Project Motor Swap

[FJ1200W]

I've been studying the oiling system and wanted to share these lubrication diagrams. If I can make any improvements, let me know, I had trouble tracking some of it, especially in #4.

My focus is on the upper end.

I scheduled a meeting with my machinist this afternoon, weather permitting.

[FJ1200W]

In the past I had smoothed out the sharp edges on the pistons - does anyone think this is worth the effort?

[CutterBill]

Lubrication system: there are a million FJ's all over the world, being soundly thrashed and abused with stock oil systems and they work just fine. Exactly what problem are you trying to solve?

Smoothing off the piston edges: Is it worth it? No.  But is it fun and makes you feel better? Oh absolutely, that's why I do it. 
Bill

[FJ1200W]

Lubrication system: there are a million FJ's all over the world, being soundly thrashed and abused with stock oil systems and they work just fine. Exactly what problem are you trying to solve?

Smoothing off the piston edges: Is it worth it? No.  But is it fun and makes you feel better? Oh absolutely, that's why I do it.  
Bill

I guess the improvement comment was two fold, mechanically and the the diagrams for future reference.

The #1 intake cam journal(s) looked a little starved. The engine has APE studs, they're fat, and I was concerned they might be restricting the oil flow. I want to dot my I's and cross my T's the best I can. I was considering enlarging those holes one drill size, just enough to maybe increase flow - But, if is is already restricted somewhere else, there is no point.

I dropped the cylinder and pistons off at my machinist just now, hopefully in a couple days I'll know if they're usable.

He has some interesting tools of his trade, one shown.

[FJ_Hooligan]

Replace the "oil supply" studs with stock and use the APE studs on the rest

[FJ1200W]

Replace the "oil supply" studs with stock and use the APE studs on the rest

It's a tough call. There are enough people running them without any issue to make me think they have to work.

And I've had a few people say they don't like them. One said they were too brittle IHHO, he had seen them snap off at the case, but it was in a higher vibration application, whatever the heck that was. And Randy does not seem to be a fan of them. As this is a budget build for me, I am going to do a close inspection and list the pro's and con's of all options.

Thanks for the feedback

[fj1289]

For me, having gone down a similar path already, it would be a no-brainer: sell the APE studs and get some stock ones (even used).  For the $$ spent figuring out a top end oiler system, you could simply buy new studs.  Really wish I had listened to similar advise in the past!

[FJ1200W]

For me, having gone down a similar path already, it would be a no-brainer: sell the APE studs and get some stock ones (even used).  For the $$ spent figuring out a top end oiler system, you could simply buy new studs.  Really wish I had listened to similar advise in the past!

I may do that, I have that complete other bike just sitting there, it could be a great donor for many parts.

And I do have a title for it..... Maybe that's where the motor will end up.

It would be fun smoking the local V-Twins on a ratty old FJ1100  

Dyno chart is a local shop and a recent HD Milwaukee 8 mild build, that's some torque and they can pull some pretty impressive times - easily.

What was the maximum RPM you ran with the shim over buckets?

[ribbert]

What was the maximum RPM you ran with the shim over buckets?

I think you'll find piston speed is the limiting revs factor for a road going FJ engine.

Noel

[Pat Conlon]

What was the maximum RPM you ran with the shim over buckets?

I think you'll find piston speed is the limiting revs factor for a road going FJ engine.

Noel

Nope, the FJ's limiting rev factor is valve float from oem valve springs.

[ribbert]

What was the maximum RPM you ran with the shim over buckets?

I think you'll find piston speed is the limiting revs factor for a road going FJ engine.

Noel

Nope, the FJ's limiting rev factor is valve float from oem valve springs.

I guess that depends on how you read the question.

There is an absolute mechanical limiting factor (excluding component failure) - valve bounce, and a practical mechanical limiting factor - piston speed.

For a road bike, such as he's building, I took it to be the latter.

Noel

Just out of interest, do you know at what revs valve bounce occurs?

[Pat Conlon]

I said valve float (from loft) not valve bounce, there is a difference.

At what RPM Valve Float on oem FJ cams with oem springs?

I have been told somewhere in the range of 10k-10.5k RPM, but I'll defer to the experts.

Bob W, Mike, Chris, Randy, David, what say you guys?

[racerrad8]

What was the maximum RPM you ran with the shim over buckets?

I think you'll find piston speed is the limiting revs factor for a road going FJ engine.

Noel

I am churning for more specifics on this opinion of Noel's of how the piston speed for the FJ engine is the limiting factor.

This will be interesting to say the least...

Randy - RPM

[Pat Conlon]

Yep, I was wondering about that....Questions for Noel:

1) FJ Piston speed: How fast is too fast?
2) If the stroke is 63.8mm at 11k rpm the FJ piston speed is 4605 FPM, is that too fast? Why?

I'm open to learning....

[racerrad8]

Yep, I was wondering about that....Questions for Noel:

1) FJ Piston speed: How fast is too fast?
2) If the stroke is 63.8mm at 11k rpm the FJ piston speed is 4605 FPM, is that too fast? Why?

I'm open to learning....

I'll add a couple more questions for Noel:

3) Why is piston speed the limiting factor of a FJ engine?
4) Have you ever observed a FJ engine failure due to excessive piston speed?
   a) If yes, what failed due to the excessive piston speed?
5) Valve "bounce" versus valve "float"; which comes first?
6) Why does one come before the other?

I too am churning for learning...

Randy - RPM