Long time no post - fresh off a top end rebuild

[Dolemite]

Long story short, I bought my first scooter, a 2012 Kymco like around March of 2012 and joined the forum around the same time as Stig. After about 2 years I sold the Kymco to my dad and bought a Burgman 400. Since then he's purchased a Vestpa GTS and Honda Reflex and i've since regained custody of my first love.

However, around 10k miles (when I sold it to my dad) it had a oil leak I couldn't pin point. Took it to a dealer and they cleaned the engine and couldn't find it either. Nice guy, didn't charge me. So NOW i've got it back and she ran ROUGH. Oil everywhere, the smell of burnt plastic when starting, the clutch was slipping like crazy and it had periodic backfire. I decided to pull the engine and see what was going on, i was intent on having her run good as new.

Turns out the head gasket had been leaking, and the exhaust gasket was toast and therefore burning up the engine shroud and making it run like crap (and possibly the reason the head gasket was leaking?) and the clutch pads were chewed up to hell and back.

So over the past few weeks I dropped in a brand new clutch and bell, new piston rings, new base/head/valve cover gaskets, timing chain tensioner gasket, oil screen, and a fresh coat of wax All in all around $260 worth of parts and a few bloody knuckles.

This was my first time rebuilding a top end, it really wasn't that tricky as I though it would be. Lots of youtube videos and a pdf shop manual are all you need, just laying out everything so it was easy to put back together was the stinker.

Now she's back on the road, getting a low voltage error code, so a new battery is due soon, but other than that she's running like a champ and i'm glad to have my Like back. It's nice to have a small scooter again for short jumps around town. I love my Burgman but small bikes are so damn fun.

20170327_185423_1 by documbie, on Flickr
20170416_115633_1 by documbie, on Flickr
20170318_112930_1 by documbie, on Flickr
20170318_182009_1 by documbie, on Flickr
20170419_144523_1 by documbie, on Flickr

[MJR]

Nice, I think it's fun rebuilding stuff and I've done a few CVT's for the Burgman 650s.

[CROSSBOLT]

Outstanding!

Karl

[ole two wheels]

You da man! Way to go.   



Mac

[vespbretta]

Nice work Dolemite!  I had to do in parts similar things unintentionally recently.
Glad to read that your scooter is back to life. It´s really a great scooter for jumps around town.
Just because being interested and curious, can you remember what torque (NM or ft-lbs or...) you used on the 4 cylinderhead nuts?
The torque specs available in the internet seem to be on the (risky?) high side imho. Did you use a torque wrench for this?
And I am still not sure if I was just right or too low with the torque I used for my 4 nuts.

I also wonder how clutch pads can look like these. What happend to them? Corrosion inside the bell? Pad thickness still wasn´t that bad.
But the original Kymco clutch pads aren´t the best anyway. Some Aftermarket clutches seem obviously better and cheaper and more durable.
Strange thing also with the exhaust-gasket. Never seen or heard of something like this. How could this happen? Were the capnuts loose or gone lost? Or is/was there a problem with the manifold flange? Or was it really just a faulty gasket? Maybe being damaged at a tire change operation?
Any ideas why the cylinderhead gasket was leaking? Overheating? Loose nuts and bolts?

[Redk]

Congrats on the successful repair !
Awesome !!

I've got a chattering clutch on a Helix I should fix, now...
Nah, I'll baby it on the get-a-way and ride the summer months first !
:-)
redk

[Dolemite]

Nice work Dolemite!  I had to do in parts similar things unintentionally recently.
Glad to read that your scooter is back to life. It´s really a great scooter for jumps around town.
Just because being interested and curious, can you remember what torque (NM or ft-lbs or...) you used on the 4 cylinderhead nuts?
The torque specs available in the internet seem to be on the (risky?) high side imho. Did you use a torque wrench for this?
And I am still not sure if I was just right or too low with the torque I used for my 4 nuts.

I also wonder how clutch pads can look like these. What happend to them? Corrosion inside the bell? Pad thickness still wasn´t that bad.
But the original Kymco clutch pads aren´t the best anyway. Some Aftermarket clutches seem obviously better and cheaper and more durable.
Strange thing also with the exhaust-gasket. Never seen or heard of something like this. How could this happen? Were the capnuts loose or gone lost? Or is/was there a problem with the manifold flange? Or was it really just a faulty gasket? Maybe being damaged at a tire change operation?
Any ideas why the cylinderhead gasket was leaking? Overheating? Loose nuts and bolts?

I torqued the head bolts to 18ft lbs as per the shop manual I have. I'm going to put around 100 miles on it then change the oil and check them again to see if they need to be retorqued. As for the exhaust gasket, the nuts were tight, but that gasket had probably been taken off and on a half dozen times, guess they don't last forever. I've got 3 now, i'll probably be replacing them after every other exhaust removal.

The clutch pads looked like a rock had gotten in there. I think maybe a piece broke off a pad, then started a cascading effect with more and more coming off over time and getting caught between the pad and bell. The bell had some noticeable grooves in it as well.

As for the head gasket leaking... you got me. I've always been careful not to overfill the oil, i'm just chalking it up to bad seating at the factory or a defect in that particular gasket. Everything else checked out fine.

[vespbretta]

Thanks Dolemite for the reply. I torqued mine only to 15-16 ft-lbs the first time, because I didn´t trust the torque specs of these unproofed sources. And I got some wide ranges of torque specs information. 13-19 ft-lbs. That was kind of a mystery.
After 3 rides and engine heat cycles I reopend the headcover and retorqued it with 17.7 ft-lbs/24NM. Except one nut, none of the others moved further. And the one that moved, moved also just a tiny little bit. So I now think that 18ft-lbs is about right indeed and can be put on without fear to break the studs or strip the threads of the engine block. For the two longer 105mm bolts M6 on the side of the cylinderhead I just put 7.4 ft-lbs/10NM on. Hope it will keep dry and no oil will leak out there from the chain chamber (no sweating).

As for the head gasket leaking....maybe the engine was running way too rich because of the broken exhaust gasket. Oxygen sensor got wrong and way too lean exhaust gas results and therefore the throttle body unit with the ECU enriched the mixture...maybe therefore the misfiring sometimes.
Fuel consumption then must have gone up too noticably.
I ride mine with ~2.6Liters/100km or ~88miles/gallon.

Thanks for your detailed report and all the provided information. Helps us all to improve and grow.
Have fun and ride safe! 

[Stig / Major Tom]

Hey Dolemite,
Good to see you again. And I well remember your black scooter with all those stickers on it.
Good fix, and thanks for sharing it all with us. Kymco parts area bargain compared to some....speaking of stupidly expensive parts....How're things with your Burg 400?    Still enjoying it?

We always appreciate more views of our LIKE's innards.
Regards, Stig

[Dolemite]

Do I still love the Burgman? Absolutely! Sold my car when I got her. THAT is a dependable scooter. I've got Dr Puley sliders installed and a Givi Airflow windshield, I own the interstates around here

[MJR]

I've got Dr Puley sliders installed and a Givi Airflow windshield, I own the interstates around here

What weight rollers are stock and what weight sliders did you go with?

[Dolemite]

What weight rollers are stock and what weight sliders did you go with?

For the Burgman? Can't remember off the top of my head but on both my Like and the Burgman I stuck pretty close to the stock weights.
I think i've got 20grams in the Burg and 14grams in the Like. I think stock for both is 19 for the Burg and 13 13.5 for the Like?

[MJR]

I bought some 26 gram ones for my Aprilia Atlantic 500 which has 28.5 gram stock.

[Dolemite]

I bought some 26 gram ones for my Aprilia Atlantic 500 which has 28.5 gram stock.

That's heavy, i'm guessing it takes 6 rollers? Burgman takes 8.

[MJR]

That's heavy, i'm guessing it takes 6 rollers? Burgman takes 8.

Yes it's a 6 roller variator on the '03 Atlantic.