Honda Ch80 Please Help

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Honda Ch80 Please Help

Postby rboiar » Fri Jul 11, 2014 9:46 pm

[quote][/quote]I hope I am in the right place and can get some help here :lol:

I bought a Honda CH80 scooter on Craigslist...its a 2000 Elite in very nice shape 502 miles would not start.

Figured it was a dirty carb...thought I had really made out only paying $360.

Turns out I spent about $50 in parts for gaskets and other misc items...still would not start? Bought a compression testor from Harbor Freight...0 psi...no compression at all...yeah, I opened the throttle all the way and had the plug grounded..I even put some oil into the spartk plug hole...nothing!

Any ideas? :roll:


Thanks

~Robert
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Re: Honda Ch80 Please Help

Postby rboiar » Sat Jul 12, 2014 6:46 am

:shock: Took apart the scooter further last night...discovered that the cylinder head looks pretty good. Vavles were filthy from combustion...but did not appear to be leaking when I put some hydrolic fluid on the base where the springs connect. Pretty rough test... Thinking I will have to continue on testing... will test the cylinder head more tommorow. Need to do a few more checks on the head before I go further...It is so nasty right now...will clean with Isopropal... I can't tell whats going on...hopefully someone will reply to this thread today :P
Last edited by rboiar on Wed Jul 16, 2014 1:31 am, edited 1 time in total.
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Re: Honda Ch80 Please Help

Postby Scooterboy45 » Sat Jul 12, 2014 10:24 pm

Just a long shot but smell your oil to see is gas has gotten into the oil. If so, do an oil change. Sometimes a machine will either develop a carb problem which floods the cylinder with gas, or the cyl. will get flooded from multiple failed attempts to start the machine. If this happens, the gas in the oil thins out the oil and you loose compression. Like I said, it is a long shot but smell the oil and hope I am right. Good luck.
Neil in MA.
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Re: Honda Ch80 Please Help

Postby rboiar » Sun Jul 13, 2014 2:54 pm

:lol: It was the intake valve. After soaking the cylinder head in a solvent (isoprpal Alcohol) and scrubbing with scotch brite the valves cleaned up nicely. When I held a flashlight to the valve side and looked in the intake hole lots of light...in fact even without the flashlight I could see daylight on one side. Not to mention the vavle head itself when I first opened it up and turned it over one corner of the valve was clean metal the rest black (like it had been rubbing the piston)

So, my next question would be how do you get the valves back on. I took them off with a 16mm half inch socket...compressed the spring till the cotters fell out.
If I bought an intake vavle how would I get this back together?

Thanks
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Re: Honda Ch80 Please Help

Postby slonaker » Sun Jul 13, 2014 6:58 pm

Here is a link to a manual. Hopefully it is for your bike...

http://www.motorscooterguide.net/Honda/ ... te-80.html

Patrick
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Re: Honda Ch80 Please Help

Postby rboiar » Mon Jul 14, 2014 9:32 pm

Yep that is the manual...However they call for a special tool to remove and install valves...I checked online its about $100...so any other way to get the valves back on? Any good old boy tricks out there. I was thinking about using the 16mm socket with something else inside it and a c-clamp to press down and hold cotters simultainiously 8)
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Re: Honda Ch80 Please Help/ valve back in

Postby gascap » Fri Jul 18, 2014 8:46 pm

Cut a short piece of pipe-say 1 to 2inches long, the size needed to fit onto the valve spring keeper, then cut a big slice out that will allow you to get those little retainers into place. use that c clamp to compress the valve spring and that piece of pipe down carefully enough to get them in. Wear safety glasses doing it Try to do it somewhere clean so if things go pop and parts fly you can find them . Be patient, don't force it.
There is a tool for this, called a valve spring compressor. It's got a split foot that goes over the valve spring keeper, the other end pushes on the valve head.
Was it rust? you had a stuck valve? Good job. Turn the motor over by hand after timing up the cam, in case it's off, that way if it is not right and hits it it can be retimed without damaging the valve.hope this helps.
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Re: Honda Ch80 Please Help

Postby rboiar » Fri Jul 18, 2014 10:00 pm

Awesome Bro!!!! Thank you 8) No it was not rust...seemed like it was banging into the piston ever so slightly...mabe a .002 " Everything else was black as night and one sliver of the intake vavle was bright shiny metal...I held a flashlight up and could see light comign through. I have a new valve assy now...going to install it tommorow.

I really would like to fix the old one up and sell it or keep for spare...I was beginning to think I would not get an answer. I see what you are saying...I think I can fabricate this tool and put the valve on safely. What kind of pipe material would you suggest? Electrical, copper, ???

Wierd thing about the timing...I can not seem to crank the crankshaft all the way around clockwise or counter clockwise...its like the starter is stopping it?

Anyway I wonder if I can get to TDC on both intake and exhaust...and I will definitly check it twice before firing up the engine. One issue I had was the crankshaft was so rusted I had to use some de-ruster to see the mark for T...I am not sure if there are different T makings...one for intake and exhaust? Also how the Camshaft goes back in...according to the manual so that the alignment marks are as shown in a diagram...is there any trick to getting that chain on there at the right timing spot?

Thanks,

Robert
Last edited by rboiar on Fri Jul 18, 2014 10:08 pm, edited 1 time in total.
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Re: Honda Ch80 Please Help

Postby slonaker » Fri Jul 18, 2014 10:07 pm

Some auto parts stores will loan you a generic valve spring tool for free, and they are about $13 at Harbor Freight.

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Re: Honda Ch80 Please Help

Postby gascap » Sat Jul 19, 2014 7:35 am

Use steel water pipe, if you have none a close nipple at lowes is a dollar or so.
Before you spend any money on this, take the time to try to get the crank to go around. Guide the cam chain with a dowel or rod through it, so it doesn't get gobbed up in the cam chain gallery and prevent rotation. Real easy here. You have to find out why it won't go around. I have seen ball bearing and roller type crankshaft bearings rust up and seize, and get rust in them causing the "not all the way around" condition you have.I have a 67 bsa441 now that did that. Rod big end bearing.
How long did this set around? Is the cam chain rusted? Look down the cam chain galley with a flashlight, maybe you can see something. I've seen those chains rust enough they won't go around the sprockets.Sometimes the con rod bearings rust, sometimes the crank outer ones rust. The fact that the crank is rusty enough you can't make out the marks is not a good clue. . I don't want to rain on the parade, but you gotta know why it won't go around next.
What causes internal rust? Every morning that there is dew on the grass, that same principal causes the moisture in the air to condense inside of motors, trans, car and van interiors-everything air touches. That causes rust over time. even switches get corroded inside from it. Salt air may make it worse. That moisture reactivates salt also. I could ramble on forever, but that ain't gonna fix anything. let us know.
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Re: Honda Ch80 Please Help

Postby rboiar » Sat Jul 19, 2014 11:06 pm

:D

It started! Had to adjust the throttle cable a bit...after it started...took it for a spin. Oil light came on after a while...small leak when I got her back in tha garage.

Other than that I am super excieted that it started. I am guessing that the valve issue was causing the flywheel not to spin all the way...I didnt ever force it...The starter was forcing it and banging the intake valve. The whole new cylinder head did the trip fast.

The bike had been siting around for 13 years...in an attached garage. Really the flywheel is the worst spot of rust on the bike. After I set it at TDC I adjusted the valve clearance to .002. Put everything back together and it started right up...had that idle issue at first...its getting better the more I adjust the throttle.

I am going to have to investigate that oil leak.
Thanks for all your help...I am going to work on replacing that intake valve so I can have a backup...will let you know how my fabricated tool works out :P
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Re: Honda Ch80 Please Help

Postby gascap » Sun Jul 20, 2014 8:40 am

Great going. Glad it wasn't rusted up.
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Re: Honda Ch80 Please Help

Postby rboiar » Tue Jul 22, 2014 11:51 pm

Oil leak was on cylinder head...fabricated a gasket using basic gasket materal from auto store...used extra cylinderhead to make impression onto gasket material with oil. Cut out gasket with xacto knife set. Placed the gasket into the scooter tonight...ran it fro about 10 miles...so far... no leaks

Will keep this post updated when I get the intake valve and try to replace with fabricated tool 8)
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