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Discussion Starter #1
Bike: 2012 GSX R750

Problem: 5th 6th gear rev shoots RPM up to about 9-10k while acceleration is delayed then they time up again. This only happens 3 times
Problem: Bike lost top end speed can go Faster but delayed response & significant power loss

Bike has 15,500 miles on it.

K & N filter , slip on m4, oil changed.


Spark plug & Valve adjustment are scheduled for today.

The mechanic claims my clutch isn’t slipping.

any advice
Second time posting
 

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Dreaming of buttsecks for years...
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Something is slipping. Usually it's the clutch, especially when the problem happens in 5-6 gear. I'd like to know what your "mechanic" did to rule out the clutch. If this behavior immediately followed the oil change, what oil did you use?

First thing is to check the clutch adjustment. Then if you want to confirm it's the clutch, put the front wheel against a wall, put it in 6th, hold the front brake and rev it to about 10k and dump the clutch and give it gas like you're trying to wheelie. If it's not the clutch, it'll die instantly. If it is the clutch, it will run for just a second and then die.
 

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Discussion Starter #3
Something is slipping. Usually it's the clutch, especially when the problem happens in 5-6 gear. I'd like to know what your "mechanic" did to rule out the clutch. If this behavior immediately followed the oil change, what oil did you use?

First thing is to check the clutch adjustment. Then if you want to confirm it's the clutch, put the front wheel against a wall, put it in 6th, hold the front brake and rev it to about 10k and dump the clutch and give it gas like you're trying to wheelie. If it's not the clutch, it'll die instantly. If it is the clutch, it will run for just a second and then die.
They put in Motul 5w 40. I had 10w 40 Mobil 1 when this happened. It seems the Motul kept it from having the problem it once did.
Haha are you joking when you say to do this? Sounds like suicide or a good way to mess up the engine. Is there another way to see if it’s the clutch?

Mechanic rode the bike and said it’s not my clutch because it’s only 5th and 6th gear that this happens. They suggested spark plug change & valve adjustment.
 

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I hope it’s just the Valves causing this and not a tranny issue.
Wow, talk about gullible. I'm sure they like you at that 'shop'.

Plugs and valves are not going to cause what you are describing.
You described a slipping clutch. You probably burned it up some as many newbies do- assumig you are.
Perhaps it just needed a simple clutch adjstment?
 

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Discussion Starter #7
Wow, talk about gullible. I'm sure they like you at that 'shop'.

Plugs and valves are not going to cause what you are describing.
You described a slipping clutch. You probably burned it up some as many newbies do- assumig you are.
Perhaps it just needed a simple clutch adjstment?
Gullible not so quite not educated in this field & I plan on changing that as a dedicated rider. I trusted the shop and they were going to have my bike just sit for a “valve adjustment” hahaha you are correct!!! My suspicion grew as they barely messed with it just took it for a test run.
Most of the power loss can be attributed to a bad air filter job I did. Forgot to bolt it back down inside with the two screws securing the air filter in place. Fixed that. Noticed I didn’t have the right side air intake hose (by fairing) flush. There was a large gap allowing air to penetrate.
Possible why it was running so awful. Now is it spark plug changing time or new clutch after I fixed that issue?

Thanks for your knowledge and time by the way.

what are some problems a bad air filter job can cause? I rode like that for about 4 days or so.
 

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Mobil1? Like just regular old Mobil1 and not the motorcycle specific?

Your botched air filter would have either worked just fine, or would have allowed MORE air into the system and it would have run fine.
 

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Discussion Starter #9
Mobil1? Like just regular old Mobil1 and not the motorcycle specific?

Your botched air filter would have either worked just fine, or would have allowed MORE air into the system and it would have run fine.
AThey put in 5w 40 motul

I put in 10w 40 motorcycle specific 4T oil.
I adjusted the air intake and my bike is running way better. But I still have top end power loss and the bike is running at a higher RPM at the same speed it used to run at a lower RPM. The mechanic just rode the bikeZ. He suggested to check the air filter job I did. It did improve the bikes performance. I may swap out the k&n filter for a stock one.
How do I adjust the clutch? Oh know how to from the handle bar but how do I do it from the clutch itself? The mechanic told me once your clutch needs adjusting it’s a sign you have to replace it lol.
 

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The mechanic told me once your clutch needs adjusting it’s a sign you have to replace it lol.
Wow...

If you can get a service manual it will save you a ton of cash. It will also explain how to do things properly and help you avoid folks like the mechanic you're currently dealing with. In addition to the adjuster at the handlebar, there is an adjuster and lock-nut just to the other side of the front sprocket cover at the top where the clutch cable comes through. You will need to raise the tank. With that said, here is the adjustment procedure out of the 2011+ GSX-R 600 service manual, should be the same for your 750:
1) Lift and support the tank.
2) Turn the adjuster at the handlebar all the way into the clutch lever assembly.
3) Loosen the lock-nut (under the tank and just on the other side of the sprocket cover) and turn the clutch cable adjuster (bolt with clutch cable running though it) to obtain the prober cable play (10-15 mm at the end of the clutch lever). However, if you are running shorty levers this will be off. If so, just ensure you have a 2-4mm gap between the clutch lever and perch where the adjuster is. In other words, the gap that is created when you pull the lever in.
4) On the right side of the engine, remove the clutch release adjuster cap. It is directly below your oil fill cap and about 2.5" in diameter.
5) Loosen the lock-nut and turn out the adjusting screw (in the middle of the lock-nut) two or three rotations.
6) From there, slowly turn in the adjusting screw until you feel resistance.
7) From the point of resistance, turn out the adjusting screw one rotation. Then tighten the lock-nut while holding the screw in place.
8) Turn the cable adjuster (under the tank) to gain approximate free play at lever and then tighten the lock-nut.
9) Turn the adjuster at the lever to obtain proper free play at the lever.
10) Tighten clutch release adjuster cap (11 Nm)
11) Lower tank.
 

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Discussion Starter #11
Wow...

If you can get a service manual it will save you a ton of cash. It will also explain how to do things properly and help you avoid folks like the mechanic you're currently dealing with. In addition to the adjuster at the handlebar, there is an adjuster and lock-nut just to the other side of the front sprocket cover at the top where the clutch cable comes through. You will need to raise the tank. With that said, here is the adjustment procedure out of the 2011+ GSX-R 600 service manual, should be the same for your 750:
1) Lift and support the tank.
2) Turn the adjuster at the handlebar all the way into the clutch lever assembly.
3) Loosen the lock-nut (under the tank and just on the other side of the sprocket cover) and turn the clutch cable adjuster (bolt with clutch cable running though it) to obtain the prober cable play (10-15 mm at the end of the clutch lever). However, if you are running shorty levers this will be off. If so, just ensure you have a 2-4mm gap between the clutch lever and perch where the adjuster is. In other words, the gap that is created when you pull the lever in.
4) On the right side of the engine, remove the clutch release adjuster cap. It is directly below your oil fill cap and about 2.5" in diameter.
5) Loosen the lock-nut and turn out the adjusting screw (in the middle of the lock-nut) two or three rotations.
6) From there, slowly turn in the adjusting screw until you feel resistance.
7) From the point of resistance, turn out the adjusting screw one rotation. Then tighten the lock-nut while holding the screw in place.
8) Turn the cable adjuster (under the tank) to gain approximate free play at lever and then tighten the lock-nut.
9) Turn the adjuster at the lever to obtain proper free play at the lever.
10) Tighten clutch release adjuster cap (11 Nm)
11) Lower tank.
Yes that mechanic was complete BS! My club buddies just adjusted my clutch at the handlebar and wow! I finally have to use force to throw the clutch in. It was so loose! Thanks. Once I adjust it underneath the tank I’m sure I’ll have the problem fixed. I’m new to riding but no excuse why a mechanic would need to buy a new clutch vs adjust. They were going to take me to the cleaners behind this lol. 2.5 hours for a valve adjustment $250 & 1.5 hours for spark plug change $150. I just saved $400 in frivolous work. Thanks again.
I will definitely get a service manual. The mechanics use them at the shop I was at. Young guys under 30. I’m probably going to find a new mechanic cuz they probably adjusted my clutch to make me come back. They also overfilled my oil.
I’ll def go buy a manual tomorrow and get to work.
 

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Great, glad your club helped you out and kudos to the folks on this forum who pointed you towards your clutch. We were all new riding (and wrenching) once. There are definitely good and bad mechanics/dealerships out there - hope you find a good one for the future.
 

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Discussion Starter #13
Great, glad your club helped you out and kudos to the folks on this forum who pointed you towards your clutch. We were all new riding (and wrenching) once. There are definitely good and bad mechanics/dealerships out there - hope you find a good one for the future.
Yes this site saved me around 4K in “bikes is just about done” fees haha. I can’t believe you typed all that out by hand. You can gauge a persons character by how they treat others who are of no benefit. ✌ Righteous!!!
 

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Ok, first and foremost you need to find a new mechanic. The one you have seems to be an idiot.
 

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Ok, first and foremost you need to find a new mechanic. The one you have seems to be an idiot.
This is true! I want to find a mechanic that lets me watch him work. They had a 50-60 foot separation.
plus I’ve had complications already.

Any SoCal recommendations?

714-562 area
 

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Yes this site saved me around 4K in “bikes is just about done” fees haha. I can’t believe you typed all that out by hand. You can gauge a persons character by how they treat others who are of no benefit. ✌ Righteous!!!
Thank you, happy to help. Just pay it forward whenever you can. In my opinion, we can all benefit from looking out for one other. 👍
 

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Discussion Starter #17
Sounds like the clutch is not holding IMO. Issues with spark plugs or valve train would be apparent in all gears.
Correct some bikers I rode with called it as soon as I was explaining they cut me off. Walked to my bike played with the clutch sweet spot. Mine was wayyyyy to loose. Soon as he adjusted the handle bar clutch I was able to wheelie in 1st gear for once. My bike quite acting up at higher speeds and feels way better. I need to adjust it two other places fasho but waiting for a manual. I’m more visual with the words.
 

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Thank you, happy to help. Just pay it forward whenever you can. In my opinion, we can all benefit from looking out for one other. 👍
[/QUOTE
This bike has lead me to some great connections and cool people.
 
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