Bottom end failure - 2018 EC300

[Booki]

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?

[Anders]

Originally Posted by Booki

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.

[Gasser Nate]

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...

[Booki]

Originally Posted by Anders

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?

[Booki]

Have a look and see what you think -

https://imgur.com/a/TOzzYSk

[blitz11]

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.

[Booki]

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?

[Booki]

Originally Posted by blitz11

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

[maxfli11]

The 2018, possibly other models also had main bearings that have plastic cages. They do fail in the 100 hour range consistently. Don't know why GG would do this other than to save a dollar. They were going through a financial crunch around that time. I've got a friend with one that just got his back together. Get the metal cage bearings to replace with.

[Anders]

My puller is a 27x1 rh thread.

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