Rebuilding carbs, need opinions...

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Sugs
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Rebuilding carbs, need opinions...

#1

Post by Sugs »

So I'm in the process of rebuilding my carbs. What complicates this some is the fact that I have a '79 block with '77 764A carb "bodies". Notice the "quotes". Bike came to me this way, no biggie. When pulling the air and fuel jets for cleaning, I noticed that a few of them didn't seem to match size wise, and all but one(idle #35) of the fuel jets are aftermarket as they don't have the Keihin stamp or jet number. Also, the marked air jets are sized for '79 carb bodies, except for two idle air jets that are sized #110 for the '77. I'm going to try my local Marshalls hardware to find some drill blanks to check sizes on the fuel and air jets, and also the float seat holes as one seems smaller than the rest(I couldn't find any specs on the float seat hole size though).

I'm leaning towards making sure all air and fuel jets and float seats match '79 specs, even though they are '77 carb bodies. What do you guys think?

Also, where to find #130 air jets to replace the incorrect #110's? I've checked siriusconinc.com but they don't list them specifically, just the fuel jets. Some place aftermarket to get these?

I suppose there is a small possibility(I think unlikely) that I have cams and ignition from a '77 but I'm not sure how to tell.

Anything else I should check? Needle differences? I do have the Randakk kit for once it all goes back together.
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Re: Rebuilding carbs, need opinions...

#2

Post by ericheath »

Perhaps you should see which cams are in it. Lots of 78-79 owners put early cams and carbs in them. The 78-79's have a 431 stamped into the side of the cam. Wingovations website has a good pic of them. 75-77's came with no marks. The other item that changed is the 78-79's had a smaller throats and I think smaller intake runners. Needles are different. Randakk has a good description of the differences. Each year is different. As long as you aren't mixing carbs within the same set, they will run pretty close to the same. If it were me, I would go with 77 jetting, because the 77 jetting is set up for 32mm throats. 78-79 jetting is designed for a 31mm throats. Going with a 130 air jet in 77 carbs are apt to make it lean and boggy on take offs. Most guys with 75-77 carbs go down from stock 110 idle air jets to around a 100. (Randakk has specifics for each year- it helps)

A quick glance and they look the same, they're not.
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77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
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Re: Rebuilding carbs, need opinions...

#3

Post by Whiskerfish »

Right here is the chart: https://www.ngwclub.com/forum/viewtopic ... 52&t=43630

I went the other way. I am running a 77 engine with 78 carbs. Took some tinkering to get it right but I am happy with it now.
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Re: Rebuilding carbs, need opinions...

#4

Post by Sugs »

Thanks for the replies guys. Whiskerfish, found that chart you posted with a search a few days ago and printed it, very helpful. Also have Randakk's chart. Just verified the needles this morning and they are also from a '79.

ericheath, you think that 1mm difference in the venturi is enough to warrant the change if I find that I also have '79 cams? Trying to source needles and air jets for a '77 could be a challenge, or I can try to find a complete decent set of '77 carbs that haven't been molested.

As far as the cam mark, couldn't find that picture at Wingovations. Is it visible by just taking the covers off, or do I have to remove the cam?
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Re: Rebuilding carbs, need opinions...

#5

Post by ericheath »

This is better - from Roncar
IMG_1731.PNG
IMG_1731.PNG (578.93 KiB) Viewed 266 times
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
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Sugs
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Re: Rebuilding carbs, need opinions...

#6

Post by Sugs »

Thanks for the picture Eric.

OK, I have confirmed that I also have '79 cams. Both left and right have the 431 stamp.

So only carb bodies are '77. Everything else is '79.
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