I have searched and cant really find any definite info on this ..
Ok I know the 3TJ1 was the first of the 400's to have the engine mounts on the head .
But apart from this what excatly is the difference in the rest of the 400 motor's ..
I have checked out some specs and apart from different bore and stroke ..
This is what I came up with....from http://www.motorcyclespecs.co.za/model/ ... 0%2086.htm
The EN2 was the first of them to have the 56 x 40.5 mm bore and stroke .So in theory all that is required is a head swap to make it fit a 3TJ.
The EN1 and the 1WG (Genesis) both have the 54 x 43.6 mm bore and stroke.
But then I came on this showing different figures.. http://www.madsi.co.uk/models.aspx

Is this to do with imports and Uk spec bikes or american spec etc etc etc ...
Can someone please clear it up for me and maybe give me some more precise info..

Cheers ,..

Nothing is ever as simple as bolting on a different head.
The TJ's crank is lighter ...

petrolhead wrote: This is what I came up with....from http://www.motorcyclespecs.co.za/model/ ... 0%2086.htm

Cheers ,..

I'd take that with a pinch of salt- they got the rear wheel size wrong

http://www.bikez.com/motorcycles/yamaha ... r_1991.php

http://www.bikez.com/motorcycles/yamaha ... 0_1989.php

I seen a thread somewhere about alot of the engine been stamped 1WG as a engine number ..
That is what was on the engine I took out, and my previous 3TJ1 was the same 1WG as engine number .
Asked a mate who has a 3TJ and his engine is marked 3TJ so what is the difference .

crank cases are the same the 1wg crank is heavier barrels and head are differant to 3tj, all the 3tj engines ive seen and thats alot all have 1wg on the cases apart from 4dx models and have 3tj on barrels and head. As far as I know the stroke is the same but could be wrong.

All 3tj engines are stamped 1WG

I compared the manuals for the American FZR 400, and Japanese imports, valve sizes are identical, so they are interchangeable? What is the difference between the intake valves in the 3T1, 3TJ2-6? In the catalog they have different markings. As well as marking a different pistons 4DX (3TJ-11631-01-00), how they differ and why 3T1 (3TJ-11631-00-00) does not repair the size of the pistons?

So if I were to buy a gasket kit for a 1WG and use it on a 3TJ... it would... work? Work for 80% of the gaskets? Waste my money?

It depends which gaskets .... if your talking about head and base gaskets then ... maybe but it isn't something I'd be looking to try and see if it works. If the head gasket's water holes are in a different place then you could end up with either rebuilding it again or a completely knackered engine.

Thanks for the quick response.

It's mostly for the engine covers. I have a line on engine gaskets really cheap for a 1WG. Regular price for the 3TJ.

Are the water pumps different between the two?