cuts out and want start when hot ? help please!

tommyboy · Post by **tommyboy** » Tue Jan 09, 2007 3:26 pm

hi i have a 1989 h model 400 that cuts out and stops when i pull over or stop the bike at a junction and will not re start untill 10 mins and lots of jump and bump starting (f-kin thing)

it runs very well when cold and starts first flick on choke and can do around 15-20 miles before it dies,

the battery is always fully charged and when it stops it spins over forever until it goes flat! ive been trying to solve this prob for a long time now and im getting to the end of our relation ship !

ive tryed !
new plugs
cleaned and checked carbs about three times
adjusted float hights
run bike on a clean can of fresh fuel with the tank removed and still cut out when hot!
needle gets to half way on temp guage
checked all electric conections i think!
cleaned contacts on fuel pump
doesent seem to run out of fuel when it does it! carbs are always full
doesent loose its spark or still seems to have a spark

im thinking some thing is breaking down when hot as i can get it to do this now when just on idel sitting in the garage all striped air box of and tank, running on a seprate tank of clean fuel that ive made up

the fuel pump seems to slow right down when it does it just the odd tick but the pressure is always there and the float bowls are always full even if they were getting stuck a would of thought i could tap them to free them of but it still will not start
ive noticed that the plugs when removed after its cut a bone dry and pefect colour and never seem to be wet!

it some times back fires when spinning it over to get it going and the idel gets a bit eratic before it sopund like it drops on to 2 cylinder and stops

i checked the valve clearances when it cut out and they all had gaps about .12 or 8 thou as i thought it might be tight valves creating no vacume to suck full in but if you block the carbs one by one with your hand it drarws up loads of fuel

so im down to something breaking down on the electric side coil, cdi,reg,fuel pump relay ?

does the fan switch play any part of the ignition as ive never heared it run but it never prob running long or hot enough to hear it come on ?

help !

Post by **masterofinsanity** » Tue Jan 09, 2007 3:32 pm

whats' the side stand switch like mate?

tommyboy · Post by **tommyboy** » Tue Jan 09, 2007 3:51 pm

hi both the clutch and the side stand look ok and the bike cuts with stand up or down if i by pass both do you just join the wires together, and why would they give trouble when hot!

Post by **masterofinsanity** » Tue Jan 09, 2007 3:57 pm

just trying to rule out the simple things which are usually the culprits, the zxrs were prone to hot starting problems but yours seems to be all over the place, definitely sounds like it could be a short somewhere in the loom, there is a small connector i can't remember if its green or yellow? green i think on the right hand side of the battery which is a known problem, it usually corrodes and can cause problems, have a look?

tommyboy · Post by **tommyboy** » Tue Jan 09, 2007 5:36 pm

hi thanks ive been over the loom that i can see the bikes a minter not the usal young mans mess and has only covered a 9500 miles and there are no real signs of blue corroded wires anywere its driving me mad!!! that wire was a black and yellow bullet connector looked clean

please keep it coming as im out of idears !!

tommyboy · Post by **tommyboy** » Tue Jan 09, 2007 7:05 pm

hopefully i will get to the bottom of this soon so i will let you know what it was ive got some bits ariving soon ,set coils leads and caps, more plugs,cdi unit,fuel pump,rec/regulator,crank pick up , fuel relay,fues box if this dont do it its got to be the loom or switch gear as im convinced its not fuel the only way it could be fuel is starvasion and the carbs are always full up when it cuts !

hipringle · Post by **hipringle** » Tue Jan 09, 2007 7:20 pm

I know I,m no help but when you swap all those bits over & if its no different I may be interested in buying things off you if you want to sell, coils, pump etc etc,
cheers.

tommyboy · Post by **tommyboy** » Wed Jan 10, 2007 4:57 pm

well im well and truly fixed!!!!!! it was the pick up coil that works off the crank and when you think about it is the only electrical part of the ignition system thats bolted to the engine or inside the engine running the same temp as the engine and oil apart from plugs,

this is why it was breaking down at the same temp and mile range and must have a elec winding in the pick up senser that was expanding and breaking the conection some were and explains why as it cooled down for 5-10 mins it srinks and makes the connection again and re-starts

but i had a spark when it breaks down ? this must be were its not got a strong enough signal for the coils to fire under compression through the cdi unit, and the spark just breaks down under compression

anyway it sorted now ran it up until the fan cut in which i was not able to do before and gave it a very long road test in the pissing down rain stoped loads of times and it started first flick of the button no matter how long or short i left it ha ha ha ha im very happy and thanks to david of ebay for the bits !!!

Post by **masterofinsanity** » Wed Jan 10, 2007 5:00 pm

nice one, hope this will help others in the same situation.

SplaTZXR400 · Post by **SplaTZXR400** » Wed Jan 10, 2007 5:06 pm

check the vacuum tubes are tight that go tot he cilenders, 1 - 4 and 2- 3. probly wont make a difference but check them for breaks being rubber as this makes it hard to start. check your mixture, mines set on 1 3/4 turns out n it seems perfect. tho as for cuttin out, check you oil n coolant for evidence of a blown gasket. i had this happen to me it would die every 3 miles wen it was hot and wouldn't start till it cooled down. coolant would get into the engine. check connections on the coils, on mine if u wiggle them then it dies. so i clamped them tight with plers. worth a try. i wouldn't worry about the slow tickin on the pump, these things use little fuel wen idlin n tick only occasionaly. as long as your gettin the right pressure and the bowls have fuel, there shouldn't be problem. check the rubbers on the cilender inlet manifold. they need to be tight to create a seal, well not really if had mine undone an it runs the same, but worth a look. erm, i have heard the capacitors (CDI) can get hot and break down and dont work and the coils aswell, apparently. maybe thats y it cuts out. so a car mechanic told me. erm..not sure wot else to suggest mate, get the new parts and swap em round i spose. let us no how it goes.

tommyboy · Post by **tommyboy** » Wed Jan 10, 2007 5:44 pm

thanks splatzxr400 but ive fixed it read the above !!!

SplaTZXR400 · Post by **SplaTZXR400** » Wed Jan 10, 2007 5:49 pm

blime was i writing that long, that wasn't there before i posted, glad u fixed it.

Post by **masterofinsanity** » Wed Jan 10, 2007 9:58 pm

that was quite funny