Bottom end failure - 2018 EC300

Booki

New member
Was riding my EC300 the other week and my rear wheel locked up on me!

Immediately I thought oh f$%^ - Managed to start it and she sounded absolutely horrible with a grumbling/rumbling noise from the bottom end. Not good!

It got me to a main road and got my riding buddies to get the car and pick me up for tow home.


Have removed the engine from the bike and started stripping it down, top end looks great (bike has 101 hours), but have realised I need a flywheel puller to continue my inspection of the bottom end.

Does anybody have one?

This flywheel bolt was a right hand thread, I believe its a 27mm x 1mm RH puller I need?

Has anybody had their bottom end fail?

Absolutely shattered its failed on me :(

From my readings there is one particular bearing on the ignition/flywheel side that has a plastic cage? Known failure point?
 
Was riding my EC300 the other week and my rear wheel locked up on me!

Immediately I thought oh f$%^ - Managed to start it and she sounded absolutely horrible with a grumbling/rumbling noise from the bottom end. Not good!

It got me to a main road and got my riding buddies to get the car and pick me up for tow home.


Have removed the engine from the bike and started stripping it down, top end looks great (bike has 101 hours), but have realised I need a flywheel puller to continue my inspection of the bottom end.

Does anybody have one?

This flywheel bolt was a right hand thread, I believe its a 27mm x 1mm RH puller I need?

Has anybody had their bottom end fail?

Absolutely shattered its failed on me :(

From my readings there is one particular bearing on the ignition/flywheel side that has a plastic cage? Known failure point?

Did you look for lose countersunk M6 bolts in the crankcase? That happened to my 2015 EC200 right before Christmas.
http://www.gasgasrider.org/forum/showthread.php?t=25449

I will pop over to the wokshop and have a look at my extractor in an hour or three and report back. I presume its the same on 2015 and 2018.

Do you have the worksop manual? If not, I can send it to you as a pdf.
 
The puller is the same as used on the trials models.
Interested to see what the issue is. Hopefully they have sorted out the loose/ un loctited crank bolts by now...
 
Not much help but a lot of the 2018/2019 models for sale in the uk have had the main bearings replaced between 50/150 hours . Seems common
 
What?? Mains at 50 hours? That is definitely not common. Every bike I have owned gets way more than that out of mains. Must be drowning the things or something. Current ride has over 160 on stock mains and my mate we go riding with has around 560 hours on stock mains and crank that are only now getting a little grumbly.
I usually replaced them after 300-400 hours when the rod is showing a little play.
 
Interesting, well so far can confirm the flywheel thread is infact a 27mm x 1mm RH thread - have the tool on order so will need to wait for that to come in before I can tear down further.

I do have some photo's of the piston I am going to post up shortly.
 
Did you look for lose countersunk M6 bolts in the crankcase? That happened to my 2015 EC200 right before Christmas.
http://www.gasgasrider.org/forum/showthread.php?t=25449

I will pop over to the wokshop and have a look at my extractor in an hour or three and report back. I presume its the same on 2015 and 2018.

Do you have the worksop manual? If not, I can send it to you as a pdf.

I have a workshop manual, I wonder if I hvae the same one as you?
2018 GasGas workshop Manual E300.pdf - 9.37mb

Not very detailed for a workshop manual (compared to say a Yamaha manual) hows yours?
 
I think that you must be a much better rider than am I.

I had 440 hours on my piston (bottom end hours unknown - but tight with just a bit of polish on the small end of the rod), but i rarely ride it on the pipe, and most of that time was riding behind my daughters (both of whom are now faster than I am). My piston has much less ring-blow by, the bottom of the piston was shiny clean, and I had no scoring or "abrasions."

My guess is that you might have had a less than ideally sealed air filter, bad air filter (i had an air filter split on the outer layer once - ouch), or really lean oil mixtures. It's hard to say without more information. i could send pictures of the piston if you're interested.

Dirt might explain a bottom end failure, too. Hard to say for sure w/o the tear down.
 
So I have the motor apart and found a damaged ignition side bearing.

The other side bearing looks pretty toasty - the black i believe is burnt oil, there is also a bit of pitting on the case as well!

Anybody have any insights on how I can prevent this?
 

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I think that you must be a much better rider than am I.

I had 440 hours on my piston (bottom end hours unknown - but tight with just a bit of polish on the small end of the rod), but i rarely ride it on the pipe, and most of that time was riding behind my daughters (both of whom are now faster than I am). My piston has much less ring-blow by, the bottom of the piston was shiny clean, and I had no scoring or "abrasions."

My guess is that you might have had a less than ideally sealed air filter, bad air filter (i had an air filter split on the outer layer once - ouch), or really lean oil mixtures. It's hard to say without more information. i could send pictures of the piston if you're interested.

Dirt might explain a bottom end failure, too. Hard to say for sure w/o the tear down.

Definitely not a better rider! I normally stick to the low end power of the bike and am hardly on the pipe giving it a hard time.

I didn't really see any dirt/debris in the case or on the piston, the intact tract was pretty clean too - so not sure if its related to dirt.

I noticed I had the pilot jet one sizer smaller than stock, the piston measured a bit undersize otherwise I can't really see anything else out of the ordinary, hopefully more knowledgeable people will chime in
 
Now that you mention it, it was quite dry...Something is wrong with those bearings getting the correct lubrication I think?

I have not torn down a 2 stroke motor before but would have expected at least some oil down there?

Bike was running a 40 pilot instead of a 42, not sure if that would have made a huge difference..
 
Good eye on the dry. When i pulled my top end, looking down past the rod, i had a puddle of Klotz R50 in the bottom end. (I also have spooge issues, but i'll take a bit of spooge to have some "splash" lubrication down there. )

Hmmm. Blocked bearing lube passages from the transfer port area?
 
Good eye on the dry. When i pulled my top end, looking down past the rod, i had a puddle of Klotz R50 in the bottom end. (I also have spooge issues, but i'll take a bit of spooge to have some "splash" lubrication down there. )

Hmmm. Blocked bearing lube passages from the transfer port area?

Or accidentally been run without oil?



Interesting - My bike also had spooge out the exhaust as well, that dry oily stuff that looks like a nest? I wonder if it was run without oil, I always premix my fuel but I did leave my Jerry can at a mates place and maybe they tampered with the fuel...I assume its unlikely but still a possibility. Though I would have thought a top end would have siezed and not spun a bottom.

The oil passages to the bottom end were not blocked at all.
 
any chance it has been drowned and left with water in there?

Has been drowned during my time, around 70 hours ago.

Tipped up side down, spark plug out and water pumped out - started it up and rode the rest of the day. Drained gearbox oil and didn't think anything else of it.

Unless it had been drowed before my ownership within the 5 hours of use from the previous owner, but seems unlikely.
 
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