A forum for owners of Yamaha TTR250 trail and enduro bikes!

Members Login
Post Info TOPIC: 350 base gasket leaking


Veteran Member

Status: Offline
Posts: 50
Date:
350 base gasket leaking
Permalink  
 


For four months ran perfectly without any issue. Yesterday I noticed the base gasket leaking even though I had used blue hylomar for both gaskets. Any opinion is most welcome.



Attachments
__________________


Super Guru

Status: Offline
Posts: 2484
Date:
Permalink  
 

Thats a shame, was it all torqued properly?, not had a problem with mine. Anyone else ?



__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

Yes Steve, torqued properly and after 1000 km when readjusting the valves, retorqued 3 bolts to spec (probably loosened while running it in).

__________________


Super Guru

Status: Offline
Posts: 1202
Date:
Permalink  
 

Sorry to hear of this.
I've not had issues with base gasket leaks on either of the 350s I use, but it is such a small contact area the chances of a leak are higher than on a 250. I did initially have a leak from the head gasket around the cam chain gallery (right hand side of the bike) on bike number 1, but it seemed to resolve itself.
Did it start after you retorqued the head bolts? (Not suggesting you were doing something wrong but maybe releasing the pressure broke what was a good seal in the beginning?)


__________________


Super Guru

Status: Offline
Posts: 2484
Date:
Permalink  
 

As in Bri's post

https://ttr250.activeboard.com/t62677316/cylinder-head-torque-sequence-and-settings-diagram/

 

 



__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

I run the engine in for about 1100 km (1 month period)and then I readjusted the valves and retorqued three head bolts that had loosened for some reason. Then it run for another three months and about a week ago it started to leak. It still runs well. I will probably leave it as it is for now, is this recommended guys?
Here in Greece the temperature exceeds 40 degrees Celsius, could have contributed maybe...and hard off-road mountain climbing...
And yes Simon, both times torqued to spec according to Brian's diagram in Steve's reply.
Thanks for the support guys!



-- Edited by Christos on Friday 30th of July 2021 02:48:23 PM

__________________


Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

Hello guys,

I am about to replace head and base gaskets. Those of you who have upgraded to 350, do you torque the head bolts once and for all? If not, after how many heat cycles or km did you retorque them?

__________________


Super Guru

Status: Offline
Posts: 1202
Date:
Permalink  
 

I have not retorqued either of the 2 I am responsible for. I would like to hear from Gadget - his has probably been worked the hardest!

Only use a very thin smear of sealant, but check the joint where the 2 halves of the crankcase meet - sometimes there is a step there. You can shave it carefully with a sharp blade to make it less severe.

Good luck!

__________________


Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

mossproof wrote:

I have not retorqued either of the 2 I am responsible for. I would like to hear from Gadget - his has probably been worked the hardest!

Only use a very thin smear of sealant, but check the joint where the 2 halves of the crankcase meet - sometimes there is a step there. You can shave it carefully with a sharp blade to make it less severe.

Good luck!


 Thanks Simon!



__________________


Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

Christos wrote:
mossproof wrote:

I have not retorqued either of the 2 I am responsible for. I would like to hear from Gadget - his has probably been worked the hardest!

Only use a very thin smear of sealant, but check the joint where the 2 halves of the crankcase meet - sometimes there is a step there. You can shave it carefully with a sharp blade to make it less severe.

Good luck!


 Thanks Simon!


 So, I changed the gaskets, everything according to specs. I notice that the base gasket is protruding a bit, right side of the photo, after torqueing. Is it the same on your 350s Simon?

Just to be sure...



-- Edited by Christos on Sunday 24th of October 2021 11:25:02 AM

Attachments
__________________


Super Guru

Status: Offline
Posts: 1202
Date:
Permalink  
 

That's normal - it is the same on my 350 and on a standard barrel.
Fingers crossed for you

__________________


Veteran Member

Status: Offline
Posts: 50
Date:
Permalink  
 

mossproof wrote:

That's normal - it is the same on my 350 and on a standard barrel.
Fingers crossed for you


 Fingers crossed indeed! Thanks a lot!



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard