What frame is the engine going in?

I wonder if it would squeeze into an FZR400RR frame :shock: Seen a 1000exup in a 400 so there's a good chance. There's a bloke with a turbo charged Firebalde engine in one, for some reason he's fitted a longer swing arm. Thundercat 600 engine bolts in with a pair of £40 spacer plates, the 400 is 60...

I wonder if it would squeeze into an FZR400RR frame

Zephyr swingarms fit, you'll need to change the rear wheel bearings and get spacers made, 750 and 1100 need a sleeve for the swingarm spindle as well, I think the 550 doesn't.

750 and 1100 are a bit longer than stock, I don't know about the 550.

Some Z750s and GPZ750s had BST34s, so they might be standard 750 carbs.

Closest motor to a Z1 you are ever going to get and copied almost directly from the Z engine design. Even the cylinder stud spacings are the same and the GS head will drop straight on the Z motor. A mod that was popular in drag racing to take advantage of the GS's bigger valves until the 'J' motors...

Z1100R jetting should work, as they have a Unitrak engine and BST34 carbs.

That was missing from my Z1000J when I bought it.

If you mean a ZRX1100 front end then the forks are much the same length as the ones I have, I don't know about the offset. I'll probably end up buying a set of Z1000J or GPZ1100B forks and yokes and getting spacers made up for a 17" wheel to fit, this seems to be the easiest answer for getting ...

As a rough guide I would check the headrace bearing sizes. Would it not be easier to get longer fork tubes? drew Checked the headrace bearings and looks like the stem on the ST is biiger than the J, the top bearing of an ST is the same bearing as the bottom bearing of a J Longer fork tubes would be...

As above really, there's a set of 40mm 1979 Z1000ST forks and yokes on ebay, would these bolt straight onto my 1982 Z1000J2. 40mm is 2mm bigger than the standard 38mm J forks, my bike currently has an 89 FZR1000 EXUP front end fitted which is too short so the bike tips into corners and lacks ground ...

I just use a c spanner. https://uk.rs-online.com/web/p/c-spanners/8280239?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_CatchAll-_-Ad+Group+Catch+All-_-PRODUCT_GROUP&matchtype=&pla-367227450683&s_kwcid=AL!7457!3!226080437215!!!g!367227450683!&gclid=EAIaIQobChMIk5e8j_bB5gIVhbTtCh0QeAm2EAQY...

Does anyone know what size Castle Socket I need for a Z1000J2 steering stem nut, I'm sick of using a hammer and screwdriver to do these up and fancy doing it to the correct torque for a change.

Don't put it back to standard, it'll be awful, flexible and dull. Relive your youth and do the mods as you suggest like you would've done back in the day - trust me, it makes an average bike into a good one! :wink: (If you hadn't guessed I'm not a rivet counter - I don't get it as nobody had a stan...

https://www.cybike.co.uk/About-Us

Used to be able to get them, or order from Japan, from Webike

https://japan.webike.net/products/21239964.html