Engine swap, 92 engine in 89 chassis

[higbonzo]

Hey all,

Been a while since I participated on the site.  I am still out here, just busy with life and all that jazz. 

     I finally swapped out my 89 engine with a bad starter clutch  (it will be getting a total rebuild) and put in the 92 engine that has been on the motor stand for a couple of years.  Just as a point of reference, if you are not already savvy, these two engine cases are not exactly the same, so it take a little adapting to get the motors to swap.  The rear lower mounting points have no opening for bushing on the 92's, as they are designed for carrier bolts.  The front mounts can be managed by removing and replacing bushings as necessary.  It was also necessary to shim the engine towards the clutch side to get the alignment for the sprocket correct.

     It sure will be nice not having to bump start my bike every time I wanted to go for a ride, although it was quite easy because of the slop in my driveway   Now I need to put a new Pirelli Angle GT on the front and I will be good to go.  While I have the wheel off I am going to install a set of 6 pot YZF750 calipers I have laying around and see how they work over the stock calipers. 

Anyways, Just thought I would share.

Later...

[Steve_in_Florida]

Hey Phil,
Nice to hear from you.

Pictures, please. Others may be interested in the details of your swap.

Steve

[higbonzo]

Hey Steve,

Ya, it's been awhile.  I had a Donzi GT that was eating up a lot of my time.  It was tons of fun, but the flywheel ring gear went and I just couldn't find the energy to fix, so I sold the boat.  Been feeling better lately so I decided to knock out this engine swap.  It is not as easy as you might think, it is a solid 8hrs of work for one person.  Pressing out the motor mount bushings are a pain.  And it takes quite a bit of finagling to get the engine in and out without destroying anything.  I did get it all figured out though, and it's almost a plug and play project, almost   

Here are the only pics I have, 92 engine on stand and a sweet ass 89 FJ with 92 FJ engine installed.

Later...

[higbonzo]

Update on the 92 engine in the 89 chassis.

First -  Not having any rubber mounts on the rear mounting points causes more vibration through the bike.  It does feels a little tighter have it tied together this way, but I will be getting the original engine repair as soon as I can afford rebuild.

Second -  You are not able to remove the original oil filter housing from the bike.  You must remove the kick stand switch to clear bottom of frame.

Other than these 2, and other issue stated earlier, works fine.  I just took her for a spin today and bike runs a buck 25 smooth as ever.

Later...

[jscgdunn]

I did this swap as well. I had my machinist drill out the rear bottom mounts to accept the 89 bushings.  I drilled out the triangle top mounts to accept the larger 3XW rod and used threaded rod for the long cross bolt.

Jeff

[higbonzo]

I am not sure I could afford to have the rear bottom holes machined, and not quite sure how it would be machined as a complete engine, I know it sounds expensive.   

I had no issue using the 89 rear top mounting bolt.  I believe the engine cases are the same except for machining and maybe some slight casting changes.  I know I couldn't mount the 89 original ground cable in the same position because the bolts used on the 92 are a much larger diameter at the mounting point (3 larger bolts in case).  This area is strengthened due to the fact this point is now used to mount a large carrier/motor mount for the upper rear mounting point of engine to chassis.  This was done in later years because of chassis changes and the use of softer/larger mounts to remove vibration from engine to chassis.  There is actually quite a dramatic difference between in the way the rear section of engine is attached to the chassis.  The front is actually quite different as well.  Yamaha used large motor mounts on the front and rear lower mounting points to remove vibration in the later FJ's.  The engine was attached to the mounts then attached to the chassis, where as the 89 have smaller insert bushings at mounting points on the engine which is then directly bolted to chassis.  Thus causing more vibration, but giving a slightly stiffer chassis feel over later year bikes.  I have never look into it, but I would imagine the earlier model FJ's have an even cruder way of attaching the engine to chassis.  The more the engine is directly part of the chassis the better over all fell you get from the bike.  But, at the cost of more vibrations to your body and hands.  It would be cool if the made poly bushings for the bikes.  OK, I digress... sorry.

Later...

Phil