XJR400 advice needed

[Cossackmannie]

Hi all,
This posting is more of a pre-emptive measure in case the damage to the motor on the XJR400 is beyond repair and I would then need a replacement.

What I'd like to find out is this- What models have the same bottom end as the XJR400 or would be a suitable swap?

As far as I can tell, the FZ400 and FZ600 look very similar. Also the XJ600. If anyone has a motor that fits the bill (or frame) please let me know.

Please don't tell me to just bin it. I want to get this bike on the road simply to prove a point to someone I know. (Looking forward to the drive-by gloating already!!:lol: )

As I'm not well-versed with the models and specs of the various 400's like you guys and girls, so I'd really appreciate any help/advice offered.

Thanks in advance folks

Ian

[Evilchicken0]

We don't get a lot of XJR questions here but if they are similar in their roots to the FZR's then I'd say your probably right the engine crankcases would be common to other bikes.
The XJ600 is the same engine as the FZ600 with some small differences not sure if the FZ400 was aircooled or not.
Of those engines I'd take the FZ600 ... cross my fingers and home the whole thing would plug into the XJR frame.

[Kayla850]

I think you'd have a good chance of getting an FZ or XJ600 (pre-divvy) engine to work- wasn't the FZ400 liquid cooled?

[jim157]

^^^
Yeah, the FZ400R was definitely liquid cooled.

[Evilchicken0]

Ok - if "we" run with the FZ600 (it had a little bit more torque and fizz than the XJ600 version), the next step is to take some pictures of your engine and the donor engines (ebay's good for this).

Thing is though this is an engine from about 1988 and there's no garentee it will be any better than your original XJR.

So, what's the problem with your engine ??? and what's the budget ???

[Cossackmannie]

I've been checking the differences between the FZ and the XJR. Physically, the bottom ends are the same. Probably go with the XJ motor if the XJR's motor doesn't work out.

My mate bought the bike from a local f**kwit and subsequently found out the reason for the motor not turning over past TDC on cylinder 3. The f**kwit had tried to change the plugs without removing the tank or cleaning out the debris which dropped into the bores. To top this off, the head was siezed on the studs!!!
He gave it to me after he lost patience with it. Managed to get the head off and found a stone amongst other things in bore 3. The valves are ok but the piston crown has slight damage to one side, making it touch the bore. The motor hasn't been run but the damage is a result of him trying to bumpstart it.

There's no real budget to follow as it's a side project to mess with while I work on the RGV. I'm not really fussed about originality or keeping it a 400 either.

Cheers for the replies.

Ian

[Evilchicken0]

Ah, so you know a spanner when you see one
The FZ (as I remember it) had smaller carbs, different cams and used a 4 into 1 pipe for more torque over the XJ engine but really I'd go for the younger or lower milage engine.

You might be able to clean up the piston and hone the barrel on your engine. You'd probably get all the barrels honed then skim the them and the head. Decoke and probably new rings and soft link cam chain you'd be good to go.
I reckon a 600 might be tired by now too, so you might end up doing this anyway. XJR600 would be nice though

[blackbird]

cossackmannie? rings a bell from aberdeen bikers. I have a fzr400 engine out you can have a look at and a couple of 600s in frames, since your no far away

[Cossackmannie]

Hi Blackbird,
Just noticed your reply. Got new gaskets now. Base gasket from a snowmobile dealer in Germany, Head gasket from an auction agent in japan and access to a web-based microfiche in Russia!
The motor is now back together and seems fine. Was going to lob it back into the frame but with all the rust round the welds on the frame, I'll strip it down for blasting and powdercoat.
So far, the bike was a freebie and I've spent £109 on gaskets and dowels. Wheels and frame for coating- est £175, paintwork by myself- est £130 for materials and time, fluids and service items- est £60. So, looking at £475-£500 plus MOT and road tax. At that price, I'm not really fussed about the motor lasting so, if it does go bang at some point, I'll stick an XJ600 lump in it.
One thing it will need at some point is a pair of airbox side covers but they can wait for now.

Blackbird-
Might take you up on the looksee over the FZR and the 600 motors.

Cheers

Ian

[blackbird]

aye no bother. I am away at work for about a month but will check in here when I can