bike will simply not fire up!!!!

[jakeymara]

Hi hope I can get some help here.

I tried the bike last Saturday, (she was firing up the week before albeit a bit rough from standing over the winter), she turned over OK and sparked OK, but she just would not fire up, so I suspected gummed up carb jets.

I dismantled the lower end of carb and ultrasonically cleaned the pilot, main and air bleed valve, cleaner did a nice job to be fair. Replaced the jets but still no joy.

Ordered carb repair kits and replaced all pilot and main jets, plus air screw as I was on. I inspected the float needles, but were not worn so I left the original ones in.

Refitted the carbs but again no joy, same as before. I then turned over with the air box off, to see if the cylinders were actually sucking in air, I felt a bit of blow back in one cylinder so I suspected valve clearances. Opening the throttle i.e. to use the main system fuel did come spluttering out.

I have just checked the valve shim clearances and all exhausts are OK, one is just on limit at 0.002 inch. 2 inlets are OK at 0.004 inch and 2 are on 0.0015 inch. So another job to sort but at least I know they need doing!!

Would tight shim clearances be sufficient to stop the bike starting? As 2 clyinder valve sets are actually OK, I still suspect the carbs are the problem not the shims. Is it the float height, which look like a right "ball ache" to sort out? Last Jap carb float I messed about with was on a Datsun 120Y, in the end I went to a scrap yard and fitted another one.

I have faffed on with them to the point I feel the only way this bike will go is in bits on EBay!!

Is there a Z carb specialist in our area who could look at them for me???

On a day like tihs I am off on a Triumph, at least they are dead simple to fix.

[compo z1r]

take it you'v checked the compression and all electric's think its more than
carbs,

[Pigford]

If you're getting fuel in, hows the SPARKS

[jakeymara]

All the plugs spark, it was one of the first things I checked.

I thought about compression, checked number 4 cylinder only at the moment. Using the kick starter, as battery was flat, gives about 70 psi when the engine is stone cold. A bit low, but you are supposed to check this when engine is hot anyway.

[Steve S]

Whats the battery charge like,low voltage can play havoc with things especially with electronic ignition,are your plugs okay as well.........start with the basics and work through.

[Pigford]

As Steve S says, need a good fully charged battery, good fuel & Denso plugs (NOT NGK).......

If points.... re check........

[jakeymara]

Its a DYNA S system, might try new plugs they work but new ones may be the answer.

Battery is pretty good, but it is not liking contiuous starting with nothing in return folrm the engine.

is 70 psi OK for a stone cold engine?

[Rich]

Check the little holes in the choke fuel pipes are clear.

[paulmceleney]

check your condenser you can still have a spark if there faulty but the engine will not start i found this out a long time ago when i work in a garage try everything strip the engine had all the mechanics trying to fix it for me but and in the end the forman mechanic had a look and it was a faulty condenser hope this helps

[ted1r]

You have put fresh fuel in I take it.


Ted

[Pigford]

check your condenser you can still have a spark if there faulty but the engine will not start i found this out a long time ago when i work in a garage try everything strip the engine had all the mechanics trying to fix it for me but and in the end the forman mechanic had a look and it was a faulty condenser hope this helps

Paul, he's got Dyna S which does away with all the points & condensers

[jakeymara]

Well a few things to think about, I hope it is nothing too serious....touch wood. Sometimes it is a simple thing.

I went white when "compo" mentioned compression tho', as it crossed my mind as well. I just tend to think the worst and work back from there.

Does anyone know what the carb float level is supposed to be, instead of using the tube connected to the drain plug technique. This just tells you if fuel is at the correct level, adjustment is not so easy. I have seen these float level gauges, but I cannot find a ref to float levels so it seems pointless getting one.

I come back to this, as with my Datsun 120Y, the float was set too high and I ended up completely filling the engine and exhausts with petrol trying to start the car. I am mentally scarred by it.

[Pigford]

Not 100% but think 20mm ain't far off.... one of the other boys may know for STD carbs

[jakeymara]

Thanks Pigford.

Ted, yes I binned a tank of old petrol and put fresh in last week.

The moral of this is don't put your bike to bed over winter, keep using it. She was running sweet at the end of October!

[ted1r]

Fair comment but the wax can settle in the bottom of the tank ,even though you binned it it still could be there,Ive had this problem with the Z1r this winter.

Ted