Starting problem, any ideas?

Ok, the GSX is being a bit of a bastard and is flatly refusing to start properly. Compression is good as it farts along reasonably well on the ether/kero mix within aerostart, but getting beyond that is really starting to perplex me. I can feel it wanting to start, like the engine is assisting the starter motor in rotating the crank, but it never takes off on its own.

I have taken the carbs out and taken them apart numerous times.
The choke section has been thoroughly sorted ( was near seized before), as has the high speed jet (cleaned RIGHT out), the pilot air (bit of crap) AND fuel jets (both were thoroughly blocked and a total fucking mess), the pilot needle (where you adjust the air/fuel ratio for running has been cleaned up as well. The float needle seat has been removed and the microfilter there has been cleaned on both the left & right carb.

I suspect i may have got blocked passages within the carb (*sigh* if this is the case looks like i'll have to remove the effing carbs again (this will be the fourth time) strip the bastard, remove all the rubber from the bastage and soak the casings in carby cleaner).

Anyone else got any bright ideas on what to look for? does it sound like im going down the right track? I'll do you guys a deal, if you can provide a useful suggestions i'll happily also take some sledging about it being a spewzuki.

Cheers,
Mike.

mmaate ......... start at the beginning
Turn it over with the starter.....pull the plug........is it wet with fuel ??

I had one of these from new when they came out and I always had problems with carbs. The float needle thingy would get stuck up in the closed position occasionally even when the bowl drained of fuel and the float dropped. I used to fix it by pulling up at a servo, pulling the fuel line off from the tank and giving it a blast of compressed air down the fuel line. This blew the needle valve out and hey presto.

Given that yours is 20 something years old that probably isn't it though

Have you been using proper carb cleaner and compressed air to clean the carbs? It was the only effective way I found to do the Z's carbs, and I still think I've got to go back and redo number 3's pilot circuit. When it turns to varnish that stuff can be bloody hard to remove. I had to do mine about 4 or 5 times just to get everything. Luckily with the pods I can have the carbs off or on in about 5 minutes

The other problem is that it can be a pain in the but tracking down the cause of some of these problems. I thought for ages I had jetting issues until I got the ignition system sorted out by replacing a dodgy bullet connector....by which time I'd changed the jets so often I actually did have jetting issues and had to put the originals back in.

Like a fe wof the others have said - back to basics. Fuel, air, spark, timing. Taking out No1 plug after trying to start will show if it's wet with fuel. If it's warm it has been trying to ignite, but what colour is it. From that you should be able to tell if it's too rich or too lean. If it's barely warm or cold, does it have a spark and what colour is that - if it ain't bright blue it's weak. Does it ever back fire while turning over? That could be an irregular spark or very out timing? Does this bike have points of CDI? Check points, condensor and coils. Check plug leads and caps, change plugs. All fairly cheap fixes, all have a massive effect on the strenght of the spark.

are you getting any 'pops' or 'bangs' out of the zorst ?? anything ?? If not, then your plugs are probably shot. Are the plug leads on the right way ?? Ignition timing could also be out, and the battery voltage needs checking as well....

Gotta box of matches ??

ok i'll start from the beginning, after doing various other engine bits, i stripped the carbs as little as i thought i could get away with as to me carbs are still a bit of voodoo.

mmaate ......... start at the beginning
Turn it over with the starter.....pull the plug........is it wet with fuel ??

Well i know the ignition works, spraying a bunch of aerostart down the carbs gets it kicked over and running, quite well actually. So im reasonably confident that the plugs/HT works well.

When im testing this it stops with the aerostart runs out. I'll still need to run a plug chop test to see if any fuel was getting through, i might try that tonight.

I had one of these from new when they came out and I always had problems with carbs. The float needle thingy would get stuck up in the closed position occasionally even when the bowl drained of fuel and the float dropped.

I had that float sticking issue as you can see if you look earlier in my restoring it thread. I sorted it out by cleaning the seat tubes out. Copious testing seems to show it has worked in sorting it. Neat fix b.t.w .

Have you been using proper carb cleaner and compressed air to clean the carbs? It was the only effective way I found to do the Z's carbs, and I still think I've got to go back and redo number 3's pilot circuit.

Just made do with degreaser the first time around. Methinks its time for the heavy duty (petrochemical proof) gloves and the carby cleaner aerosol. I did a pretty good job of cleaning it with degreaser though, these things seem to be pretty fricking touchy with how clean some of the bits have to be. I think i'll have a good 3+ hours of farking about ahead of me tonight.

I had to do mine about 4 or 5 times just to get everything.

That inspires a bit of faith, considering how grotty the bastard things got (seriously it was disgusting)

Luckily with the pods I can have the carbs off or on in about 5 minutes

bastard.

The other problem is that it can be a pain in the but tracking down the cause of some of these problems. I thought for ages I had jetting issues until I got the ignition system sorted out by replacing a dodgy bullet connector....by which time I'd changed the jets so often I actually did have jetting issues and had to put the originals back in.

Fark i hope its not that, though i do admit i am planning on redoing some of the wiring.

Like a fe wof the others have said - back to basics. Fuel, air, spark, timing. Taking out No1 plug after trying to start will show if it's wet with fuel.

As above im planning on doing that tonight before trying the rest of the clean-the-bastard-up process

If it's warm it has been trying to ignite, but what colour is it. From that you should be able to tell if it's too rich or too lean.

I dont think its getting that far

If it's barely warm or cold, does it have a spark and what colour is that - if it ain't bright blue it's weak.

The spark appears healthy, i didn't have a spare plug to test with, and kept the plugs in and tested the spark with a nail (i got a healthy 6-7mm blue & white spark to the head) and figure the HT circuit is working well.

Does it ever back fire while turning over? That could be an irregular spark or very out timing?

Nope, not even once when loaded with the ether/aerostart mix, it either fires properly or it doesn't.

Does this bike have points of CDI?

It uses points for timing with a mechanical advance and uses an igniter box to control the voltage to the coils.

Check points, condensor and coils. Check plug leads and caps, change plugs. All fairly cheap fixes, all have a massive effect on the strenght of the spark.

Will take them into account and will replace/check them when i'mable to, but im a bit doubtfull that they're the problem due to how well it runs on the aerostart.

are you getting any 'pops' or 'bangs' out of the zorst ?? anything ?? If not, then your plugs are probably shot. Are the plug leads on the right way ?? Ignition timing could also be out, and the battery voltage needs checking as well....

Gotta box of matches ??

MAAAAAAAAAAAAAAAAAATTTEEE you posted while i was putting that big fuggoff post together *grin*. No pops, no bangs, i seriously am suspecting that no petrol is getting through from the float bowls to the carby throats, hence looking at going back and checking the carbs out. timing, unsure, battery = good, its brand new and every time i deplete it more than 1/4 empty (i.e. it still turns over but is struggling a little) i take it off the bike and charge it overnight with an intelligent charger (has a 10v cutoff and wont charge a battery if it measures below 10v as it thinks its farked), you know the sort, it trickle charges it, then topsit up as it depleates, then stops, starts, etc...

Heyo,

I used " 5 Star " Carby cleaner, bought from the reject shop !!

Dismantled the carbies completely, removing any rubber parts, so they would not get damaged by the cleaner, then soaked the rest for approx 30 mins.

Then I washed the parts in warm water (No detergent etc), and stood them to dry.

" Borrowed " my fiancees hairdryer, and dried the parts some more.

Then I broke out a couple of cans of compressed air in a can from Tandy, using the little straw that attaches onto the nozzle, and went for broke with the passages - Cleaned them out a treat !!

Finally reassembled carbies, refitted the bike (ZXR250), and hey presto, my bike would start .... And idle (Would'nt do that before).....

Hope this helps ......Good Luck .....

well she looked pretty keen about starting last night, i checked the plugs and they smelled a little like fuel and not the aerostart (i compared the petrol smell to aerostart to make sure i got it right). seemed like it wanted to kick over, but as it was late i didnt do more than a quick go. About to head to work on the other bike, will give it a go just before i leave, perhaps leaving it soaking with petrol in the carbs for 48 hours was a good thing.

Will keep the tandy/dick smiths idea in mind, quite a good suggestion actually. I'm pessimistic, but i'm still HOPING i don't have to take the bastard things out again.

I had another go at it this morning, and got it to pop and fart a bit with the choke on full. It wold run for a couple of seconds and then it would die coldly, you can crank it and then after 7-8 seconds it will go over again, but you get the same brief run and then it stops again. I'm suspecting the carbie idle circuit is failing to provide fuel and the only fuel being provided is fuel via the choke circuit and the air being pumped through via the engine being cranked over like it is.

Looks like the carbies are coming out for a *thorough* clean tonight.

have you checked the tank/fuel tap/breather hose and filter? Could be the carbies are getting a short supply of fuel?

Thats another thing im considering/was going to try. The current tap has vacuum activation for both on/reserve and you have to bleed the tap via a screw (and then suck on a length of the vacuum tube to prime the carbies), versus the one ive got spare (and im going to change over to tonight once i clean it out) which has on/res/prime.

Come to think of it i have *NO* idea why they didnt just do on/vacuum and res/prime.

[edit]Oh and a brand new inline fuel filter and all the built in filter meshes (in carbs and tank) have been cleaned too.

Does it have sustained life yet? If so, what was wrong?

dodgy fuel tap - the diaphgram in the tap is probably shot, so no fuel is being sucked from the tank to the carbs.

thats my uneducated guess for tonight