CBR 600 FY power loss

[tk338]

Just going along a dual carriageway, 1.45am going 70-ish, and suddenly my speed just started slowing, so I gave it more throttle and nothing.

I experimented giving it none, and then there was a noticable change, like just not giving it any throttle, but then when I gave it some, it would have an initial bite of power, and then I could twist it fully round with no change.

There was nowhere to stop and it was pitch black, so I carried on, the engine sounding rather louder than usual and then it went... As quickly as it came, and the bike responded normally again...

I really don't want it to happen again, the bike was fully warmed up, properly too, it does have a 33bhp restrictor kit on it, a slighty noisy CCT other than that theres nothing really to mention, any ideas?Panicked a bit because had I stopped there it would have been an accident waiting to happen!

[Acemastr]

possibly sucking some crap through from the tank, or a bit of air making its way through the system. Dirty carb perhaps, or loose connection on the spark plugs
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2017 KTM 350 XC-F - 2014 Yamaha R6 - 2005 Yamaha YZ125
2016 Toyota Tacoma Limited

[Ichy]

loose plugs caps is a good call. Several people I've spoken to have noticed the caps have a way of vibrating off the plug.

Other than that it may have been a dodgy connector in the loom somewhere or water in the fuel. The trouble with this sort of fault is that its hard to diagnose when it only happens on rare occasions.

[yen_powell]

Fuel pump letting you know it's going to die soon? How many miles on the clock?
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Blackmail is a nasty word........but not as nasty as phlegm!
XT1200Z and a DR350 in bits

[2Smoke]

I'd have thought fuel pump first, but you mention the engine sounding louder than usual so that wouldn't tally.

Bit of an odd one, maybe it was just a fluke.. But it could be worth just sticking to short journeys until you are more confident in it.
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Currently in the stable.. '89 TDR250, 86 NSR250 '79 350LC, '79 DT175MX, 82, Pasola, '98 R1, '95 Speed Triple.. all of them total sheds..

[geordiecbrblo...]

If the FY carbs or injected?

If carbs, it could have been carb-icing https://en.wikipedia.org/wiki/Carburetor_icing

If so, you could try some of this additive which works really well

https://www.opieoils.co.uk/p-809-silkolene-pro-fst-fuel-system-treatment-for-petrol-engines.aspx



Edit : Looks like a similar thread here https://www.bikechatforums.com/viewtopic.php?t=209250&start=0&postdays=0&postorder=asc&highlight=

[Ichy]

The FY is carb. I personally believe that carb icing is blamed for a lot of faults when the truth is that its rarely the right answer. Unlikely at this time of year anyway.

The increase in noise may be a red herring. You might have just concentrated on the sound of the bike while trying to work out what was going on.

Out of interest, what was the weather conditions?

[tk338]

I did wonder after if it could just have been something going through the tank, but it was so random, I'm about 60 miles into this tank and never took my eyes off if the filler cap when filling it so I don't see how something would have got in, and this powerloss lasted for almost a mile lol...

Also the bike has been running really really well, when I'm in a rush I'll still give it time to warm up, get up too temp, but I was in no rush last night and when i take things really carefully for 10 miles or so I really notice a difference in the ride, runs a lot smoother, like last night she was running like a dream.

Loose plug caps, i honestly wouldn't have a clue, lol, but then if they were loose surely they'd have stayed loose? Or am I making no sense :p You're right though Marki, first time its done it, and it came as quickly as it went, random indeed.

Fuel pump sounds scary lol, wouldn't want that breaking on me, its got almost 22k miles on the clock.

Maybe it was just my imagination, I did become very alert all of a sudden, but it did sound like the engine was revving a lot higher for a lot less work...

I kind of hope it is carb icing :p I could run something through the tank and see if that helps... Also I normally fill up with BP ultimate or V-power, but last time I didnt just because of the cost, would that have made a difference?

And finally the weather conditions were damp road, I'd ridden through a bit of rain, but it wasn't too cold to be honest, obviously you've got the wind chill factor... it was definitely above 5 or 6 Celcius I'd say and there was no ice on the road, slight wind, no fog lol

I think that answered every question there, thanks everyone for your replies! Hope I find a solution soon to be honest because I do a lot of night driving home from work, and breaking down on 75% of the roads I ride home on would not only be very inconvenient but probably also very dangerous lol

[yen_powell]

[tk338]

Ok well finally decided to take her for a testride before work see how it was today, same conditions again really but the problem got a lot more weird with experimenting lol.

Low speeds its fine no problem, speed up, slow down, anything up to 50 has a real pull (33bhp pull :p) but its fine and slowing down does seem to reset the problem which kicks in at higher speeds.

Ill try and explain this the best I can but it is weird, and unfortunately until next friday I won't have the money to take it in anywhere so if anyone has any suggestions... greatly appreciated.

Going along the dual carrigeway 70mph it was fine the bike was warmed up, but then give it the beans and it had the same effect as letting go of the throttle.... and it chugged (and it did chug) to a weary 50mph and wouldnt go anymore. Come off the dual carrigeway stop for a roundabout, pull away and it seems my full power is back on, hold in the clutch, it'll rev right up high, 10... 11k and it would more if i wanted, but that satisfied me that that was all still working so back for the home journey of the dual carrigeway again, gave it some on the slip road, up to 70 happily and sits there it'll respond if you give it more, but then go for an overtake, twist the throttle and it just disappears again, randomly!

Another thing I noticed was if I gently let it back in again there was a point where sometimes the power would kick back in again and it'd start accelerating, only to die shortly after.

Making good use of laybys to reset this problem I made my way home back into the 30 and 40 zones it was fine and into the drive the bike sounded fine again.

-

Recently I did have a problem with a fault earth. I think this was due to the heated grips because the took them apart and my throttle has been looser like more free play, but still that was maybe 1 or 2 hundred miles ago, still don't see any reason for it to just kick in now... Just another thought I had as a car nearly rear ended me

[Noxious89123]

Wouldn't be carb icing, the F-Y has heated carbs.
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[Stalk]

This may be of no use at all but I had a similar problem with a divvy 600. It had recently rained hard, the drain from the fuel filler cap was blocked and the strainer had fallen off the fuel tap. The result of these factors was water in the carbs and it ran rather badly with similar symptoms to the ones you describe. You could try draining the float bowls to see if there is water in there and that is a no cost exercise so nothing to lose. I am not sure if there is a drain screw on the carbs but someone else may know.

Cheers,
Stalk

[tk338]

[tk338]

Well the tank came up ok and I stuck my head under and had a look. But the looks of it all the pipes are ok, but then I traced the vacuum pipe along... Its been ripping itself the shread on the chain... How, and for how long I don't have a clue. Still I cut off the shredded end and tied it down and all seemed good, but then went to pick up a pillion for a short motorway ride, and after 5 minutes on it just goin 40 sounded like it was going to explode.

Clueless! Really clueless!

[tk338]

After a week and a half in the workshop they rang to say the bike was ready for collection, they'd stripped the bike cleaned the carbs and everything seemed fine... All excited I got myself down there and to riding! A few days and I get withdrawal symptoms.

Anyway!! Got the bike 10 miles only for the same problem to come up again!! Rang the shop who offered to come and collect me with a courtesy bike, but then after speaking to technicians asked if id gone through any cold areas. As it happens I had, very very cold top of a freezing hill (busy road) but probably temperatures around zero, and so they suggested carb icing could be the problem, ad to give the bike another go, it started and drove fine for all of the 2 miles I needed to go

So this may be a long shot, but Noxious, I know you said the FY has heated carbs, but a month or so ago I had a problem with a faulty earth, called out the RAC who came to fix the problem only to short half the electrics on the bike! He replaced the fuses he found that had blown, but I'm wondering could he have blown the fuse of the temp sensor, or the heater for the carbs? Maybe its a long shot? Where would I find that?

Also coming home tonight about 1am, very very cold lol, and got to 70 felt the bike bogging down again, and empty dual carriage way to i pulled the clutch in, and let the bike cruise and the revs just sit at idle, I indicated to the side, and saw my revs were sat at 1k, but after a minute rose to 1.5k where they normally sit, and surprise surprise the bike runs ok if you let it breath again... All in line with carb icing, no?

I'm no mechanic, but its just a thought If no one replies ill give the garage a ring tomorrow some time and see what they think and report back

[c_dug]

Might be different but if I remember right my GPZ carbs weren't controlled by any electrics it was literally just a feed from the radiator hoses going through the carbs if this is the case then fuses shouldn't make a difference.

The problem does sound pretty similar to carb icing to be honest, either that or fuel starvation, tried leaving the fuel cap open a little (obviously with quite an empty tank) to see if it still does it, just don't crash or petrol will go everywhere! That would eliminate a blocked breather which gives reasonably similar symptoms.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[0l0dom0l0]

On my Fazer the carb heaters are just literally very small pipes the take water directly from the rad. It is possible these are blocked so you could try playing around with those.

To rule out carb icing you could try the stuff that you put in the fuel? Can't remember the name off hand but someone will!

[Coxyzxr]

[Noxious89123]

Never had problems with icing on mine, never heard of anyone else having carb icing on a CBR6 either. ZX7Rs are some what common for carb icing no? (Or could be some other Kwak I'm thinking of.)

But yeah, they're not electrically heated, it's just plumbed into the cooling system, so the hot coolant heats them.
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[tk338]

Thanks again people for replies (:

I'm wondering about my coolant level, although I ca see my reserve is full but I think maybe I may need some in the main tank? Also c_dug I only have one key... and getting the key out of the fuel cap while its open seems impossible, so I didnt get a chance to try that, HOWEVER!!!

I filled up with bp ultimate, a tank full, and dumped some redex in there and rode a good 40 miles in cold... VERY cold temperatures and the problem has disappeared altogether, very confused! Not sure now if it was the redex or the bp ultimate that did it, but I'm thinking it was the ultimate... seeing as the problem only started when I got skint and decided to use normal bp fuel, ad last week the carbs were cleaned completely, now ok I have a solution, but its a bloody expensive one :p experimenting will be risky, but could it just mean the few tanks of normal bp fuel I used were shitty or just they dont like the bike? OR that the bike needs v-power/ultimate everytime?

[0l0dom0l0]

I expect the combination of both will have helped.

Did you put in the pro st stuff?

Check your coolant level in the radiator, and it might be worth seeing if the carb heater pipes are getting warm when riding. You could take them off and just check that they are clean.

Glad its okay. Does sound like carb icing to be honest so just see how it goes!

[tk338]