'81 Twinstar.... general old carb thread - Motorcycle Forum
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post #1 of 6 (permalink) Old 09-23-2008, 12:01 AM Thread Starter
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'81 Twinstar.... general old carb thread

I scored this bike just y'day with a good bit of horse trading. Basically, I got it for $100 and some hardware I hadn't used for years. It's clean enough, turns over nicely, is fully intact (lights, lenses, guards, pegs etc) and I'm looking forward to having fun with it.

When I brought this home, the throttle wouldn't move. I knew not to force it and instead just take stuff apart.
I've removed the cable and found that though it's dry, it's useable.
In that process of removal, I also took the screw cap off the carb and removed the slide and needle assembly.
The slide is gummy, with some sorta white residue. That gummy texture and the dry cable explained the immovable condition.
I found even the twist grip is dry and stiff. I'll be putting some white lithium grease on that.

So ....
Before reading a forum posting here, I'd been in the market for a rebuild kit. Now, having read that many kits are crap, I guess I'm better off cleaning up what I have (with due care), and go with that.

I've ridden the heck outa some older bikes, but never worked on them much. My point being... I know this carb is simple stuff, just new to me.

Can you folks gimme a rundown? Soak, scrub and reassemble?
It's just a little beginner bike with no headers or anything... I assume whatever the stock jets are, they should be fine?

If anyone is really familiar with the Twinstars... the choke is operated by a cable pull near the speedo and key switch. Can I abandon that cable pull and operate the black plastic choke lever by hand? The choke cable is dry, and the steel twist is more worn and weakened near the carb end. Once i have the refab done, with a free moving arm at the working end, it could last a good while. Opinions? Experience?

Any tips or insights to getting this back together with no surprises? It seem prettys straightforward but it's new territory to me.
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post #2 of 6 (permalink) Old 09-23-2008, 12:15 AM Thread Starter
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and a followup question...
what is that style or model of carb called, so i can refer to it generically?
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post #3 of 6 (permalink) Old 09-23-2008, 12:15 AM Thread Starter
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and a followup question...
what is that style or model of carb called, so i can refer to it generically?
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post #4 of 6 (permalink) Old 09-29-2008, 12:07 AM Thread Starter
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Eureka!! Swapped carbs and it runs...

Pls check my early threads for the prologue ... throttle was frozen, slide gummy. I'd planned to lube the cable and clean up the carb.

A friend referred me to another guy we both know. I went there, carb in hand. I was ready to dive in but this dude has a yard full of "projects" and I knew he'd have words of wisdom.

Long and short, I left with a duplicate carb off a 200cc three wheeler he'd recarbed for a big bore upgrade. He said this came off a running bike, so it should take right off. It looked like an exact duplicate, though the number stamped at the float bowl seam doesn't match.

I'd wondered if the Twinstar choke pull cable could be eliminated. This carb has the same black plastic lever, but it also has a spring detente ball bracketed to it. The choke is operated right there at the carb!!
"Ask and you shall recieve". All that extra hardware and cable are now deleted!!

I took the carb home, and bolted it all up with my original but newly oiled throttle cable. I dumped what I could out of the nearly empty tank and poured a fresh gallon or so into it.
There is an inline filter (nice to find, eh?) and the line on the tank side is large. I had to use a trashbag twist tie to clamp that from leaking at the petcock.
Otherwise the install was a no brainer.

The bike started right up, held an idle and acted like it was just another day. Damn I love Jap bikes!!!

epilogue:
The lights are wacky but that's to be expected, bulbs and old plug connectors.
I don't have a battery yet... I used cables attached to a truck battery to start it.
The electric start only clicked at the solenoid, but it kicked right over so no issue.

I rode it up the street two blocks and back... no registration, no endorsement, no headlight, etc. oh and fading daylight. I didn't push my luck.
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post #5 of 6 (permalink) Old 09-29-2008, 12:19 AM Thread Starter
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the old and new carb /choke

Am trying to attatch two pics to illustrate the differance between the two. This is a handy mod for these bikes.
This is the original, still on the bike. The black plastic choke lever is clear and the cable going to it.

Last edited by rainman97015; 01-19-2009 at 06:52 PM.
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post #6 of 6 (permalink) Old 09-29-2008, 12:21 AM Thread Starter
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pic of the new carb

the detente ball and the simple bracket are clear, as well as the same plastic lever with the empty slot for the cable.

Last edited by rainman97015; 01-19-2009 at 06:52 PM.
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