FZRSupport: the FZROnline Archive

So I've done a valve job twice now. The first time was to get them in spec but once i had it running it never ran right, it always bogged from idle, extremely hard bogging. I've cleaned the carbs an infinite amount of times now. I recently took it into a shop where the mechanic checked my carbs which were fine, sync'd them. but then when he did a compression test all of the sudden Cyl#1 had next to none compression and when a leak-down test was performed it had about 95%-100%. He thought it would be my valve clearances(too small and opening too early) but when i got the bike back i took it all apart and all my clearances except for a too big clearance on 1 exhaust valve. I changed all the shims to be on the high end of specs as some were low. I also lapped or re-seated my valves with a valve grinding compound because I thought if the clearances are fine it must not be sitting right. The valves looked fine to me, no rounding, seals good, and not burnt(cracking or wear). I finally put it back together yesterday, timing is bang on. BUT, when it started up after a few seconds of trying to get it going, ITS ALL THE SAME. Gas just spits out of the intake and you can feel lots of air coming our of that Cyl, it also still has a large bog but it does seem like it has gotten a bit better, but very little, it'll still die if i give it for long enough. I am going to do another compression test tonight and if its gone I may bring it to another shop or something as I've had this for over a year now and its taken all my money, sanity and happiness away because this damn issue causing me not to be able to finish it. Whenever I take the carbs off, i see a lot of white "mist" or "smoke?" in the intake boots, mostly for Cyl2,3,4 less in #1, which is odd because it used to be complete opposite.

Bike has Pods(weren't on when spitting gas), Muzzy Can, 110 Main Jet(way higher than stock 87.5), new intake boots.

Another thing was gas suddenly was leaking out the bottom of my carb which I have never had before, also when I take the carbs off there is a lot of gas sitting on the boots and I have no idea where it came from. It sits on the top of the boot on the outer ring.

Any ideas are EXTREMELY APPRECIATED. Thank you.

You may have stuck floats, or fouled float needles, or cracked floats that are full of gas.

You may have misinstalled the cams when you did the clearances; I've seen mis-timed, and I've seen intake and exhaust swapped (!).

DonTZ125 wrote:You may have stuck floats, or fouled float needles, or cracked floats that are full of gas.

You may have misinstalled the cams when you did the clearances; I've seen mis-timed, and I've seen intake and exhaust swapped (!).

Carbs are totally fine, cylinder has 0 compression, cams are in timing and not swapped. Clearances are going to be rechecked shortly but they should be in spec.

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Did you check the iginion-coils, the spark-plugs and the spark-plug cables before? Sounds a bit like the cylinder is running without ignition...

By the way i had a strange nearby-sound and also some bogging while running the motor and a power-leak when it was definitely in a warm operating state last week,too...
But the problem was, the thermo-unit didn´t seem to work ,which was caused by rusty connectors,and wasn´t connected any more to the frame due to a lost bolt...
So i cleaned the connectors, replaced the lost bolt, checked also the cams once more ( a few weeks ago i had adjusted the valveclearance, checked just for ensuring there is really no timing-problem ), exchanged one o-ring from the left-hand waterpipe which had a very small leakage(connected to the lower connectionpoint of the radiator and the cylinder), for beeing sure also changed the spark-plugs to a spare-set from a motor with geardefect (where the spark-plugs had been changed just around 400 km before the gears died, another motor was cheaper than a gasket-set,so i changed the motor instead of repairing the defective up to now ) and after all it ran well again at a little testride this afternoon

You're persisting with the pods then ???
If you've lost compression in one piston and youre sure it isn't the valves then it has to be piston rings, but if it was that I'd expect it to be smoking. Obviously if you've cured the compression then carry on.

I reckon it could be the emulsion tubes / needles - so get the needles out and look for a polished spot on them, this will mean they're rubbing on the tubes which in turn go out of round. The result is ok is running until the needle rotates then it can be lean / rich. Buy or borrow another set of carbs, ditch those pods and use an airbox then try it. You could put it on a dyno that will tell if it's electrics or mixture but it can work out expensive quick.
Are you using new / newish plugs, change them if theyre not.
If it was the cams I'd expect it to have picked up by now so just have look at the timing pics below and if that's all ok then I doubt its that.

TDC flywheel lines up with forward crank case joint



Cam shafts timing with Exhaust on the left

Evilchicken0 wrote:You're persisting with the pods then ???
If you've lost compression in one piston and youre sure it isn't the valves then it has to be piston rings, but if it was that I'd expect it to be smoking. Obviously if you've cured the compression then carry on.

I reckon it could be the emulsion tubes / needles - so get the needles out and look for a polished spot on them, this will mean they're rubbing on the tubes which in turn go out of round. The result is ok is running until the needle rotates then it can be lean / rich. Buy or borrow another set of carbs, ditch those pods and use an airbox then try it. You could put it on a dyno that will tell if it's electrics or mixture but it can work out expensive quick.
Are you using new / newish plugs, change them if theyre not.
If it was the cams I'd expect it to have picked up by now so just have look at the timing pics below and if that's all ok then I doubt its that.

TDC flywheel lines up with forward crank case joint



Cam shafts timing with Exhaust on the left

Rings looked okay. Pods should be fine if previous owner ran the bike fine before. Carbs seem to be perfect but the spitting gas must be my valves and bogging is the 1 cylinder not firing at all. Plugs are new and are a higher heat plug. Timing is bang on. I think I am going to have someone machine my head and valves.

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TomcatMJ wrote:Did you check the iginion-coils, the spark-plugs and the spark-plug cables before? Sounds a bit like the cylinder is running without ignition...

By the way i had a strange nearby-sound and also some bogging while running the motor and a power-leak when it was definitely in a warm operating state last week,too...
But the problem was, the thermo-unit didn´t seem to work ,which was caused by rusty connectors,and wasn´t connected any more to the frame due to a lost bolt...
So i cleaned the connectors, replaced the lost bolt, checked also the cams once more ( a few weeks ago i had adjusted the valveclearance, checked just for ensuring there is really no timing-problem ), exchanged one o-ring from the left-hand waterpipe which had a very small leakage(connected to the lower connectionpoint of the radiator and the cylinder), for beeing sure also changed the spark-plugs to a spare-set from a motor with geardefect (where the spark-plugs had been changed just around 400 km before the gears died, another motor was cheaper than a gasket-set,so i changed the motor instead of repairing the defective up to now ) and after all it ran well again at a little testride this afternoon

Ignition coil to that cylinder was weak which I fixed but it wouldn't make a difference since I have 0 compression in it. I have a cooling issue as well where thermo may not open or fan may not come on. Bogging is because that cylinder does not work at all.

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Evilchicken0 wrote:You're persisting with the pods then ???
If you've lost compression in one piston and youre sure it isn't the valves then it has to be piston rings, but if it was that I'd expect it to be smoking. Obviously if you've cured the compression then carry on.

I reckon it could be the emulsion tubes / needles - so get the needles out and look for a polished spot on them, this will mean they're rubbing on the tubes which in turn go out of round. The result is ok is running until the needle rotates then it can be lean / rich. Buy or borrow another set of carbs, ditch those pods and use an airbox then try it. You could put it on a dyno that will tell if it's electrics or mixture but it can work out expensive quick.
Are you using new / newish plugs, change them if theyre not.
If it was the cams I'd expect it to have picked up by now so just have look at the timing pics below and if that's all ok then I doubt its that.

TDC flywheel lines up with forward crank case joint



Cam shafts timing with Exhaust on the left

ALSO, those cams are a lot different than my 1wg, on of your timing marks is to the right as mine are both upright. I still have the pods because I cant afford a airbox right now and if it ran before okay theres no reason why it shouldnt now but ill see. My main issue at the moment isnt with the carb shooting gas its also more that the one cylinder isnt even firing.

snydes wrote:

ALSO, those cams are a lot different than my 1wg, on of your timing marks is to the right as mine are both upright. I still have the pods because I cant afford a airbox right now and if it ran before okay theres no reason why it shouldnt now but ill see. My main issue at the moment isnt with the carb shooting gas its also more that the one cylinder isnt even firing.

OK - have you checked the manual for the cam timing ?
Have a look at that first, mine's a 3tj so a later version (1990) but if the cams are out then that might well be it.

I wouldn't waste any more money on your engine, the money to get it machined would be better spent on a different head or 600 replacement.

Evilchicken0 wrote:

snydes wrote:

ALSO, those cams are a lot different than my 1wg, on of your timing marks is to the right as mine are both upright. I still have the pods because I cant afford a airbox right now and if it ran before okay theres no reason why it shouldnt now but ill see. My main issue at the moment isnt with the carb shooting gas its also more that the one cylinder isnt even firing.

OK - have you checked the manual for the cam timing ?
Have a look at that first, mine's a 3tj so a later version (1990) but if the cams are out then that might well be it.

I wouldn't waste any more money on your engine, the money to get it machined would be better spent on a different head or 600 replacement.

I did check timing and its bang on. Buying a new head is i think too much

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UPDATE: So checking clearances tonight, one of my intakes is totally out of spec. Will fix it shortly and respond. When I fired the bike up today it seemed to run MUCH better than before which one of the valves is now in spec which could mean that it's this last valve causing it's screw up. AS for the carb shooting gas, that's definitely because the leak of air coming from the cylinder through the carb is spraying it up words

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FINAL UPDATE:

So went back to check clearances, turns out one of the intakes had a WAY bigger shim (170) vs the shim in the intake valve beside it (135) so once switched, put bike back together and that cylinder works again(YESSSSS). It did bog but didn't spit any gas. Fixed bogging with Pilot Adjustment screws so now it runs mint. Time to fix fairings, check cooling, and RIDE IT FOR THE FIRST TIME!


THANK YOU ALL SO MUCH WHO HELPED ME FIX THIS ISSUE, IT MADE THIS PROJECT SO MUCH BETTER.

Also to add, EvilChicken0, the pods work flawless on the bike, made the bogging reduce greatly. Maybe ill get an airbox down the road.

So you got two shims crossed over - easy mistake to make and I'm glad you found it.

Quick simple question, is there any way to adjust when the cooling fan comes on? This bike gets extremely hot quick and the fan only turns on about 3mm-5mm from the red line of temperature. This is a bit concerning since the fan almost doesnt seem like it will cool it fast enough. In a nutshell, I'd like to reduce the temperature that it decides to turn on, I could add a manual switch which I have already tested but its also sketchy as I could leave it on and kill the bike battery.

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For the 1000 i know some guys here in germany who exchanged the thermoswitch against one of a Nissan Bluebird (T12 or U12, don´t remember exactly which one they used) to solve the same Problem as you are looking for a solution for ...i guess this Model was named also Nissan Auster in other countries/continents...maybe its also fitting to the 400 if the diameters and lenght of the treads are the the same. The Nissan Thermoswitch opens and closes usually around 10 degree earlier than the ones of the FZRs.