NC 24 Starting issue

[streethawk999]

Guys

im looking for some help with my nc24

Bought 2 years ago and have been doing a complete rebuild due to rotten collector box, Long and short is i cant get the thing to start amd am rapidly loosing patience with it

after many hours messing it started and was running on 3 !! then complety died and now wont start

my mate tested the electrical system and diagnosed that the cdi unit was producing irregular spark voultage so i bought a replacement from ebay, Fitted and still wont start but now have a good spark on all 4 plugs.

Tonight i have had the tank off and confirmed that the fuel tap works and that fuel is getting to the carbs (float chambers were full) but no futher. i took the bowls off the carbs and removed the needles and they all look clean and free from blockages.

The only other thing i have noticed is that there are 3 clamps missing from the rubber intakes into the chambers there fastened to the carb but not the block !!

any help is much appreciated

thanks in advance

Mark

[BigDonk]

check your battery I learnt from the forum that if your battery is a bit tired it does not have the grunt to start the bike, it will turn it over but will not start it, I got a new battery from the bay of E £23 from millers bits I think, I also brought new plugs,air filter, my only cheat was to spary a bit of perol down each carb and hey ho, started first go
I had the same problem only firing on 2 or 3 then nothing, which is annoying and does tend cause spanners and such like being thrown about the garage when is does not start

[Neosophist]

You can get a Decent Varta battery from tayna.co.uk for 19.00, I wouldn't buy a chepaer one they just dont last.

Connect it upto a bigger battery (ie car) with some jump leads if your sure theres no electrical shorts and see if the extra power helps it start.

You should be using full choke and no throttle at all until its running, any throttle is likely to kill it.

try it in 5 second bursts then leave it 30 seconds. If it doesnt catch after a couple of goes something is amiss

[streethawk999]

thanks guys

been using a car battery thats fully charged with leads and its spins nice and fast just makes a popping sound and then back fires when you stop cranking !!

im really stuck as how to fix this !!

[BigDonk]

Yep that sounds just like mine was doing, I checked my plugs , which where a mess, I got new ones, also one of the spark plug cap rubbers wasn't allowing the thread of the spark plug top to line up and fit in the spark plug cap so I would never get a spark in one pot at all. so I trimmed the rubber slightly by 10mm, and then you feel/hear the the thread clicking into the cap,

[streethawk999]

i had a really week spark on number 3 but after diagnostic comp confriming the cdi unit was throwing out a poor vaultage every other spark, have replaced this now and the comp confirms i have a really good strong spark but seen to be getting no fuel.

What i can figure out is why the float bowls are full and the floats are working but no petrol is being drawn in to the chamber ??

Checked all injectors etc and all clear

[Neosophist]

Petrol must be being drawn in if your getting back-firing.

Either plug leads are in the wrong order or the valve timing is messed up.

Start with plug-leads first. Test each plug for spark by holding plug to cylinder head. then make sure it is going to the correct cylinder.

Make sure your using full choke and no throttle though.

[streethawk999]

Bit of an update

still nto managed to start the thing !!

i have now tested by the fuel problem by filling placing a little in each chamber and cranking the bike over but still no joy, Theres a really good strong spark but wont fire, am using a fully charged car battery of my VR6.

The bike was running on 3 so find it hard to believe that its a timing issue as i have never had the engine open.

so im now stuck i have fuel and spark but wont go !!!

[Neosophist]

Hmm.

Do you have the old igntiion box still at hand to try?

Cleaned up the plugs with a wire-brush?

[streethawk999]

yeah i still have it, when i tested the cdi it was throwing out a really low voltage every 3rd crank causing a week spark.

have taken apart all the connections and some were furred up so cleaned up and put back together, then checked that the coils were all connected up correct and each HT lead went to the correct cyclinder.

thanks for all the replys