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

Members Login
Username 
 
Password 
    Remember Me  
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> New to Me TTR - some questions
Post Info TOPIC: New to Me TTR - some questions
Rooster


Member

Status: Offline
Posts: 13
Date:
New to Me TTR - some questions
Permalink  
 

I've had a few bikes before and generally do my own wrenching.  Decided to pick up a dirt bike after leaving road bikes a couple years ago.  Paid 900 bucks for this 1999 TTR.  The Carb was a basket case.  Accelerator pump was bad.  Somebody had lost the check valve no.  Pilot jet was gunked up.  Somehow it still ran with the choke pulled out.  Despite that the bike seems to have had pretty light use for a 20 year old machine.  Still has what I believe is the original dunlop front tire on it.

20180725_212738.jpg

While I'm waiting for carb parts to come in I decided to pull the valve cover off and check the clearances and cam chain.  Which brings me to my first question.  I attached a pic of the alignment of the cams.  They seem to be just barely out of alignment.  I'm assuming this is due to the cam chain stretching.  The chain seems to be pretty tight not really any slack at the top between the cams.   I think its probably ok but I just want to check with the experts

20180729_091828.jpg

Second question my intake valve clearances were .08 and .1 exhaust were .20.  I know the one intake is slightly out of spec.  Do you think it will be ok for a while?  I'm assuming it will be ok as it's just barely out of spec.  I've never done shimmed valves before and I'm worried I'll screw it up.

I'll post some pics in the restoration thread as I bring it back to life.



Attachments
__________________
mossproof


Super Guru

Status: Offline
Posts: 1436
Date:
Permalink  
 

Welcome to the forum Joe.
Loads of pictorial help in the repairs and maintenance section, such as:

ttr250.activeboard.com/t59506155/how-much-free-play-on-a-cam-chain/

As you suggest, looks like your chain is slightly stretched.

I find the cams rattle a bit at the wider end of the adjustment scale, but that's better than being too tight and the valves not closing properly. 0.08 is maybe a little tight. Don't fear the shims! The only thing you can get badly wrong is misaligning the cam shaft caps and cracking one. (Oh, or dropping a shim down the cam chain gallery!) Use the table in the manual to pick the correct shim replacement. Check clearance again when it's back together. What could possibly go wrong

http://www.ttr250.com/TTR250-valve-clearance-check-and-adjustment-how-to-guide.htm


Simon.



-- Edited by mossproof on Monday 30th of July 2018 10:34:07 PM



-- Edited by mossproof on Monday 30th of July 2018 10:37:53 PM

__________________
Rooster


Member

Status: Offline
Posts: 13
Date:
Permalink  
 

Thanks for the input!  I'm considering doing the shims myself but i'm going to wait until the Carb is sorted and running well before I tackle that.  I'm going to take a look at the table and see what I need.  Not really looking forward to doing the chain as it seems a bit more involved.



__________________
tom13


Senior Member

Status: Offline
Posts: 230
Date:
Permalink  
 


Google translator.
Rooster - replacement of washers is not difficult. I did it once in my life and I did it. I used a magnetic tip to insert the washer.

__________________

Grandpa Tom

 
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> New to Me TTR - some questions


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard