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Discussion Starter · #1 ·
Hello all, I’m glad to be here, I hope to get riding again so I can share and learn from everyone riding this epitome of motorcycle perfection in my opinion.

I recently had my k6 1000 rebuilt with over sized bearings until I can source a good crankshaft and possibly bottom end. Stock ECU but I’m suspecting a shady mechanic and flashed but I’m not sure, the area I’m in is notorious for these things.

my bike came back and won’t rev past 4K in gear, and my codes are c24 and 27, it hits that RPM and start to backfire and sputter, along with the fact it’s riding and idling rough, while I was inspecting the plugs and coils, I noticed my bike had misfired in cylinders 3 and 4, to the extent my intake had started melting due to the heat from
the throttle bodies! I’m going tomorrow to see if the Camshaft sensor is the issue, but I have my doubts on if that’ll work, and look at switching out coil packs to see if that makes a difference, but if those two are out the question what should I change while at the shop (I do the work myself but have parts around) to test and see if that fixes my issue, thank you all in advance, this one’s really stumped me
 

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Hi bro.
I would do following:

1) Make shure for all plugs are sparkling regularly with powerful blue or white sparks between electrodes exactly (not between the skirt and the central electrode insulator). Make video of plugs sparkling and watch it at slow speed for easy checking.

2) Inspect the spark plugs, replace those for known good ones

3) Replace coils for known good ones, inspect contact inside of each coil for rust and dirt, clean it or replace the coil for new one if contact is damaged.

4) Check coil wire couplers contact for rust and any contaminates (coil and piggiback wire side both).

5) Turn ignition on and make sure for 12v on O/W wire in each coil wire coupler. If not present than check wire continuity between O/W wire contact in the coupler and the immobi block (or fuel pump relay for US/Canadian).

6) Check for wire continuity between all coil coupler signal wires and ECM (see wire color codes on the electric chart in the Shop Manual).

Good luck!
 

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Discussion Starter · #3 ·
Hi bro.
I would do following:

1) Make shure for all plugs are sparkling regularly with powerful blue or white sparks between electrodes exactly (not beteen the skirt and the central electrode insulator). Make video of plugs sparkling and watch it at slow speed for checking.

2) Inspect the spark plugs, replace those for known good ones

3) Replace coils for known good ones, inspect contact inside each coil for rust and dirt, clean it or replace the coil for new one if contact is damaged.

4) Check coil wire couplers contact for rust and any contaminates (coil and piggiback wire side both).

5) Turn ignition on and make sure for 12v on O/W wire in each coil wire coupler. If not present than check wire continuity between O/W wire contact in the coupler and the immobi block (or fuel pump relay for US/Canadian).

6) Check for wire continuity between all coil coupler signal wires and ECM (see wire color codes on the electric chart in the Shop Manual).

Good luck!
Thank you so much dude, parts will be here in about 2 hours, I’ll go through the list you wrote it’s helped narrow down my diagnosis path
 

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Sounds like a possible timing issue to me.
Everyone always replaces plugs and COP (coil on plug)- which rarely go bad.
Good luck, let us know what you find out.
 
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Hello all, I’m glad to be here, I hope to get riding again so I can share and learn from everyone riding this epitome of motorcycle perfection in my opinion.

I recently had my k6 1000 rebuilt with over sized bearings until I can source a good crankshaft and possibly bottom end. Stock ECU but I’m suspecting a shady mechanic and flashed but I’m not sure, the area I’m in is notorious for these things.

my bike came back and won’t rev past 4K in gear, and my codes are c24 and 27, it hits that RPM and start to backfire and sputter, along with the fact it’s riding and idling rough, while I was inspecting the plugs and coils, I noticed my bike had misfired in cylinders 3 and 4, to the extent my intake had started melting due to the heat from
the throttle bodies! I’m going tomorrow to see if the Camshaft sensor is the issue, but I have my doubts on if that’ll work, and look at switching out coil packs to see if that makes a difference, but if those two are out the question what should I change while at the shop (I do the work myself but have parts around) to test and see if that fixes my issue, thank you all in advance, this one’s really stumped me
How did it run before the rebuild? What was the rebuilt for, could that be the problem?

I think step 1 here has to be a compression test. Without that data you're working blind.
 

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Spun rod rod bearing ☹
Ouch. Bad news, sorry to hear.

I noticed what seems to be a few of those here recently. Did you find any reason? Sometimes these bikes rev too fast for their own good, like I always felt that 'rev-bombing' is a very destructive thing worth avoiding, especially for bikes over 10krpm red lines. Get a loud horn! Not saying you've done that, but behaviour best avoided I think. GSXRs rev so fast, I think it would be better to have a low rev limit on them when not under load/clutch in/neutral.

I still think looking at compression test data is the first step. If the chain has slipped or something else mechanically bad it should show up straight away.

Sounds like a possible timing issue to me.
Everyone always replaces plugs and COP (coil on plug)- which rarely go bad.
(y)

I had two coil packs go bad, one failed and the other was weak spark/reading low resistances. I bought a replacement set off a recent low mileage later bike and kept the two 'good' ones for spares. So they do go, definitely a 'thing'.
 

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Discussion Starter · #9 ·
Ouch. Bad news, sorry to hear.

I noticed what seems to be a few of those here recently. Did you find any reason? Sometimes these bikes rev too fast for their own good, like I always felt that 'rev-bombing' is a very destructive thing worth avoiding, especially for bikes over 10krpm red lines. Get a loud horn! Not saying you've done that, but behaviour best avoided I think. GSXRs rev so fast, I think it would be better to have a low rev limit on them when not under load/clutch in/neutral.

I still think looking at compression test data is the first step. If the chain has slipped or something else mechanically bad it should show up straight away.


(y)

I had two coil packs go bad, one failed and the other was weak spark/reading low resistances. I bought a replacement set off a recent low mileage later bike and kept the two 'good' ones for spares. So they do go, definitely a 'thing'.
The engine was previously rebuilt out of spec, but ultimately it was ruled to bad low oil (still reviewing if it was my own fault as it was suspicious)

when your coil packs went out what code did it throw you??
 

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when your coil packs went out what code did it throw you??
There was no code. Just started missing a cylinder.

My anecdote, FWIW, I had just got the bike back on the road, it was a non runner when I got it and was a bit of a cat-in-a-sack purchase, cheap but unknown. It was basically on my third or so ride out after a few weeks of work on it and TBH a bit worried about whether I could rely on the exhaust valve clearance as there were a few odd signs.

I ordered a shim set and was about to do that job and, bingo, 3 cylinders! Just happened. Shit. I mean, it ran, these engines seem to run not too terribly on 3 cyls! I nursed it home, was not too far at that point.

No codes, just running terribly. Didn't rev up, stumbling at idle, but I nursed it home.

I mean, coil was probably intermittent before and why I thought something was odd. At the time I was gutted so just 'abandoned' it in the garage for a day or so until I got my head straight that this wasn't (yet another!!) case of 'world versus QRO', just stuff that happens. Spending £££ then a few weeks, and more £££, to have a scrap bike in the garage is 'disappointing' and sent me straight for a box of beers! :D

Anyway, a rational assessment a few days later by holding exhaust pipes and swapping ignition coils, that is all it was, just ignition coils. There is a test you can do, did that on all of them and one other was a bit crap too, so simply replaced them all, being a 55k 10 year old bike.

Font Parallel Rectangle Diagram Technical drawing
 

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Just to add, there was a lot of raw fuel coming out too when I was checking it, obviously being unburned. I'm sure it'd have been backfiring too, if I'd tried gunning it, but was worried the issue was that valve clearance so didn't do that.

So, yeah, might just be sparks.
 

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Sounds like a possible timing issue to me.
Everyone always replaces plugs and COP (coil on plug)- which rarely go bad.
Good luck, let us know what you find out.
If time issue is presnt than all cyls are misfire or fails. But if we trust TS only the 3 and the 4 cyls fails

I noticed my bike had misfired in cylinders 3 and 4
Also the 24/27 err codes (IGNITION SYSTEM MALFUNCTION) points us to the ignition coils/plugs/misfires issue
Font Material property Rectangle Number Circle


Next,first I would check the ignition components, this is more easy than pull of head hat and check for timing. If ignition system check succesfuly than Iwould check the timing and somesing else.
 

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If time issue is presnt than all cyls are misfire or fails. But if we trust TS only the 3 and the 4 cyls fails



Also the 24/27 err codes (IGNITION SYSTEM MALFUNCTION) points us to the ignition coils/plugs/misfires issue
View attachment 299660

Next,first I would check the ignition components, this is more easy than pull of head hat and check for timing. If ignition system check succesfuly than Iwould check the timing and somesing else.
Yeah, but maybe only if it detects a 'full failure'. I think it probably checks for open circuits on the coils, maybe?

I was surprised mine didn't throw a fault code for it, but didn't see one.
 

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I just had a thought. I have pulled the '5th wire along' black and white from the ECU to turn of the EXUP error report. Does that also turn off some other error reports?
I think you can test it by provocacy the ECM for any error, such as disconnect the STVA coupler and turn on ignition.
 
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