this may be of use to some one

[caps 999]

i was haveing a brose for some dt articles andfound this site could be of use to someone has allot of old articles on it
www.eurospares.com/graphics.htm

[YZ250H]

Hey Caps,

I notice you are restoring a 250J at the moment.  Do you have any ideas on how you are going to get around Mr Yamaha's ingenious idea of putting the cooling water through the head stem.  If you got ideas I'd be interested to hear them.

Cheers

[caps 999]

im actually using the stock routing the seals were rather cheap and if you use distilled water you wont get any rust the 250s arnt bad like that its the 125 and 80 you should watch out for

[YZ250H]

Sorry mate, I didn't get to finish that last post properly as my 2yo daughter was yelling at me for attention.
I was asking because I've got a 125 J and H both with that ingenious system.  I bought all the seals for the J (which cost about $100) put her together, filled her up and green fluid spilled all over the floor from the bottom steering head bearing.  .  I thought I did a good job of cleaning inside the steering head with a wire brush fitting on the rotary tool (possibly the most useful tool I have ever bought).

The only thing I am going to try now is bars leaks before I admit defeat and just run the hoses directly to the radiator.  Not really worried about the H/J hybrid as that's a thrasher/race bike maybe, but I'd really like to have the real deal for the other H I'm going to do.  Any suggestions   I could replace the steering head tube, but that would be a major drama I'd reckon.  Stainless could be the go so it wouldn't rust, but could cost more than the whole bike is worth.  I'd need to restamp the numbers too.

Any ideas - I've seen a lot with the hoses run direct, so Im guessing there isn't a fix.

BTW - what model YZ80 had that stupid setup ?? I have only ever seen one photo of one on ebay.  I really hope it's not the H model.

Cheers 

[caps 999]

its the 80j that has that system how many seals were there all up in your j system and was there alot of rust in your frame as ive bought 5 250j frames none of which had headstem rust just 2 of them had abit of frame rot underneth im pretty sure the 125 were not for that though the 250 seems to be a little thicker around there

[YZ250H]

Caps,

There where 2 proper seals and more of what I would call a separator that went in the middle.  I wouldn't have said the rusting in the steering head was heavy, but there was some minor pitting.  Not exactly sure what the separator did.  There is one part on the J model that's not on the H, but I can't recall what it is.  I think my real problem is with the steering stem on the triple tree.  There was only very minor pitting on that.  I gave the whole thing quite a good coating of high temperature water proof grease.  Could that be a cause of the leak???.  It's really got me a bit buggered as I thought I had prepared the whole thing very well.

I haven't seen the state of the H steering head yet (still making its way towards me from down south).  Hopefully it's in better condition than the J.

Cheers

[caps 999]

this shot of ypic should help you make sure you got the order of seals right theres 3 main seals in the 125j

20=o ring
19=spacer
13=nut
12=cap
7=bearing
10=seal
8=cyinder
9=o ring
4=seal
5=c clip
11=seal
one more thing did you change the seal under the clamps

[DJRacing]

YZ250H, dont use bars leak. It has a bad habit of clogging up the water flow passages. On my YZ125J I had a new steering stem made. (a bit of work involved) but it wasnt to expensive. The middle half-seal separates the returning hot water from the cooler water coming from the radiator. The o-rings have to be viton o-rings as these are heat proof. So at the end I rebuilt the whole thing but it still leaks. The leak is very very minimal because I have only had to top the radiator up just a couple of times over 3yrs. But as I say it still leaks because after a race there is always a couple of drops on the front guard but certainly nothing to worry about. There are 4 of the viton o-rings, 2 full oil seals and 1 half oil seal.
But please dont use bars leaks.

[caps 999]

it seem to be a facr of life with the 125 j i havent had any problems with the 250 j went together nicely

[YZ250H]

Thanks for the heads up DJ.  A wealth of knowledge as usual and much appreciated.   I won't put the bars leaks in.  The last thing I need is another siezed engine (mind you I would know how to fix it after my recent escapades).  As I said I'll still go for the hoses direct to the radiator for the J and try to fix the H.  I might have to pick your brains a bit re the steering stem - sounds like the way to go.  How on earth did you weld (??) it to the triple clamp ??.   I'd say anyone with a 125J or H would say you have solved the problem even though you get a few drops 

For the J I bought all the seals, the separator for the hot/cold water separator and a new genuine O ring (items 11, 4 and 10).  Also bought the aluminium piston (item 8 ) then I found out it was still jammed in the steering head  .

At the moment the water in the J doesn't run out, but still drips pretty quickly.  I could probably ride for half an hour before having to top up the radiator, but that's a pain in the butt.  Longer hoses may be Ok for a thrasher, but I'd really like to have it all working properly for the H (which I hope to make a GQ/very neat rider).

I think the H is on it's way so I'll see what condition the steering stem is in (where the sealing main problem obviously is)

Maybe the 250J steering stem is made from different alloy or maybe Caps is just a lucky bugger 

[DJRacing]

An engineer made the steering stem for me, its a press fit into the bottom triples and he made it out of a solid piece and drilled the holes from the top and bottom and then wielded a cap on the top and put the treads on. I gave him the old one to copy from and all the seals etc to get as accurate as he could with the measurements. I could ask him  how much it was because I cant remember now and if you liked the price you could always send your bottom triple to him and you will get a nice new one back. I also gave him the bearing for the bottom triple and he pressed that on for me as will. Alot of VMXers use him over here but when he see us walking into his workshop he always starts laughing because of the wierd looking things we bring in for him to make.

[YZ250H]

Sounds like the go DJ.  I'll wait for the stem to arrive to see what order it is in then get the details off you if it's no good.  I don't like the chances actually 'cause the H already has the longer hoses with it.

Actually the more I think about it I might do it for the J as well.  The hoses running from the radiator to the motor have got to affect the steering.  I'm sure the tree is the same for the H and J, so I'll wait for the other one to arrive and get one done at a time.  Otherwise I'll be without a a ride AGAIN.  And we all know that sucks.

[All Things 414]

Gee. Didn't the Japs make life a whole lot easier for us all.........

[YZ250H]

Most times Mr Yamaha got it right, but IMHO he got it very wrong this time.  Luckily it only took him 2 (?!) years to realise the error of his ways.