How I've come to own a modified Z1000J and it's refurb

[1962royp]

Yes unitrac pistons.
How many lines has the cams got on?
The threads need helicoiling simple job.

[Julian_Boolean]

I don't think my cams have any lines, Rob Weed showed me his J cams with the lines, mine don't have them, I can take some pictures of the cams later but I'm having a rest now after pulling it apart.

[Julian_Boolean]

Does Unitrak pistons mean I have a Unitrak crank, I assume it does due to the 18mm gudgeon pins.

[1962royp]

I think so
cams have 1 line 2 lines and no lines unitrac ones have none so get the treads repaired.
A very good parts site to check is CMSL from holland i check a lot on here.

[Julian_Boolean]

Next question, what the bloody hell is the two half head gasket about, how does that work, is the big o ring round the cam chain all that seals the centre of the head, are both gasket faces supposed to be flat?

[Al]

Yes and Yes

AL

[Julian_Boolean]

Mine had the wrong head gasket, it had a one piece gasket and the o ring, the gasket was too big for the bore, there's a ring of gungy carbon round each of the combustion chambers.

[Al]

Unitrak 1100 same as 1100R same as that other one i forget.
No grooves on cams, cam base circle 28.35mm Lobe 37.85mm, lift 9.5mm.
Head has threaded boss between cyl's 1 and 2 on inlet side, bi-spherical domes, bigger valves different valve angle between inlet and exhaust blah blah blah.
Barrels; have no counter bores round the four outer oil carrying stud holes as yours.
Crank has 18mm pins though it is possible to have early 17mm rods reamed / honed to 18mm.

AL

[Al]

Sounds like it had a wiseco / cometic 1170 gasket.
AL

[Julian_Boolean]

Unitrak 1100 same as 1100R same as that other one i forget.
No grooves on cams, cam base circle 28.35mm Lobe 37.85mm, lift 9.5mm.
Head has threaded boss between cyl's 1 and 2 on inlet side, bi-spherical domes, bigger valves different valve angle between inlet and exhaust blah blah blah.
Barrels; have no counter bores round the four outer oil carrying stud holes as yours.
Crank has 18mm pins though it is possible to have early 17mm rods reamed / honed to 18mm.

AL

Not sure if you're saying mine is a Unitrak barrel or not, and I hope it's got a Unitrak crank as reamed out small ends really doesn't sound good.

[Al]

My understanding was that they originally tried 'O' rings, then more or maybe less 'O' rings all of which leaked before deciding later on that no 'O' rings was the way to go. Youre barrels have none and i thought that it was by the time of the Unitrak /Z1100R that this practice was in force.
These would appear as counter-bores round the outside stud holes in the top face of the barrels not to be confused with the counter-bores in the lower face for the locating dowels.
I see youre point about the small ends. I think they are a little small but half a mil increase per side on the diameter isn't much.

If you use a one piece gasket it is best not to use the supplied cam tunnel 'O' ring but fill the groove just proud with high temp RTV like Loctite SI 5980 or similar.
I think i have some two piece 1100 head gaskets laying about if you need some.

Cam cap bolt threads can be a real drama with these. If youre getting the barrels helicoiled it would be worth testing the bolts and threads there whilst the head is off. Dont tighten them as it says in the manual; 5 to 6 lbs/ft maximum is adequate if you have a very low range and accurate torque wrench. The bolts 'waist' and stretch very easily also.

AL

[zed1015]

Unitrak 1100 same as 1100R.

AL

Not sure if you're saying mine is a Unitrak barrel or not, and I hope it's got a Unitrak crank as reamed out small ends really doesn't sound good.

As AL has already said above.
If your bike is a genuine 1100r then the engine is the SAME as the Unitrack which it does appear to be.
No honed out little ends etc.
It was the Z1000R that had the 'J' motor with 17mm pins.
Yours has 18mm as std so no need to worry.

[Julian_Boolean]

Mine definitely isn't a genuine 1100R, frame number starts KZT00J and was first registered in November 1982.
The engine number also starts KZT00J, so the crankcases are Z1000J, which makes me wonder why some would put Unitrak parts into 1000J crankcases.
The wiring loom looks like Unitrak as it's a bit too long for the bike.
The ignition pickup and igniter are Unitrak.

God knows what I've bought, or more to the point, where the parts came from.

[zed1015]

Mine definitely isn't a genuine 1100R, frame number starts KZT00J and was first registered in November 1982.
The engine number also starts KZT00J, so the crankcases are Z1000J, which makes me wonder why some would put Unitrak parts into 1000J crankcases.
The wiring loom looks like Unitrak as it's a bit too long for the bike.
The ignition pickup and igniter are Unitrak.

God knows what I've bought, or more to the point, where the parts came from.

J and Uni cases are basically the same apart from the numbers and all the guts just swop over.
Simplest way to upgrade the motor without all the rigmarole of involving DVLA (which now needs a confirmation letter from the MOT station to get a change of engine number on the V5)
It's no big deal and if the engine sprocket is held on by a nut rather than a bolt it's most likely got the stronger uni box in it too.

[Julian_Boolean]

I didn't know that about the DVLA and engine numbers, last time I switched engines in a bike was in 1985 with 250LC engines.
Gearbox sprocket is held on by a nut and I think it's got a 6 bolt clutch.