1982 Honda Magna - pumps fuel into the air box! HELP!

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rknm
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1982 Honda Magna - pumps fuel into the air box! HELP!

#1 Unread post by rknm » Fri Jul 07, 2006 12:18 am

Hi. Well, I bought a basket case from a fellow...1982 Honda Magna, V45! Love these bikes!

Maybe should have left it there! Anyway, he TRIED to clean the carbs... Screwed up and forgot to re-install some parts.. So, I spent $100 for NEW parts... He ALSO thought that EVERY contact point in the carbs needed BLUE SILICONE! ARRGGHHH Hours cleaning and replacing O-Rings... So, hours later, after wiggling the carb rack back in there... Connected EVERYTHING UP.... VA ROOM! It starts! Runs OK... Then it starts to flood some... Then REAL bad... Smokes, not bad, but excessive exhaust...

I lift up the tank, look in the air box. There is a GOLD shield in the bottom of the air box, which covers, what APPEARS to be 2 overflows from the CARB RACK... Well, the UPPER is just POURING GAS into the airbox! I removed the Gold thing, and see 2 little rubber ports... I start it again, and the UPPER is Shooting a STREAM of GAS!!! The lower port is NOT... I shut the fuel valve OFF and the stream quits...

[b]ANY IDEAS WHY the UPPER set of carbs seem to be causing a STREAM of FUEL into the airbox! [/b]

Everthing seems to be connected correctly.. I checked on-line resources and microfische and NO LUCK, NO CLUES!

[b]HELP!!![/b]

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TechTMW
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#2 Unread post by TechTMW » Fri Jul 07, 2006 2:41 am

I am NOT familiar with the Magna carb setup.

That out of the way, it SOUNDS like the two hoses from the carbs to the airbox are for the equalization of pressure in the float boals. They are just supposed to be a vent basically. What's probably happening is that one of your needle valves is faulty and allowing fuel to continuously stream into the float bowl, which is in turn coming out the vent.

Course, anyone who knows more about Magnas might have a better guess :wink:
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#3 Unread post by xsyamahadg » Fri Jul 07, 2006 5:58 am

TechTMH is on the right track. I would check the carb float setting, it might be set too high and not shutting off the needle valve when the float bowl is full. If you have a shop manual, it will tell you how to set the float to factory specs. If the bike has been messed with as you described, the float itself might have a hole in it, check to see if there is any gas inside of the float. Also, some floats will stick at the little axel where the float rides up and down, make sure the float works up and down freely on the axel. I would concentrate my efforts on the float and needle valve before looking anywhere else. XS
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#4 Unread post by rknm » Wed Jul 19, 2006 10:17 pm

Well, you fellows were RIGHT ON. Turns out is was NOT a faulty part, it was a FAULTY person who INSTALLED the needle valve/float assembly before I got it!

I could not beleive I missed it! It LOOKED like it was in the correct position, but once I removed the carb assembly, AGAIN... INSPECTED things MORE closely and pulled the float, I discovered the previous assembly error by the former owner. NEVER PUT THE NEEDLE VALVE IN THE SEAT!!! I corrected it and VA-ROOM! RUNS GREAT! 85 MPH, 3RD GEAR and not near RED LINE YET, 3 more gears to go!

Bike is scarey fast! Runs AWESOME!

Thanks for the tips! You were both right... There was an error in the carb bank and that caused the flooding issue. Was an EASY FIX, once discovered...

This site is AWESOME! Thanks for the help!

Lesson here: Unless you know what you are doing, don't tear apart things you don't know how to fix. It makes it harder for those of us that DO have general motorcycle knowledge fix it right the FIRST TIME.

:D

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#5 Unread post by xsyamahadg » Thu Jul 20, 2006 6:03 am

rknm, you are right, the early V45s were fast, I owned a 1983. Keep in mind, they are a good bike, but not noted for their abilities in the twisties, they are designed for high speed running, but not for the swervies. Also, oil is cheap maintainence, on that bike, change the oil often....like 1200 miles or so. Enjoy the Magna !! XS
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Re: 1982 Honda Magna - pumps fuel into the air box! HELP!

#6 Unread post by Madmak93 » Sat Apr 06, 2019 4:11 pm

I had the same issue but my bike was fine when I parked it in the fall. I didn’t licence it last year but I put a lot of miles on it the year before. I would start it every few months last year and ran it for a long time each time.
I took a screwdriver and tapped the carbs with the engine off and it stopped streaming gas but it wouldn’t idle properly. It’s not quite riding season here in northern Alberta and it’s only a few degrees above freezing. When I tried to start it again the streaming gas was back.
Not looking forward to taking those carbs off. Think I’ll wait for some warmer weather. Not sure if I should get a carb kit and do the rebuild while I’m at it. It ran so good before this issue and I don’t want to screw it up if I don’t have too.

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