'92 140,000Km rebuild.

[SlowOldGuy]

I'm not so sure that something is "coming off the valve."

That could be crap baked onto the valve over the miles of operation during the combustion process.

The crap on the stem/seat side is a common build up of combustion products on the exhaust valves and fuel contaminants on the intake valves.

I replaced all my valves a few years ago due to pitting on the valve seat face.  I don't see any of that on your valves.  Looks like a cleanup and a bit of lapping and you're good to go!

DavidR.

[tmkaos]

It's very definately only on the exhaust valves.. it's a goldy-bronze colour. I wondered if was a ceramic coating, but I guess it's not factory whatever it is.

You are most likely right David, I just thought if was something from the combustion process it would be on the intake valves too as they are exposed to the same process - although admitedly they don't have the hot exhaust gasses flowing around the back of them.

I'm going to drop the 2 worst affected ones into our ultrasonic and see what that does to them I think.

[ribbert]

It's very definately only on the exhaust valves.. it's a goldy-bronze colour. I wondered if was a ceramic coating, but I guess it's not factory whatever it is.

You are most likely right David, I just thought if was something from the combustion process it would be on the intake valves too as they are exposed to the same process - although admitedly they don't have the hot exhaust gasses flowing around the back of them.

I'm going to drop the 2 worst affected ones into our ultrasonic and see what that does to them I think.

I'm with David, that IS crud build-up, common on exhaust valves, you can scrape it off then clean it up on a wire wheel.

Noel

[tmkaos]

I'm not so sure that something is "coming off the valve."

That could be crap baked onto the valve over the miles of operation during the combustion process.

The crap on the stem/seat side is a common build up of combustion products on the exhaust valves and fuel contaminants on the intake valves.

I replaced all my valves a few years ago due to pitting on the valve seat face.  I don't see any of that on your valves.  Looks like a cleanup and a bit of lapping and you're good to go!

DavidR.

I'm with David, that IS crud build-up, common on exhaust valves, you can scrape it off then clean it up on a wire wheel.

Noel

Awesome, that's put my mind at rest. I'll scrape away then 

Cheers guys!

James

[tmkaos]

Hi everyone,

Just thought I'd give a bit of an update and summary on the progress, or lack of it, since last year... had 3 weeks away at the bach with the family over New Years, boating, fishing reading and eating way too much, but now we're back into it..

The head needs new valve seals, the old ones were so brittle they fell apart as I removed them. The guides are ok, relap in the valves and we should be good to go. I ran the valves through our ultrasonic and all the crap on them came right off, thanks to Noel and David R for help on that issue.. the cams and cam chain and tensioner all look in good condition, very little wear on all the cam chain guides so that's good so I won't touch any of that. I've decided against slotting the cam gears, while I have the expertise to actually do the machining, I'm not really sure on how to go about setting it up and tuning, nor will I be in a postion to do heaps of testing once it's running. I'll need to be using the bike asap.

The bores are scratched in a few places. The pistons look ok, no major scores or wear on them. I'm attempting to get a local engine rebuilder to tell me whether or not i can just re-hone the bores to clean them out, or whether I'll have to go to the .25mm oversize pistons. The bores measure close to the upper limit anyway so I imagine I'll be going up a size. I'm also trying to locate another set of lower km bores in case I can swap it out and not go through the expensive of new pistons and reboring etc. However, used FJ parts don't really exist in NZ, there's not too many of them around. It's slightly tricky to co-ordinate logistics as I only have a push-bike to get me to work and around, my wife has our car at home with her for the baby. So i can only take bike parts to and from work, and out to workshops about once a week. I've got the car today, so the block is going with me to a local engine builder today for a chat after work.

The rest of the motor is staying as is. I'll be replacing the starter motor brushes and doing the alternator regulator, but I'm not touching the bottom end. It'l get a clean out and a repaint. I pulled off the clutch cover to have a look and it looks brand new in there.

I've taken off all the aluminium covers off the motor and I'm shining them up, should look good with the new paint.

I'm doing the timing advance mod, and giving her fresh valve springs, combine that with clean combustion chambers, fresh valve seals and lapped valves, new rings and a fresh hone/rebore and I reckon we should be back to at least factory horsepower if not slightly more on a 21 year old engine with 140,000km, not bad.

Randy is still waiting patiently for my order of parts as I don't want to go back him for more orders for parts, I'll just do it all at once.

Apart from all that I've cleaned up the engine mounts, painted the headers, they were an attractive shade or rust before, I will be rebuilding the rear brake caliper when I order parts from Randy, checked all the intake boots for cracks - some found but they don't penetrate all the way through. I'll keep an eye on them. Cleaned up and serviced my rear-set footpegs, all the bearings needed attention. I've serviced the swingarm bearings and all the lower rear suspension linkages, I had the rear shock (factory) rebuilt about 1500km ago when I put in new tarrozzi fork tubes in the front and race-tech emulators this was prior to Randy developing his new shock valves. So the suspension is good to go, and front brakes are aftermarket Brembos anyway, I've also just put stainless lines all on the bike and it got Chinese wave rotors last year too.

She'll be a new bike!

Looking forward to picking back up a few more ponies in the motor..

Let you know what the engine guys say about the bores.

Happy riding,

James

[ribbert]

Hi everyone,

I've decided against slotting the cam gears, while I have the expertise to actually do the machining, I'm not really sure on how to go about setting it up and tuning, nor will I be in a postion to do heaps of testing once it's running. I'll need to be using the bike asap.

The idea of slotting the sprockets is to achieve standard timing, not change it, so there is no dialing in to do once it's running.
Assuming they left the factory with the valve timing spot on, as the motor gets some miles on it wear makes it impossible to line the marks up so the slotting is just for that, not to modify it.
I couldn't get my last motor within a half tooth of standard timing. The sprockets allowed me to line them up perfectly and I was surprised at the difference it made.
If your marks line up perfectly after you have reassembled and turned over by hand a couple of times then it's not an issue.
Noel
Noel

[tmkaos]

The idea of slotting the sprockets is to achieve standard timing, not change it, so there is no dialing in to do once it's running.
Assuming they left the factory with the valve timing spot on, as the motor gets some miles on it wear makes it impossible to line the marks up so the slotting is just for that, not to modify it.
I couldn't get my last motor within a half tooth of standard timing. The sprockets allowed me to line them up perfectly and I was surprised at the difference it made.
If your marks line up perfectly after you have reassembled and turned over by hand a couple of times then it's not an issue.
Noel
Noel

That's a damn good point Noel. Maybe I should reconsider. When I pulled it apart I checked it first and the dot on the cams lined up perfectly central in the hole in the #3 cam cap at TDC.. But for a little more effort and 20mins of machining I guess I should do it..

We had one of our customers come in today, he is the engine builder for a fully race-spec'd late 1970's era CB1000. We make up cam chain tensioners and guides for his race motors and have recently started producing them in enough quantity to export them. Aparently demand for them in the States is unbelievable. Anyway, he knows his engines and he had a look at my bores. He reckons all it needs is a re-hone, which is awesome so I'll still take it to an engine shop to have that done but it's looking like I WON"T have to go down the new piston track..

James

[tmkaos]

Ok so we're getting some traction again now.

Dropped into my local engine reconditioner last night, he took one look at my bores and allayed any of my fears with a simple, "Shit mate, storm in a teacup. She'll be right." So he's re-honing them for me this morning at a cost of $40. Sweet.
So now I' waiting on Randy to get back to me about new rings - they're not listed on his site, so I've emailed him, then I can bash my credit card against the exchange rates and spend a lot of money buying all the other goodies I need.

While I wait I'm thinking about what Noel said about slotting the cam gears. Can anyone confirm my initial thoughts that I would just extend the bolt holes either side by a couple of millimeters following the same PCD? What then locks the gears in position on the cams? Do you just rely on the bolts clamping it up tight enough?

Cheers,

James

[SlowOldGuy]

Yep, the clamping force of the 2 bolts is plenty to keep the sprockets from slipping.

I have Falicon slotted sprockets on my '85.  I went the whole cam degreeing route with dial indicators and degree wheel.  A lot of work and math and I couldn't really tell a difference.  So much so that I didn't bother doing it to my '93.

But if you have a motor with a lot of miles and are just going to center the alignment marks, then it's probably worth the effort

DavidR.

[FJ1100mjk]

Not the first time I've heard someone comment that cam degreeing didn't produce any noticeable gains.

Has anyone else gotten anything worthwhile out of the time and expense of doing it?

[tmkaos]

Not the first time I've heard someone comment that cam degreeing didn't produce any noticeable gains.

Has anyone else gotten anything worthwhile out of the time and expense of doing it?

When it first got bought up last year in this post I looked up a whle bunch of posts about it - I think thru Andyb's FAQ - cheers for that info Andy, and the general consensus seemed to be that you can gain a small amount of hp in certain areas of the rev range but you lose a corresponding amount elsewhere, which kind of makes sense, the laws of physics being what they are and all.  I guess if you are drag racing or circuit racing then that might be something you'd accept..

James

[Pat Conlon]

http://www.fjowners.com/index.php?topic=712.0

We talked about slotted cam gears back in '09. Look at Randy's post #30 in this topic.  Cheers!

[ribbert]

Not the first time I've heard someone comment that cam degreeing didn't produce any noticeable gains.

Has anyone else gotten anything worthwhile out of the time and expense of doing it?

I did, but I couldn't get the cams within half a tooth of the timing marks and fitted them to achieve standard valve timing. That made a big difference.
If your cams line up, spend the money somewhere else.
I also agree, the consensus is there are no gains, for road riding anyway, to be had by fiddling around with the valve timing.
Noel

[FJ1100mjk]

Pat:

Looked over all the posts in the link, including Randy's. Thanks.

The following that I read from a copy and paste by andyb cemented it for me...

"The only down fall was the HUGE power lost between 4000 and 6500. If you have ever ridden your FJ on the highway, you will know that that is where the engine cruises. That's what gave it the "roll-on" power that makes our bikes so much fun.

I turned my lovable FJ into a dreadfully serious not so streetable road rocket."

Marty

[fj1289]

The milder the state of tune of the engine, the less critical any tuning parameter is -- or stated another way, the milder the state of tune, the wider the "sweet spot" is.

If a mildly tuned engine has the jetting slightly off, ignition timing slightly off, or cam timing slightly off, the engine will still run well. On a more aggressively tuned engine (bigger bore, higher compression, larger cams, larger valves, etc) each of those tuning factors will be more critical and the engine will "fall off" more for smaller variations in tuning factors.

In racing, lets say a GOOD rider/driver may be able to cut .5% off his lap time with a 1 or 2% increase in power.  If a lap is 1 minute long he may save .3 seconds per lap -- might be the difference between a consistent podium finisher and a field filler. On the street I seriously doubt you'd notice the difference.