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 -> This one has me stumped
Post Info TOPIC: This one has me stumped
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
This one has me stumped
Permalink  
 

Today I made a disappointing discovery. You may have seen my thread on a seized speedo drive. I have resolved that and have some 3-tab washers en route from Brian. I have now found that these will be of no use as the bits on the hub that should cause the washer to spin are not present, obviously broken off at some time. I will need to buy a new wheel to get my speedo working. I know some will say just get an electronic one, but I am not keen on them.

Anyway, this has me stumped............I went to fit the wheel tonight complete with new bearings. I had the bearings fitted by my mechanic as he charges little for this and I have been rather busy lately. For some reason it was impossible to get it back together correctly. It is clear by looking at the wear lines on the spindle exactly where the spacer on the disc side should sit and it is clearly not going far enough into the hub, which would appear to mean that the bearing is not in the correct position. There is no play in the central spacer so both bearings are the correct distance apart. The wider part of the stepped spacer is obviously made to be a snug fit in the bearing rubber seal however the spacer sits so far out that the wider part of the spacer does not even touch the seal, never mind slide into it.  I also know the spacer is not in thecorrect position because it is not possible to get the caliper square on the disc.

See pic of how far the spacer sticks out when held against the inner bearing race.

The only ways this could happen (as far as I can work out!) is if either the bearings are too wide or the bearing on the speedo drive is too far in and the disc side bearing is too far out.

Anybody got any suggestions?

I will talk it over with the chap who fitted the bearings tomorrow. It will be most unlike him if he has made an error.

 

 



__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
Permalink  
 

Don`t know if this will help, but here are pics looking at both bearings.

 



__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
rattlyolddt


Senior Member

Status: Offline
Posts: 108
Date:
Permalink  
 

Cant think what it could be. Unless you have somehow got the spacers the wrong way round? They sometimes look like they should go one way but dont.

As for the speedo, have your mechanic weld some blobs to replace the missing bits. Takes 5 mins.

Has worked on my.dt for a year so far!!

Ed

__________________
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

You need to check the internal diameter of the inner bearing race and check it against the spacer.

The bearings should be different. The internal diameter of the LH bearing should be 17mm I think...... The RH one is 15mm. If the same bearings have been used then that is the likely problem.

I agree with Ed, get some ali blobs tacked on in approx the right position to drive the 3-tab washer and you should be OK. You have the pattern on the LH side to copy.

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/ 
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
Permalink  
 

rattlyolddt wrote:

Cant think what it could be. Unless you have somehow got the spacers the wrong way round? They sometimes look like they should go one way but dont.

 I have been assembling it as shown in the manual as far as I can see. The disc side spacer can only go one way, otherwise it would not slide through the bearing seal.



__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
Permalink  
 

Clutching at straws here but should the two bearings be identical or should the disc side have a larger internal hole?
The disc side spacer has three diameters. The largest sits against the fork leg and the middle section fits snugly through the bearing seal. Currently the smallest diameter part bears on the inner race of the bearing. It has occurred to me that if the bearing on this side had a larger hole the spacer would partly slide into the bearing and I reckon that would probably be about right to get it all to assemble correctly.

__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

MarkShelley wrote:

Clutching at straws here but should the two bearings be identical or should the disc side have a larger internal hole?
The disc side spacer has three diameters. The largest sits against the fork leg and the middle section fits snugly through the bearing seal. Currently the smallest diameter part bears on the inner race of the bearing. It has occurred to me that if the bearing on this side had a larger hole the spacer would partly slide into the bearing and I reckon that would probably be about right to get it all to assemble correctly.

 See my earlier reply Mark. The bearings are different. The disc side bearing needs to have an internal diameter of 17mm to accomodate the spacer. Only 15mm on the speedo drive side.

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/ 
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
Permalink  
 

I completely missed your post Brian. This is obviously the problem! I will have to chastise my mechanic for nearly making my head head explode! One day I will get this b****y bike on the road!

Would somebody be so kind as to post a pic of what the blobs should look like to give my welder something to aim for?



__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
TTRfan


Super Guru

Status: Offline
Posts: 8606
Date:
Permalink  
 

MarkShelley wrote:

Would somebody be so kind as to post a pic of what the blobs should look like to give my welder something to aim for?

 Pic below shows what the hub tabs should look like wink

IMG_0028.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/ 
MarkShelley


Veteran Member

Status: Offline
Posts: 75
Date:
Permalink  
 

The same as the redundant ones on the disc side then.

__________________

This old world keeps spinning round

It`s a wonder tall trees aint laying down.
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> This one has me stumped


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard