1990 FJ12 Rebuild in Ireland

[Mypoorfudge]

Hi folks,
Hope you all having a good break over Christmas.
I am down with bad flu and stomach bug. Just able to get at the laptop now after eight days.

Anyway enough of the misery and on to FJ related matters.

After getting some good advice from Randy and some members (much appreciated) a box of new parts for the engine build arrived from RPM a couple of months ago.

Compared to some engines I have worked on, the FJ is relatively simple but I am seriously lacking experience with the FJ engine.

So with my box of bits I set about the top end rebuild of the engine.

Im linking some photos below ......

Valve train dissassembled and cleaned. Everything kept in sequence.


All valves re-ground


Head and combustion chambers cleaned.


All the important parts cleans and ready.


New valve seals installed.

[big r]

Looking good

[Pat Conlon]

Good on ya! 

Spend $150 and replace those tired oem valve springs.... Kookaloo on steroids: 10k+rpm and no valve float



http://rpmracingca.com/proddetail.asp?prod=Head%3AValveSpringsHP

[Mypoorfudge]

After getting all the valves springs and new seals back in I installed the new head gasket.

New oil seals on the 2 bolts as well, copper washers also.

Torqued the head down following the Haynes manual.
The reassembly of the camshafts followed.

A new cam chain installed, a split chain with a rivet link.

All shim buckets and shims installed back where the came from.

Getting the timing we found a bit tricky. Eventually managed to get all the dots and marks lined up.

I installed the cam chain tensioner along the way as well and found it difficult as there was so much pressure on the spring it took a few attempts to get it in. IS this normal guys ?.

I left the engine this way for a couple of days and when I went back to it, my intention was to go through the shims and see what changes I needed to make.

I think I might have a problem here.

I checked the clearance on the first two cylinders and I have none or very little. On at least 4 shims, I have no clearance at all.

Anyone any ideas.

Something similar happened to me years ago with a Honda CX500 engine. Turns out I was 180 degrees out with my timing.

Would I have made a similar mistake with this ??.

Any help or advice greatfully received.

[ally]

I'm doing pretty much the same thing at the moment, damaged a bucket when the valve tool slipped off :doh:

had a real problem getting the damaged bucket and a couple other 'normal' buckets out, pretty much zero clearance in the bore on some

one exhaust bucket was lathered in grease so somebody had been in before and a couple of nasty dings evident also, on the plus the pistons and head are nice and clean so was running ok prior, on the downside 6 studs are rusty as, getting a mate to make some up

sadly insufficient funds for new springs

[Mypoorfudge]

Good on ya! 

Spend $150 and replace those tired oem valve springs.... Kookaloo on steroids: 10k+rpm and no valve float

Pat,

see my second post, the head is back together. All springs and valves were well within spec and the rebuild is not intended to give me high performance.

I think there is a law here banning you from going over 9000 rpm. Instant removal of driving liceince  

[Mypoorfudge]

I'm doing pretty much the same thing at the moment, damaged a bucket when the valve tool slipped off :doh:

had a real problem getting the damaged bucket and a couple other 'normal' buckets out, pretty much zero clearance in the bore on some

one exhaust bucket was lathered in grease so somebody had been in before and a couple of nasty dings evident also, on the plus the pistons and head are nice and clean so was running ok prior, on the downside 6 studs are rusty as, getting a mate to make some up

sadly insufficient funds for new springs

I feel your pain ally on the springs. You could drop a small fortune into one of these engines without much effort but I aint going there. I want to get this bike back on the road.

Ally did you have any clearance issues like I described with the shims.

I had no issues thankfully with damaged buckets.

[ally]

I'm a little ways behind you, it's stripped at present, struggling with enthusiasm to crack on, I must get my @rse in gear though

I need to dress the shim bores, finish cleaning the valves then lap, still waiting on the studs

I've purchased a few toys from randy, I've the fork valves to go on, bar dampers, spin on filter (done), I'm living on a heavily reduced pension so my spending power is poor now, I'm collecting parts to fettle my c90, I've a loom swap to do on my dr750, rear caliper on the mz660 and more, I just have to creep along and pick up spares when I stumble upon them

still the top end rebuild, shim, carb balance, head bearings, forks, caliper rebuilds, front wheel bearings and boots to go yet (I've everything but the tyres)

I started at the back and came forward, I only manage an hour or two before I get too tired to continue so it's slow going!

[Pat Conlon]

......I left the engine this way for a couple of days and when I went back to it, my intention was to go through the shims and see what changes I needed to make.

I think I might have a problem here.

I checked the clearance on the first two cylinders and I have none or very little. On at least 4 shims, I have no clearance at all.

Anyone any ideas.

Just a thought: if you lapped your valves, the valves now sit lower on the seats, meaning the stem is now longer and the bucket/shim to cam clearances change.

I'll defer to the experts.

You move fast....No worries on the valve springs, looks like you used Viton valve seals which are superior to oem.

I love to see this work!  Kudos!

[Motofun]

Cutting new seats will affect clearances, having the clearances tighten up is to be expected.  Did you deck the head while you were in there?  It's usually recommended but I've gotten away without it.

[Mypoorfudge]

Thank you for the suggestions guys regarding the valve seats.

I should clarify though.

The head was in good shape and the engine is not a high mileage one. I basically re-polished the valve seats.

They were ok, so I gave them a good polish/clean with the two pastes, just to bring that nice even grey colour back.

Do you still think that would have made the difference.

[oldktmdude]

Thank you for the suggestions guys regarding the valve seats.

I should clarify though.

The head was in good shape and the engine is not a high mileage one. I basically re-polished the valve seats.

They were ok, so I gave them a good polish/clean with the two pastes, just to bring that nice even grey colour back.

Do you still think that would have made the difference.

Lapping (polishing) the valve seats will definitely cause the valve clearances to tighten up. Depending on how much valve and seat material you removed will govern the size difference to the shims. If there is no clearance, it is difficult to determine the correct shim size until you can get the feeler gauge in to measure the gap. You will have to remove the shim and fit a thinner one so you can get a gap reference.
   Regards, Pete.

[Pat Conlon]

^^^ +1 on what Jack and Pete said. Set your valves with new shims as needed. Put a couple hundred miles on the new top end then open her back up and recheck your (cold) clearances and re torque (25 ft/lbs) your head nuts and change your oil..

[Mypoorfudge]

Wow!

Just by polishing the valve seats, it can change that much. I would say that no material was removed at all, just cleaned up.

So it looks as if I may go through all the shims in there, find the narrowest one and hope that it is slim enough to fit in and give me a gap where I now have none?.

I only have the shims that are in the engine already so I will have to see how that works out.

[Pat Conlon]

Not so much that you removed the metal on the valve edges or from the valve seats, but you certainly removed a built up layer of carbon.
What kind of clearances did you have before? I'll bet a jelly donut they were tight to begin with.

When you rotate that crank to turn the cams, be sure you have a shim in *all your buckets* (even if it's the wrong size shim) without that, the sharp edges of the buckets will ruin the face surface of the cams.