Servicing ZXR400 Project for Track day, any recommendations?

[JovoMan]

Greetings

Ok I bought a budget project bike 90 ZXR400 with the intention of having a go at some track days and then becoming world moto GP champion a year from now, ok not realistic I know....make that 2 years then.

So I've added a few parts and got the thing up and running down the road and back whopeeee!!!
It runs ok but dies when revs drop, also stutters occasionally, I suspect carbs and stuff. Anyway pretty much decided Im taking it in somewhere in Auckland for a tune-up / full service as I cant do the tricky stuff.
Can anyone recommend some good mechanics / shops etc that still allow you to keep your arms and legs.

Ideally would like the thing Dyno'd but am on a budget ($500). To get around that I can do half the service myself and let the garage do the rest. Nothing serious, just want to go around the track on a tuned up stock bike, although did find a second hand performance exhaust I added, sounds good after that.
Engine has done 63k's.

[FilthyLuka]

Sounds like carbs, there is a guy out west who is a MASTER with the carbs. Warren Bridges, drop me a PM and i will give you his number. He has done the racing thing before so he can probably also give you pointers on what you need to lockwire and maybe even do it for ya if you ask nicely...

Aight, heres what ya do:

Fluids, check brake fluids, anti-freeze. Replace oil and filter (decent oil)
Check cables, lube em up. Clutch and throttle ect.
Lockwire everything that needs to be lockwired
Take of anything that dont need to be there (pillion pegs and such, probably don't need to do this, but shaving off a bit of weight never hurt)
Replace plugs if they are arse, clean em up and gap em if they are still good

Trailer the bitch out west (glen eden) and get warren to do a carb jet (new pipe eh?) and balance

Ah, you might wanna check the camchain and tensioner too

Since you are getting a carb jet, if you want to gut the airbox or put pods on i suggest you do it now so you dont need to go get the carbs jetted again.

Have fun :)

[JovoMan]

Thanks FilthyLuka, yea i read somewhere about the lockwire stuff so most useful thx.

Gonna do just that then, am sending you a PM now. putting pods on yea great idea...wish I knew what that meant :rolleyes:

[FROSTY]

Mate I'd love to have a zxr back in my gargre--Im out west --Ill happily do the lockwiring n stuff with ya.
carb wise I can show ya what to do to clean em out -at least then you'll know you're starting with a clean slate

[FilthyLuka]

putting pods on yea great idea...wish I knew what that meant

Pod filters... Instead of having an airbox, you have one "pod" per carburettor. K & N airfilters should sort ya out, im running em on the GSXR750, they are sexy. Do a google search and all will be clear

[FROSTY]

Don't wanna put a downer on this guys but--Been there done that with the no air filter/pod filter thing.
Doogal and I experimented for ages on my ZXR race bike.It was a total disaster
Hey Ive got a fglass tank for one in my gargre if you want it

[The Pastor]

I have pods on my cbr250.

WOT works great, who cared about mid range..

Actually the only time it doesnt work to well is when you are in a higher gear than you need to be (i.e., cruising in 6th) at low rpm and then you give it WOT. if you work the gears properly its fine.

Remember you will have to work on the carbs, and it takes a bit of know how / time and imho, you'll never get it 100% maybe up to 95%....

[FilthyLuka]

Don't wanna put a downer on this guys but--Been there done that with the no air filter/pod filter thing.
Doogal and I experimented for ages on my ZXR race bike.It was a total disaster
Hey Ive got a fglass tank for one in my gargre if you want it

Wouldn't know about the ZXR's, but after tuning the carbs on my GSXR it ran sweet with the pods :) Then again it is a street bike and isn't hauling arse around a track all day long.

Mate, show up to frosty's with a six pack and talk shite for a bit, im sure you will learn some really usefull stuff 'bout your ZXR

[FROSTY]

First things first methinks.
Dump the oil n filter. see if any lil nastys come to light.
Haul the carbs out clean the jets.
Seal up the inlet ports propperly
Fit airbox propperly with filter in.
Getting high performance out of an old motor can lead to a power of wallet pain.
MY suggestion here dude. --Do as little as possible to the engine but focus on the suspension and brakes.
I'd be on TM right now looking for ex race 120 fronts and 160 rears

THEN if you are just loving it look at performance upgrades or maybee buy a bike thats faster period.

[JovoMan]

Thx Frosty
Just what I'm thinking. For me I'm looking to have some fun mastering corner speed and entry / exit etc. If I want to beat everyone down the straight I'll just rob a bank first.
I can do basic maintenance & even take the thing apart if I want. I just end up with extra bolts when it goes back (not good).
When is your next evening workshop thing?, Id be keen to start coming along to learn stuff.

[FROSTY]

dunno dude--BUT do come grab the fglass tank

[westie]

I'm running only half the air box but I have a dampener across the openeing. The dampener is required to stop the motor leaning out at high revs/speed helps suck the juice through.

[FROSTY]

I'm running only half the air box but I have a dampener across the openeing. The dampener is required to stop the motor leaning out at high revs/speed helps suck the juice through.
Youre game with that loverly pumace dust blowing around taupo

[westie]

Youre game with that loverly pumace dust blowing around taupo

Is that what it is?... I figure it is great grinding paste. Laps the valves and cleans the cylinders as it goes through:laugh:

Just taken air box off though. Running 102 main jets lifted modified needles and extra rich mixture. its got more even power and its midrange is good.
Just gotta see if its faster.

[JovoMan]

UPDATE
Started work on bike this weekend after waiting a few weeks for CarbTune product to arrive.
Changed oil / filter, checked plugs and all that etc,
After *cough* hours finally figured out where the gauge hoses attach to and got some readings after running engine warm. Cyclinder 2 is way higher than the rest. Ok next step is to turn screws and note changes but now problem is engine dies after a few minutes running. Adjusted idle but makes no difference. Changed Fuel Filter but same. Could it be Fuel Pump? how do you tell if its working? And any ideas what else it could be causing this. I cant get the engine to run long enough to make appropriate changes to the carbs.

Cheers for the offer Frosty, just want to get this thing working first and on track and see where it goes from there.

[westie]

UPDATE
I cant get the engine to run long enough to make appropriate changes to the carbs.


Have you set up the petrol tank so the engine has a fuel source?

[Hoon]

I'd do a compression test first just to see where you're at. No amount of carb fiddling is going to fix a tired engine.

But carbs can be a real pain to troubleshoot - especially if you have inherited the problem from someone else. Easiest and quickest way is to slap in a working set of carbs and see how that goes. Balancing the carbs is something I'd do right at the end as its more of a fine tuning thing.

Just so happens that I have a spare set of H carbs with no main jets. You can have them for $100 and use your old jets. Also got a Dynojet Stage 1 Jet Kit lying around somewhere too.

[JovoMan]

Have you set up the petrol tank so the engine has a fuel source?

yep made sure of that

[FilthyLuka]

Blocked breather on the tank perhaps? Runs untill it builds up a vacuum and then stops?

Blocked fuel line? If you turn to fuel tap on with the line off the carbs, do you get a steady petrol stream?

Spark on all cyclinders?

[JovoMan]

UPDATE - At this rate should be finished ready for the track day in MAY 2011, I'm enjoying my cheap labour though!

Took out the fuel pump, connected tank directly to carbs and SWEET! Engine is purring whoohooohooheee. I even went further connected the carbtune thing up & with it running nicely ideling, Cyclinder 2 is high, BUT when revving all cyclinders same and smooth as a smoothee! For the guys who know a little about carbtuning is that normal?:wacko:

Anyway back to figuring out why the pump is not working I notice the relay is not in its socket doohh! So with full battery capacity & pumps connected, start up & nothing, no fuel. Ok I switch around the in & out fuel hoses and next time I get flow (hmmm). The flow is spurting out though.....my question is what should the flow running out look like? full on tap flow (like gravity direct), trickle or what. Because with it spurting engine doesnt run enough & dies.

Nearly there, at least now I know its Fuel feed. :blink:

[3phase]

If the engine runs gravity feed but not on the pump i'd suspect the fuel pump
if you can't get hold of one to try it l;et me know
I have a spare you can borrow