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

Members Login
Username 
 
Password 
    Remember Me  
The TTR250 FAQ web pages -> TTR250 -> Projects and restorations -> TTR refresh
Post Info TOPIC: TTR refresh
gregorious77


Member

Status: Offline
Posts: 19
Date:
TTR refresh
Permalink  
 

So my mate has a white TTR250 which is in need of some TLC.

The sprag was slipping so we decided to strip her down to fix it up.

When trying to remove the flywheel I noticed the crank bearing had play in it and the flywheel can move up and down a fraction. Once finally removed (pain in the ass) we can see that the inner race can turn on the crank so definately not good on that count!!!

Going to strip the engine right down to check the crank to see if it has been damaged by the bearing being worn!! Hopefully the crank is OK and we just need to replace the main bearings.

The sprag is worn so needs to be replaced but the faces on the flywheel and gear are fine so he has got away with that one.

 

So the plan is full engine strip, replace bearings and sprag, check valve clearances etc and rebuild. Costs so far are for gaskets, bearings and sprag circa £270

So far the flywheel and sprag are off, starter off, exhaust off, carb off and engine removed from frame.

 

Does anyone have any tips for the full strip and case splitting ahead of us?



__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

Hi Greg

Lin did a brilliant "show and tell" on his engine rebuild. He removed and replaced virtually every bearing in the crankcases so it is very thorough! See here

Brian

PS looking forward to hearing back from Lin as to how his rebuilt engine performed over his Easter break!



__________________

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/ 
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

OK as promised.

Cam cover off.


Cam wheels marked up with paint pen.


Dodgy clearances!!!


Anyone know what the bent/broken part next to the gear selector shaft is? Oil pressure switch?



I know it needs a clean and we should have done this before stripping the engine!!!
It will be cleaned next before opening up any further.

__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

The forum software thought they were spam for some odd reason no

It looks like you may have a sheared bolt in what is one of the two sockets for the case saver or speedo sender cover. What year is the bike?

Brian

PS This is what it should look like:

23 March 2011 - Steves engine 003.jpg



__________________

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/ 
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

I thought it looked like a cap head machine screw myself.
Dont know the year of the bike its a white one and it was reg in 93 but has no frame number as I said in a different thread.

Only this


And this on the headstock!!!


and only 4GY on the engine.

__________________
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

Took the lid off and checked valve clearances as a first port of call for the strip/rebuild.
1 in spec three very tight!
Piccys to follow. We will document the whole thing in photos and details on here so others can use the info later if required.

__________________
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

tried to upload pics and stuff but it disappeared twice so I have given up?!?

__________________
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

And now they appear! ha ha

__________________
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

one of the long bolts on the timing chain side snapped the thread off!
anyone know where we can get one?
More piccys to follow when I have time.
My mate has been cracking on with the strip and me and my wife have a newborn baby so not had a lot of time to go out and help him!

__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

Bad luck cry

If you let me know exactly which one, I can let you have a used one foc.

See here and let me know the number.

PM me the number and address details.

Congratulations on the new arrival wink

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/ 
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

Nice one. I did just send you an email about it.
PM on its way.

__________________
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

OK so crank is shot I believe.
scored on one side and both side the bearings just drop on and off!!!
Measured the crank where the bearing fits at 27.97 both sides. this was with calipers so not as accurate as a micrometer but I would have thought it should be 28mm + a small amount - nothing.

So anyone got a crank that is not scrap for sale?

__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

Just checked two cranks and all four jounals are about 28.03 but, same as you, I used vernier calipers.

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/ 
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

I think that this one is deffo no good. the bearing inner race can be turned by hand on the shaft!!!
Do you have any cranks for sale?


__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

gregorious77 wrote:

I think that this one is deffo no good. the bearing inner race can be turned by hand on the shaft!!!
Do you have any cranks for sale?

 I have got one in stock that is in reasonable condition. The big end seems OK but there is some scoring on the little end journal. However, a gudgeon pin sits in OK and there doesn't seem to be excessive play.

£50 including courier charge if you want it. If you aren't happy with it then I will give you a complete refund and pay for its return.

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/ 
gregorious77


Member

Status: Offline
Posts: 19
Date:
Permalink  
 

OK sounds good to me.
Will get back to you with a shopping list as we need bearings etc too.

__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
The TTR250 FAQ web pages -> TTR250 -> Projects and restorations -> TTR refresh


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard