'13 EC300 Blown Transmission

[bkoz]

Hello to the forum. I have my friends 2013 EC300 in my garage right now with a slight transmission "issue".



The worst part is the RHS case is cracked at the shift drum bearing bore.





I have a few questions I was hoping the board could help me with:

- I am guessing that Gas Gas recommends replacing both case halves together?

- The owner has a paper copy of the '05 shop manual. It looks like there are very few changes engine wise from '05 to '13 minus electric start?

- The owner also has a '05 250. We are thinking of pulling the '05 bottom end and bolting on the '13 jug and flywheel/electric start. Will this fly?

- The '13 engines top end tested out to 135psi on the compression tester. I am guessing this is low. The top ring looks to have a pretty large gap just looking at it. What do you guys like to see as far as a good compression test?

 

[memphis2857]

I wonder what caused the failure?
Wasn't 13 the first year they made some engine changes. Idk for sure


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[Jakobi]

There are some small changes from year to year. The 2013 model has some porting changes in the cylinder but the bottom end should be the same as earlier models (at least 07+), but I can't confirm that an 05 will fit. If they're the same externally (inc engine mount) they should be good to go.

135psi is low, but some testers capture the volume of the plumbing and the gauge too. The extra cc's here can skew the reading substantially.

Those cases look rooted. How did this happen? Not a pretty sight by any means.

05+ workshop manual works just fine. Just disregard a few of the torque specs. Some will have you scratching your head.

 

[bkoz]

There are some small changes from year to year. The 2013 model has some porting changes in the cylinder but the bottom end should be the same as earlier models (at least 07+), but I can't confirm that an 05 will fit. If they're the same externally (inc engine mount) they should be good to go.

The 2 engines look identical. The '13 even has the cylinder head boss that is used on the '05 frame but is not connected to anything on the '13.

135psi is low, but some testers capture the volume of the plumbing and the gauge too. The extra cc's here can skew the reading substantially.

I thought it was low. I know he sucked some dust at some point. The top ring definitely has excessive end gap.

Those cases look rooted. How did this happen? Not a pretty sight by any means.

I honestly think a broken chain guide was the cause. He threw the chain and managed to break a couple teeth off of the front sprocket. The next ride his tranny let go. My guess it is all related.
I think the case can be salvaged. The crack in the bearing bore is minor. I know a great tig welder. And it would be easy to machine the bore after. That bearing sees very little torque.

05+ workshop manual works just fine. Just disregard a few of the torque specs. Some will have you scratching your head.

Any specific torque's to watch for?

 

[Jakobi]

If you're confident and have contacts that can repair it, then why not!

I have had a 2010 and 2013 and there are some cylinder variances, but the heads are the same. Same goes for bottom end too.

On the main page there is a link to the torque spec sheet, much better! The ones that are wrong are mostly the clutch hub nut, and pri drive nut. Manual specs around 40Nm from memory.. Way on the low side.

 

[bkoz]

A quick update.

I swapped the '13 estart assembly onto the '05 engine and swapped the '05 into the '13's frame. It fit perfectly.

We are still waiting on a parts quote from Gas Gas to see if the '13 bottom end is worth fixing.

 

[gasgasxc]

Where are you located?
Does he wanna sell that 05 roller?

 

[bkoz]

Its stripped and scrapped. The only good part of it was the engine, rear shock and wheels. He is keeping all that.