CH80 only 30 mph?

[wood10214]

I Finally got my 85 elite 80 start and run without any problem, but it only reach 30 mph with WOT
Does any one can tell me what should I look for?
The only thing I know is it doesn't has the OEM air filter.
Thank You!

[Mystic]

it should do 45 all day long, maybe the valves are dirty or the belt is worn??

[wood10214]

it should do 45 all day long, maybe the valves are dirty or the belt is worn??

OMG, I just finsh put the new cylinder and piston in this engine, now I need to take off the head again?
the belt do looks OK to me.

[zuphilius]

Belt may look fine but you need to measure the width.

Adjust the valves. This is a big issue in engine performance.

Flat rollers?

[wood10214]

Belt may look fine but you need to measure the width.

Adjust the valves. This is a big issue in engine performance.

Flat rollers?

OK, I'll measure the width of the belt, and check the roller, hope does Not need to take the head off again

[Mystic]

With a new cylinder and piston i wouldnt push it to WOT too much 4 stroke shouldnt be as bad though. You should have decarbonized and adjusted the valves while you were in there always a good idea to at least replace the valve seals when you do a top end, all new gaskets for that matter. it only has what, 2 valves? havent taken one apart so not completely sure.

btw was the piston and cylinder just scarred or did the piston shatter? in my experience when a piston breaks people try to keep starting it and the piston tilts and hits the valves as they open sure hope thats not the case then again if it was the case it probably wouldnt even start

[wood10214]

With a new cylinder and piston i wouldnt push it to WOT too much 4 stroke shouldnt be as bad though. You should have decarbonized and adjusted the valves while you were in there always a good idea to at least replace the valve seals when you do a top end, all new gaskets for that matter. it only has what, 2 valves? havent taken one apart so not completely sure.

yes, it only has 2 valves, I never done this before, that is the reason I only replace what was wrong, never thought of to replace/check what should be done while the head is off.

[Mystic]

not sure but there should be 2 caps on the head that you can take off to adjust the rocker arms. take them off with the motor at top dead center. wiggle the rockers they should have play in them if not turn with a flathead till they a slight wiggle then after you check everything else you may have to take the head off and take the valves out and clean the carbon and reseat, its really easy to do if they arent damage. a little valve compound and an electric drill and replace the valve seals if you have to do all that, maybe not

[wood10214]

not sure but there should be 2 caps on the head that you can take off to adjust the rocker arms. take them off with the motor at top dead center. wiggle the rockers they should have play in them if not turn with a flathead till they a slight wiggle then after you check everything else you may have to take the head off and take the valves out and clean the carbon and reseat, its really easy to do if they arent damage. a little valve compound and an electric drill and replace the valve seals if you have to do all that, maybe not

Thank you for all the info, it mean the rocker arms should have play, ( I remember it doesn't have any play on mine), I'll wait for few days before I do this.
what part do I need the drill? any drilling? to what?

[Mystic]

you can use the drill with a wire brush attachment to clean the carbon from the valves and combustion chamber also before you put the springs back on the valves you can reseat them by putting valve compound around the edge of the valve where it seats and put the valve back in then attach the drill to the end of the valve then you can push it in and out lightly while it spins so the valve compound makes the valve seat. before you put the spring back on check for a bright even ring around the valve where the compound ground in. clean all the compound off before you put everything back together

btw both rocker arms will only have play at Top Dead Center, if not at tdc one rocker will be tight and the other loose, most 4 strokes have a cap you take off on the flywheel side of the engine so you can align timing marks, dont know if the ch80 has an auto decompression but to be on the safe side rotate the tire backwards when aligning the timing mark

[wikked_spree57]

the missing air cleaner could be a culprit. just because it is 4 stroke doesn't mean it don't need to be there haha. you also have to give the fresh engine time to break in, you won't really reach top speed til it does. I've rebuilt lots of 150cc China junkers and customers complain of only 45... duh! lol I tell them to call back in 500 miles and I hear 65ish haha

[wood10214]

the missing air cleaner could be a culprit. just because it is 4 stroke doesn't mean it don't need to be there haha. you also have to give the fresh engine time to break in, you won't really reach top speed til it does. I've rebuilt lots of 150cc China junkers and customers complain of only 45... duh! lol I tell them to call back in 500 miles and I hear 65ish haha

Thank you! my OEM air filter is on its way, for now, I'll take this CH80 to back street ride every night to break in.

Belt may look fine but you need to measure the width.
Adjust the valves. This is a big issue in engine performance.
Flat rollers?

Check the Belt and roller Tomorrow, Thanks.

With a new cylinder and piston i wouldnt push it to WOT too much 4 stroke shouldnt be as bad though. You should have decarbonized and adjusted the valves while you were in there always a good idea to at least replace the valve seals when you do a top end, all new gaskets for that matter. it only has what, 2 valves? havent taken one apart so not completely sure.

I know this should be done at the time I replace the piston, but if this engine can get its top speed back, I'll hold to this, to adjust and clean the valves sounds not too hard to be done, but the "taking apart and put back togetter" was the part it killing me.

[wood10214]

Ok, Found one problem for this slow scooter, the rollers have a flat spot all the way to the metal.
I never buy roller, so, where is the good place for it?
and also, I watch some youtube about change the roller, but I didn't see they pack it with grease,but the one I just took off is pack with grease, is the grease needed?
Thank You for your help!

[Mystic]

I have no idea hahahha never actually worked on a ch80 but i wouldnt think grease is supposed to be in there. clean all the grease off with solvent then do a search for rollers on ebay or call honda

[wood10214]

I have no idea hahahha never actually worked on a ch80 but i wouldnt think grease is supposed to be in there. clean all the grease off with solvent then do a search for rollers on ebay or call honda

Thanks again, the grease may be the problem for the flat roller, hope someone here can comfirm it.
I think bear's honda dealer has the best price for the roller, only thing they ship UPS for every thing, last time it took more than 1 week to get a gaskets, if they send post office, should only take 3-5 days, I'll order from them again, before I order, did the roller has choice or just stock only?