89 FJ1200 engine and gearbox rebuild

[simi_ed]

Hold on, Gabe (aka Mr. Big Spender),  Don't be so quick to buy those new cams.  My intuition tells me that the cam material is much harder than the aluminum in the cylinder head.  So, would 'new' cams be any better?  What are the diameters of the journals vs. spec.?  

Next, it has been rumored that some engine builders think the cams may be too tight and occasionally seize & break under certain conditions; a bit more clearance would allow more oil space, and perhaps prevent the described seizure and resulting destruction.

Now, if you want to upgrade to aftermarket hi-po cams, that's another story, but don't delude yourself that the journals are worn out on the cams and therefore you need to buy hi-po cams to get new journals.  Big end & small end inserts worn?  Sure, and they're relatively cheap to replace, since you're already in that far.

Free advice, worth all you paid for it ...

Otherwise, you seem to be doing a bang-up job and documenting it very well for yourself and all of us.  Thanks!

[JMR]

You don't need new cams....they look fine. Also...what do you mean by replacing the "bearing caps"? Are you talking about the bearing shells? I'd check to make sure the big end of the rods are round.....I have personally seen them all over the place which requires cutting the cap and sizing the big end ID.

[DeltaFlyer]

You don't need new cams....they look fine. Also...what do you mean by replacing the "bearing caps"? Are you talking about the bearing shells? I'd check to make sure the big end of the rods are round.....I have personally seen them all over the place which requires cutting the cap and sizing the big end ID.

Yeah, sorry, I meant the bearing shells.... where the f*** did I get 'caps' from? LOL!

I'll take a look at the big ends today.

[DeltaFlyer]

Hold on, Gabe (aka Mr. Big Spender),  Don't be so quick to buy those new cams.  My intuition tells me that the cam material is much harder than the aluminum in the cylinder head.  So, would 'new' cams be any better?  What are the diameters of the journals vs. spec.?  

Next, it has been rumored that some engine builders think the cams may be too tight and occasionally seize & break under certain conditions; a bit more clearance would allow more oil space, and perhaps prevent the described seizure and resulting destruction.

Now, if you want to upgrade to aftermarket hi-po cams, that's another story, but don't delude yourself that the journals are worn out on the cams and therefore you need to buy hi-po cams to get new journals.  Big end & small end inserts worn?  Sure, and they're relatively cheap to replace, since you're already in that far.

Free advice, worth all you paid for it ...

Otherwise, you seem to be doing a bang-up job and documenting it very well for yourself and all of us.  Thanks!

You're right, of course, I didn't take enough time to think it through. Posted tired at the end of a long shift and a bunch of work on the bike. Heck, I had already checked the journal diameters and knew they're all in spec when I posted that (results posted back on page 2 of this thread)....  feeling a bit foolish as a result.

I also had a chat with my machinist earlier today, he's an old school guy that has built more high performance engines than I've had hot dinners, and he basically said the same as you. The cams are fine since I'm building for reliability and longevity, not increased performance, and being an air cooled motor the oil clearances being toward the larger end of the scale are not necessarily a bad thing.

Conclusion - these cams are going back in as is, so I guess I'll just have to continue spending all my money on wimmin and drink instead.  

[JMR]

Hold on, Gabe (aka Mr. Big Spender),  Don't be so quick to buy those new cams.  My intuition tells me that the cam material is much harder than the aluminum in the cylinder head.  So, would 'new' cams be any better?  What are the diameters of the journals vs. spec.?  

Next, it has been rumored that some engine builders think the cams may be too tight and occasionally seize & break under certain conditions; a bit more clearance would allow more oil space, and perhaps prevent the described seizure and resulting destruction.

Now, if you want to upgrade to aftermarket hi-po cams, that's another story, but don't delude yourself that the journals are worn out on the cams and therefore you need to buy hi-po cams to get new journals.  Big end & small end inserts worn?  Sure, and they're relatively cheap to replace, since you're already in that far.

Free advice, worth all you paid for it ...

Otherwise, you seem to be doing a bang-up job and documenting it very well for yourself and all of us.  Thanks!

You're right, of course, I didn't take enough time to think it through. Posted tired at the end of a long shift and a bunch of work on the bike. Heck, I had already checked the journal diameters and knew they're all in spec when I posted that (results posted back on page 2 of this thread)....  feeling a bit foolish as a result.

I also had a chat with my machinist earlier today, he's an old school guy that has built more high performance engines than I've had hot dinners, and he basically said the same as you. The cams are fine since I'm building for reliability and longevity, not increased performance, and being an air cooled motor the oil clearances being toward the larger end of the scale are not necessarily a bad thing.

Conclusion - these cams are going back in as is, so I guess I'll just have to continue spending all my money on wimmin and drink instead.  

[DeltaFlyer]

I went through the big ends today and surprisingly they are all in spec for oil clearance, so I lubed them an torqued them back up.

All the shells looked typically like this one...




I plastigauged them at 12 o'clock where the wear is most evident.


One less thing to worry about.

Cheers,
Gabe,

[DeltaFlyer]

Guys, what do you recommend for sealing the crank case halves?

It's a liquid gasket, is there any particular product that stands out above the rest for our application?

[Pat Conlon]

Yamabond. Not too much, as it peels off and clogs your oil pickup screen.

Randy @ RPM has pictures of this on engines he has worked on....

[racerrad8]

Here is all I will ever use; Permatex Ultra Black

I have seen a lot of different stuff used with good & bad results.

Randy - RPM

[ribbert]

Here is all I will ever use; Permatex Ultra Black

I have seen a lot of different stuff used with good & bad results.

Randy - RPM

I've probably had as many engines (all sorts) apart as Randy and over a much more diverse range of applications and I swear by this stuff. Like Randy I have tried and seen used all manner of products but this is the best. Also great if you need pull it apart again at some point.

Use sparingly.

As it also says, it is a gasket maker. I use it a lot on engines where gaskets are no longer available. Anyone that has hand made fibre gaskets knows what a PIA that is.

Noel

[DeltaFlyer]

Thanks guys. Permatex ultra black it is then.

[DeltaFlyer]

My RPM order came in the other day but I've been quite busy lately and have had no time for the project. I unpacked it on Friday and the very first impression I got was just how well packed everything was! I buy quite a bit of stuff online and nothing has ever arrived packed anywhere near as well as this. Seriously. Someone spent a lot of time and care packing this order. Needless to say everything was present and accounted for, with an itemized packing list included. I didn't take pics of all the goodies (I was a bit too excited and forgot) but I'll post a few next time..... and I needed a second box when it came time to put it all away because I couldn't figure out how to re-pack it back into the same box as it was LOL!

Thank you, Randy.    

...........................................

I wire brushed the head studs and they came up nice and shiny, then I hit them with several coats of cold galvanizing paint.



I think I'm about ready to start the reassembly. Except for a few bits that haven't arrived yet, like the Permax Ultra Black, and the cylinder head isn't back from the machinist for another week.... and the output shaft seal I forgot to order from RPM  

I have a question about those thin orange o-rings between the cylinder block and the crankcase, are they absolutely necessary? the joint has a gasket, so what purpose do those o-rings serve? I ask because I don't have new ones and the old ones pretty much disintegrated during disassembly. So can I get away with leaving them out?

Cheers,
Gabe.

[DeltaFlyer]

I have a question about those thin orange o-rings between the cylinder block and the crankcase, are they absolutely necessary? the joint has a gasket, so what purpose do those o-rings serve? I ask because I don't have new ones and the old ones pretty much disintegrated during disassembly. So can I get away with leaving them out?

Cheers,
Gabe.

....anyone?

[FJ111200]

....anyone?

You can leave them out.

[DeltaFlyer]

Just a quick update. The bike is nearly back together again, just waiting on the new valve shims to finish the top end.

Engine back in bike, new oil radiator is in, just have to hook up the electricals, ignition, ect. then fit the exhaust.

Reassembly went very smoothly, which means that I probably made a monumental stuffup that I will discover when I try to start her up and everything goes pear shaped. 

I should be firing up the 'new' engine late next week.