Transmission Circlips

[LuckyStriker86]

This is my first post! I have been trolling this forum for several years for tidbits of info, but I am now in need of some more info. I have a 1996 FZR600 that I put about 27,000 miles on over the years (just checked the valve clearance for the first time and all within spec!! ) and about 2 years ago I purchased a 1989 FZR400. After getting it running I could swear that it was faster than my 600. After I blew out 2nd gear and started to pull the engine out; what do you know....599cc stamped on the jugs!!! HAHA it is faster than my 600! The previous owner didn't even know that someone did a 600 swap on it prior to his purchase. Well, since the motor came out I started to acquire the parts for a 660 build. I have been snapping pics here and there, so I will have a nice write up at some point.

Now to my real question...

Just wondering if anyone has had any experience putting the engine cases back together. I lost a few teeth on second gear so I disassembled and replaced the gear. Now I am not sure if I need to put the half circle circlips on the top and the bottom of the bearings that support the transmission shafts. There are slots in the case that accept the circlips on both the top and bottom half, but I don't remember if they were on both sides of the bearings. Either they were only in one half of the case, or I lost the other set. Here are a couple pics of what I am talking about. Also, from the parts diagrams that I look at, they only show one clip per bearing. Cant...figure...out...how to post pics.

https://www.flickr.com/photos/122155488 ... 590347495/

https://www.flickr.com/photos/122155488 ... 590348645/

https://www.flickr.com/photos/122155488 ... 590721564/

[LuckyStriker86]

Anyone....??? Any thoughts?

[willandrip]

The bearing set rings; only one half so they are not truly a ring; go into the lower crankcase.

Had a look at the Workshop manual to confirm this.

You might be able to see fret marks where they have sat if you look carefully; they are to prevent axial play only.

[LuckyStriker86]

Thanks for the reply. I had a look at the service manual too. It just seems weird to me that they would only be on half of the bearing. Also, BOTH the upper and lower crankcase have grooves to accept those circlips (set rings). It would make sense to have them on both top and bottom of the bearing to help prevent misalignment.

If anyone else has any other thoughts please speak up, otherwise this thing is going together in the next couple days with only clips in the lower case.

[willandrip]

The crank case halves are assembled and then machined/line bored/ reamed; it would be more work/cost to only make
the ring groove in one half of the case.

If there were 1 single clip like a circlip; it takes more time/cost to assemble.

If two separate halves were fitted; as above plus much more chance of mishap as the two halves are mated.

Alignment is provided by the very accurate bearing housing faces; this is also why c/case halves should not be mismatched.
The pegs prevent outer shell rotation; as stated the ring is only to prevent axial movement

Yamaha have made large sums of money by designing/building engines economically.


On another note; Whilst looking at the parts fiche for this assy. I happened to note that some of the trans. shaft circlips
originate from the YDS7/YR5 that were introduced circa 1971/72.
Just goes to show how vehicles develop over many generations and certainly not a bad heritage at all for the Fzr.