ATTN all yamaha GURU's

[Bigdog]

SO, I finally got the new lower engine cases for my 92 FJ1200.  Everything looks great and from what I've been told the cases should be able to be swapped out.  BUT I want to make sure.  The case numbers are 4JN and 4CR.  I just want to make sure from some other people that the cases are compatible.
Thanks
Dan

[rktmanfj]

SO, I finally got the new lower engine cases for my 92 FJ1200.  Everything looks great and from what I've been told the cases should be able to be swapped out.  BUT I want to make sure.  The case numbers are 4JN and 4CR.  I just want to make sure from some other people that the cases are compatible.
Thanks
Dan

Someone correct me if I am wrong, but I thought case halves are matched pairs...     

[craigo]

SO, I finally got the new lower engine cases for my 92 FJ1200.  Everything looks great and from what I've been told the cases should be able to be swapped out.  BUT I want to make sure.  The case numbers are 4JN and 4CR.  I just want to make sure from some other people that the cases are compatible.
Thanks
Dan

Someone correct me if I am wrong, but I thought case halves are matched pairs...      

Yeah, you're right, I seem to remember reading that somewhere as well.... I think during the discussion of the APE case studs.

CraigO

[Bigdog]

The cases ARE matched pairs.  I have TWO complete sets, the junk set that is on the bike that I have to replace and the new set that I just bought.  One set of cases are the 4CR cases and the other set is a 4JN.

[racerrad8]

They are all the same1100 & 1200; with the exception of five bolts that the diameter size was increased. The three on the back of the case from the top(for the rubber mounted engines) and the two front corners.

1250/1300 have a few other modifications.

Other than that the cases are all the same.

Randy - RPM

[FJ111200]

Yeah i noticed those bolt sizes when i made my XJR.
And just out of interest i used 36Y cases for my XJR1200.

[Bigdog]

So, just to be a little more specific the new PAIR of cases that I bought are 4JN.  They came off a XJ1250.  The cases that I need to replace that are already ON the bike are the 4CR.  I know that there may be differences in bolt hole diameter, and unfortunately I dont have any of the case bolts for the new cases but I am guessing that once I figure out the length and thread I should be able to buy them.  Does anyone know of any reason why the cases could not be swapped out, or any words of wisdom for the swap out?
thanks, Dan

[FJ111200]

I take it that you mean XJR and not XJ.
Note that on the XJR lower case there is a needle roller bearing, at one of the rear mounting points, where one of the rubber engine dampers goes. This needs to be drifted out so that an FJ rubber damper can go in its place.

[RichBaker]

Randy @RPM is the best person to answer these questions, and supply the parts you need...... just send him an email explaining what you want to do, and he can give you all the correct answers..... if he doesn't respond to this thread 1st.   

[racerrad8]

If it came from a legend car, you are going to have bore out the left lower mount because they come to America for the race car with only a 1/2" hole.

That along with the mounting bolts, and shift shaft length are the only differences...

Randy - RPM

Send me an email if you have more questions...

randy@rpmracingca.com

[Bigdog]

Randy, the cases are off a Legends Car so I am surmising that I am going to need to bore out the corresponding case mount holes....
So, as long as I resize the mounting holes to accommodate the larger bolt holes for the rubber mounts I should be set correct?  Also, I GREATLY appreciate the info.  It's nice to have people to bounce ideas off from.  Any ideas where I can procure a shift shaft that would be the correct length to fit the new case?  Also the new cases came with the front sprocket cover.  Are there any issues that would prevent me from using this cover on my bike?  I am sure that I'll have more questions to follow. 
Dan