Starting Problems SP Race Bike

mike684 · Post by **mike684** » Tue May 22, 2007 11:12 pm

Hi guys, I'm quite new to the sit and am looking for some help. I've got a ZXR400 SP (L model) and can't get it to start.

Brief history. Bike was imported into Felixstowe Feb '05 from Japan. I bought the machine in Nov '06 and not had tme to look at it until now. Was bought 'as seen' for a reduced price as it wasn't running. Basically I reckon it has sat for between 2-3 yers without running.

Here is what I have tried, done, checked and replaced. For starters it is a genuine SP (flatslides with TPS, different Ignitor Unit from standard L, fully adjustable forks etc.).

What is happening is the starter is turning over and the engine is trying to fire. It will give a few pops and bangs with the choke slide to on, but that's about it. If I give the throtte a twist and turn it over it will fire once indicating about 2k on the tacho but then dies. Sometimes if I keep the starter turning for a bit it will be firing ok but dies as soon as I let go of the starter button. I've tried the old trick of putting a squirt of engine oil down each bore and turning it over without the 'plugs in to get some compression in the cylinders and baking the 'plugs in an oven until they are roasting hot, but this has no effect.

At first I thought it was running way to rich and appeared to be flooding, hence the leaning of the needles and mixture. Then I was wondering about compression but it seems to be ok when the piston rings have been sealed with oil (the amout of times I've been turing it over the petrol is just washing the oil away).

1) Cleaned carbs.

2) Leaned the carbs by adjusting the needle circlips by 2 rings and leaning the air adjuster.

3) Changed the spark plugs (actually just used the ones I'd just taken out of my GSXR750 so I know they're 'working' ok), but it's acting the same on 2 different sets so I don't think it's 'plugs.

4) Compression tested. Next to nothing but back up to tolerance when squirting oil direct down the bores to seal the piston rings (8kg/cm2).

5) Checked the valve clearances. All ok.

6) Cams out to make sure they're aligned correctly and not on the slotted adjusters. Ok.

7) Checked the coils. Output side reading 24.4Kohms.

Changed the coils. Replacements 14Kohms so well within tolerance.

Basically the only things I've not checked or changed is the 'plug caps and brand new 'plugs. Changing the coils is making it try harder to fire, but i'm still not sure if the fuel is burning on the wasted spark, as I'm getting flames up the inlet tract and out of the bellmouths.

One final thing is there are no clamps on the carb rubbers at he top of the inlet track, but all the bikes I've ever worked on have been ok without them tightened while I was working on them anyway. Are these small bore engines sensitive to this? Or is it a nightmare scenario and it's an Ignitor problem?

Any ideas? I'm stumped

and it's p*ssing me off!!

Cheers,
Mike

tomzxr400 · Post by **tomzxr400** » Tue May 22, 2007 11:49 pm

first off it should fire with the carb holders loose has done for me loads of times
you say you cleaned the carbs did you check all the o rings, float valves,mixture screws, etc for sighns of wear?
and could also check the float height
does sound like its the carbs to me also it does take some time to get fuel through the carbs once they have been stripped ive flattened many a battery trying seems to go almost first time off a bump though

Post by **masterofinsanity** » Wed May 23, 2007 10:00 am

have you checked the HT leads?

Post by **Northern ANdy** » Wed May 23, 2007 11:37 am

compression that I would say. a dry bore should still give plenty of compression, oil isn't neccesary for a good amout if the tolerances are ok.

You think how little oil is actually in a bore when the engine is running.

mike684 · Post by **mike684** » Wed May 23, 2007 7:30 pm

I've checked the carbs. O rings, float valve and everything fine with the exception of the adjuster screw on cylinder 4 is mangled and unadjustable. Even in a worst case scenario it should still run on 3 cylinders.

It won't entertain a bump start.

HT leads have been changed and 2 old sets have been tried.

I spoke to the bloke who's a mechanic in my local bike shop and his words are 'Small bore machines can be an absoute c*@! to fire when they've been sitting.' Anything under 750cc he reckons can lose the oil from the rings in a short period of time and need to have oil put down the bores to seal them up, and if it still takes a bit of starting the petrol in the cylinders can wash oil away. I'm only putting in 1ml of oil/ cylinder and even at that a load of it is escaping from the relief channels.

I've just bought new 'plugs so I'm about to get into the garage and give them a go!

mike684 · Post by **mike684** » Wed May 23, 2007 9:00 pm

Just tried new plugs and getting same thing. Going to try and borrow different ignitor unit to try (means having to butcher another wiring loom though).

p.s. Don't think it's fuel related- 'plugs are wet when I take them out after trying to start the thing.

Post by **Northern ANdy** » Wed May 23, 2007 9:44 pm

sorry but your mechanic is abit off the mark there. Never had any trouble firing up old bikes. Just recently there has been atleast two threads of people who have fired their bike up after 5 years sitting with no trouble other than dry oil gallery.

Post by **Northern ANdy** » Wed May 23, 2007 9:46 pm

have you actually got a healthy spark at each plug by the way?

coils not wrongly connected?

mike684 · Post by **mike684** » Wed May 23, 2007 10:32 pm

Got good blue sparks on every plug. Checked the coil connections time and again. Definately right way round.

I can send my wiring diagram if anyone fancies taking a look to see if they can see anything I might be missing....can't see the wood for the trees and all that...

BTW I've got a complete wiring diagram for an SP if anyone wants it or to post it on the site & does anyone have a pic of what the SP crank end ignition rotor looks like. Mine has 2 large extrusions and only 1 small one-beside the marker for 1-4 TDC.

Post by **masterofinsanity** » Wed May 23, 2007 11:07 pm

hi, can you email me what you have on the SP wiring diagram etc and i'll post it up here.

Post by **Northern ANdy** » Thu May 24, 2007 10:49 am

I have a picture of a standard L pickup lobe.

http://www.ermaxuk.co.uk/pages3/dbc.php ... roduct=301

http://www.ermaxuk.co.uk/pages3/dbc.php ... roduct=301

i could look over the diagram but don't think it would help without being there

mike684 · Post by **mike684** » Thu May 24, 2007 9:58 pm

Just had some success!! Turns out the TPS is knackered. As soon as I unplugged it, the bike started first time. Feel like a twat that something as simple was so blissfully overlooked. Suppose you just live and learn!!

Next problem I have is with the wiring of the switches. I turn on the kill switch and hit the starter button. Starter turns and the bike fires no probs. Let go of the starter button and the engine dies.

I can hold down the starter and the engine will turn for as long as the button is held down. I can even kill the ignition via the kill switch, but if the starter button is held down the engine will continue to run. Is there a sparky out there that can help? As previously posted I've got a wiring diagram of what I've got on the bike.

Post by **Northern ANdy** » Fri May 25, 2007 12:07 am

on my bike the engine wont turn over without the kill switch in RUN position

Post by **masterofinsanity** » Fri May 25, 2007 10:24 am

Northern ANdy wrote:I have a picture of a standard L pickup lobe.

http://www.ermaxuk.co.uk/pages3/dbc.php ... roduct=301

http://www.ermaxuk.co.uk/pages3/dbc.php ... roduct=301

i could look over the diagram but don't think it would help without being there

that don't look like a pickup lobe to me

Post by **Northern ANdy** » Fri May 25, 2007 10:39 am

lol posted teh wrong one