Bottom end failure - 2018 EC300
 

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...

My puller is a 27x1 rh thread.

Sent fra min YAL-L21 via Tapatalk

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.

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?

Have a look and see what you think -

https://imgur.com/a/TOzzYSk

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.