Hello Guest User,
Please feel free to have a look around the forum but be aware that as an unregistered guest you can't see all of it and you can't post.
To access these 'Registered Users Only' areas simply register and login.
Please feel free to have a look around the forum but be aware that as an unregistered guest you can't see all of it and you can't post.
To access these 'Registered Users Only' areas simply register and login.
Carbs on an 1100 Unitrack engine
Moderators: paul doran, Taffus, KeithZ1R, chrisu
-
- 100Club
- Posts: 159
- Joined: 1st Sep 2008
- Location: Nottingham
Carbs on an 1100 Unitrack engine
Hope someone has already tried this and has some base settings /advice please
Any help/advice on jetting/set up target settings from anyone out there who has fitted a set of 34mm Mikuni CV diaphragm carbs to replace the injection system on a GPZ1100A Unitrack motor.
I am using an 1100 shaft standard Kawasaki air box, stock GPZ1100 A Unitrack motor with 4 in to 1 exhaust with road legal silencer.
I have started at 140 main jets 4.0 pilots 4CG15 jet needles .
I am not looking for maximum flat out power more a decent spread of power and not fussy to use on the road.
Fingers crossed
Thanks
Roger Hill
Any help/advice on jetting/set up target settings from anyone out there who has fitted a set of 34mm Mikuni CV diaphragm carbs to replace the injection system on a GPZ1100A Unitrack motor.
I am using an 1100 shaft standard Kawasaki air box, stock GPZ1100 A Unitrack motor with 4 in to 1 exhaust with road legal silencer.
I have started at 140 main jets 4.0 pilots 4CG15 jet needles .
I am not looking for maximum flat out power more a decent spread of power and not fussy to use on the road.
Fingers crossed
Thanks
Roger Hill
Re: Carbs on an 1100 Unitrack engine
I haven't got the specific specs but look at the stock jetting for the z1100r or the 1000J and go up on the main slightly.
The 1100 motors, spectre etc are also very close to the Unitrack including using the bathtub head but with shim over valve adjustment.
The 1100 motors, spectre etc are also very close to the Unitrack including using the bathtub head but with shim over valve adjustment.
Last edited by zed1015 on Tue Jan 07, 2020 11:47 am, edited 2 times in total.
-
- Custard Cream
- Posts: 804
- Joined: 20th Oct 2016
- Location: Ipswich
Re: Carbs on an 1100 Unitrack engine
Z1100R jetting should work, as they have a Unitrak engine and BST34 carbs.
An expanding collection of parts pretending to be a Z1100R and a Yamaha FZ750
Re: Carbs on an 1100 Unitrack engine
Main jets for the 1984 1100R1in factory manual dated 1988 are;
Cylinders 1 & 4 130
Cylinders 2 & 3 135
With a restrictive exhaust and a standard air filter i would go with those based on modern flame proof petrols.
With a less restrictive exhaust and a single K&N air filter in the box; 135 and 137.5 respectively
I had best results with 130 and 132.5 respectively with a set up designed for the track and with the needles raised by 1 notch on the middle two pots.
Are they J carbs with the coasting enricheners? If so they will have a three pointed cover held on by three screws with a central grub screw and lock nut sticking out.
If so it may help to lower the needles on the two outer pots by one notch!
140 is not a bad place to start though and it wont be running weak which of course would be not ideal.
B9ES plugs as well.
AL
Cylinders 1 & 4 130
Cylinders 2 & 3 135
With a restrictive exhaust and a standard air filter i would go with those based on modern flame proof petrols.
With a less restrictive exhaust and a single K&N air filter in the box; 135 and 137.5 respectively
I had best results with 130 and 132.5 respectively with a set up designed for the track and with the needles raised by 1 notch on the middle two pots.
Are they J carbs with the coasting enricheners? If so they will have a three pointed cover held on by three screws with a central grub screw and lock nut sticking out.
If so it may help to lower the needles on the two outer pots by one notch!
140 is not a bad place to start though and it wont be running weak which of course would be not ideal.
B9ES plugs as well.
AL
1981 J1
-
- 100Club
- Posts: 159
- Joined: 1st Sep 2008
- Location: Nottingham
Re: Carbs on an 1100 Unitrack engine
Thanks to everyone who has replied so far.
I am a long way short of firing the thing up yet but have managed to convince my mates to get involved as it has stood as an abandoned project for the last three years.
Its slowly coming together now and I am just sorting out the carbs.
The carb castings are 34mn z750 (originally black factory finish with black plastic tops )they have been stripped to bare castings and ultrasonic cleaned and reassembled on to newly replated mount rails .
The internals have been replaced with slides,jet holder tubes ,Jet needles etc from a set of 34mm Mikunis that were damaged.
they have the Kawasaki choke mechanism not Suz**I so were from one of the 1000/1100 models .
I have fitted new pilot jets .O rings gaskets float needles and seats the diaphragms are all good.
Hope to have it making smoke and noise by Easter (ish) the rate its going.
Good call on the 1100R spec Al I will steer towards that set up once it is running.
Once again thanks to everyone who has taken the time to reply.
I will let you know how its going in a few weeks.
Roger Hill
I am a long way short of firing the thing up yet but have managed to convince my mates to get involved as it has stood as an abandoned project for the last three years.
Its slowly coming together now and I am just sorting out the carbs.
The carb castings are 34mn z750 (originally black factory finish with black plastic tops )they have been stripped to bare castings and ultrasonic cleaned and reassembled on to newly replated mount rails .
The internals have been replaced with slides,jet holder tubes ,Jet needles etc from a set of 34mm Mikunis that were damaged.
they have the Kawasaki choke mechanism not Suz**I so were from one of the 1000/1100 models .
I have fitted new pilot jets .O rings gaskets float needles and seats the diaphragms are all good.
Hope to have it making smoke and noise by Easter (ish) the rate its going.
Good call on the 1100R spec Al I will steer towards that set up once it is running.
Once again thanks to everyone who has taken the time to reply.
I will let you know how its going in a few weeks.
Roger Hill
-
- Custard Cream
- Posts: 804
- Joined: 20th Oct 2016
- Location: Ipswich
Re: Carbs on an 1100 Unitrack engine
Some Z750s and GPZ750s had BST34s, so they might be standard 750 carbs.
An expanding collection of parts pretending to be a Z1100R and a Yamaha FZ750
-
- new poster
- Posts: 5
- Joined: 22nd Oct 2018
- Location: Salford
Re: Carbs on an 1100 Unitrack engine
Fitting appropriate jets is sound advice until you add the four into one pipe.
Some work well without too much tweeking. Others are problematical.
Do not get bogged down with main jet substitutions and needle heights.
All problems go away when air constrictors are installed in the air bleed hole to the main jet.
Air bleed constriction reduces the amount of air available within the emulsion tube. Therefore, suction
or vacuum in the carb has a greater effect on drawing fuel from the emulsion tube because the bleed or
vent to atmosphere is reduced.
Steve Smethurst
Some work well without too much tweeking. Others are problematical.
Do not get bogged down with main jet substitutions and needle heights.
All problems go away when air constrictors are installed in the air bleed hole to the main jet.
Air bleed constriction reduces the amount of air available within the emulsion tube. Therefore, suction
or vacuum in the carb has a greater effect on drawing fuel from the emulsion tube because the bleed or
vent to atmosphere is reduced.
Steve Smethurst
Re: Carbs on an 1100 Unitrack engine
stephensmethurst wrote:Fitting appropriate jets is sound advice until you add the four into one pipe.
Some work well without too much tweeking. Others are problematical.
Do not get bogged down with main jet substitutions and needle heights.
All problems go away when air constrictors are installed in the air bleed hole to the main jet.
Air bleed constriction reduces the amount of air available within the emulsion tube. Therefore, suction
or vacuum in the carb has a greater effect on drawing fuel from the emulsion tube because the bleed or
vent to atmosphere is reduced.
Steve Smethurst
IF you are going to run without the airbox I can supply the air corrector jets mentioned above.
-
- 100Club
- Posts: 159
- Joined: 1st Sep 2008
- Location: Nottingham
Re: Carbs on an 1100 Unitrack engine
Hi thanks to everyone who has replied to my original question.
I have ordered a set of main jets as per z1100 Lawson spec and will try them first.
I am using a stock air box and filter rather than pod filters.
Exhaust front section is a Delkevic stainless 4 into 1 .
I have not as yet got an end can but will be fitting something that is road legal rather than free flowing (noisy)
Steve would you still suggest fitting the air constrictor jets in the air bleed holes with a stock air box and filter ?
Still loads to do but its getting there.
I have ordered a set of main jets as per z1100 Lawson spec and will try them first.
I am using a stock air box and filter rather than pod filters.
Exhaust front section is a Delkevic stainless 4 into 1 .
I have not as yet got an end can but will be fitting something that is road legal rather than free flowing (noisy)
Steve would you still suggest fitting the air constrictor jets in the air bleed holes with a stock air box and filter ?
Still loads to do but its getting there.
-
- Custard Cream
- Posts: 804
- Joined: 20th Oct 2016
- Location: Ipswich
Re: Carbs on an 1100 Unitrack engine
What frame is the engine going in?
An expanding collection of parts pretending to be a Z1100R and a Yamaha FZ750
-
- 100Club
- Posts: 159
- Joined: 1st Sep 2008
- Location: Nottingham
Re: Carbs on an 1100 Unitrack engine
Its a modified gpz1100 b1 frame
Its been slimmed down slightly at the back of the top tubes and had a new set of front tank mounts fitted to take a pattern Z1 tank and the rear end has been changed to take a pattern Z1 fender B2 forks with clamps fitted to take Z1 style high bars.
The idea being a GPZ1
Its moved forward a bit more since the pictures but still had a way to go.
Its been slimmed down slightly at the back of the top tubes and had a new set of front tank mounts fitted to take a pattern Z1 tank and the rear end has been changed to take a pattern Z1 fender B2 forks with clamps fitted to take Z1 style high bars.
The idea being a GPZ1
Its moved forward a bit more since the pictures but still had a way to go.
Re: Carbs on an 1100 Unitrack engine
Hi Roger, Bike looks very good , my B2 has pod filters on BS 34's and a dynojet kit so have no jetting advice for you but I am curious as to whether a stock airbox will fit a B1/2 frame because the battery is much lower than on a 1000J/R and I was under the impression it would not fit without cutting bits off .The Gpz's I have seen
with an airbox have used a Unitrak 750 airbox which is a bit smaller.
with an airbox have used a Unitrak 750 airbox which is a bit smaller.
-
- 100Club
- Posts: 159
- Joined: 1st Sep 2008
- Location: Nottingham
Re: Carbs on an 1100 Unitrack engine
I have lowered the battery tray so that the battery sits further back and lower down .
Who is online
Users browsing this forum: No registered users and 143 guests