southpaw109
southpaw109 New Reader
10/16/10 4:39 p.m.

I got a 1971 Honda CT70 and it was running great till a few months ago and the throttle decided it didn't want to return to idle while I was riding. Now that I have some free time I would like to restore and repair this little buger to its street legal state. So I have come to you guys and maybe gals(?) for your help/ advice/ assistance.

Thanks, Brandon

I took the throttle assembly apart trying to find the reason but I'm not much of a mechanic.

southpaw109
southpaw109 New Reader
10/16/10 4:42 p.m.

The images didn't load properly but follow this link to see the images ----> Trail 70

Woody
Woody SuperDork
10/16/10 7:40 p.m.

I know a little bit about 1971 CT70's. They do not have a throttle return spring. You need to manually return the throttle to the closed position.

http://grassrootsmotorsports.com/forum/grm/71-honda-ct70-mini-trail-vintage-pit-bike-update/1645/page1/#post21137

Photobucket

alex
alex SuperDork
10/16/10 11:28 p.m.

The slide-type throttle in that carb is pretty easy to hang up. I'd vote for a thorough carb cleaning - but make sure to note the positions of all the adjustment screws before you take it apart.

southpaw109
southpaw109 New Reader
10/17/10 3:41 p.m.

Alright, Im pretty sure the carb is well in need of a cleaning and a tune up. Any suggestions on how to properly clean and possibly tune it?

stuart in mn
stuart in mn SuperDork
10/17/10 3:52 p.m.
Woody wrote: I know a little bit about 1971 CT70's. They do not have a throttle return spring. You need to manually return the throttle to the closed position.

I knew a guy when I was in high school who bought one new, and that's right - no return spring. I remember him talking about how he'd ride the thing to the next town 20 miles away without touching the handlebars - just crank it wide open and sit back. :)

Jensenman
Jensenman SuperDork
10/17/10 7:35 p.m.

If it has the 'slide' type of throttle, those things will wear and the 'screw' on the inside of the throttle tube will ride over the slide, causing it to jam. Had a Mini Trail 50 do that to me way back when. The 'slide' is #15 in the (proudly hotlinked!) picture below.

Matt B
Matt B HalfDork
10/17/10 8:13 p.m.

And here I thought we were going to talk about excuses to give cops . . .

southpaw109
southpaw109 New Reader
10/17/10 11:34 p.m.

Well this could be used as an excuse to give to the cop, because its basically twist and let go and she just goes.

I guess I should have been a little more specific, I cant get the bike to throttle down, I've twisted the throttle back to idle position and I have made sure the cable is free to move yet the motor is pegged.

Woody
Woody SuperDork
10/18/10 7:46 a.m.

The general consensus in the CT 70 world is not to bother rebuilding the carb unless you're shooting for a 100 point show bike. Replacement carbs are only about $70 from Dr. ATV. The look a little different, but they work a lot better.

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