Oh dear..... CT110 seized, running but not healthy

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RangaBlitzFanga

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Wide open throttle @ about 85kph downhill. Rear wheel locked up and freed about 3 times (with some very bad noises) until I came to a stop. I was expecting it to be solid but it did kick over (very little compression) and after a few goes it fired up. Doesn't sound good though, very tap tap tap'y like valves are way out of spec. Limped it home

After getting it home and slowly pushing it through the stroke there is compression and no strange noises, Bottom end seems fine and shifts ok

Good idea to take the head off I presume? I've never done it before so would appreciate a tear-down guide

edit: as it's cooling down its getting MORE compression. It's now got more than it ever has, it's a little hard to turn over on the compression stroke barefoot
 
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RangaBlitzFanga said:
Wide open throttle @ about 85kph downhill. Rear wheel locked up and freed about 3 times (with some very bad noises) until I came to a stop. I was expecting it to be solid but it did kick over (very little compression) and after a few goes it fired up. Doesn't sound good though, very tap tap tap'y like valves are way out of spec. Limped it home

After getting it home and slowly pushing it through the stroke there is compression and no strange noises, Bottom end seems fine and shifts ok

Good idea to take the head off I presume? I've never done it before so would appreciate a tear-down guide
Click to expand...

you probably wont need a guide once you get a roll on but okay
1. take carby and exhaust off (just off the header of cause)

2. on the left side of your head there will be a magneto or a points (like a disy on your car) go ahead and take the cover off and assume the next steps to get the magneto and whatnot off untill you can see the cam gear

3. To de-tension the cam chain there will be a bolt/nut on your bottom end on the left side of the bottom case (no.... not the oil drain lol) but you have prolly mistaken it for a oil drain once or twice look out its spring loaded a bit (may also drip a little oil but only a bit so a rag might do instead of putting a drain bowl under there

4. flick the chain off the cam gear (work your fingers around as because it should be loose now)

5. undo the four nuts on the top of your head on a x pattern remembering where the copper washer is.. if there are any more bolts to the cylinder then un do them (you will probably need a open ender for that)

6. Pull the head off and hope that you dont have to catch broken bits lol and then you will want to pull the cylinder off that should be one or two more bolts alike the extra bolt on the head
 
It may have more compression if a valve stem seal or if the head gasket is damaged allowing oil in the combustion chamber, even if the rings have allowed oil past the piston, what sort of tension does the cam chain have if you pull the cam cover off?
 
Since you have not pulled a head off before i guess i should include what you should look for once the head is off..
naturally any damage to the valves and head and the piston (likley if you over revved the lil thing)
pull the head inspection plate off and have a look in there (maybe broke a rocker)
look for scratches on the bore of cause and the piston.. look to see if all the rings are there
next look for slop in the bottom end.. by grabbing the piston and trying to move it up and down and see if there is any slop and if there is note where it is because that what you are going to have to replace...
next check the bottom end bearings by spinning the crank it should have little resistance and should be quiet.. as in wirring is tolerable but grinding and crunching is bad.


if all that checks out (un likley if you hurt it over reving) then start looking at the gears and whatnot but you probably just bent a valve so lets hope thats it and it did not kill the seat as so its cheap to repair and also time to install some stronger springs
 
if you damaged your bottom end bearing and you dont want to work on it it may be cheaper to buy a lifan 140 or somthing like that (gpx 125 maybe)
 
ok i'm about to take to it with the tools. So I don't have to remember the orientation of anything atm? that can all be set later?
 
Even if you pull the head off and its not on TDC there is 3 things to remember when putting back together, the piston must be at the top of the stroke, the cam lobes must be facing towards the bottom end and the flywheel T notch must be a 12 oclock.
 
well it looks like i've hit the sound barrier

I've removed everything up to the rocker cover. It won't budge and i'm not willing to give it any more than 1 or 2 quick wacks as the sound will travel to all neighbors. Will have at it tomorrow. Manual says to remove rocker arms before taking the cylinder head off? it's loose enough I can feel it seperated from the engine

So far everything looks ok nothing alarming no chunks of metal anywhere. Camshaft looks good as far as I can tell, no nicks or scratches, just some normal wear

edit: once I get the head off. How do I go about removing the valves (do I need to?) as I don't have a valve compressor

edit2: Gaskets, since this is a simple low compression air cooled engine with no water passages. Do I still need to use proper gaskets or can I use liquid gasket? I wouldn't on a water cooled engine due to the potential for getting pressurised water into the head, however there's no water in this case?
 
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RangaBlitzFanga said:
well it looks like i've hit the sound barrier

I've removed everything up to the rocker cover. It won't budge and i'm not willing to give it any more than 1 or 2 quick wacks as the sound will travel to all neighbors. Will have at it tomorrow. Manual says to remove rocker arms before taking the cylinder head off? it's loose enough I can feel it seperated from the engine

So far everything looks ok nothing alarming no chunks of metal anywhere. Camshaft looks good as far as I can tell, no nicks or scratches, just some normal wear

edit: once I get the head off. How do I go about removing the valves (do I need to?) as I don't have a valve compressor

edit2: Gaskets, since this is a simple low compression air cooled engine with no water passages. Do I still need to use proper gaskets or can I use liquid gasket? I wouldn't on a water cooled engine due to the potential for getting pressurised water into the head, however there's no water in this case?
Click to expand...

When you do get the head off do a seal test on the head(both valves closed of course). Leave the plug in also, you want to sit the head on the bench so the valves are faceing up and is level as possible, you want to fill the combustion chamber up with metho or fuel and once lapping at the top check in the exhaust and intake ports for any fluid getting thru the valves, if the fluid dissapears instantly you have a bent valve, if it seeps slowly then the valve may just need re-seating, if no fluid loss then all is good. I would not use liquid gasket as the loss of the thickness of the gasket could potentially cause the piston to hit the head or the piston and valves may connect. The rockers do not require removing to remove the head but if valves need removeing then they will once the head is off.
 
what about if I keep the existing gasket, but if there's rips or tears I fill it in with liquid gasket? I'm not majorly concerned if it only lasts a couple months. But assuming nothing needs to be replaced i'd like to get it working tomorrow

Was thinking of doing rings as well as I know compression is down a bit, then again i'm only concerned with power output and I can't imagine it'd make much of a noticeable difference on such a piddly engine?
 
if you wanted to you could smear a little gasket sealer on there.. only a little bit
you could/should do the rings but lets focus on what you broke here.. if you dont have the head off then you dont know yet

also after you tale the camchain off dont go kicking it because if the cam is not at tdc position you will probably bend a valve
 
Can anyone say carbon?
imag0113yg.jpg

imag0114jk.jpg


that engine is FILTHY, but the head looks fine to me, no metal shards, rocker arms move smoothly. I can't see the valve springs very well but I can only barely move either one with both hands so don't think a spring is broken
Filled the head with WD40 and left it for 5 minutes, not even a dribble came around

Just about to get to the cylinder
 
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cant see the pics mate but yeah try to get it out with degreaser maybe?
 
/facepalm. I just pulled the dipstick. its DRY! :cursing:
I checked it a few rides ago, how that much oil escaped I don't know, probably right into the cylinder looking at that piston. That might have been responsible for something :hmmm:

So new piston and rings. Question is what can I do with that cylinder? is it fixable?
 
MMMMM, that piston has got hot and from my experience a hone will not remove the damage the piston has done to the barrel, im surprised you got the gudgeon pin out as once they get hot like that they will fuse to the piston and seeing the colouring on the pin it was just about ready to, id try and source a new barrel mate, unless you can get it bored but not sure if you can get an oversized piston.
 
plenty of oversize pistons up to 1mm oversize http://www.ebay.com.au/itm/CT110-Po...orcycle_Parts_Accessories&hash=item3a7f4c588d

That looks like what I need?
How much should a hone/bore generally cost so I have an idea of what to look for?
and I presume they'll be able to measure and tell me what size piston I need?

edit: actually, running my fingers around the bore, I can't even feel anything whatsoever? maybe just a hone?
 
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With the piston looking like that id reckon a hone wont get it all, but a boreing will. Go to a cylinder head company or a place that builds motorbikes or mods and see them about a hone or bore.
 
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