First 1000 km of ownership

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Bill Kemp
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First 1000 km of ownership

Post by Bill Kemp »

Well everyone.

I have ridden the 1980 Honda CBX for 1000 km now. It has been quite a journey.

First of all I want to thank all of the members who have helped me getting the bike into its perfect running condition.

I bought the bike from an estate. I posted an ad looking for a CBX and the executor contacted me and I ended up purchasing the bike.

The bike is all original with the exception of the wheels. The owner had installed Lester rims on the bike and also upgraded to the heavier 630 chain and sprocket set that came with the 1979 model. Unfortunately the original wheels are no where to be found.

The bike when I got it had 8952 km on it. The last time it was ridden by the previous owner was in 1988.

The tank was nasty dirty inside but outside it was lovely. A lot of cleaning to get it into a condition to put gas in.

The stock pipes are really nice by the headers but there is a dime sized hole in the top of each muffler at the end of the exhaust pipe. I wish there was a way to fix this as everything else is great on the pipes.

I pulled the carbs completely apart and did a thorough cleaning and reassembled them. All carbs were taken off the rack and completely taken apart. It has all the original brass parts in the carb except 1 mixture screw that the tip broke off when removing it.

When I did the carbs I also had to tap the pilot jets with a 4-40 tap and remove them. They were completely clogged. On the advice of Bobcat I used a #79 drill bit and drilled out the jets to between a 35 size and a 38 size. Bob advised me that this would make starts easier and also provide a more balanced flow. It starts and runs great. Thanks for that tip Bob.

I rebuilt all the brakes. The master cylinders for the front and rear as well as all calipers were totally cleaned and rebuilt.

The forks were taken apart and fully cleaned out and filled with nice clean brand new fork oil.

I also had measured all valve clearances on the CBX and moved valve shims around and also put in other ones (obtained by Bobcat thanks buddy) so that I was able to get all the valve clearances at .004” intake and .005” exhaust.

I was having a real tough time syncing the carbs as I could not get them balanced very well with my carbtune Pro unit. Previously I had used that on my other bikes and it worked fantastic.

So I decided to try out the Digi Sync digital unit that can do all 6 carbs at once. Well I was able to get all the carbs synced up according to the device but it sounded like crap. All I can say is that this unit did not do what it claims to be able to do.

In the meantime I was trying to figure out why my Carbtune Pro had worked so great in the past and not on my CBX.

WELL I went to the carbtune website and low and behold in the instruction section they stated that the hoses had to be put on a certain way. The hoses have little dampeners about 10 cm from one end of the hose. The area with the dampening ends are to attach near the carb bodies and not near the carbtune device. (I had put the hoses on the wrong way) who would have thought it would make a difference but it was remarkable.

All of a sudden my carbtune pro worked like before and I was back in business. I able to get the CBX in perfect carb sync. It is running so smoothly now. Amazing. When I compared the digi sync readings to the carbtune you can see how far off the carbs were and why it sounded terrible even though the digi sync said it was in perfect order.

See pictures of gauges.

Picture 1: The top picture of the Carbtune Pro is after I synced the carbs

Picture 2: is the Digi Sync that showed that my CBX carbs were in perfect sync but sounded terrible

Picture 3: is when I put the carbtune pro back on the bike (after correcting the hose ends). This shows just how much the digi sync was out. This was for only carbs 1,2,3,4. When I did it on the other side carbs 5,6 were also not correct.

Anyway I just went out for a ride and am amazed at how smooth, powerful, and fast the bike is. It really is amazing that carbureted bikes can be so smooth and powerful. Everyone always wants a fuel injected bike but I have to say that this bike runs great. I suggest that anyone that is having troubles with their bikes not running well do a complete carb cleaning and a proper carb sync.

The members on the forum are amazingly helpful. I cannot thank them enough.

Anyway, I thought I would post about the first 1000 km of joy. My CBX will pass into the 10,000 original km range on the next ride. I am so fortunate to have found an unmolested bike with such low km on it and will try to keep it running perfectly while it is in my possession.

Take care all.

Bill Kemp
Proud owner of a 1980 Honda CBX that runs amazing
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Last edited by Bill Kemp on Fri Aug 19, 2022 9:11 pm, edited 2 times in total.

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NobleHops
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Re: First 1000 km of ownership

Post by NobleHops »

What a fantastic update. Thanks Bill.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

steve murdoch icoa #5322
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Re: First 1000 km of ownership

Post by steve murdoch icoa #5322 »

Congrats, Bill.
All your hard work has paid off.

Bill Kemp
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Re: First 1000 km of ownership

Post by Bill Kemp »

Thanks guys.

I have to admit that I learned a ton from you guys. It was a real pleasure to work on this bike and the best thing is that I did the work myself and gained knowledge along the way.

They are great bikes

daves79x
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Re: First 1000 km of ownership

Post by daves79x »

Congrats on all that Bill! Thanks for the update.

Dave

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Jeff Bennetts
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Re: First 1000 km of ownership

Post by Jeff Bennetts »

Congratulations, enjoy the rest of the summer!

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shiskowd
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Re: First 1000 km of ownership

Post by shiskowd »

I would suggest your digi sync is broken or you didn't let it auto-calibrate prior to turning on the engine. Below is a recent sync, the vacuum signals are always in this range (150-170 mBar) at just under 1,000 RPM (I've sync'd 3 different engines). The instrument is so sensitive it's difficult to get them closer than 5 mBar's.

Great that it's running great now.

Image
2022 KTM 890R, 1982 Pro-Link, 1979 CBX 'Z, 1975 Moto Guzzi 850T
Long Sleeping '79 CBX Restoration > viewtopic.php?f=102&t=11699

Bill Kemp
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Re: First 1000 km of ownership

Post by Bill Kemp »

The bike was at full operating temperature and the digi sync was turned on before starting the bike and it self calibrated itself

Perhaps I got a faulty one off of Amazon Canada. I am not saying that all Digi Sync gauges are bad.

All I know is that it did not work for me like the Carbtune Pro does.

No intent to bash any products out there

Respectfully

Bill Kemp

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Re: First 1000 km of ownership

Post by DiggerZor1 »

Congratulations, Bill. It was very interesting to read your thoughts on motorcycles. I plan to sell my old 1980 Honda CBX soon because it doesn't run as well as it used to. Especially since I recently started visiting this site -- https://zumroad.com/automotive, which publishes automotive news -- and I think I will still buy some new Honda. However, I've always enjoyed riding a bike since I've been doing it since I was a kid. Maybe I will consider buying a new car. Good luck to you, Bill.
Last edited by DiggerZor1 on Sun Sep 18, 2022 2:30 pm, edited 1 time in total.

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bobcat
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Re: First 1000 km of ownership

Post by bobcat »

If you otherwise like the bike, don't give up on it. You will find plenty of help
here to correct how it works ! Just describe how it's not "working as well" !
Bob
82 CBX, 81 CBX, CB1100F, 79/82 CB900F (avatar)

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