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CB72 Carb - Throttle Slide locating Peg Loose

Fuel System: Gas (Petrol) tanks, Carburators
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Phil-UK
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Posts: 229
Joined: Thu Oct 19, 2006 7:04 am
Location: ENGLAND

CB72 Carb - Throttle Slide locating Peg Loose

Post by Phil-UK » Thu Apr 30, 2009 3:29 am

Hi

My CB72 has always had a tendency to hang the slides despite replacing the return springs,
slackening the mounting bolts and making sure the flange is flat. If I snap the throttle open
with the engine stopped I can hear the slides returning to the bottom on both carbs.

So I eventually put them through an ultrasonic cleaner to see if there was any hidden crap
and have now noticed that the "peg" that locates the throttle slide in the carb body is actually
NOT cast into the carb but is a separate piece that pushes in from the side through a slot.
On both carbs this is loose.

Does anyone know :-
1) How far into the carb it should stick out .. is it critical ?
2) How did Honda originally fix them in ... epoxy ?

LM .. any thoughts ?

I'm assuming that because they are loos they could be dragging on the slides and helping
hold them open ...

cheers

Phil

rbaselt
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Posts: 209
Joined: Sat Apr 08, 2006 7:24 pm
Location: Seal Beach, CA

Post by rbaselt » Fri May 01, 2009 6:47 am

Phil,
Never heard of this problem before. Suppose you could try epoxy. They were probably made as an interference fit originally.

Most of the old carbs I've encountered have had sticky slides. I just use fine emery paper with lots of water to polish the slides and remove high spots. Sometimes you need to use the same treatment on the bores. --Randall

cknight
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Joined: Wed Apr 05, 2006 3:55 pm
Location: Daytona Beach, FL

Post by cknight » Fri May 01, 2009 7:05 am

I've encountered this a few times. The tab protrudes about 1.5mm into the slide bore. Just make sure it doesn't bottom out in the groove in the slide. Honda originally used a "glue" to secure the tab. Clean thoroughly, install the tab, then a dab of JB Weld on the outside of the locating boss and the tab (sealing the area to eliminate possible vacuum leaks), and you'll be ready to go. Regards, Chase

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