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

Members Login
Post Info TOPIC: Base gasket and sealant?


Senior Member

Status: Offline
Posts: 416
Date:
Base gasket and sealant?
Permalink  
 


Hi All

Got a question about replacing base gaskets on these bikes. 

Mine started leaking on my first ttr some time back, replaced it and wasn't overly happy with the surface of the barrel once I spent hours taking the old gasket off. Anyway, after about 4000klms it started leaking again. 

That bike was written off (still have it) and my new TTR, that I bought from a friend and he had a professional mechanic, do a top end rebuild, new piston etc. about 1000k prior to me buying it now has a hint of a weep of oil at the base gasket. 

So at some point I will be doing it again. On both motors, it seems. 

I think sealant is needed and would use 3 bond like they do OEM on the cases etc. 

 

Question is should I apply it both sides of the gasket?

 

Cheers Leigh.

 

 



__________________


Super Guru

Status: Offline
Posts: 8052
Date:
Permalink  
 

Hi Leigh

I am not a fan of sealants and only ever grease gaskets (both sides) in the vain hope that they stay in one piece on any future tear down biggrin

A mate who doesn't like to take any chances always uses Wellseal on everything but it's a bit expensive! Example here.

I confess to using sealant on my BSA A10 though and I use Blue Hylomar on one side of the chain case gasket and grease on the other so it stays in one piece when the cover is taken off - usually....

It is unusual for TTR head gaskets to blow and there is usually something "fixable" that causes it.

I had it happen twice on one engine before I realised that the front LH head bolt wasn't torquing down on the head but binding on its threads. The solution was to run a thread cleaner down the crankcase holes and spin the head bolt in and out until it ran totally free.

Also, where a base gasket has leaked, the RH front bolt hole can fill up with oil and, if my memory serves me correctly, it is a blind hole so make sure there is no oil in it before fitting the bolt else it will hydraulic.

Good luck!

Brian

 

 



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Super Guru

Status: Offline
Posts: 1015
Date:
Permalink  
 

I use a very fine smear of flange sealant on both sides of the base gasket. I would rather spend time cleaning the surfaces much later than have a leak sooner.

__________________


Guru

Status: Offline
Posts: 885
Date:
Permalink  
 

silicone & such sealants drop into oil & block oilways mr honda yamaha etc did not use them clean up the surfaces just my opinion john

__________________


Senior Member

Status: Offline
Posts: 416
Date:
Permalink  
 

All good points gentleman

I recently removed the clutch side engine cover and the gasket took hours to get off and again, using a razor blade and brake cleaner and summoning the patience of mother Teresa it still left a less than smooth surface. The gasket sealed and no leaks but wonder if I am doing something wrong? Just seems to easy to score and mark the aluminum surface. I just think how many times can you do this before the surface is really stuffed. But then gasket sealant would sort that nicely you would think? I'm dreading it as I need to remove again to adjust or replace the clutch on this new TTR so it's like, how many times can I do this before the surface is ruined.



Removing gasket sealant is way easier (in past experience) than these gaskets that seem to get superglued down. I like the idea of using grease both sides thats gotta help in removing it but I really like the idea of using sealant with gasket and doing the job once.

I think most (and I have in the past) use way too much sealant and it squeezes out and can cause problems (I guess) as you say Jonyboy. I feel if you use a fine amount, there is minimal chance of that occurring. Mr Yamaha certainly uses it on the cases though, and I know 3 bond is used OEM by most bike manufacturers so feel confident in using it.

Can only experiment I guess, but next time I do this I will use a fine amount of sealant both sides of the gasket as you say Mossproof and hedge my bets.

Do you smear it on the gasket itself, or the metal surfaces? Prob doesn't matter.

Cheers Leigh

__________________
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