Honda Spree and Elite 50 Forums

I have an MB5 (guess which year) it runs really nice and starts up first kick. but only when the choke is pulled out. I can adjust the rpms with the choke. When its all the way out it will rev all the way up to 11K (when its warmed up) then I can lower the idle down to about 1.5K by pushing the choke almost all the way in. Once I rev it past the idle jet it bogs instantly and dies. carb is cleaned beautifully. Also, the farther I turn the screw in the higher the rpms get. Theres only one screw on this carb and its not the one that moves the slide. I have no clue what size the main jet is but it does look huge. When its cold I can rev it just fine even with the choke pushed in. once it warms up it needs that choke on to stay running. someone please help me get this thing going. I can make a video if its needed.

you have a major air leak somewhere

Damnit I was afraid of that.

I just went back out to try some jets that I forgot I had laying around. I popped a 90 in and fired it back up. Still revs up with choke out. But does run with the choke in. Also when I turn the screw OUT it starts revving the nuts off it. I have it turned almost all the way in and its idling nicely with the choke in. I'm gonna have to agree with Pauly that it must be getting air from somewhere else.

I suspect the pilot circuit... have thought I had my carb cleaned on my 50s - only to find out that I had a blockage in the pilot. Have you pushed compressed air on this circuit?

The choke is holding up the throttle body up to keep it idling in lieu of the pilot circuit. You can chase other things... but I would start on this circuit. It keeps the bike idling.

Ensure your air box is tight (sealed) to the carb and intake too... good luck. The MB5 looks like a cool machine.

No airbox. I'm gonna try and find another Carb.

I've had a lot of trouble running small engines without an airbox. It just gets too lean. I'll bet if you put a finger over part of the air intake you can get it to run well without the choke. It's just too lean, and changing the jets will help above midrange, but at lows revs the pilot jet is just too small.

Just noticed something...

The carb is SUPPOSED to have 2 screws, some * broke the screw off in the carb. so the one that adjusts the slide is screwed all the way in. I wonder if this has anything to do with my problem LOL

Yes... its broke so no harm no foul. Its most likely brass. Get a small drill bit... drill a small hole in the broken part of the screw. Get and easy-out and light tap / hammer it into the hole. Then you should be able to put a wrench on the end of the easy-out turn it counter clockwise. Viola.

You can get a new throat adjustment screw online for cheap (get your carb type / number). Next get mb5 air box... and you will have the unique MB5 working. Or just sell it to me.

http://www.ebay.com/sch/i.html?_trksid= ... &_from=R40

LOL I've been contemplating getting rid of my 1 and a half MB5's.

I know! I just want to ride something that works. Right now I have an SE50 with a bad case/ oil seal, a SB50 with a constant fuel problem, a garelli VIP that won't fire, an MB5 that won't run right, an mb5 parts bike, and a naked se50 with no motor. Its getting frustrating. I even offered a guy both of my scoots just to get my MB5 and garelli on the road. He was all for it but has no way of picking them up. I can't catch a break lol.

How much do the MB5 go for, really? There's one I saw on CL for $1100 with ~4k miles

I've seen so much fluctuation in the prices lately. I've seen them up to your price and all the way down to 400 for a busted one. Al depends on the market and quality I guess. I know most people I talk to about them have no clue what I'm talking about.