Considering Engine Swap

[PeteGLH]

Hey fellas,

Here is some of the bike's history.

'84 FJ1100,  131,xxx KM's  Pretty much 100% stock with the exception of a K&N drop-in filter.

I use the bike as my daily commuter in the summer, and truly, I love it.  Esthetically,  she has been well maintained and looks stunning.  However, as with any 29 year old bike, she has developped certain issues. The engine itself has started to leak oil from the bottom end,  and 2nd gear is popping out.  Now she also feels quite rattley,  and somehow I think the engine (while still going strong) is not as fresh as it should and just doesn't have that purr to it that I feel it should. 

As far as the 2nd gear is concerned, I've read about the upgraded gear fork modification and had considered it as a winter project. But with the mileage on the engine,  it would seem pointless to take it out of the bike for the trans fix without re-freshing the engine itself.

Here's where I'm getting at:

I think I could manage have a killer deal on a complete 1993 47,000km 1200 engine, accessories and trans.  Fuel pump is also available.  I'm not too worried about the physical swap itself,  I am mechanicallly inclined and I do have access  to a convienient workspace to get this done.   

My issues are with fitment.  I would think the 1993 engine would fit the 1984 chassis without modification,  but then again,  I've looked around and heard some talk about notching the valve cover to make it fit or something like that. 

Other point,  I would like to keep my stock '84 headers and exhaust, and chin fairing  (just gives such an awesome look to the bike).  Would the headers bolt up to the newer 1200 engine,  or would I need to keep the exhaust of the '93?

Last but not least,  fuel pump?  My initial thinking would be to try and run the standard 1100 carbs with a tweak here and there to compensate for the extra displacement.  Would I benefit from fitting the fuel pump?  (Would this require any modification to the 84 fuel tank, petcock mod maybe?) 

Basically, I'm trying to get this bike back to Kookaloo worthy status.  I'm trying to do this as cost-effectively as possible.  Purist that I am, I would keep the matching 1100 engine for an eventual rebuild, it's just that I think there could be a way to just swap the engines and drive it for a couple of years that way until I have the means to fix-up the older engine (if there is any point to that in the end).

Any tips on this swap?  Should I stay away,  move in,  get my foot in the door.

I've looked for a write-up on this one,  haven't got much back from the forum search.  If someone can kindly direct,  I will be glad to read on.

Thanks all.

Here's a picture taken today of the ol'gurl.  Just looks too awesome to let go.





 

 

[Harvy]

Hey fellas,

Here is some of the bike's history.

'84 FJ1100,  131,xxx KM's  Pretty much 100% stock with the exception of a K&N drop-in filter.

I use the bike as my daily commuter in the summer, and truly, I love it.  Esthetically,  she has been well maintained and looks stunning.  However, as with any 29 year old bike, she has developped certain issues. The engine itself has started to leak oil from the bottom end,  and 2nd gear is popping out.  Now she also feels quite rattley,  and somehow I think the engine (while still going strong) is not as fresh as it should and just doesn't have that purr to it that I feel it should. 

As far as the 2nd gear is concerned, I've read about the upgraded gear fork modification and had considered it as a winter project. But with the mileage on the engine,  it would seem pointless to take it out of the bike for the trans fix without re-freshing the engine itself.

Here's where I'm getting at:

I think I could manage have a killer deal on a complete 1993 47,000km 1200 engine, accessories and trans.  Fuel pump is also available.  I'm not too worried about the physical swap itself,  I am mechanicallly inclined and I do have access  to a convienient workspace to get this done.   

My issues are with fitment.  I would think the 1993 engine would fit the 1984 chassis without modification,  but then again,  I've looked around and heard some talk about notching the valve cover to make it fit or something like that.

Engine should be a straight bolt in......I am pretty sure the case mounting points are all the same. Don't know about any problems with the valve cover. 

Other point,  I would like to keep my stock '84 headers and exhaust, and chin fairing  (just gives such an awesome look to the bike).  Would the headers bolt up to the newer 1200 engine,  or would I need to keep the exhaust of the '93?

Yes headers will fit. The old '84 headers were dual wall (have an inner and an outer pipe), while the '93 are single wall....but the actual diameter at the exhaust port is the same.

Last but not least,  fuel pump?  My initial thinking would be to try and run the standard 1100 carbs with a tweak here and there to compensate for the extra displacement.  Would I benefit from fitting the fuel pump?  (Would this require any modification to the 84 fuel tank, petcock mod maybe?)

If you want to use the fuel pump, you will have to change to fuel pump carbs, as the fuel inlet needle seat is different (smaller on the pump carbs). All depends on the condition of your existing fuel delivery components - if they work fine now stick with them. The petcock bolt pattern is different on '93 so that petcock will not fit your tank. 

Basically, I'm trying to get this bike back to Kookaloo worthy status.  I'm trying to do this as cost-effectively as possible.  Purist that I am, I would keep the matching 1100 engine for an eventual rebuild, it's just that I think there could be a way to just swap the engines and drive it for a couple of years that way until I have the means to fix-up the older engine (if there is any point to that in the end).

Any tips on this swap?  Should I stay away,  move in,  get my foot in the door.

Other more experienced members than I will be sure to chime in. Sounds like you have a good project....... enjoy!

Cheers
Harvy

I've looked for a write-up on this one,  haven't got much back from the forum search.  If someone can kindly direct,  I will be glad to read on.

Thanks all.

[Arnie]

While the mount POINTS look to be at the same location, the mounts may be different.
The '84 uses a damper at the front mounts while the '93 uses a collar (the one we've been beating out and greasing) for vibration control.  They MAY be interchangable, but you should check this carefully.

What difference is there in appearance between the '84 and '93 headers?  Are the '84 headers larger diameter to allow for the double wall?

Arnie

[Harvy]

While the mount POINTS look to be at the same location, the mounts may be different.
The '84 uses a damper at the front mounts while the '93 uses a collar (the one we've been beating out and greasing) for vibration control.  They MAY be interchangable, but you should check this carefully.

What difference is there in appearance between the '84 and '93 headers?  Are the '84 headers larger diameter to allow for the double wall?

Arnie

Arnie....the 4-1 pipe on my '91 was originally designed for and came off an 1100....... port diameter is the same........ so my thinking is that the OEM headers will fit.

Harvy

[oldktmdude]

  Apart from what Harvy and Arnie have already said, the only other thing that comes to mind is that the CDI boxes will need swapping. The exhaust should not be an issue. You may want to consider using the removable frame tubes from the '93 so you can keep the original anti-vibe mounts. Sounds like the best plan of attack to fix the second gear issue and the 1100's high mileage condition.  Regards, Pete.

[Arnie]

Harvy said, "Arnie....the 4-1 pipe on my '91 was originally designed for and came off an 1100....... port diameter is the same........ so my thinking is that the OEM headers will fit."
Harvy

They'll fit with no problems, I was just thinking that the OD of the double wall pipes might be larger even though the inner (working) pipe is the same size.

Pete said, "You may want to consider using the removable frame tubes from the '93 so you can keep the original anti-vibe mounts."

IF they'll fit, this would be great.  I think that the '93 lower frame tubes are slightly longer to allow for the anti-vibe mounts.  Measure carefully.
I'm not trying to rain on your parade, just advising you approach the swap with caution.

Arnie

[Harvy]

Point taken Arnie. Yes Pete - I forgot about the ignition differences.......swapping the ignition box would be a quick solution.

Harvy

[ribbert]

The three answers so far are not absolutely sure and I wouldn't have a clue but I have been left with the distinct impression from here some time back that the cases are different and not interchangeable.
So much so that I passed on some good deals on motors.

Noel

[Harvy]

The three answers so far are not absolutely sure and I wouldn't have a clue but I have been left with the distinct impression from here some time back that the cases are different and not interchangeable.
So much so that I passed on some good deals on motors.

Noel

Interesting Noel.... I thought the same thing, but I recall a post from RPM Randy some time back saying that the case mounting points are the same - just the frame mounting points are different?

Harvy

[aviationfred]

I looked up the crank case part numbers on Partzilla. 84' through 90' share the same part numbers. The 91' to 93' share a slightly different part number. The difference is the 3 digit prefix. I would look to Randy for the definitive answer on whether the late model 1200 engine will bolt into the 1100 frame. My gut feeling says yes it should with no issues.

Fred

[rktmanfj]

Isn't this basically the same swap that Irishluck was tryin' to do?     

[jscgdunn]

Point taken Arnie. Yes Pete - I forgot about the ignition differences.......swapping the ignition box would be a quick solution.

Harvy

Just went through this on the frame....the 92 is a toatally different frame.  That said, the lower frame rails from an 86 are the same as an 89...I am the proud owner of an 86 set, and 89 set (thanks Fred) , and two 92 sets.

Jeff

[paulfj03]

Last year I successfully installed an 86 engine into a 92 frame.  It was pretty straightforward.  I removed the 92 upper rear engine mounting bracket and 2 case bolts with it to attach to the rear of the 86; removed the left front aluminum bushing and the rubber damper, and the front lower motor mounts on the 86 engine;  The 92 upper front collars and mounts then fit into the 86 engine.  The lower rear mounts were the same.  Then just installed the 86 engine into the 92 frame.

for the 1100, the ignition would have to be kept with the engine...

So, the mounting and frames of the 1100 and the 86-87 1200s (probably the 88-90 as well) are the same... so if I 'm right, the 1100 swap with the late model frame is the same as what I did (86), only I didnt have the ignition difference, and carbs and settings.

So to install the 93 into the 84 is just the reverse of what I did.....with the ignition change, and carbeurator settings and jets....

[Harvy]

Isn't this basically the same swap that Irishluck was tryin' to do?     

Is THAT what he was trying to do.....

[Arnie]

Randy weighed in on this. 
He said, "P.s. all of the motor mounts are the same...even on the XJR1300"  on his Bump in the Road topic.

I'll take his word for it. 

Arnie