and I feared the worst but that worked out. The speedo/ tach is broken so I will need another one of those, tach drive cable is missing, tires are rotting, rear fender is cracking from sun exposure, I'm sure more will come up but that's what I'm looking at right now. Once I get it running good I will bust this thing down and send the frame tank and fenders to get powder coated to restore this thing to showroom condition. |
|
|
|
Post by Lucass2T on Oct 8, 2019 12:46:51 GMT -5
Man theres so many parts available for these bikes. You can fit a nsr 6 speed gearbox in there and mb-8 motors are plug and play. Theres are plug n play 125cc big bore kits available from malossi, athena, parmakit etc. Suzuki RM85 reeds fit right away in the mb8 cylinders, need a 1/2 inch spacer tho. HPI makes inner rotor ignitions and Homoet even makes an exhaust for 50 the and the 125cc motor. Good info! I heard of the mb8 motor but we don't have that bike here in the states so its hard to find that motor here. I already have a malossi 70cc kit, hi compression head, hpi inner rotor ignition, and mlm pipe from treats. Also, I heard of swapping in a cr80 six speed and clutch assy into the mb5 cases, I haven't heard about the ysr so I will look into that further. You need the early 80´s Elsinore motor. But that only works with the mb8 motor, not the mb5 engines. EDIT: No, it DOES work with the mb5 motor. Making your MB5 faster! I have learned how to make your MB5 faster, without importing European parts, just go down to your local Honda dealer or salvage yard. A Honda 1980-82 CR80 (air cooled) has some parts that bolt on and some that require slight modification 6-speed tranny - The CR80 (80-82) 6-speed tranny will fit right into your MB5 cases, you must use the all the gears, shafts, washers, shift drum, shift forks, etc. Big Clutch - UPDATE The CR80 clutch is a 4 fiber plate/3 metal plate clutch that also bolts in (MB5 has a 3 fiber/2metal plate clutch). From the CR80, you only need to use the outer hub and one more fiber and steel plate, but I highly recommend you replace all the plates as a set. The inner hub, basket, springs, and plates are the same as the MB5. 80cc Cylinder. - The CR80 cylinder can work, but does require a good amount of modification. This modification is only for those mechanically inclined. You use the CR80 cylinder (cyl), base and head gasket, but use the MB5 head. The transfer ports on the MB5 cases are not big enough to accommodate the CR80 cyl., so you have to weld on more aluminum around the side of the cyl mounting on the cases. You would know what I mean if you lay to CR80 base gasket on the MB5 cases. Plus you must weld on aluminum behind the flywheel on the left and above the crankshaft gear on the right. This must be done because when you grind away the material to match the transfer ports of the CR80 cases the area is too thin so you must add material. The best way is to have CR80 cases next to you when you do this mod., so you can match them the best. You must use the CR80 crankshaft/rod assembly because of differences in the rod, don't worry, it is a direct swap. Then use the CR80 cyl studs. You will need to modify the MB5 head for the bigger bore, this will need to be done on a lathe so you can reshape and expand the combustion area, easily done on a lathe. Then, put your motor together and drill a new head stay hole in the frame, this is pretty easy. Use the CR80 reeds, intake and carburetor. You will need a pipe to match the power, either use the stock CR80 pipe, cut, rotate, weld and make it fit, or if you are 2-stroke tuner, make your own pipe for the power you want. Greg, the guy that did this mod said with the CR80 cyl, carb, and a custom pipe said 70 mph, and wheelies in the first 2 gears! - What won't work: The CR80 head won't work, no head mount, you'll need the modified MB5 head. The MB5 cyl studs are too short and base/head gaskets are wrong size, use the CR's. The MB5 crankshaft/rod assembly, must use CR's, it is a easy direct swap The MB5 reeds, intake and carb are different than the CR80, won't work, use the CR's. Stock MB5 pipe won't work, wrong mount, wrong size, wrong power, all wrong for 80cc The CR80 complete motor will NOT bolt directly into the MB5 frame, but you can custom mount it in there, better yet, use a bigger and better motor if you are going to do a swap. If you have more questions, feel free to email me dallas, or even better, email Greg, the man who has done these mods. (his old MB5 with these mods is pictured in the pics section, the one with the Porsche symbol in the background) All info used by permission of Greg M. |
|
|
|
Post by fugaziiv on Oct 8, 2019 12:51:25 GMT -5
I've always wanted an MB5. Way cool.
Matt
|
|
|
|
Post by Lucass2T on Oct 8, 2019 12:54:21 GMT -5
|
|
|
|
Post by geoffh on Oct 8, 2019 15:13:40 GMT -5
Your climate is so good to old vehicles,please start a build thread,it might not be a scoot but I,m sure no one will mind.
Geof
|
|
|
|
Post by milly on Oct 8, 2019 15:38:26 GMT -5
I owned one of these when I still had hair on me head years ago and from memory they suffered big end failure due to not very good lubrication. I am sure someone will chime in who knows them better or there is most likely something on the internet birdman |
|
|
|
Post by Lucass2T on Oct 8, 2019 15:53:06 GMT -5
I owned one of these when I still had hair on me head years ago and from memory they suffered big end failure due to not very good lubrication. I am sure someone will chime in who knows them better or there is most likely something on the internet birdman It wasn't really big end failure but it was crank related tho. The left crank bearing seat had too much room making the bearing sit a little loose in its seat. Over time it would get worse and it would feel like you had a worn out bearing but in reality the whole bearing was loose in its seat. I had a dirtbike shop mill a few mm from the pocket and put a steel ring back in. You can compare it re-sleeving a worn out cylinder. |
|
|
|
Post by ryan_ott on Oct 8, 2019 18:30:46 GMT -5
I’ve always wanted one but whenever they come up for sale around here it’s either way too much or I’ve nothing to spare at the time. Glad to see another 2T saved and getting back on the road.
|
|
|
|
Post by birdman on Oct 8, 2019 21:02:16 GMT -5
Lucass2T I'm already hip to the cr80 and am searching locally for one and ebay for an engine assembly. If I never find one to do the big clutch and six speed swap it's no big deal. I don't want to molest this bike too too bad. I want to be able to put it all back to stock in the event I sell it or take it to a show or something, but if I source another block to work on or an mb8 that will literally drop in all bets are off. Just no cutting or welding on this thing. And hondamb5.com has been a good source of info, shop manual and wiring diagram have been invaluable thus far. If you find an mb8 motor over there and want to sell it to me I have dollars that convert to quid pretty easy from what I hear. Lol you guys get all the cool stuff over there across the pond.
|
|
|
|
Post by birdman on Dec 29, 2019 13:05:01 GMT -5
Made some minor progress and got all the lights working. The headlight I got from treats came with a 35w bulb and it blew out the first time I revved the engine. After I consulted the factory manual and it says the stock lighting circuit puts out 60w so the 35w bulb never stood a chance. I sourced a rare 60w rp10 bulb and it's holding up good so far. Then the flasher was faulty preventing the blinkers from working, after replacing that, all the blinkers are working great except one, the section that retains the bulb on the l/f blinker housing is bent and not making good contact. So a NOS OEM honda blinker is on the way. The air filter was missing as well as the air box coupler so that's sorted, I'm happy to report now that it's running as it should in stock trim. When time allows I'll break it down and send the frame tank and fenders off to get a fresh coat of "helio red" paint (I decided against powder coating)
|
|
