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Greetings All,
I'm new to the forum.
If anyone wants to know how to rid your Kat of engine vibration I have a solution.
All the best!!
Introduction
When Suzuki built this engine they did it perfectly. Every component was manufactured to the closest tolerances and measurements. So why does it vibrate?
The initial 1000km run in phase is where the metals in the engine bed down, settle in, and wear themselves into a comfortable moving position. Where the metals settle is dependent on one important factor and that is:
Each cylinders breathing capacity i.e. Are they breathing evenly and equally?
How the engine breathes in and out is therefore dependent on the following:
1. Is each inlet valve set to exactly the same specification? Can she breathe in evenly?
2. Is each exhaust valve set to exactly the same specification? Can she breathe out evenly?
3. Are the carburettors (Throttle Bodies) balanced to breathe in evenly?
4. Are the exhaust header ports the same size to allow even and equal breathing out into the main pipe?
Uneven breathing results in uneven cylinder temperatures and uneven compression. This translates into uneven pressures on metal components resulting in uneven wear and bedding down of components.
Now many of you at this stage might be thinking, “tell me something new”
So here it is.
In an effort to keep costs down the initial engine setup out of the factory was very poor. The valve tappets were not set exactly the same. The balancing was not perfect and the exhaust header ports were of different sizes as a result of the welding leaving excesses behind, blocking the ports and causing uneven backpressure. This in particular resulted in the exhaust valves closing at different speeds relative to each cylinder. The higher the back pressure the quicker the valve is forced closed.
The end result was that during the initial run in period each cylinder settled according to it’s individual uneven breathing capability bedding the rings, bearings, valves, tappets etc. differently for each cylinder. The metals settled down into a state other than what was originally designed as a result of the varying temperatures and pressures between cylinders.
This resulted finally in the notorious engine vibration between 4500 and 5000rpm.
What I’ve discovered here in Australia is that few people bothered to reset the valve tappets after the initial 1000km run in period or 1st service because the spec says you do it every 12000km and I suspect this may be the case worldwide. It’s just so much work and therefore very costly.
Therein lies only part of the problem.
So How Do you Fix It?
Recognise that your engine was designed as close to perfect as one could get and that the metal components have been forced into a state other than what they were designed to do.
What we want to do is reset the motor and it’s metal components into the state intended by the designer.
To do this we need to go through a new run in period irrespective of the age of the engine.
Besides the right tools, you will require three things to get this right.
1. Patience
2. Time
3. Discipline in following the procedures I’ll set out for you
Follow these steps in the exact order as set out and you will have a smooth running GSX750F with little to no vibration at any revs.
Step One – Breathing out
Grind out the header ports as described here http://www.motorcycleanchor.com/katana/header.html
This will even out the engine’s capacity to get rid of exhaust gasses and even out the closing of the exhaust valves. I.e. Each cylinder’s exhaust valve will close at the same point of the exhaust stroke.
Step Two – The Lungs
Reset your valve tappets
First read this to understand precision adjustment:
http://www.motorcycleanchor.com/motorcycle/how_to/mc_valve_adj.html
Then follow this procedure to get it right:
http://www.motorcycleanchor.com/katana/trinc/valve.htm
Set your valve tappets to :
Inlet - .005in or .127mm
Exhaust - .008in or .203mm
Step 3 – The Fuel
With the engine breathing out more evenly and freely, more fuel will be required to get the engine functioning optimally. Don’t mistake this for higher fuel consumption. This is about efficiency. A more efficient engine uses less fuel overall.
Rejet according to this procedure but consider the info below. http://www.motorcycleanchor.com/katana/trinc/jetkit.htm
If you’re at sea level replace only the main jets with size 122.5 if your originals are 117.
Otherwise leave them standard.
Leave the needles alone at this stage. The factory setting is the retainer clip in the 3rd notch from the top of the needle.
Set your mixture screws at 2 and 3¼ turns out from fully closed.
Set float levels at 14mm. Critical!!
NOTE!!
This entire process must be followed in the exact order as set out above before you restart the bike or you will not achieve the end objective – The ultimate smooth GSX750F
Step 4 – Throttle Position Switch ( Sensor)
The position of the Throttle Position Switch determines ignition timing or spark plug firing at a point of acceleration. Due to copy right laws I am unable to publish the settings however an internet search through http://www.carlsalter.com/motorcycle-manuals.asp will help you. This may not be critical. My TPS was out of spec but generally this is not the case.
Step 5 – Breathing In
Get your engine to breathe in evenly. Imagine trying to run a marathon with one lung sucking in less air than the other. You won’t make it. Neither will your bike.
Balance your carburettors according to this procedure http://www.motorcycleanchor.com/katana/trinc/sync.htm
So What Now?
What you now have is a motor that is set up for the new run in period.
All components are set as close to exactly the same.
Your problem is that the metals have not settled into their natural state from the time you got the bike.
Once the engine starts running with all the settings and adjustments described above, the metals will start to shift and settle into their natural state but because they were forced out of that to start with you will find later that your valve settings and carburettor balancing will progressively shift out of sync. This is a good thing. The rings, bearings, valves and tappets now start to take their correct place and the breathing alters as a result of even compression and temperatures.
Step 4 – How patient are you?
After 1000km treat your bike as new and reset your valve tappets.
They will be different to what you set them last. Not all of them but at least 55% of them. When I started this process only 1 of 16 valves was correct. After the first reset, 11 valves had changed. On the third check they were all still exactly as I had set them before. Yes this was 2000km after the first adjustment!!
While resetting the valve tappets, do the oil change and replace the filter if it’s due on your maintenance schedule.
Step 5 – Reset The Breathing In
Now rebalance the Carburettors.
With a readjustment of the valves the breathing will have altered.
Step 6 – Another 1000km Later
Recheck and reset valve tappets and then do your final carburettor balancing.
Conclusion
If this procedure does not smooth out your engine, something else is wrong and that is a separate discussion. This write up assumes that all components are clean and fully functional.
If you love your bike and want to get the best out of it, reduce it’s wear factor and increase performance while dropping fuel consumption then this write up should serve you well.
You will now only redo valve tappet adjustment after 12000km and recheck the carburettor balancing after 5000km, or every 2000Km if you’re as obsessive about perfection as me.
Remember
Use the best oil you can afford
Use the highest octane fuel – I only use 98
Treat her with respect and she’ll do the same
I'm new to the forum.
If anyone wants to know how to rid your Kat of engine vibration I have a solution.
All the best!!
1998-2005 Suzuki GSX750F Engine Setup – European Spec
Introduction
When Suzuki built this engine they did it perfectly. Every component was manufactured to the closest tolerances and measurements. So why does it vibrate?
The initial 1000km run in phase is where the metals in the engine bed down, settle in, and wear themselves into a comfortable moving position. Where the metals settle is dependent on one important factor and that is:
Each cylinders breathing capacity i.e. Are they breathing evenly and equally?
How the engine breathes in and out is therefore dependent on the following:
1. Is each inlet valve set to exactly the same specification? Can she breathe in evenly?
2. Is each exhaust valve set to exactly the same specification? Can she breathe out evenly?
3. Are the carburettors (Throttle Bodies) balanced to breathe in evenly?
4. Are the exhaust header ports the same size to allow even and equal breathing out into the main pipe?
Uneven breathing results in uneven cylinder temperatures and uneven compression. This translates into uneven pressures on metal components resulting in uneven wear and bedding down of components.
Now many of you at this stage might be thinking, “tell me something new”
So here it is.
In an effort to keep costs down the initial engine setup out of the factory was very poor. The valve tappets were not set exactly the same. The balancing was not perfect and the exhaust header ports were of different sizes as a result of the welding leaving excesses behind, blocking the ports and causing uneven backpressure. This in particular resulted in the exhaust valves closing at different speeds relative to each cylinder. The higher the back pressure the quicker the valve is forced closed.
The end result was that during the initial run in period each cylinder settled according to it’s individual uneven breathing capability bedding the rings, bearings, valves, tappets etc. differently for each cylinder. The metals settled down into a state other than what was originally designed as a result of the varying temperatures and pressures between cylinders.
This resulted finally in the notorious engine vibration between 4500 and 5000rpm.
What I’ve discovered here in Australia is that few people bothered to reset the valve tappets after the initial 1000km run in period or 1st service because the spec says you do it every 12000km and I suspect this may be the case worldwide. It’s just so much work and therefore very costly.
Therein lies only part of the problem.
So How Do you Fix It?
Recognise that your engine was designed as close to perfect as one could get and that the metal components have been forced into a state other than what they were designed to do.
What we want to do is reset the motor and it’s metal components into the state intended by the designer.
To do this we need to go through a new run in period irrespective of the age of the engine.
Besides the right tools, you will require three things to get this right.
1. Patience
2. Time
3. Discipline in following the procedures I’ll set out for you
Follow these steps in the exact order as set out and you will have a smooth running GSX750F with little to no vibration at any revs.
Step One – Breathing out
Grind out the header ports as described here http://www.motorcycleanchor.com/katana/header.html
This will even out the engine’s capacity to get rid of exhaust gasses and even out the closing of the exhaust valves. I.e. Each cylinder’s exhaust valve will close at the same point of the exhaust stroke.
Step Two – The Lungs
Reset your valve tappets
First read this to understand precision adjustment:
http://www.motorcycleanchor.com/motorcycle/how_to/mc_valve_adj.html
Then follow this procedure to get it right:
http://www.motorcycleanchor.com/katana/trinc/valve.htm
Set your valve tappets to :
Inlet - .005in or .127mm
Exhaust - .008in or .203mm
Step 3 – The Fuel
With the engine breathing out more evenly and freely, more fuel will be required to get the engine functioning optimally. Don’t mistake this for higher fuel consumption. This is about efficiency. A more efficient engine uses less fuel overall.
Rejet according to this procedure but consider the info below. http://www.motorcycleanchor.com/katana/trinc/jetkit.htm
If you’re at sea level replace only the main jets with size 122.5 if your originals are 117.
Otherwise leave them standard.
Leave the needles alone at this stage. The factory setting is the retainer clip in the 3rd notch from the top of the needle.
Set your mixture screws at 2 and 3¼ turns out from fully closed.
Set float levels at 14mm. Critical!!
NOTE!!
This entire process must be followed in the exact order as set out above before you restart the bike or you will not achieve the end objective – The ultimate smooth GSX750F
Step 4 – Throttle Position Switch ( Sensor)
The position of the Throttle Position Switch determines ignition timing or spark plug firing at a point of acceleration. Due to copy right laws I am unable to publish the settings however an internet search through http://www.carlsalter.com/motorcycle-manuals.asp will help you. This may not be critical. My TPS was out of spec but generally this is not the case.
Step 5 – Breathing In
Get your engine to breathe in evenly. Imagine trying to run a marathon with one lung sucking in less air than the other. You won’t make it. Neither will your bike.
Balance your carburettors according to this procedure http://www.motorcycleanchor.com/katana/trinc/sync.htm
So What Now?
What you now have is a motor that is set up for the new run in period.
All components are set as close to exactly the same.
Your problem is that the metals have not settled into their natural state from the time you got the bike.
Once the engine starts running with all the settings and adjustments described above, the metals will start to shift and settle into their natural state but because they were forced out of that to start with you will find later that your valve settings and carburettor balancing will progressively shift out of sync. This is a good thing. The rings, bearings, valves and tappets now start to take their correct place and the breathing alters as a result of even compression and temperatures.
Step 4 – How patient are you?
After 1000km treat your bike as new and reset your valve tappets.
They will be different to what you set them last. Not all of them but at least 55% of them. When I started this process only 1 of 16 valves was correct. After the first reset, 11 valves had changed. On the third check they were all still exactly as I had set them before. Yes this was 2000km after the first adjustment!!
While resetting the valve tappets, do the oil change and replace the filter if it’s due on your maintenance schedule.
Step 5 – Reset The Breathing In
Now rebalance the Carburettors.
With a readjustment of the valves the breathing will have altered.
Step 6 – Another 1000km Later
Recheck and reset valve tappets and then do your final carburettor balancing.
Conclusion
If this procedure does not smooth out your engine, something else is wrong and that is a separate discussion. This write up assumes that all components are clean and fully functional.
If you love your bike and want to get the best out of it, reduce it’s wear factor and increase performance while dropping fuel consumption then this write up should serve you well.
You will now only redo valve tappet adjustment after 12000km and recheck the carburettor balancing after 5000km, or every 2000Km if you’re as obsessive about perfection as me.
Remember
Use the best oil you can afford
Use the highest octane fuel – I only use 98
Treat her with respect and she’ll do the same
RIDE SAFE !!
Disclaimer
All work, links and processes described herein are to be used at the risk of the reader!!
Disclaimer
All work, links and processes described herein are to be used at the risk of the reader!!
I havnt been here nearly as long as others. 
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