GPz1100 A3 sneezing

My 83 Gpz 1100 sometime "sneeze" at low to moderate engine speed, about 2500-3000 rpm.
It happens at low speed, about 50 km/ h, never at higher speed.
what's the reason ?
The bike has its original DFI. The temp sensors, injectors, TPS, ignition works as they are supposed to, when tested with a multimeter.

Jompa wrote: My 83 Gpz 1100 sometime "sneeze" at low to moderate engine speed, about 2500-3000 rpm.
It happens at low speed, about 50 km/ h, never at higher speed.
what's the reason ?
The bike has its original DFI. The temp sensors, injectors, TPS, ignition works as they are supposed to, when tested with a multimeter.

What do you mean by "sneezing?" Not sure what that means. Please describe. Thanks.

1st verify valve adj correct.
2nd verify throttle body sync.
3rd you can bump TPS ahead.
4th install adj F/P reg.

Sneezing is the sound wich comes out of your nose when you are chilled, says my norwegian/english wordbook.
My gpz sometimes make a sound like a sneeze, "Tchong".
The enginge doesnt stop, it runs kike normal afterwards.

I have checked the valves and the clearance is right, between 0,08 and 0.18 mm.
Camchain is okay and throttles syncronised.

Jompa wrote: Sneezing is the sound wich comes out of your nose when you are chilled, says my norwegian/english wordbook.
My gpz sometimes make a sound like a sneeze, "Tchong".
The enginge doesnt stop, it runs kike normal afterwards.

I have checked the valves and the clearance is right, between 0,08 and 0.18 mm.
Camchain is okay and throttles syncronised.

If this condition is repeatable, by that I mean, every time you hit this point in the throttle it "sneezes" then I'd more closely examine the TPS both when cold and at operating temp. Check it when cold, then get the bike up to normal temp and then unplug the TPS and meter the resistance as you slowly open the throttle. Wondering if there is a spot where the TPS is problematic and causing this glitch. Comparing both may tell you this. Also, check for any vacuum leaks.

Jompa wrote: Sneezing is the sound wich comes out of your nose when you are chilled, says my norwegian/english wordbook.
My gpz sometimes make a sound like a sneeze, "Tchong".
The enginge doesnt stop, it runs kike normal afterwards.

I have checked the valves and the clearance is right, between 0,08 and 0.18 mm.
Camchain is okay and throttles syncronised.

Sounds like you have the common "lean" stumble as I did. Read this :

kzrider.com/forum/3-carburetor/403310-in...-my-gpz1100-dfi-long

Breaker19 wrote:

Jompa wrote: Sneezing is the sound wich comes out of your nose when you are chilled, says my norwegian/english wordbook.
My gpz sometimes make a sound like a sneeze, "Tchong".
The enginge doesnt stop, it runs kike normal afterwards.

I have checked the valves and the clearance is right, between 0,08 and 0.18 mm.
Camchain is okay and throttles syncronised.

If this condition is repeatable, by that I mean, every time you hit this point in the throttle it "sneezes" then I'd more closely examine the TPS both when cold and at operating temp. Check it when cold, then get the bike up to normal temp and then unplug the TPS and meter the resistance as you slowly open the throttle. Wondering if there is a spot where the TPS is problematic and causing this glitch. Comparing both may tell you this. Also, check for any vacuum leaks.

I can`t say its repeateble, just happens some now and then. But it always happens at low rpm.
I have tried to change the TPS with another old one. I`ll try to measure it at both cold and warm temp. The electronics seems to work well, no green flash under the saddle.
I have been wondering about the fuel pressure regulator, it is vacuumcontrolled and maybe the vacuum at 1/4 throttle may cause the regulator failing ? It always happends when I`m riding at constant speed and constant low rpm.
Or is the engingine simply backfiring ?

Polar_Bus wrote:

Sounds like you have the common "lean" stumble as I did. Read this :

kzrider.com/forum/3-carburetor/403310-in...-my-gpz1100-dfi-long [/quote]

I`already read yuor topic. Interresting, I`ll try your mod.

I like those wheels on your '85 are they gold ? Just curious where are you from, They didn't make a GPZ1100 A3 in the USA, so you must have a "across the pond" version... :laugh:

Polar_Bus wrote: I like those wheels on your '85 are they gold ? Just curious where are you from, They didn't make a GPZ1100 A3 in the USA, so you must have a "across the pond" version... :laugh:

Shit, I wrote A3, my bike is a A1 (83)
No, the wheels are without painting, its the sun making them shine on the photo. They will be original red, someday..... The bike is an 83, not 85. I bought it 2 years ago, it was dark blue then,and restored it in the winter. The bike was in a quite bad shape, I had to buy a lot of new and used parts. Pistons, rings, exhaust mufflers, rear shockabsorber, fork sealings, chain and sprockets, inlet valves, one exhaust valve, seat cover, and lots of other parts.
Cylinders,head and clutch are overhauled, not the bottom of the engine. Also rear suspension.
There is still sometihing to do, my plan is getting it close to original shape.
Done most of the work myself, not the paint job.
Decals from AFE-graphics.
I`m from Norway, so the bike is a european type. Not very different from the US bikes.

Jompa wrote:

Polar_Bus wrote: I like those wheels on your '85 are they gold ? Just curious where are you from, They didn't make a GPZ1100 A3 in the USA, so you must have a "across the pond" version... :laugh:

Shit, I wrote A3, my bike is a A1 (83)
No, the wheels are without painting, its the sun making them shine on the photo. They will be original red, someday..... The bike is an 83, not 85. I bought it 2 years ago, it was dark blue then,and restored it in the winter. The bike was in a quite bad shape, I had to buy a lot of new and used parts. Pistons, rings, exhaust mufflers, rear shockabsorber, fork sealings, chain and sprockets, inlet valves, one exhaust valve, seat cover, and lots of other parts.
Cylinders,head and clutch are overhauled, not the bottom of the engine. Also rear suspension.
There is still sometihing to do, my plan is getting it close to original shape.
Done most of the work myself, not the paint job.
Decals from AFE-graphics.
I`m from Norway, so the bike is a european type. Not very different from the US bikes.

I have a TON of spare GPz parts, I also have some '83 A1 decals (they are useless to me I have an A2) you can have them for just the shipping costs. Good luck with the bike ! Good for you for restoring to OEM original !

Jompa wrote: Sneezing is the sound wich comes out of your nose when you are chilled, says my norwegian/english wordbook.
My gpz sometimes make a sound like a sneeze, "Tchong".
The enginge doesnt stop, it runs kike normal afterwards.

I have checked the valves and the clearance is right, between 0,08 and 0.18 mm.
Camchain is okay and throttles syncronised.

mine does it as well when ure going slow in to high a gear ..