no going back, now, motor out!

[Iahawk]

I posted a few months back about my bad engine vibration and the curly metal shavings in my oil at the last drain. Not good. I'm still convinced it's the crank or crank bearings...and to look at them I have to pull the motor and crack the case.

So I ordered all the gaskets, o rings and oil seals that will be replaced when I open it up. All parts plus 2 new tools (special socket for the starter clutch nut and a flywheel puller) cost me about $100 USD before shipping. Very reasonable.

It was actually very easy to pull the motor, which I've never done before. First step is to strip the bodywork, which I've detailed before. then pull CVT cover, disconnect rear brake line, tire hugger, intake manifold (I left intake, carb and airbox connected as one unit), a few vacuum lines, the starter cable and stator cable, rear shocks, remove exhaust and remove the one long engine hanger bolt and nut. I supported the motor from beneath with wood and supported the front of the motor with a clamp, clamping under the valve cover and over the front seat support bar.

Then push the motor slightly down and back, while still connected to the rear wheel. Pretty easy to remove and move around. Then I took off the rear wheel and carried the motor down to my basement workbench. I'm guessing it weighs around 50 lbs?

I won't tear the engine down until I have my replacement gaskets here. Those should arrive this week (all Kymco OEM parts). I'll wait to order the new crank until I verify that it needs one. $177 USD at Solano cycle. I'll also check my local dealer.

Why go to all this trouble? I find it enjoyable to work on things. To me it's a cheap price to pay for some fun. If it needs a crank and I repalce it I'll be into this repair for about $300 USD. Lots of hobbies cost much more than $300! I'm looking forward to a fun winter project and to learn more about how these little GY6 motors go together.  I've already watched a bunch of youtube videos on this...doesn't look complicated at all. Attached a few pics.

More to come.

[Ruffus]

@hawk, you're so right about costs of fun. Keep us posted.

[Stig / Major Tom]

8 o'clock every Tuesday evening in the basement of the Methodist church....

"Hello, my name is Hawk. I take my scooters apart and I can't help it."

"Welcome, Hawk!"

(it's OK Hawk --- I attend a like group for Nocturnal Rain Riders)

Stig

[Iahawk]

hahahaha....I believe it is a sickness! I....must.....pull...things...apart!  Even as a kid I'd try to take all kinds of things apart. My problem was (is?) that I'd usually break something in the process and not be able to put it back together, again!

Already ran into my first issue..the universal flywheel puller I bought seems to have the wrong thread pitch...it almost wants to thread in but then just keeps spinning...sigh.........

Edit - I feel dumb...left hand threads on the flywheel puller. Works like a champ, now.

[CROSSBOLT]

hahahaha....I believe it is a sickness! I....must.....pull...things...apart!  Even as a kid I'd try to take all kinds of things apart. My problem was (is?) that I'd usually break something in the process and not be able to put it back together, again!

Already ran into my first issue..the universal flywheel puller I bought seems to have the wrong thread pitch...it almost wants to thread in but then just keeps spinning...sigh.........

Edit - I feel dumb...left hand threads on the flywheel puller. Works like a champ, now.

You shoulda been in the Navy! We took things apart regularly when they worked fine just to reassemble them!

[Iahawk]

had to start digging in a bit..removed plastic shrouds, fan, flywheel, stator, cracked first cover and removed,  then loosened starter clutch nut (used impact wrench on that one, also left hand thread like the flywheel). Will pull starter gear and starter clutch, chain and oil pump.

Not sure when gaskets will arrive so don't want to get too far into this. traveling for work this week so back at it next weekend.

Interesting to note that oil level at full is about 1" (roughly) below the crankshaft, that's higher than I would have thought.

[Iahawk]

2 more pics

[Ruffus]

@hawk, good job. IF you do the other side (timing side) watch whether he timing chain guiding is worn out. If so, replace.

[Iahawk]

thanks, Ruffus, I'll be sure to take a look at that.

[Iahawk]

I have the gaskets and o rings necessary to reassemble my 163cc Kymco motor (aka 200). You need the 2 case gaskets, cylinder gasket, head gasket and cam chain tensioner gasket plus the o ring for the cam chain tensioner screw. I also have an exhaust gasket and a new intake o ring. The motor also requires 2 new oil seals for the crank (already had those). The only other o ring that could be needed is if you replace the plastic cam chain guides, one of them has a screw with an o ring that would be replaced (mine looks fine so will leave it be).

Of course, there are additional gaskets and seals if you're taking the transmission end apart, which I'm not.

pics attached of Kymco OEM gaskets / o rings...plus some gratuitous motorcycle parts porn of my new water pump and o rings for my little Ninja!

(edit - forgot about the new rubber mount case bushings..existing ones are all somewhat torn when examined closely. Not sure how much of an effect new ones will have but I will find out)

[Iahawk]

OK, finally got off my rear and started putting my motor back together.

Started off with installing my valves, springs and keepers (those little keepers are kind of a pain..used a magnet and assembly lube to stick them in place). Then cleaned, degreased and 'brake cleaned' the engine cases inside and out as there were lots of little pieces of old gasket material in all the crevices.

 Then I installed my 2 crank seals (using assembly lube, it was easy). Next up was pressing out and installing the 3 engine hanger bushings (mine were all somewhat torn when examined very closely). Using grade 8 bolt, washers and nuts, plus various sockets I was able to push out the old and push in the new bushings.

 Of course in the middle of this I sliced my finger open on one of the engine cases, bled everywhere...and also caught my towel that I had under the motor on fire - using a little butane torch to heat the engine case around the bushings. With the bleeding finally stopped and the little fire put out immediately.

Got stuck on the little bushing in the back of the motor, that the rear shock attaches to. I need a longer bolt to get it out and called it a day. I'll start again tomorrow.

[Iahawk]

clean case and oil seal

[Iahawk]

and method I used to push out and in the hanger bushings

[CROSSBOLT]

What, I say, WHAT was the source of the metal shavings? Did I sleep through that part? Gotta know, man! Gotta!

[Iahawk]

Karl, after the teardown I found nothing! Nothing! The curly shavings were magnetic and there isn't much magnetic in this engine. I thought I'd find the smoking gun, but I got nothin! from rockers to cam, bearings, nothing looked bad. There were a few aluminum casting shavings but those wouldn't get picked up with the magnet. Found a piece of crud keeping the exhaust valve from completely closing, not sure if that would give me the shaking I had? Still a mystery.