Z900 A4 Starting( or not) for 1st time after full restoration

[Gray17]

Afternoon Guys, well that big moment has finally arrived, after nearly 18 months i am finally at the stage to start the engine after full strip and rebuild, along with rest of bike.
Charged battery fully and checked coils getting power, spun it over on starter to build up oil pressure, oil light went out after few seconds and no leaks anywhere, so far so good! Necxt put gallon of peterol in brand new tank for 1st time, carbs have all been stripped, cleaned and new gasket kit fitted. I also statically set the float heights, and ensured all sliders at same height.
Turned on fuel, waited a few mins then loosened float chamber screws fuel came out of left hsnd side 2 carbs, but nothing on right hand 2, which is strange as its a twin outlet tap and fuel flows out of both pipes? However i had also checked for a spark at plugs and yes thats present.
So 3 things needed , compression- well theres plenty of that on all 4 cylinders,
Fuel well i know that at least 2 carbs have fuel in them, have to investigate the other side 2 why they dont seem to be getting any?
Cant believe both floats are stuck on same side.
And Spark- well def got that and new plugs all gapped correctly.
Thought it would have fired up on at least 2 cylinders but nothing at all.
I Know the cam timings correct, Checked it several times, however its possible spark is way out, but even then would expect it to cough or back fire.
Any suggestions before i start re stripping bits off it again please
Just been through that with loom which turned out to be bad earth to rear, ran brand new cable which has solved the issue of dim rear lights and indicators.
Cheers

[sean_rfi]

Hello Graham,
I think that I would resolve the issue with the two carbs not receiving fuel before anything else.
Assuming that the carbs are operating ok and delivering fuel and you have power to the coils and the plug is sparking it has to be a timing issue of some sort?

[Gray17]

Thanks for reply Sean, yes was thinking that myself, with that in mind i put a small drip tray under each carb and removed float drain screws, there was hardly any fuel came out of L/H 2 and none out of R/H 2. Even with fuel tap on, think i may have a blockage in tap itself, next job is to unscrew bottom of tap and check filter, otherwise its drain fuel tank. Which isnt easy. Not sure what everyone else is like but on mine i cant lift the tank at rear as tap catches on frame, so you have to undo the 26mm nut on tap to remove tank, problem its got fuel in, which will go everywhere!. Oh well got to be done.
I also re checked all sparks on all 4 cylinders. Def present, also removed points cover and checked the markings def spark at set points, what i dont know is whether ive inadvertently swopped the coils around on the wires bullets ie 2 and 3 sparking when it should be 1 and 4 and vice a versa. If this is possible?
Will sort fuel issue out 1st though, may need new tap, or have to remove carbs again, which are a nightmare to get in and out ( sure you all know this) as you cant move airbox back to clear outlet rubbers due to frame. Think the rubber isnt as supple as it should be even when warmed up, so maybe need new ones, more expense.
Will keep updated

[wilsonsjw11]

Prove that the fuel cap is venting by opening it and then opening the fuel tap, a blocked vent hole in the cap is a common problem.
Regards
Steve

[Gray17]

Thanks yes had thought of that its a brand new cap, but tried with cap open and closed so tank vent isnt the cause in this instance.
Taps not new but was working ok before strip down, 1st port of call to check flow, both carb feed pipes are new and clear too and not kinked, both T pieces are clean with new o rings.
On modern bikes inj Fuel system is pressurised by pump, obv older bikes use gravity, so its easy to get vapour lock.
The fact no fuel getting to float chambers or very little, proves theres a blockage somewhere. Tank is Zpower A4 brand new and tap hole completely clear, know pipes clear and carbs too, floats were all working perfectly on the bench, of course thats 6 months ago when i had them apart, but cant believe all 4 float needles stuck, its got to be the tap. Least hope so We shall see!

[Stugill]

Good morning.

Apologies if I'm getting the eggs out, can you swop the fuel pipes over to the other outlets and see if the problem moves?

Stu

[zapo]

To help removal of tank turn the tap 90 degrees first

[zed9]

To check for correct coil spark place no4 spark plug loose on cylinder head and with ignition on gently open 1&4 points with finger or tool. If points are open just short them with screwdriver or bit of wire for spark.

To check fuel tap (asume you tried reserve and main) fit length of hose to tap outlet on bank not working make sure end is above tank height tun tap on and blow down hose you should hear some small bubbles from inside tank.

If you have to remove tank and tap lean against something so rear is upright using plentys of old sheets/curtains/coats to protect pant. Tap be be easily removed no spillage.

[Gray17]

Hi Guys, firstly thanks for all the tips and suggestions, armed with these i set about the task, firstly removed fuel tap and cleaned it thoroughly, these was a bit of sediment in lower bowl but not to the degree it would have clogged it up, then stripped tap checked all components and blew through each to outlet to check all ok so back together and re fitted to tank, drained old fual and put new gallon of E10 just in case old fuel gone off. Next checked spark against rotor plate, 1 and 4 sparking at correct place, same with 2 and 3.
Re fitted carb drain screws with new rubber o rings, turned tap to reserve, battery fully charged, choke on full, fired straight up which is great, bit of smoke but thats expected as was generous with oil on re build.
Next tried battery charge with fluke meter, not good, on tickover was 14.6v, when revved went to 15.9v, blew front headlight and main 20a fuse, thinking either rectifier or regulator faulty. Have ordered a new combined unit. So have to wait till that arrives.
Got a slight leak on carb 3, think float sticking do thats another issue to sort.
Oh and the rev counter works fine but sticks at 2k when stopped, gave it a tap and it settled back to 0 now these were ok so not sure why doing this now, needle fairly sturdy not fluctuating so know damping fluid ok, hoping it may settle.
Glad it runs and sounds good after engine rebuild and head work. Which is always a worry!
Grateful for all your inputs.
Im determined to get this on road soon.

[warren3200gt]

Good on you Gray, makes all the effort and hassle a dim and distant memory. Just snagging to do now? Every build has a few niggles to sort.

[Gray17]

Thanks Warren, yes its a great weight off my mind, a lot of work could have gone to pot if it refused to start.
Theres a few issues to sort out. Blowing fuse being the main one, however i checked all electrics on battery and everything was fine, can only summise fuse blowing due to excessive volts from faulty regulator, hope new combined unit addresses this. Theres no oil leaks which is great and pressure seems good lamp goes out immediately on start. Rear wheel spins in Neutral but guess thats cos oil is thick, stops when you apply rear brake and clutch disengages when 1st gear selected so again another win.
As for sticking tacho it didnt do it on the bench when tested with drill, however could only get it to 4000 rpm, but it sticks on the way down at 2, a tap frees it again, perhaps it will resolve with use it has been nearly a year since i refurbed clocks so fingers crossed.
Once finished ill get some photos uploaded.
Update today, replaced 20a fuse and re tested everything on battery, everything works as it should, did have to replace halogen front headlight as that blew when revved also ( no inline resistor fitted) which may be needed? Im assuming the fact not blown again, means issue is def with charging circuit, soon as new unit arrives ill remove original regulator and rectifier. Hopefully that will solve the issues.

[gray]

So 2 adjacent carbs are dry , both fed by the same pipe from the tap. But when the tap is turned on, with both pipes disconnected, fuel flows from both outlets. Suggests a blocked feed pipe to me.

[warren3200gt]

So 2 adjacent carbs are dry , both fed by the same pipe from the tap. But when the tap is turned on, with both pipes disconnected, fuel flows from both outlets. Suggests a blocked feed pipe to me.

Or T or vent.