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I ride like I mean it
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92 Posts
Discussion Starter · #1 ·
The last serious work I had done on my 99' r6 was 2.5 years ago. The valve clearances were checked, some shims replaced and valves adjusted. Carbs rebalanced. Plugs changed.Since then I have kept the basics maintained. Regular oil and oil filter changes. Also replaced the air filter recently. Chain cleaned and lubed.

Since it has been a while since anything major was carried out, I decided to speak to the mechanics and gain advice on what could be done to renovate. I already had a new set of 4 pronged spark plugs. They suggested rebalancing the carbs and that the valves would surely not need any attention after less than 20000km since the last adjustment.

They fitted my new petrol filter, changed plugs, adjusted steering dampeners, fitted a new front tyre and balanced the carbs (which they told me were well out of sync). Upon collecting the beast, it sounded very different, far chirpier. However, the clutch had been adjusted horridly leaving virtually no play and once the bike was warmed up on the journey home I noticed the revs were hanging on their way down. At around 2-2500 rpm. I hoped it would go away, but it didnt. For the next week or two whenever the engine was warmed up, the revs would hang at 2-2500rpm. Blipping the throttle seemed to raise the revs and then it would fall to the 1500 rpm idle. However, almost every time the throttle was closed the hanging occurred.

I took the bike back and explained the problem. I was told that it was running lean, and it was probably due to misadjustment of the carbs. So I went back again the next week. Left the bike there for 4 hours returned to find it exactly where I had left it. Didnt seem to have been moved. The mechanic told me that the balancing was fine and 'shit happens'. I explained I had never experienced this hanging revs routine before and it was surely due to the adjustment of the carbs. They told me to come back yet again the next week.

Again I left the bike there at lunchtime today. Returned after work, eager and hopeful. I was speaking with the owner when the mechanic turned up on my bike, cut out the engine as he tried to ride it into the workshop, then wheeled it out in front of me, by its mirrors, which were turned fully inwards leaving them useless, kicked the stand down as it was still moving, letting the stand scrape on the concrete as it came to a stop, then walked off, leaving the engine running.

My look of disgust was seen by the owner who called the mechanic back and told him to turn off the engine. Then asked him to explain to me how carb balancing was not carb tuning...

So this chap, the same mechanic who worked on my bike 2.5 years ago, adjusting the valves and balancing the carbs began to explain to me what he thought was the problem.

He told me he had balanced the carbs again, and they were fine, perfectly in line. How he did this without taking the seat and tank and airbox off as well as dropping the radiator, I do not know...is that possible???

he said it was probably the valves, since the 'running lean' problem happened only when the engine was warmed up. Asked me when the last time I had the valves done was, I explained 2.5 years ago, by HIM. Ok, so likely not the valves then. So then he kept saying that he could tell the carbs were taking in too much air by spraying something over them and the carbs had a fit. Again, how he did this without dismantling the fairing and removing the seat and airbox, I do not understand. Is this possible???

he told me that the air screws were misadjusted, and whoever adjusted them last left one at 2 turns and another at 4 turns, which he has now righted. The last person to adjust them was HIM, 2 weeks ago, then before 2,5 years ago.

We moved on from that and he suggested it could be the manifold. And to check it would need the radiator dropping, fairing removed, seat, tank airbox removed. At least 2-3 hours work he told me.

I asked why I had never had the problem before and his explanation was...
Your carbs were so out of sync, that the problem wouldnt be seen until the carbs were balanced properly. As they are now balanced the problem can be seen. The balancing of the carbs did not cause the problem, it merely revealed it. You know, with old bikes, these things can happen at any time.

He told me had made a few adjustments and to see how it goes...

As soon as I rode off the hanging issue was worse than ever before. It seemed more constant, and at higher revs. Much closer to 2500rpm. The revs also seemed to be lurching.

Now...I am not technically capable of making sense of all of the above. I do not trust these goons. I think they are lying to me. Before I take the bike elsewhere, I would very much appreciate some advice from you smart folks!

Does their story make sense???
Can they have checked the balancing without taking the seat, tank, airbox off???
Would the problem have been revealed, not caused by their attempts to rebalance the carbs??

PLEASE HELP!
 

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Got street appeal?
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1,656 Posts
Ok, just sitting valve adjustment shouldn't change. Yes you can get to the valves from the front side via removing radiator and plastics. I still like to take the top side off personally just go to get more maneuverability for the cover.

The hanging up sounds a lot like a vacuum leak. Very common for the older bikes and it's usually located on the boots that go to the head.

YES balancing carbs will throw off air fuel mixture. You are synchronizing pretty much the carb vacuum by regulating a set air way. (equivilent to fuel injection idle air control valve). Seat and tank MUST come off for carb work.

Find a trust worthy guy with a Dyno and have it tune using a wideband 02 sensor. (roughly $400)
 

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Registered
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158 Posts
I agree, that the hanging up problem is a lean codition. Probably due to an air leak. Maybe they forgot to cap off a vacum port used for synchronizing.
 

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pin it to win it
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8,080 Posts
Vacuum leak possibly. that mechanic is shit, go somewhere else
 

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Mr. HER6
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2,084 Posts
Yup. The guy is not totally full of shit, but and mechanic worth his salt would not return the bike to you like that, and especially not try to make excuses for it. The balancing needs to be done when it's fully warm, so he certainly saw it do this. But it is expected to tweak the idle setting as part of this procedure.

An air leak is definitely a possibility. He may have forgot to plug one of the vacuum ports after balancing, or maybe the cap is cracked and letting air in. The other thing that may have happened is that the fuel screws are set too rich, or not all the same, and in order to compensate the idle was turned up. I would check the manual for the fuel screw settings and verify they are set right. Then see how it behaves. Sounds like this guy can't be trusted and is just trying to get rid of you.
 

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I get paid to get high
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735 Posts
Like everyone else said, vacuum leak or running lean. Fwiw you can't get to any of that with the tank/airbox/etc on the bike unless you are a magician. I doubt you're carbs were that out of sync if they weren't taken apart ever but not impossible. He's a pos, run from this guy.
 

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I ride like I mean it
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92 Posts
Discussion Starter · #7 · (Edited)
Is there any sense whatsoever to his explanation that the hanging carb problem/vacuum leak was there before I took the bike in for the carbs to be done, but I didn't notice, the problem didn't show, because...the carbs were so out of sync???

And since he synched the carbs, the problem shows now as its running properly???

I do not understand that, do you guys???

Also...apparently TWICE they have re-checked the carbs without removing the tank and air box...which is straight out nonsense???

many thanks for all the responses. Its much appreciated.

I will get onto a reliable mechanic today.
 

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Mr. HER6
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2,084 Posts
When synching the carbs you will always be adjusting the idle after each throttle adjustment. Getting it to idle properly is part of the process. Sounds like the guy was doing it with the engine cold (which is wrong) so he didn't notice it. Now that he "finished" the job and it sucks when the engine warms up, he's giving you the run-around so he doesn't have to take the time to go back to fix what he should have done properly.
 

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I ride like I mean it
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92 Posts
Discussion Starter · #9 ·
They were indeed skanking me. I took the beast to a different mechanic. He fixed up the carbs then showed me the pictures of a machine which lines up the carbs in lights. The state of them when I brought it in was shocking, none were anywhere near each other. After he fixed them up, all straight and the sound and feel were much better. Also, the hanging had completely vanished.

The same machine to measure the carbs balancing also measured something else, vacuum leakage perhaps. He told me that my valve seatings were ****ed. Bike had probably been thrashed somewhat in the past ( I think the previous owner used it on the track ). And that the work to fix them up is worth more than the bike itself. Out if interest, how much would such work cost??

I am happy to ride the bike still, carry out the regular oil, pads, filter, tyre changes. I still love the way I can throw it about. It starts everytime, seems quick enough at 0-100km/h in 2-3 seconds and I have no burning desire for a more perfect bike.

But am I deluding myself??? Will the engine explode at some stage?? Valve seat problems are deadly?? Or just lead to a steady lessening in performance??

Also...

Where can I purchase the 2 inch metal screw bit that goes between the oggy knob and the bike???
 

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iRun
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33,317 Posts
Not sure what an oggy knob is...


Did you inform the owner of the previous shop of the quality of his mechanics?
 

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I ride like I mean it
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92 Posts
Discussion Starter · #11 ·
The oggy knobs are what the aussies here call the sturdy knobs which are attached to either side of the bike to withstand the brunt of a fall and slide.

As for the mechanics, I am writing my complaint and demand for a refund this evening. I kept the pictures the decent mechanic printed out for me of the carb balancing routine.
 

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"The Dude abides .. "
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4,719 Posts
there are multiple companies out there that sell "frame sliders".
will the motor suddenly blow up? nobody can predict that. The fact it has ran this long and still makes good power is a good thing though.. Your engine has steel valves. while it won't rev as high as a 3rd gen r6 (06+) the steel valves last a lot longer. At some point you can pay a small fee to have the new found (good) mechanic do a "leak down test". simple air leak pressure test of cylinder, measuring leak past the valves and rings. Your guy will explain what is good-fair-bad leak down. this is just a basic test to get an overall general picture of the engine. IF it's say 5% leak down and pretty even across all 4 cyl, that is very good. 1-2% is a new motor. 10% a racer will tear down, 15% or more? or 1 that is worse ? may consider time for a rebuild. Still won't tell you the low end bearing condition, but just if you ever hear a knock, shut it off.
I suspect you will get years of trouble free riding if you just don't totally thrash it.
 

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Registered
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74 Posts
Just ride it. If it runs good, don't even think about it twice. I bought an older gsxr1000 a few years ago with 30k miles. That bike was stunted, drag raced, and who knows what else, beat to hell, no maintenance and it still ran fine. Even after 30k miles it could still run 1/4 mile times from when it was new. I don't think these sport bikes need as much maintenance as most would believe.
 

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Tha 5 star Manic Mechanic
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1,126 Posts
Your valves if they are leaking will only reduce the performance of the motorcycle more as time goes by, they will not in and of themselves "blow" anything up. It sounds like the mechanic used what is known to those of us in the industry as the "vacuummate", its a very nice tool if you have the means to own one, I have used them many many times myself and they are very accurate, much more so than the old mercury sticks or dial gauges, as those are prone to wear and or weather conditions/and user adjustment for accuracy.
 

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Premium Member
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252 Posts
Ya im with the other guys. I know cars better then bikes but in most cases an engine is an engine and your engine wont blow up on you aw in Kaboom. People use the term "I blew my engine" in most cases referring to internal parts that have been damaged to the point where the performance is not there any more. Cant say price wise what it would cost for parts but it would be a great winter project to do yourself and learn about your bike. Its just labour really that sucks for that kind of job. Good Luck hope it all works out
 
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