17th Oct 2009, 07:28

My 1980 C70 Passport has been a headache, I have put new fuel lines from the tank to the carb. Put a new carb and air cleaner on him, but the little bike still has a flat spot. I tried adjusting the idle screw and pilot screw, but nothing works, he idles fine, first gear runs good until under strain, he pops and cracks when you try to give him the fuel quickly, reduce throttle and he comes back and increase throttle slowly and he's OK. Once you get pass that mid range and you're at full throttle, the bike runs great. Can anybody help? Thanks.

25th Oct 2009, 18:40

Hey, guy with the flat spot problem. I do believe is is a spark issue. I have had this happen, and it only took a cleaning of the contacts in the magneto and some wd40 in the spark plug hole, and it fixed it. Maybe even a spark plug. If the wire is touching or cracked, it could jump under lots of acceleration.

8th Apr 2010, 19:16

I have a red 1982 C70 Honda Passport. I have put 8000 miles on the bike. It is all stock with no modifications. Its top speed is 45 on big hills. It seems to run best around 30-35 MPH. I'm happy as a clam going 30 MPH, so the bike is well suited for my attitude.

For regular use, I just use the second and third gear 98 percent of the time. Down shifting into second gear from third when coming to a stop seems like the best way to run the gears. Another trick in the downshift is to shift slow from third into second. First gear will get you up any hill out there, and that's the only time I use it.

I'm really happy with the Passport, because it is very dependable. It does complain a little when I'm riding in 33 F air, and the engine will vapor lock after a quick stop after long runs, but it always restarts.

The only major repair I need to do is install new tires. I can not believe I've almost wore out a set of tires.

I run the high octane gas with Techtron in it from Chevron. The bike runs smooth.

I get lots of interesting reactions from people. The most common one is other bikers who say it was the first motorcycle they had when they started riding.

I have noticed that the more I ride the bike, the better it runs, but that's probably because it's a Honda.

19th Apr 2010, 08:27

I have a 1983 Passport C70 in decent shape. I was wondering what the value of this bike is today??

2nd May 2010, 10:06

The price of your motorcycle depends on what others sold for in the area where you want to sell.

To give you an idea, I bought one of mine in July 2009 for 1200 Canadian dollars in Cambridge Ontario. A 1984 in very good shape.

Early that year I bought a 1983 that needed a lot of cosmetic work, new tires, new leg shield, for 500 Canadian dollars.

Please note that I have spent about 800 additional for all the work done to this one.


4th Jul 2010, 09:01

Just bought 1983 Passport and the blinkers, taillight and brake lights don't work. I replaced the bulbs, but they're still not working. Any suggestions on how to fix?

1st Dec 2010, 02:45

I also encountered that problem. I own a second hand C70, just check the contactor; maybe it is rusty.

9th Jun 2011, 22:26

The C70 does not have a clutch. Maybe your C70 has been modified with a clutch kit, but the fact is the C70 does not have a clutch.

3rd Sep 2011, 07:44

I think you have it backwards, if you go to a larger rear sprocket, your top end would be slower, although you would have more power in the bottom, not faster... think about it.

28th Jan 2012, 02:29

I had a C70 V reg 1980, and it would do the clock down hill 55mph.

17th Feb 2012, 05:12

I'd just like to say I have a Honda C90 1993. It has a race camshaft, a 20mm carb, bigger bore manifolds and exhaust, and I run it on high octane fuel.. I had to change the sprocket set up to the highest top speed I could get. My bike hits 70mph - fact!

18th Feb 2012, 22:42

Check back on my earlier comments, I had 92mph out of mine.

5th Oct 2012, 15:44

The C70 does have a clutch. It has an automatic clutch. Read a repair manual and educate yourself in the mechanics of an engine. This will make your life easier when working on your bike, and also make you realize your mistake when you quote "The C70 does not have a clutch".

10th Dec 2012, 09:48

I was looking a buying a 1982 C-70. Now I know that 70mph is a little much, but I was hoping to get at least a top speed of 55 to 60. I am 6'0 and 200 lbs; is this possible? How much did you spend in total on the additional parts to make your bike do 70mph?

15th Dec 2012, 14:42

No, I think your top speed on a flat will be more like 50 mph at best.

27th Jul 2014, 18:11

I need some help, I'm going nuts. I have a 1986 Honda Cub, it had a Loncin 90cc semi auto, but after many miles it failed. I put on a Loncin 110cc manual, with a PZ19 mm Dekni carb and a standard cub exhaust and air box. I have tried every combination of air filter, gauze, paper, you name it! There are no air leaks. I have also tried every combination of jets from 30 to 40 idle, and 75 to 100 main. The only way I can get it to run without getting lean is to block 2 air filter holes, or whack a 100 main jet in, but it used to do 130 MPG and now does 60. The only thing I can think is exhaust back pressure. Any advice is welcome.

Thanks, Trev.

9th Jul 2016, 19:10


Riding a 1983 C70. No problems with it to this point.

On the way home last night, it suddenly started chugging. At full throttle, it started jerking back and forth and losing acceleration. I couldn't get it to accelerate over 15 mph or so. If I tried slowing down or shifting down to 1st, it would usually stall out and take a while to crank back running. Had some luck opening up the choke and adjusting it as I rode, but only to keep me at the same 12-15 mph speed.

Any ideas on what might be causing the issue, or what I can check?

20th Mar 2019, 19:39

Sounds like a carburetor issue.

28th Sep 2019, 10:32

Likely a dumb question, but can anyone share a video or tip on down shifting a 1981 C70 without it trying to buck you off? It's fine if I roll up to a stop sign and downshift from 3rd, but anytime I try to downshift while rolling, it jerks, bad. I can drive a manual car, but am new to this clutch-less business, I've only had the bike about a week and the "how to" crash course was just a simple "nope, just push the gear pedal and you're good".


3rd Nov 2019, 17:24

For the person who said it was "bucking" when downshifting when rolling - you need to push down on the toe shifter and HOLD it down until you're rolling slow enough to engage 2nd gear (which is going to feel slower than when you were accelerating from 2nd to 3rd, but it is what it is) then let the shifter return to position.

There's nothing you can do about it except to learn your bike.

Because there's no clutch lever, your only control is how long you press that toe shifter down for before you let it back up. Let it back up too fast, and the bike will jerk. Incidentally, you can do a lot in 3rd with this bike; if I'm rolling slow enough (like to a light that changes) I won't bother to downshift; it just takes a little longer to get back to speed.

Hope this helps.

14th May 2021, 12:49

The 1980 Honda C70 does have a clutch... I don't know where you got yours from but... all C70s have clutches... not a manual clutch, but wait for it, an automatic clutch.