Bottom End Gone!

[julian5000]

Hi All

Just looking for thoughts and advice on my 2011 EC250. Pretty sure something down low has spat the dummy!

I was riding couple weekends ago, first it died (almost as if it had lost all spark), but it kick started easily and was off again. Was running great then oops! Rear locked up and I came to a grinding halt.

The kickstarter was jammed so I put it in neutral and luckily there was towing available, so I rode the ATV Of Shame back to the trailer.

The kick starter didn't take much to move, pushed it by hand and it didn't take too much to get it moving again. But it wasn't feeling or sounding too happy through the stroke.

I stripped it down and this is what I found, nothing major wrong I could spot up top:

Here's a video of the piston:

https://imgur.com/a/EcljJIZ

I did find the bolt that holds the power valve lever arm at the top was sheared off, but it was in place and enough was left to stay in place, this pic from RockefellerGG's excellent rebuild thread:

Down below things were a bit more interesting. I couldn't feel any up/down movement in the conrod, and the big end bearing feels smooth as, and what I can see of the roller bearings look good.

But something down here's not happy! These flakes were plucked from a nook in the crank:

There seems to be staining on the crank but no pitting that I can feel:

I'm still not sure if I will split the cases myself. I haven't done it before, but there's some great resources such as the thread I mentioned.

Any tips or tricks or things to look out for? Any alarm bells or warnings for me to heed? There's a few parts lists floating around, I'm pretty keen to do it all properly and make the motor like new again. I've done pretty much everything else on the bike, and it's such a good bike for a shorty like me.

Cheers in advance for any input. If there's interest I'll post my journey!

 

[(F5)]

Hey dude. Check my crank failure modes thread from a few weeks back. What you are seeing is the left hand side bearing plastic cage.

My rod once taken apart of my 07 was getting worn so was glad I took the extra plunge to change it. Mine was an 07 and first time done. Your 11 is much newer but still 7 years on so recommend the same.

Case comes apart real easy except the left hand thread on crank. Best done on the bike.

 

[julian5000]

Yeah same scenario, seems like that's the way it goes.

The slivers in mine are sticking to a magnet though, so not plastic? Probably irrelevant at this stage as it needs a rebuild.

Case comes apart real easy except the left hand thread on crank. Best done on the bike.

Oops, it's already out. I've got a rattle gun, might just need a fat mate to come and sit on it.

I see you got a new rod too. Being down here in New Zealand we generally have to give up kidneys for parts, so I'm trying to get my head around what I'll need to order.

Did you sort your idle issue?

 

[RBrider]

Cage on my mag side bearing came apart on my '01 XC 200. Locked up the engine. I put it in 6th gear and rolled it back & forth till it freed up, then rode it about 5 miles back to the truck. Felt like the engine was going to jump out of the frame. Lucky for me, the ride out didn't do anymore damage.

The rebuild is pretty straightforward. Just make sure you flush everything good to remove all the metal bits.

RB

 

[fred99999au]

Oops, it's already out. I've got a rattle gun, might just need a fat mate to come and sit on it.

use a chain around the sprocket and put it in gear. Then rattle gun to your hearts content. Probably a higher gear the better. Attach the chain to something sturdy on the engine.

 

[(F5)]

I got a woosner rod kit from motozone for nz$200 which was cheaper than I could bring one in from US. Nice bit of kit however had to by some 1mm thrust washers but think it was R2 that carry all that sort of stuff to supply local bike shops.

Motocross parts nz has various bearings. I was lucky with a mate having gasket set and seals already in his spares.

 

[julian5000]

Cheers for the advice all, I'll try the chain around the sprocket this weekend.

I got a woosner rod kit from motozone for nz$200 which was cheaper than I could bring one in from US. Nice bit of kit however had to by some 1mm thrust washers but think it was R2 that carry all that sort of stuff to supply local bike shops. Motocross parts nz has various bearings. I was lucky with a mate having gasket set and seals already in his spares.

Choice I can chase up some parts. It's common to send the crank off to get rebuilt right? All that pressing and truing - tools and skills I don't have.

Some more dumb questions: I'll need these tools at least right?
- Flywheel puller
- Case splitter

Hoping I can call in a couple favours from my friendly mechanic who I've referred quite a bit of work to.

 

[Zman]

Flywheel puller for sure, but I do not think you will need the case puller. I have split the cases on six GG engines and never needed a puller to do it. Just do not use a screwdriver or pry bar between the cases as you can damage the cases. All of those were pre 2006 engines so I do not know if GG reduced mfg clearances over time or not.

 

[(F5)]

Flywheel puller but case splitter not required due to the bearing construction being a sleeve.
Find someone decent to rebuild the crank.

I used a mate but will be plenty of DirtBike shops that can do it but ask around. If near Palmy Norf Pete Sales at Total is always a good choice.

 

[julian5000]

Flywheel puller but case splitter not required due to the bearing construction being a sleeve.

Ok, dumb question #3, how do you know which flywheel puller to get?

Find someone decent to rebuild the crank. I used a mate but will be plenty of DirtBike shops that can do it but ask around. If near Palmy Norf Pete Sales at Total is always a good choice.

I'm in Tauranga, I'll make some enquiries. Definitely want it all done right.

Cheers.

 

[(F5)]

Um, it's the most common on that suits 90% of common jap bikes. Use a dab of grease on the face to crank end to prevent damage.

This will explain
https://www.motoxparts.co.nz/p/flywheel-puller-universal-nac-tools
27x1mm

I like the motion-pro one, simple robust, can give it a shock with a hammer.


Like go hold flywheel with this to undo. Have to position carefully so don't snag pulsar coil. Available from supercheap etc for not much.

https://www.google.com/search?client=tablet-android-samsung&ei=M2R8W5jlL5f3hwP82oDABA&q=chain+vise+grip&oq=+chain+vice&gs_l=mobile-gws-wiz-serp.1.1.0i10l5.100298.112298..113867...2.0..0.329.6400.2-26j1......0....1.......5..0j46j0i71j35i39j0i67j0i131i67j0i131j46i67j46i131.fM1aqi6erD4#imgrc=rd7j8NovOpOvkM:

 

[Harry]

Julian - crank main bearings and seals can be bought through industrial bearing supply shops such as Saeco Wilson NZ.

Connecting rod is the same as Honda Cr250 (check years)

Attached is a list of bearings and seals for my 02 EC300

 

[julian5000]

Awesome, thanks guys. Aiming to crack into tear down on the weekend.

If you're in my neck I owe you a beer.

 

[(F5)]

I used Saeco for 20 years but now their prices hammer the chap off the street so they can give thier trade customers 50% discount as a starting point

 

[julian5000]

Yep, that'll do it...

Crank bearing is toast. To confirm, I should:

- get the crank rebuilt
- see if any other bearings in the cases are feeling rough
- order new bearings and seals
- might as well do top end while i'm in here (although top end isn't that old)

anything else i should check while i'm in here?

cheers

 

[Gasser Nate]

I would replace all bearings and seals while it is split. If the top end isn?t that old you can do it in the frame later easily enough. Last thing you want to do is strip it down in a months time because a bearing did not get replaced. Check the gears for wear and chipping as well. Make sure the little plastic guide that the shift shaft scorpion rides on is in good shape. The early four strokes had a alloy one that held its shape better. They are not hard to make on a lathe though.

 

[(F5)]

Check gearbox bearing but they live in oil and should really last the lifetime of the bike.

Measure the ring end gap. 0.5 to 0.8mm on a 300. Mine was barely worn after several years so it went back. Ran great today, idle issue gone.