Yamaha FZR400R - Restore'n'Rebuild (IMAGE HEAVY)

I did carefully drill an appropriately sized hole and measured the depth, ended up being close to 15mm hollowed out, piloted at 1mm and finished with a 3mm. Worked like a charm

 

Attempted to run the bike again, this time I was getting fuel leak through Cylinders 3 & 4 - Cursing and grumbling off came the carbies again.

This time after much digging through forums I found something vaguely resembling a setting for the float height. Embarking on this thoroughly confusing setup, I roughed up a small aluminium Z bracket to the correct height (Apparently 25mm) and struggled through figuring out how to set these - going with a "close enough was good enough" I put them back on the bike.

Aaaaand promptly flooded cylinders 3 & 4 badly enough to need the plugs cleaned, with that done I finally got some life out of the beast with some 'Start ya Bastard' and then got it running on its own steam again.

Now the real issue, other than a marginally small main jet all the settings I can think of have been reset to factory specs and yet I really struggle to get this bike to idle, a little blip on the throttle and it jumps up but falls in steps and then if I am not careful will stall. It also won't rev above about 7k, it revs up but then leans out and struggles.

Not sure what to do now -.-

 

Hey Grey - My float needles appear to be in good condition, no stickiness or anything - I don't recognise the seat at all :/ the needle itself sits into the plastic housing

Seen above, just under the Float Adj Tang.

I've set the pilot screws very carefully to exactly 2.5 turns with 1 turn = 360 degrees.

The main jet in the FZR400A is indeed an 87.5 but the 3EN2 is a rare and weird model, it uses a stagered main jet size.
With Cyl 1&4 using a 92.5 and Cyl 2&3 using a 90.0


I will have to check the fuel levels next time, but it's proving to be extremely difficult to find accurate information on what setting is what over the vast array of FZR 400's which all use totally different parts.
Which, I am sure you understand with the Fizzer-250's being all jumbled up as well haha

 

So I realised it's been ages since I updated this. Bad MashtX!

I've since ordered, received and fitted the correct OE jets and refitted everything. Fixed the float heights as far as I can tell. The 3EN2 uses the same float settings as the 3HE 600's due to being virtually identical carbs.
So with that sorted by flooding problem seemed to be solved and boom! I had a bike that starts, but still would not rev properly or idle well. Hmm.

Breaking out my digital thermo I saw that the engine appears to be choosing cylinders at random to not fire correctly.
I am almost 100% sure it's the dodgy useless and frankly sh*t OEM ignition coils...

So first measure was to replace the wires and plug caps with NGK SD05F ends and new wire to match.
This netted a more stable idle and slightly better response but still having all of the same issues.

So yeah, one day at uni I finally broke down and cracked it.
Dynatek 2.2ohm high performance coils are go!!

2 weeks later they show up. Check out how good they look!


So yeah, there is certainly more to this update but I am feeling the need to tinker maybe tonight or tomorrow I'll post the results of these new shinies

 

Lots of tinkering tonight! Couple of epic fails but I got the new coils running.
Downside? Cyl 3 is still running at like 50 deg and all others are 200-220 deg.

Yeah totally confused now /o\

 

Sounds like a good plan of attack, I'll have a whirl at that on the weekend.

I know the leads/caps/plugs are all good because they are all new and I tested them before fitting.

Stupid bloody fizzers!

 

So this weekend, on a spur of the moment trip one of my best mates flew up from Tassie to hang out and we spent Saturday working on this little piece of work.

We tried a couple of tricks to get the motor happy and with no luck. Tried to get my compression tester hooked up aaaand I don't have the right fitting... Lame.

Fearlessly we thought we should drop the motor and crack valve cover, have a look at the cams and if all good maybe check valve clearances.

Yeah. That didn't go to plan.



That's the intake side, cylinder 3.
That cylinder is becoming a royal pain in my rectum....

Time to move in and tear down the engine, might seem extreme but I didn't know how much damage this engine had suffered.



Again, that's cylinder 3. Wtf.
Other were dirty but not bad by any stretch compared to that



Yep, again. Cylinder 3.

Almost all cylinders showed bad signs of wear from piston to cylinder wall but not so bad as this one.
You may also be able to see small chunks taken out of the piston from what I assume to be metal shards impacting the piston surface.



Also cracked the sump, there was a huge amount of sludge, which was bad but not an engine killer.
What was worrying was the metal in there, some flakes and other smaller pieces that felt like sandpaper when rubbing against the sump.
Fun.

Result = dead motor.

 

Mhm, I'm going to import an engine from Japan come tax time I think. Easiest and definately cheapest option.

In the mean time, I want to use this to learn about engine rebuilds so I'm going to slowly rebuild it and work on learning porting and polishing the exhaust ports and etc.
Make it a long term thing haha

 

Very interesting, I did have heard of those V4 monster engines. Incredible stuff.

I also realise that there really isn't more power to be made, but I would like to learn the skills how to but it's hard to justify possibly ruining a good engine. So working on this one seems like a good idea to me.

I doubt this engine will ever work properly again so I'll do my best to learn all I can before I totally resign it to the grave