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Boy have I got a job for Ducatiman,
I inherited a Honda Forman that sat outside un moved for at least 10 years the airbox was completely full of water completely submerging the carb. had to drill a hole in the box to drain it.
I'm pretty sure the carb might need some service. pulled the plug ,no oil in the cylinder have yet to drain the crankcase. I'm sure it full of water.

Might just put the thing back on the pile I found it on.

FOG
 

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Discussion Starter #62 (Edited)
i don't need to tell you, @fog a carb submerged in water for such an extended period is going to suffer from extremely corroded surfaces, both moving and non moving. Yup, sounds like trash.
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And the '73 750 carb project delayed...an accelerator pump diaphragm kit ordered...badly distorted, degraded rubber diaphragm and missing return spring. *Imperative* to renew. Already ordered.

Though this Honda is a '73....I believe these carbs are from a later model '77-'78. Some research reveals parts differences in the bodies and the pump shaft dimensions vary...yup, I'm going with 77-78 carbset swapped over in the distant past.
 

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Discussion Starter #63 (Edited)
finished these fi' hunnerds up today. will be fine runners.

24 hours in and out. Try that at your local shop.
 

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Helicoiled bowl threads. Gasket sealer on bowl seal surfaces. way oversized MIKUNI MAIN JETS (mikuni mains on Keihin carbs...yes, you read that right), undocumented needles, 4 plugged solid pilot jets (these are old press-in type pilots). Cracking float valve viton tips. And more....even more. Somebody was in these long long ago.

These, though old, are tricky in certain respects (extensive mechanical linkages open the slides) . Owner made the right decision sending them...way over his capabilities.

In any event... good progress is underway getting these *47 year old* Keihins from 1973 back to fully functional.
The Honda dirt bikes of my youth used Keihin carbs. IIRC the slide mechanism on those was as simple and direct as you could imagine; a screw on cover with the throttle cable, spring and slide assembly. Push the slide in, screw on the cover. That is, if I'm not remembering through a romanticized memory.

I'd be curious to see some detail pics of those units. I've owned two 4 cyl Hondas , but never touched the carbs. That was in the days before ethanol infused gas.
 

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Discussion Starter #65
Extensive linkage type slides on these, 3 pieces to actuate each slide, return springs, clips, blah blah....a lotta poop. On these, R & R a needle is far beyond 4 screws and pulling a diaphragm/slide like on a EX.

As usual, they are back together, no pics, I get on a roll, concentration mandatory (no errors) and pics are furthest from my mind.
I'll remove a slide cover and a bowl for a pic or 2. While awaiting parts still must synch and fix a boogered bowl thread anyways. Gross overtightening, the standard kneejerk reaction to stopping a leak.... rather than simply replacing the flattened oring/gasket causing the leak to begin with!

PS these old things weigh a ton. The main thing, they'll be runners for the owner. He remarked it started with a shot of start fluid, but of course died. Understandable, were badly in need of service.
 

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Discussion Starter #66 (Edited)
Ancient press in type pilot jets, looka that warped, hardened accel diaphragm!
float and mechanical slide linkage.

This set intended to be functional rather than a work of art resto, especially at the agreed upon price point.
Guaranteed to be a fine runner.
 

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I love those linkage covers.
BTW, I couldn't find the diaphragm in the pics. The closest thing I saw was a piece of old shoe leather in the second pic.
Thanks for taking the time to shoot some photos.
 

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Discussion Starter #68
I love those linkage covers.
BTW, I couldn't find the diaphragm in the pics. The closest thing I saw was a piece of old shoe leather in the second pic.
Thanks for taking the time to shoot some photos.
bingo, 'phragm hard as a rock (but you knew that)
The long shaft length tipped me these are not '73 carbs, but a later vintage '77 or '78 confirmed via some playing around with part numbers and parts book research.
 

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According to my understanding, the floats in the Honda cars of the period could become porous and cause issues. I had it happen to me on a two year old Accord I drove across the country for Auto-Driveaway (points go to anyone who knows who they are). The dealer who fixed it didn't seem surprised and it sounded like it wasn't unusual.

I believe they used Keihin carburetors on those too, so if you have problems with high fuel level when bench testing, they're a potential culprit.
 

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A buddy of mine and I did a drive-away back in '66 or '67 from California to Wisconsin. He wanted to get back to his hometown and I went along to co-drive and to keep him company. The car was a big old Dodge or Plymouth, sucked gas like there was no tomorrow, but at least it didn't develop mechanical issues. I don't remember if it was the same company, but it could have been. The only alternative at the time would have been to load the car on a flatcar and ship it by rail. It was cheaper to drive 'em, even if it was a gas guzzler because those were the days of 25 cent (or less) gas.

I wound up staying in Wisconsin, getting the first job I'd ever had that paid decent money, and enjoyed partying on a grand scale. (Except for the Northern winter, which was brutal.) Madison was a college town with lots of bars, lakes, beaches, and of course, college girls. What a great place and time to be a young guy. It was several years before I finally made it back to Calif. OK, how many points do I get? (And apologies for the thread jack, but it was K-woppa who threw down the challenge!)
 

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LOL! So I did. You win 1000 Internet points.

As a young semi-vagabond, I walked into their Boston office with my girlfriend and asked if they had anything going to the Oregon Coast. They said the only West Coast delivery was LA. I replied "close enough". Two people behind the counter looked at each other, obviously wondering if I would take off to Oregon with the car. Then without a background check, they gave me the contract to sign, the car owner's mother picked us up, took us to her house and we took off to LA in the Honda. Ah, the good old days.

BTW, sorry ducatiman. I figured I should answer, since I started it. I'll watch it from now on.
 

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Discussion Starter #72 (Edited)
Nearing completion on mid 70's Honda 750 carbs...encountered yet another compromised bowl thread (actually on the body of course) ......requiring drilling/tapping using an oversize screw. Of course, years ago someone overtightened to the usual 92 ft/lb in the extreme avoidance of having to replace a crushed, leaking bowl gasket. Heaven forbid replacing a worn $4 part and instead wreck the threads via gross negligence.
Pic of tapping new thread after drilling.....NO mistakes allowed, these old carbs are rare and worth the effort saving.


jfer7.jpg
 

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Quick question, the guy I bought my 1988 ex 500 from had Moxi carb airflow filters on. There's no airbox or filter. He did the delete I believe. I'm trying to figure out the correct diameter specs so I can purchase new carburetor filters. Thinking about going with K&N. The filters on as of now are coming unglued...
 
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fi hunners in the house today, dead floats, major corrosion on float seats, crushed crystalized orings everywhere needing to be pried out, chip by chip. Badly in need of the oft mentioned "consumables".
The bowl screws were grossly overtightened in misguided attempt to prevent the flattened orings from leaking, I'm finding this quite a common occurrence.
The pilot screws still corked with factory plugs...we'll break in, do what we gotta do there too.
In the end, no other major issues besides the usual clogged brass ....predict they''ll return to leak free, fine performing...may even look good while doing so.

eli1.jpg eli2.jpg
 
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