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ian505050

Collected my YZ400F 1998 and i have a few issues.

8 posts in this topic

Hi, hopefully after spending some time searching this forum and the rest of the internet you can help me confirm a few issues and resolutions for my bike.

 

Below is a snap of the bike i have just purchased. I have had a WR250F for the past 2 years and fancied something with a bit more power.

 

DSC03146_zps0a585a49.jpg

 

My issues so far:-

 

1.) I noticed my bike had an oil leak after i ran it in my garage for 5 minutes. After cleaning the bike and resting it against the wall i found that i had a nice little puddle of oil and it seems to be coming from the main drive shaft. (see photos below), Can some confirm that the link i have posted below is the correct part to fix my issue. I am 99% sure its correct even though it does not state it fits my bike in the link i believe the All Balls  Part Number 25-4019 seems to be correct.

 

https://www.catalyst-findit.co.uk/index.php?c=d2f5d910014f2842ada1bbc16c273aae&vat=ex&rpp=100&dest=prod&pid=17-9217&PHPSESSID=a42408a6cf74f184cc1e0ec7a1649cf2

 

IMAG0226_zps3cc5ce38.jpg

 

IMAG0230_zpsc08f01d8.jpg

 

2.) My second issue i noticed when rolling the bike around the garage and grabbing the front brake. When i apply the brake there seemed to be a jolt feeling i could feel. I think it may be free play in the head bearings, but is there anything else i should look for?

 

I am going to have a look at the old head bearing and probably buy the head bearings in the link below

 

https://www.catalyst-findit.co.uk/index.php?c=d2f5d910014f2842ada1bbc16c273aae&rpp=100&dest=prod&pid=17-1268.AB&PHPSESSID=a42408a6cf74f184cc1e0ec7a1649cf2

 

 

3) On my WR250F i have an oil bleed bolt that you undo after an oil change to confirm you have oil pressure, The photo below shows my YZ400F 98 and there seems to be a ball bearing in place of this bolt? Why would this be like this? My brothers WR400F has the same ball bearing in the same spot. Any Ideas?

 

DSC03159_zpsb69678b9.jpg

 

4) Finally........................ It seems my bike has a major bodge on the sump plug at the lowest point on the engine. It does not leak but what should i do with this? I have not tried to undo it yet. Any suggestions would be appreciated.

 

DSC03151_zps261e9233.jpg

 

Thanks in advance for any assistance you can offer. I have used the search function quite a bit but would like your opinion on my specific bike with the photos shown.

 

I will update this post with some good quality photos as i fix the above issues and anymore i find to hopefully help others at a later date

 

Kind Regards Ian

 

 

 

 

 

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  1. Most of the seal kit should work.  The only difference may be in the lock washer, which may seem large for the 400 nut.  BTW, that listing is for a quad.  "YFZ450" is a quad. "YZ450F" is a bike.  Personally, I use only OEM seals and bearings.

Head bearings, fork bushings, or loose rotor rivets (the rotor "floats" on its center by design), etc.

The plug came from the factory that way.  There is, frankly, not much reason to doubt you have oil pressure if you had it when you shut it off before the oil change, but if you insist, you can loosen the banjo fitting at the oil manifold and check that way.  Careful not to twist the fitting, which could break the soldered joint.

You're going to have to clean that up and evaluate the damage first.  If it's stripped threads, there are a number of workmanlike ways to repair them.  If there's a crack involved, you need some welding done.

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Right, a little update with a few photos as i love it when i find a post with some decent snaps.

 

I decided to have a look at the drive shaft seal. 

 

First i removed the plate cover

 

DSC03193_zps9351f846.jpg

 

Then wiggled the collar out,with a small drop of plusgas it came out easy.

 

DSC03195_zps72d61611.jpg

 

It had a few grooves worn in it

 

DSC03196_zps0d1c4a7b.jpg

 

A photo with the collar removed

 

DSC03200_zps40a730b2.jpg

 

the seal seems to be stuck out further than i thought is should be?

 

DSC03202_zpse9112589.jpg

 

It came out easily enough after applying a small amount of plusgas and using a flat bladed screw driver it popped out easily.

 

DSC03204_zpsab2e9e6f.jpg

 

Seal looked fine from the side that was facing out

 

DSC03205_zpscded56f2.jpg

 

The side of the seal that was facing in looked like this, i could not see and grit that may have caused this.

 

DSC03207_zpsd55dd2f7.jpg

 

In the next photo i am holding the old seal of the drive shaft and it seams the old seal has another identical seal behind it? The seal behind it is facing so the hollowed out section of the seal is facing inwards? The opposite way to the one i just removed.

 

DSC03210_zps59935ea0.jpg

 

I also found this, is this the o-ring that is supposed to sit behind the bearing or could it be just part of the damaged seal?

 

DSC03212_zpse85a1001.jpg

 

DSC03213_zpsb4bac1ea.jpg

 

At this point i decided before i try and remove what i believe to be a second seal fitted in error by the previous owner that i should consult someone off here first before i do damage to the second seal trying to remove it.

 

In the drive shaft seal tit you get:-

 

Kit Includes:

  • Upgraded oil seal,Hardened steel bushing.,O-Ring (where applicable).Snap ring or lock washer (where applicable).
Why would you get the o-ring that sits behind the bearing in the kit? 
Edited by ian505050

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The O-ring belongs there, and it doesn't sit behind the bearing. The parts fiche just makes it look that way.  It sits in a groove just behind the inboard end of the splines and seals against oil trying to escape between the shaft and seal collar.  Install the new O-ring first, then smear a bit of oil on the inside of the collar and install it.  Here, it is sometimes useful to put the sprocket and nut in place so as to use the two to run the collar all the way in.  Then, remove the sprocket again to install the seal.

 

The second seal does not belong there, and the bike obviously went under a sort of "goon" repair previously.  When installing the seal, there are two important points to concern yourself with:

 

  1. It has to be square with the bore
  2. It should not be pushed in past flush with the outside of the crankcase.  If you can, leave it about a half millimeter higher than flush. This is so as to keep the lip of the seal from overhanging the "castellated" (notched) portion of the collar, which would of course defeat the seal entirely. 

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The O-ring belongs there, and it doesn't sit behind the bearing. The parts fiche just makes it look that way.  It sits in a groove just behind the inboard end of the splines and seals against oil trying to escape between the shaft and seal collar.  Install the new O-ring first, then smear a bit of oil on the inside of the collar and install it.  Here it is sometimes useful to put the sprocket and nut in place so as to use these two to run the collar all the way in.  Then, remove the sprocket again to install the seal.

 

The second seal does not belong there, and the bike obviously went under a sort of "goon" repair previously.  When installing the seal, there are two important points to concern yourself with:

 

  1. It has to be square with the bore
  2. It should not be pushed in past flush with the outside of the crankcase.  If you can, leave it about a half millimeter higher than flush. This is so as to keep the lip of the seal from overhanging the "castellated" (notched) portion of the collar, which would of course defeat the seal entirely. 

 

 

Ok, thanks again for the help. Can you confirm which way the seal is supposed to be fitted. The seal that is currently fitted to the bike in the last photo has not been removed yet and has the channel cut out in the seal facing inwards to the center of the engine, but the parts fiche seems to suggest that the seal is fitted the other way,

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Anyway decided to put the suspension to the test and check for leaks and found that my front right has a slight leak after some really aggressive pushing and pulling as you can see in the photo below.

 

DSC03266_zps80d81b8f.jpg

 

I had a look up at the seal as the bike came with a receipt saying in had new fork seals about a year ago.

 

DSC03264_zpsea5cf548.jpg

 

I decided to make a fork seal scraper out of an old milk bottle carton. I should really buy a proper tool TBF

 

DSC03273_zps57c5815f.jpg

 

After scraping the fork seal about 6 times i tested for leaks and i think it may have made a slight improvement but not perfect as it was still leaking a little. Am i correct in thinking that forks bend naturally a little over time through use? I am just scratching my head a little on why its leaking.

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Can you confirm which way the seal is supposed to be fitted(?)

 

The closed side with the ID lettering faces out.  Spring loaded lip in.

 

The previous owner apparently had the ingenious idea that he would put one seal in the right way to keep oil in, then add another facing inside out to keep water and dirt out. :rolleyes:

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