My Troublesome FZR

[Gizzard1533]

Well as the sun was shining, im off work and feeling better I decided to fiddle around with the FZR. First off I tried to get it running, took a while but it started. I thought great.

Left it idling with the occasional blip of the throttle and it idled absolutely fine no mishap or nothing.
Wheeled it out whilst still running, put my lid on, engaged first, moved 5 metres and BAM it stalled, Great im thinking i can check the float bowls, undone the drain screws and fuel flowed out, first thought was great the fuel system is still in operation, but at the same time im thinking fook, something else is wrong, may not be such an easy fix now. I went to start the bike again and it didn't even want to 'bog' like usual, weren't even feeling like it was wanting to start. I left it a few mins, ignition off. turned the ignition back on, fuel pumped made a noise lasted about a second, it then wanted to bog. Great its doing the usual thing. With this I decided to take the fuel pipe from the pump to carbs and put the carb side into a bowl, hoping that this would show me continous fuel flow, which it didn't. it pumped no more than 100ml no matter how many time you turned the key. this put the thought that my relay had broken down inside the TCI and it only supplied the 'prime' supply.

As I remembered from last time, If i removed the air box the bike picked up the revs again. with this in my mind i didn't want to remove the whole airbox at first, so i thought i'd remove the air filter to see if this was restricting the flow of air. Filter out there was no change....

I removed the whole airbox and the revs jumped back to normal and it reved just like normal, I decided to put the tank, tank cover, and seats back in place and go for a quick spin up and down my street, (cant go to far MOT 5 days over due ) I done 10 passes of my street which works out to be around a mile (which i normally managed before it dies). After this mile i pulled back onto my drive and the bike still ran fine.

Now to me this is showing that the Airbox is directly at fault. I know you shouldn't run an engine with an air filter but i am honestly at a loose end as to what i can do from here on? Any suggestions would be great please

[pnbell]

Well, it certainly seems as though the Airbox is restricting the engine air.. At idle the engine won't require much air, but with Revs and Load obviously it's not getting enough air...

So, and it seems like you must have checked this already, but Are all the Air Passages clear? (Not Spider Webs, Mouse Nests, or Shop Rags??) There has to be something clogging, the Airbox itself is not very restrictive...

[Gizzard1533]

All the passages are clear, the funnel leading to the filter is clear, and each velocity stack is clear. I'm really not sure what is causing the issue. Is it possible to push the velocity stacks to far into the airbox so they touch the top of the airbox???

[pnbell]

Hey, what about the Plugs? have you pulled them out to check them? Give them a good cleaning?? I had an old CB350 that ran like crap, would idle, but reved like Hell, POP'ing and eventually would die and not start.

Cleaned the plugs (install new ones) and like magic ran and drove pretty good.

*Maybe the extra air helps the plugs fire...? All just shots in the dark of course...

[Gizzard1533]

Hey, what about the Plugs? have you pulled them out to check them? Give them a good cleaning?? I had an old CB350 that ran like crap, would idle, but reved like Hell, POP'ing and eventually would die and not start.

Cleaned the plugs (install new ones) and like magic ran and drove pretty good.

*Maybe the extra air helps the plugs fire...? All just shots in the dark of course...

Plugs areo my next thing. But they were cleaned when i fitted them. They were reused from when i took the bike off the road. I've never heard of air helping plugs fire but im just trained mechanic not an experienced one LOL

Sent from my GT-I9100 using Tapatalk 2

[pnbell]

Well you said the bike idle'd ok at first, then you went to drive it and the engine died. After that the engine was bogging out.

- So my thought is that maybe the dirty plugs were working 'OK' at first, but when you accelerated the extra fuel 'fouled' the already dirty plugs to the point where they barely spark... Now you are giving the engine (which is running rich due to weak spark and un-burnt fuel) more air which is helping it run!

HA HA! Again this is all hypothetical guessing... I am NOT a Trained Mechanic; just a guy who has always been too cheap to A) buy well running vehicles and B) pay a mechanic...

[Gizzard1533]

Well you said the bike idle'd ok at first, then you went to drive it and the engine died. After that the engine was bogging out.

- So my thought is that maybe the dirty plugs were working 'OK' at first, but when you accelerated the extra fuel 'fouled' the already dirty plugs to the point where they barely spark... Now you are giving the engine (which is running rich due to weak spark and un-burnt fuel) more air which is helping it run!

HA HA! Again this is all hypothetical guessing... I am NOT a Trained Mechanic; just a guy who has always been too cheap to A) buy well running vehicles and B) pay a mechanic...

Put it that way and yeah that does sound logical. When you first said it i didn't even think about the mixture aspect of it.

Aha just like me then, 205 quid for my first big bike , which by the way has never caused me any problems like this

Sent from my GT-I9100 using Tapatalk 2

[Gizzard1533]

Well had a play today, the top hole of the carb venturi was clean so no issues there.

I cleaned the Pilot Air Jet and then was all fine.

I then tried it with air box on again............. Low and behold the same issue arrises again!!!

Tried it with just the velocity stacks............ Little improvement but after a few passes same problem shows up again!!!

Bare open carbs........... She runs perfect

WHAT THE HELL IS GOING ON?!?!?!?!?!?!

I'm running out of idea's, Other than some Dyno time to get a real idea???

[pnbell]

Did you end up checking the plugs?
Weird..

[Gizzard1533]

Did you end up checking the plugs?
Weird..

Yeah i replaced all the plugs for fresh new ones so i am completely stumpted....

Sent from my GT-I9100 using Tapatalk 2

[Gizzard1533]

Well i am extremely happy to report back that i now have a fully working and fully functioning FZR again and my god am i happy. After spending hours messing around with it and test riding to no prevail. I sent the bike off to a local bike shop, however for 140 quid they had done a compression check and valve check. So after i found this out i told them to stop working on it and deliver it back to me, they did however give me a few tips and advice. They said i had real low compression and what appeared to be a cylinder head leak. So with this in mind i set about working on it again. I replaced the head gasket and lapped in all the valves, once the engine was rebuilt i spent a full day, getting the timing and valve clearances spot on. With the engine back in the frame and everyting connected up, i went to start it, and withing 2 mins of cranking the bike fired right up, this already put a smile on my face as it took around 10 mins after the first rebuild (i drained two batteries!!). i then let it warm up and nothing reared its ugly head, so im still smiling. A few days ago i took it for a short test ride around my village, covered around four miles on it and it behaved absolutely fine, payday came the following day and it was straight down to the MOT centre. The bike passed with flying colours and he paid me compliments on how well the bike looked and how the bike was mechanically. By now im smiling that much my face is hurting. Yesterday came the official test ride day, I covered 40 miles on it and the bike ran like an absolute dream, no mishaps no anything. I'm still wearing the ear to ear smile i was yesterday once i got off the bike. Cant wait for sunday as im due to go out with a mate for a days riding. Fingers crossed the weathers good

[pnbell]

Wow. so tip of the day: When in doubt rebuild the engine! HA HA

Well glad to hear you can smile and ride again! (plus i bet you learned a bit)

[Gizzard1533]

Wow. so tip of the day: When in doubt rebuild the engine! HA HA

Well glad to hear you can smile and ride again! (plus i bet you learned a bit)

Yeah when in doubt strip the engine using oem parts and 24 hours of your time into it.

The bikes much better than before, and i'm still smiling, even if when i took it on a dual carriage way i lost the left hand side fairing . Im still smiling ear to ear though .

Sent from my GT-I9100 using Tapatalk 2