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Discussion starter · #1 ·
Hi all,

So I've been through as many threads as I can to try and find a solution to the sudden kick when I try to roll the throttle back on.

I have a K5 GSXR 750. I love everything about it, apart from the dangerous sudden kick when try to get back on the gas.

Mine does not do this intermittently, it does it all the time, every time I ride it. However, it only does it between a certain rev range, annoyingly within the rev range we problably all like to ride these bikes at.

This is when mine does and doesn't do it.............

Below 4800rpm it is absolutely fine. I can roll off the throttle from any rev range braking in to a corner, tip the bike in and, as long as the engine is below 4800rpm I can roll the throttle back on and fuel delivery is perfect, the power transmits smoothly through to the rear wheal and the bike stays planted.

Above 4800rpm is a nightmare, especially if the bike is right over. If I attempt to roll the throttle back on above 4800rpm the power is delivered to the rear wheel with a dangerously abrupt sudden kick which really unsettles the bike and when lent over, this is just scary.

I have experimented a lot with this problem when riding to diagnose when it happens.

Day to day riding on the road I can kind of ride around this problem as I just try make sure the revs are below 4800rpm when I roll the throttle back on, or keep the throttle very slightly cracked. There are corners though where i really wish I didn't have to do this.

We do a fair few track days through the summer and the first ones are gonna be within the next two months. This is first time I'll be taking the K5 to the track and I really want to get this problem fixed because I do not want to ride on the track having to keep revs below 4800rpm!

I wrote this description because I didn't find anyone with the same herky jerky problem as mine. If anyone has this problem or has seen it on this forum can you please add the links so I can see what their fixes were.

Cheers all
 
Discussion starter · #3 ·
How's your chain adjustment?
Chain adjustment is good, just under an inch of free play top and bottom when sitting on the bike.

As I mentioned before, it only does this when above 4800rpm. It makes no different what speed I am doing or what gear I am in it purely related to the rev range I am in, really frustrating to ride with.
 
Chain slack is checked when the bike is on the side stand not when sitting on it. Excessive wear on the rear cush drive could cause this issue you describe. If the bike has no power commander, or other fuel controller I doubt it has been tuned. If it just has a slip-on maybe a non issue but full system would benefit from a fuel tune. Obviously make sure the chain and sprockets are within service limits, and the chain has no tight spots. Throttle cable slack should be checked too as too loose will cause abrupt on off throttle control.
 
I would do a fuel flow test and while the tank was up, inspect the air filter. Testing the R/R is worthwhile, too. 5k rpm is the magic number when the stator starts pushing out enough pixies to run the bike without battery assistance and if the R/R isn't regulating the voltage, you maybe over/undervolting the system momentarily, causing it to sputter a bit. Have you ever put injector cleaner through the machine?
 
Discussion starter · #8 ·
Chain slack is checked when the bike is on the side stand not when sitting on it. Excessive wear on the rear cush drive could cause this issue you describe. If the bike has no power commander, or other fuel controller I doubt it has been tuned. If it just has a slip-on maybe a non issue but full system would benefit from a fuel tune. Obviously make sure the chain and sprockets are within service limits, and the chain has no tight spots. Throttle cable slack should be checked too as too loose will cause abrupt on off throttle control.
Ok thanks, I will get the chain set properly when the bike is on the paddock stand.

I will also get it tuned properly and see what changes there are.

thanks
 
Discussion starter · #11 ·
I would do a fuel flow test and while the tank was up, inspect the air filter. Testing the R/R is worthwhile, too. 5k rpm is the magic number when the stator starts pushing out enough pixies to run the bike without battery assistance and if the R/R isn't regulating the voltage, you maybe over/undervolting the system momentarily, causing it to sputter a bit. Have you ever put injector cleaner through the machine?
How do I do a fuel flow test?

How do i test the regulator/rectifier?

I have put a fuel cleaner and engine cleaner through it yes.
 
Ok thanks, I will get the chain set properly when the bike is on the paddock stand.

I will also get it tuned properly and see what changes there are.

thanks
You don't do it on a rear stand, you do it on the side-stand. Also, you should aim for around 1-1.2"
 
+1 to the TPS check. These seem to often be maladjusted, due to being adjusted with the engine stopped, which adjusts them lower than needed. Put the bike in dealer mode and make sure the bar is at the middle when the engine is running and warmed up. Made a great difference in my case. Make sure you adjust the idle speed to whatever the manual says it should be, before checking and/or adjusting the TPS. Search the forum for more details on dealer mode and TPS adjustment, before you attempt anything.
 
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