2017 GSXR1000 lacking power, why?

[Kiwi Rider]

We have this GSXR in at work, down around 35rwhp...... it was bought new at our shop, done 23000kms and is only putting out 135 rwhp.
Will keep you posted about the cause.

 

[rubbersidedown]

What does the tech suspect kiwi? Does it have a cooling issue,why is the rad off? Does the motor run smooth? Just a loss of HP...
Same dyno? Same tech?
Rubb.

 

[Cantab]

Yacked to a fellow Tenere rider this week and that he had lost 10 -15 HP , he checked the link count on the timing chain and it was half a link out, he re-set and got his HP back. He had his dynoed at Ashburton Honda initialy.

 

[rubbersidedown]

Yacked to a fellow Tenere rider this week and that he had lost 10 -15 HP , he checked the link count on the timing chain and it was half a link out, he re-set and got his HP back. He had his dynoed at Ashburton Honda initialy.

I can see a cam(s) being out,especially if they are the adjustable,or a worn chain,but how did they come up with them being half a link out? Is that just a loose term for the number of degrees a cam might be out by?
Rubb.

 

[hayabuser]

Problem in the variable valve timing system? It was new tech on that model.

Could be something simple like the Mode switch acting funny... stuck in C Mode perhaps?

 

[Cantab]

I can see a cam(s) being out,especially if they are the adjustable,or a worn chain,but how did they come up with them being half a link out? Is that just a loose term for the number of degrees a cam might be out by?
Rubb.

The bike had its VC done by a shop before he got the bike , he just checked it himself for peace of mind (aircraft mech) he also said it was easy to be off if you hadnt checked it properly.

 

[rubbersidedown]

Problem in the variable valve timing system? It was new tech on that model.

Could be something simple like the Mode switch acting funny... stuck in C Mode perhaps?

The bike had its VC done by a shop before he got the bike , he just checked it himself for peace of mind (aircraft mech) he also said it was easy to be off if you hadnt checked it properly.

Aircraft mechanics....they are a "funny breed" aren't they...

Rubb.

 

[Kiwi Rider]

What does the tech suspect kiwi? Does it have a cooling issue,why is the rad off? Does the motor run smooth? Just a loss of HP...
Same dyno? Same tech?
Rubb.

Radiator is off because the only way to remove the valve cover is thru the front, radiator has gotta be out of the way.
All checks have been performed, all compressions were 135 psi cold.
valve clearances checked (2 of the inlets were just below the min so they were shimmed to correct clearance) and comps rechecked again at normal operating temp, 165psi. Mr Suzuki says the serviceable range is 174psi min to 210psi max.
No trouble codes appearing or logged in memory.
The throttle bodies removed to give full air availability to the cylinders.
The throttle plates primary and secondary were checked for correct operation from idle speed to 13,000rpm. All opening fully so no restriction to air.
The variable valve timing actuation is also working normally, through the full range.
The cam/valve timing checked and all marks correctly lining up at TDC.
Now, on the dyno graph the air fuel ratio graph is around 14 to 15 until it gets to 4000rpm . . . then drops to 11.5 right thru to red line, very rich.
The motor runs smoothly, just lacks power.
We are suspecting the exhaust system's catalyst may be blocked or restricted, the exhaust system is stock all the way to the muffler which is a slip on Yoshi.
This is especially possible if the owner has used leaded high octane aircraft (helicopter) fuel which is available at racetracks here in NZ.
We shall see . . .
It's only a theory we have at this stage, but we intend to test that theory by fitting a full Yoshi system and eliminate the catalyst altogether

 

[Bumblebee]

So many things affect a dyno...chain, wheel bearings, brake drag, etc....

If everything's good in that department, and the engine is healthy...it has to be the exhaust cats being plugged up?? That or the ECU thinks it's in a different mode just like was said

A real conundrum for sure...

 

[Berlin Germany]

hmmmmmmmmmmmm

what i had with my ´00 busa some 6 years ago at a "ammerschlaeger test bench"
was a lost of 40 hp by a "wrong" muffler slipped onto a akrapovic 4 in 1 exhaust
for testing we plucked out the db-eater and 38 of the 40 horses found their way back.

 

[rubbersidedown]

A bit rich and the 165psi is low,below range. Perhaps Mr.Berlin is onto something with his can theory.
Lid out thru the front,kinda neat.
Rubb.

 

[Hayabusa Wannabe]

Am I to gather from some of the above input that an exhaust restriction affects a compression test, with the engine not running and both valves closed? Please correct me or teach me what you techs are thinking.

 

[rubbersidedown]

Am I to gather from some of the above input that an exhaust restriction affects a compression test, with the engine not running and both valves closed? Please correct me or teach me what you techs are thinking.

HW...An exhaust system does not affect a comp test. As the piston rises in the bore it is not affected the back pressure down the line of any exhaust system.It's a measurement of the comp in the cyl with both valves closed.
Your mention of a compression test with the motor not running is not a comp test per say,but rather a "leak down" test.
Rubb.

 

[Hayabusa Wannabe]

and comps rechecked again at normal operating temp, 165psi.

We are suspecting the exhaust system's catalyst may be blocked or restricted

A bit rich and the 165psi is low,below range. Perhaps Mr.Berlin is onto something with his can theory.

HW...An exhaust system does not affect a comp test.

Forgive the noobity interruption, however my puny brain cells are unable to reconcile this. ^ I interpret this stream of statements as though that is exactly what you guys are implying, that the compression test indicates an exhaust problem.

 

[Berlin Germany]

(...) that an exhaust restriction affects a compression test, (...)

That should hardly be the case, because the engine turns max during testing at 300 or 400 rpm and with this super low "exhaust volume" no standard restriction of any kind disturbs.
only the throttle must really be 100% open, that means you really have to turn the grip to its end.
because
only what you can freely breathe/inhale you then can compress

 

[rubbersidedown]

Forgive the noobity interruption, however my puny brain cells are unable to reconcile this. ^ I interpret this stream of statements as though that is exactly what you guys are implying, that the compression test indicates an exhaust problem.

Kiwi mentioned a slight loss of comp as I read it...but there was no mention of a correlation between the use of the aftermarket can and failing comp. I believe that factors,not.
Rubb.

 

[rubbersidedown]

That should hardly be the case, because the engine turns max during testing at 300 or 400 rpm and with this super low "exhaust volume" no standard restriction of any kind disturbs.
only the throttle must really be 100% open, that means you really have to turn the grip to its end.
because
only what you can freely breathe/inhale you then can compress

Mr.Berlin chimed in...he is correct.
Rubb.

 

[hayabuser]

If the owner put AVGAS into that bike, it wouldn't take very long for the lead to block the cat.

Never ever put leaded gas into a vehicle with a catalytic convertor.

 

[mjl3truck]

If you had time to waste you could put a bung in the exhaust before the cat and run it with a water manometer and see what the back pressure is before and after the exhaust change. I'd be curious but time is money....

 

[Kiwi Rider]

If the owner put AVGAS into that bike, it wouldn't take very long for the lead to block the cat.

Never ever put leaded gas into a vehicle with a catalytic convertor.

Ok, ok, ok.....
NEWSFLASH!!
We fitted a OEM GSXR1000L7 standard headers and catalyst sent to us by SUZUKI NZ and fittedthe Yoshi can to it . . . .
Guess what?
Yup, full power returned, all the horses that had left the stable have now returned and are grazing happily in their paddock lol.
We can only assume the catalyst was damaged/ blocked for whatever reason.
The owner has had the bike since new and swears he never used leaded avgas in it.
It’s a mystery as to why it was blocked, I’d love to cut that cat open and survey the damage to the matrix of the catalyst, but that won’t be happening.
Anyway the owner is a happy boy, got all his horsies back..... yeeeeeehaa!