1991 Exup RU problems, please help! :)

Jolley1991 · Post by **Jolley1991** » Wed May 25, 2016 11:29 am

Hello chap's

I am new to the forum, So hello everyone

I love my FZR 1000 but it's playing up alot now and I don't know what to do! I am going away for a bike trip to Europe on the 8th June and I might have to cancel unless I can get the bike running properly.

I have had the FZR 1000 for 3 years and it's been a project I had to sell my zx9r last year which was a reliable good bike.

So far I have had the wheels poweder coated orange which look great, new Michelin pilot 2 tyres fitted, rebuilt the front brakes, rebuilt forks, new fork seals and thr stanchions have been recrhomed "one of the forks is leaking oil" so I need to sort that. The swing arm has been powder coated with all new bearings, ZX12R rear shock fitted, 1 tooth down on the front sprocket, irridium plugs and new coils fitted. Carbs have been fully rebuilt and balanced with all new seals and gaskets.

New 4 - 2 - 1 exhaust manifold fitted, exup valve removed.

I have been riding the bike the last couple of weeks and it's been fine apart from low down power issues, running rough and boggy. It's now misfiring on cylinder 3 and running really rough, hard to start.

I have replaced the fuel pump and fuel pump relay, fitted a fuel filter and changed all the fuel pipes.

I am running out of ideas now and wondered if anyone could help, I have purchased a shim kit from online, is there anyone on here who could help me check and change the shims I am more than happy to pay for your time

Best, Jolley

Post by **Stig** » Wed May 25, 2016 11:34 am

Depending on mileage if it's harder to start from warm it may be valve clearances
What are the Toobs like for wear?
Is the Exup servo still plugged into loom?
Is bike kept undercover? Make sure cylinder drain holes are clear

Jolley1991 · Post by **Jolley1991** » Wed May 25, 2016 11:51 am

Heya,

Thank you for a quick reply. The bike has 23900 mile on it which I pretty sure it genuine. Exup servo is still plugged into loom, I replaced it a while back as the old one was faulty, bike is kept in my warm garage, pretty sure the drain holes are clear as I flushed the water ways through and changed the coolant a few months back

Post by **Stig** » Wed May 25, 2016 11:58 am

Try to establish which cylinder is down then swap coils over see if misfire follows. Also do same with plugs
I'd check the tubes for wear also with it being rough low down

Jolley1991 · Post by **Jolley1991** » Wed May 25, 2016 12:06 pm

I changed the emulsion tubes with a brand new set a few months ago.

andy88 · Post by **andy88** » Fri May 27, 2016 2:12 am

Re install the exup valve..that will solve the problem.
You say NEW 4-2-1 exhaust system..was she running good untill exhaust change?

The engine was designed with different cams to run alongside the exup valve.all to do with variable back pressure etc.. Remove the valve and youve got an untuned engine,exhaust etc.
People have tried re jetting carbs etc, but still suffer from low rpm bogging and power issues etc.

I may be wrong, but best to keep original headers and exup valve etc. And go for link pipe and aftermarket race can,which will ensure you have correct gas flow via valve.
It doesnt really matter about the exup servo still being connected, as the motor itself isnt fuel injected, so theres no posh ecu and censors fitted everywhere to regulate everything.

Like i say, i may be wrong, and i will hold up my hand if i am, but personal experience says keep the valve, which means controllable smooth power, and just buy a link pipe and can.

Post by **Stig** » Fri May 27, 2016 7:17 pm

^^only certain models will run ok without the servo being plugged in. The others drop the cdi into running in limp home mode

andy88 · Post by **andy88** » Tue May 31, 2016 6:14 pm

ANY UPDATES TO YOUR PROBLEMS???

scotty · Post by **scotty** » Tue May 31, 2016 7:13 pm

Sorry to butt in....but could an incorrectly set exup valve also cause a flat spot mid range...ie 6 - 8000 rpm....

scotty

andy88 · Post by **andy88** » Tue May 31, 2016 7:32 pm

Hes running a NEW 421 SYSTEM.....NO EXUP FITTED

scotty · Post by **scotty** » Tue May 31, 2016 7:48 pm

just googled 4-2-1...lol...understand.....i'm a total newbie at bike mechanics...landy's and submarine engines i can do, bike stuff is still witchcraft to me...lol....but slowly learning...

andy88 · Post by **andy88** » Tue May 31, 2016 9:39 pm

Well if you can strip a submarine,,, you can grease my valve anyday....

.... Only joking pal....same as ANY engine, ,, grease,oil,maintain and enjoy... Half the fun of the ride is knowing you stripped it and built it...if you cant trust yourself..... Who can you trust???
Buy a manual,see how it works and dont be scared to come on here and ask questions.....thats why we're all here, to ask and share..have fun....

Andy

Post by **Stig** » Tue May 31, 2016 9:41 pm

Not even a need to buy a manual as there's a Genuine Yamaha one free to download from the tech section on the main site