CBR1000F cuts out at half throttle. Please help!

[lockhead83]

Alright!!!

I finally bought my bike CBR1000F as i believed that I got a very good deal and a value for money.

I took her out for a spin last night and man she was fun. I have posted a thread before where i wanted to know the symptoms of a bike if it's a restrictor model (power/hp restrictor). Normally a speedo is till 300 in these beast but mine is 180 which makes it quite evident that the bikes got one. I made my peace with that and thought even after the restrictors on, 100 hp should be more than i can chew.

This morning, i wanted to check what the bike is capable of. I started pushing her hard (touch 90-100, not too sure in gear one) and when i changed to push it further.... she was dead at gear two, n three. when i went to gear four, she started picking it up again. At that point I thought it could be the rev restrictor playing up. Took it too a mechanic and he rode it (motomart in welly)
He said the bike feels like shit or some 30hp bike. Well even with the restrictors (I checked some other forums where guys have previously dealt with this. There are metallic plates between cyclinders and the carb), the bike should still make 100hp...

WTF....

I am new to welly, live in a lodge, still finding a place with a garage, no tools or prior exp to open the bike and check....

Any suggestions???
How fucked am I??? lol

any one in welly wanna have a look at her.. If you fix it , I'll buy couple of shots of beers... ;)

even if i take it to the mechanic,to know what too look for or get sorted will seriously help.

Thanks in advance guys.
Cheers

[Max Preload]

Be more concise in your description of the problem. Throttle position, engine speed, regularity, sounds etc.

With that description it could be anything.

[lockhead83]

Hiya!!!

Ok...
scenario 1: When I started pushing her hard, i touched 90km at gear one.. Then switched to gear 2 n then 3.. it just wouldn't respond. Switched to gear four and i was at 100-110...

scenario 2: Now after scenario 1, i thought something is not right. So i started pushing her again from a idle position.. Boom, 60 at gear one, and the cut off.

scenario 3: I thought fuck it, let me go back home. All fine, gear 5, speed arnd 130... wanted to do more, just couldn't...

I am not too sure if this helps. :(

Thanks

[cheshirecat]

Hmm. As a starting point take the plugs out and see if it's a problem with an individual cylinder which can then take you to carb/coil issues. Check them very carefully to see if they are operating in the right temperatures or getting very hot.
The problem may not be with the restricters - it might be coils or a coil.

just a thought as I dimly remember something similar with an old cb750k2 once.

[lockhead83]

saw this...

I am scared that I might end up like this guy.. hehe::facepalm:

http://cbrforum.com/forum/archive/index.php/t-38450.html

[Paul in NZ]

The bikes new to you so you need to do a full service - filters, oil and air + change oil etc. If it has points, check that and plugs plus timing etc. I'd also check the gas tank is venting ok.

We are in Kapiti and can give you a hand if required but its a long haul up here..

[Blackbird]

One other possibility, although I'm not familiar with the CBR1000 is a dirty in-line fuel filter. Had that problem with my old BMW K100RS. At larger throttle openings (higher fuel flows), the crap in the filter collected at the outlet and starved the engine but was ok at modest throttle openings. Changed the filter and no more problems.

Just a thought....

[mrchips]

The bikes new to you so you need to do a full service - filters, oil and air + change oil etc. If it has points, check that and plugs plus timing etc. I'd also check the gas tank is venting ok.

We are in Kapiti and can give you a hand if required but its a long haul up here..

+ 1

I always give em the once over cos you never know what you may find + it's a piece of mind thing, although the previous owner's maintenance history is always worth it's weight in gold !

From your discussions with the previous owner, did he mention anything about the carbs ever being worked on ? You may find this post interesting as sounds similar to your problem (further down in the post) Low HP caused by incorrect carb reasembly (http://cbrforum.com/forum/showthread.php?t=38450&page=4)

I also found this ...Restrictor in Speedo ? (http://forum.suzukiownersclub.co.uk/showthread.php?21091-Honda-question)

I would check the air filter / air intake ducts for any blockage as a matter of course.

[lockhead83]

Just took the bike for another spin to see what exactly is happening...

The bike cuts when i give the full throttle.


Any gear when I an gradually picking up speed, it goes fine. But when, I give a full throttle, it starts picking up and then almost feel that either fuel or air supply gets disconnected.

5th gair arnd 5k rpm 140 somewhere in the middle of throttle, bike goes pretty smooth. When I want to go from there, again the same shit happens. I think whatever i have read in the last couple of hours, the culprit could be the carb (diaphragm /spring /needle combined with those stupid restrictor plates)... Can there be a restrictor in the speedo as well??Cuts after 5k?

[Paul in NZ]

Dear god.... If it feels like its running out of fuel or air then maybe it is? If you want to ride it up here I can take a look some time.

[Wannabiker]

Not sure if applicable to this model, but does it have a vaccuum actuated fuel switch from the tank....check you havent got a disconnected vaccuum hose somewhere.

+1 to check it has not had previous carb work done too.

[Flip]

Dear god.... If it feels like its running out of fuel or air then maybe it is? If you want to ride it up here I can take a look some time.

+1

Sounds like the fuel filter.

Check the fuel filter the tank breather and the fuel tap. Then check that there is a good flow by turning the tap to prime while draining the float bowl on all 4 carbs.

Check where the fuel hoses run. If they have a inverted "U" shape they may be vapour locking when the motor gets hot and running you out of fuel. I had a Triumph Trophy that did this, took me ages to find out why.

[FJRider]

Not sure if applicable to this model, but does it have a vaccuum actuated fuel switch from the tank....check you havent got a disconnected vaccuum hose somewhere.

+1 to check it has not had previous carb work done too.

Sounds like that problem to me too .... vaccum issue anyway ... maybe ...

[lockhead83]

Sounds like that problem to me too .... vaccum issue anyway ... maybe ...

Does it come in play at full throttle. Today's observation. The bike goes fine when speeding gradually (touched 150, that is 10 more than last 2 days :facepalm:)

but the moment I give a ful throttle, it goes numb.. Anyways will be either giving it to wellington motorcycles or motomart....

Thanks everyone for your help. Will keep you guys posted..Cheers!

[notme]

Might be a bit late if it's on it's way to the shop, but does the problem occur in neutral i.e. sitting in the driveway? If it cuts at full throttle when in neutral and not moving, then it's not so much related to power restriction, since you're not making much power in neutral. More likely to be related to carb assembly or adjustment as others have said, if it is repeatable at a given throttle setting independent of anything else. It would be interesting to see if it is absolutely related to full throttle, no matter what the other conditions are.

[imdying]

saw this...

I am scared that I might end up like this guy.. hehe::facepalm:

http://cbrforum.com/forum/archive/index.php/t-38450.htmlWhy would taht scare you? His fix was free, and his problem sounded very much like your own one.

I'd definitely be checking the same thing as he found, that would only be logical.

[Matt Bleck]

It may even be water in the petrol tank, drain it and check.

[MSTRS]

Carburation 101..
When an engine is going, a vacuum is created in the engine-side of the carb throat/s.
Since nature abhors a vacuum, the carb's job is to ensure that air and fuel are constantly fed into that vacuum - in the right ratios.
Opening the throttle allows greater airflow through the carb, which in turn 'pulls' more fuel through as well.
Throttle fully open means maximum air/fuel flow.

Now - here is my thinking. Since you say the engine goes ok at lower throttle settings, it is obviously getting enough air and fuel, the spark plugs are working ok and you've got 'enough' compression. Gradual acceleration works 'fine'. BUT opening the throttle fully is exposing a weakness in one of the three things that your engine needs. It could be poor spark, but unlikely. It could be poor compression, but again unlikely. Bikes don't run vacuum advance timing, so that's out as well.
Which leaves air or petrol.
If your air filter was blocked, wide open would be bad but your engine wouldn't go well at any throttle setting. If your bike has CV carbs, there may be a problem with the diaphragm/s. Fully open throttle opens the butterflies all the way, which should mean the slides automatically fully lift for max air and fuel. But I suspect that if there was a problem with the slides, it would not show up just at full-open throttle.
So that leaves fuel.
The problem won't be in the system before the carb/s, because the carb bowls hold enough for there to be a delay before insufficient fuel is available. Therefore the problem must be in the fuel bowls. It could be dirt, but usually that partially blocks jets ALL the time and/or settles to the bottom of the bowls. Which leaves water. It sits on top of petrol, and will be in globule form, so it can get sucked against the mainjet. Since the surface tension of the water is quite strong, it won't go through the jet. And neither can the fuel.
This is a very common cause of 'dead' throttle when cracked wide open.
If I'm right, you will need to drain the bowls, fuel lines and tank. If you can, fit a (new) inline filter. Put a small amount of meths or IPA (google to get the amount) in your new fuel to flush any remaining water in the system.
Test.
Fingers crossed...

[Katman]

Which leaves water. It sits on top of petrol,

Really????? :blink:

[98tls]

Nope, water will rather happily settle in the lowest part of your tank,Hence this.

[AllanB]

I presume you have fresh fuel? if not change it pronto and pop a cap of meths in there to get rid of any moisture.

1. Check the air filter, it may be filthy or have a panty pad it previously ingested restricting it (hey - it could in theory happen!). Always beware of rogue panty pads.

2. Tank breather - is it blocked? Not sure? do this with a half empty tank, open the filler and rest it on the opening - ie it will not be seated and have a gap - duct tape in on so it will not flap about but leave a air gap. Go for a ride and see if it is fixed - if so the breather is blocked.

[MSTRS]

Really????? :blink:


Nope, water will rather happily settle in the lowest part of your tank,Hence this.

:facepalm: Oooops.
I note that no-one disagreed with the rest of my theory...
People..his problem only shows up when the throttle is cracked wide open. That suggests most strongly that fuel or air is being denied in the appropriate amount.
Air is most unlikely, because it will be restricted at any throttle setting. Which leaves fuel...but not because of vacuum lock...that would also be happening at any throttle setting, and would not occur before the engine had been running awhile.

[Max Preload]

My money's on water in the float bowls and emulsion tubes and jets, originating from the tank. Meths won't make the slightest bit of difference - they'll need to be disasssembled and cleaned.

[Katman]

My money's on water in the float bowls and emulsion tubes and jets, originating from the tank. Meths won't make the slightest bit of difference - they'll need to be disasssembled and cleaned.

+1 on the meths. It doesn't work.

Do the job properly.

[notme]

Alcohol absolutely WILL remove water from fuel systems - but that may not be the problem here.

There may be water in areas that the fuel/meths mixture doesn't get to or you may have wrong/bad alcohol or summat like that, so it may have not worked for some in the past, or for the OP in this case. But in general, it's a good trick to know and worth trying if you suspect water in the tank.

Just wanted to have that fact recorded in case of others coming across this thread in future :-)

[MSTRS]

Alcohol absolutely WILL remove water from fuel systems - but that may not be the problem here.


Don't know about 'alcohol' as such, but Isopropyl Alcohol (IPA) and meths will work.
What it does is weaken the surface tension of the water, so it breaks into ever smaller droplets. Small enough to pass through jets etc.

[Katman]

You guys can believe it all you like.

I have drained water out of enough tanks that people have put meths in to safely call it an old wives tale.

[notme]

Don't know about 'alcohol' as such, but Isopropyl Alcohol (IPA) and meths will work.
What it does is weaken the surface tension of the water, so it breaks into ever smaller droplets. Small enough to pass through jets etc.

Meths and iso are alcohols.... :-)

Just don't try Jim Beam or Johnnie Walker in there.

Iso is actually better but meths is cheap and easily available. The alcohol acts as a go-between for the petrol and water, and allows the three to mix by reducing the water molecule surface tension (i.e. the solvent (alcohol) solubilizes the solute (water) so that is is in solution (the mix of water/alcohol/petrol).
Thus the mixture can go into the engine and be used until the tank is empty and the water is gone.

[notme]

You guys can believe it all you like.
Thanks for that - cos I'd have been really miffed if I had to stop believing basic chemistry....I'd be doubting the laws of thermodynamics next, and wondering why an engine doesn't fill the petrol tank when you run it backwards!

I have drained water out of enough tanks that people have put meths in to safely call it an old wives tale.



Seriously though, the fact that you have seen it NOT work only means that ... you have seen it not work. It doesn't prove that the process will not work.

[Katman]

As I said before - do the job properly.

[imdying]

Here we have a book learner, and someone with years of real world experience.

I know which one I'd listen to.

[MSTRS]

I think there's a difference between a cup of water sitting in the bottom of the fuel tank compared to a few globules in a carby bowl.
Obviously the system needs to be totally drained (tank, lines, carbs). but chances are there'll still be a small amount of water in there somewhere. Hence the IPA/meths trick to finish flushing it out.

[Katman]

but chances are there'll still be a small amount of water in there somewhere. Hence the IPA/meths trick to finish flushing it out.

Sticking the tank out in the sun or in front of the heater for a couple of hours will do the same thing.

[notme]

Here we have a book learner, and someone with years of real world experience.

I know which one I'd listen to.


Absolutely agree bud - but it's an open forum, and Katman is free to contribute.

Sorry, couldn't resist just one turn on the 'ol windemup handle!

Not sure what/who the book learning vs real world comment is actually referring to, but anyway staying on topic and trying to help the OP solve the issue:


Sticking the tank out in the sun or in front of the heater for a couple of hours will do the same thing.

lockhead83, please don't do this! If you take it all apart and want to get all the moisture out before reassembly, rinse the tank and any other fuel system bits with alcohol.

Katman - this is bad advice for many reasons. Remember that these threads come up on google searches and so on long into the future...

So, lockhead83 - any progress? For the same reason as mentioned above, if you've gotten closer to a solution a) it's interesting to know what the cause was, and b) it will help someone with a similar problem in future :yes:

[Katman]

Katman - this is bad advice for many reasons.


I'm assuming no-one's stupid enough to think I meant a gas heater.

I'm thinking more like the little fan heater that I use at work.

[notme]

Really? Care to list them?

Good point - I should do that for completeness shouldn't I?

Basically, if you say "put it in front of a heater" you can't guarantee the conditions, i.e. how far away, what type of heater, what duration. So with that in mind here's the list (well, the first few things that come to mind, there might be more)

1. Shouldn't need to be said, but gasoline + ignition source is not a good idea. A gas heater is an ignition source (duh) but less obviously - so is a fan heater, a radiant bar heater, a ceramic plate heater.....
2. Depending on the heater type, water vapour can be produced by it. Opposite of what we want
3. A radiant heater can heat one spot of the tank and not the rest. You only dry one part of the tank
4. A fan type heater can blow bits of whatever is around into the tank. Other chemicals in the air, bits of grit and crap. Not what we want in the fuel system.
5. May be a moot point if the tank is coming off anyway, but if the only reason it is coming off is to dry it in this manner, it's extra work for nothing
6. Heating of any rubber seals/hoses/gaskets attached to the tank might mean they need replacing - adding to the state of broken bike rather than helping!
7. You'll either have a motorcycle tank in the lounge or a heater in the garage. Tank in the lounge might get presents in it from the kids, might be hot to touch (unless you don't heat it much, in which case it's going to take ages to get the water driven off) and likewise a heater in the garage might mean it's running unsupervised or gets forgotten about.

Hence why rinsing the tank out with alcohol is just easier, quicker, better all round. :done:

[notme]

I'm assuming no-one's stupid enough to think I meant a gas heater.

You do know the saying about assumptions.....?

[Paul in NZ]

I talked to Sam yesterday.

He found an airfilter house was not connected properly and now the bike is running much better. It was booked into a shop today but once the weather calmed down he was going to take it for a test ride and see how much better it really was and if that was still required.

I talked him out of tearing down the carbs (for now) - he does not have a garage etc to work in and the street is no place for that kinda job PLUS I really think he should just change one thing at a time and not potentially cause issues where there are none.

As a side note - I think Sams a recent arrival to our shores - he seems like a nice chap so lets make him welcome ;-)

[MSTRS]

I talked to Sam yesterday.

He found an airfilter house was not connected properly and now the bike is running much better. It was booked into a shop today but once the weather calmed down he was going to take it for a test ride and see how much better it really was and if that was still required.

I talked him out of tearing down the carbs (for now) - he does not have a garage etc to work in and the street is no place for that kinda job PLUS I really think he should just change one thing at a time and not potentially cause issues where there are none.

As a side note - I think Sams a recent arrival to our shores - he seems like a nice chap so lets make him welcome ;-)

Good on ya Paul.
Nothing unwelcoming in here, is there? Just robust advice...albeit conflicting. :facepalm:

Yea - he doesn't need to strip the carby's at this point, but he should open the drain screws to empty the bowls. If his bike has a Prime setting on the fuel tap, it would be a good idea to let it run through the open bowl drains for a minute or two.
Outside, and somewhere that the petrol on the ground won't matter, of course!!

[Katman]

Outside, and somewhere that the petrol on the ground won't matter, of course!!

But not while he's holding a lit propane torch.


(Just to keep Allun happy). :bleh:

[lockhead83]

@ ALL,

I have been a total jerk that I haven't updated you with any progress about the bike and the suggestions kept pouring in. Firstly THANK YOU all. Really appreciate your time n effort.

The solution was fvking simple: Trust me i fixed it..:woohoo:

I started ripping the bike off just to see what's in there (please before u laugh ur guts out, this is my first big bike n have been riding an old school all this while before jumping onto this one). I noticed the air filter outlet/duct was disconnected (Air duct and the case cover were siting at an angle instead of being connected. Shot me if you don't get it...lol)

I connected the two and put everything bike n BOY OH BOY... I got what I was looking for in my bike. She's fast and responsive like any other bike.

So the solution was pretty simply. I did check the fuel/vaccum and looked for any blockage in the tank a night before as suggested in the first few post and was assured that wasn't the problem.
To add more, to my surprise, even with a speedo showing 190 as the limit, i saw the rev meter going up from 6k to 9k. It felt fast...:msn-wink:


Cheers!

[MSTRS]

Aha! Well, who woulda thunk that?
CV carbs, eh? They don't like 'live' air. ie anything other than a (properly attached) airbox will adversely affect the performance.

[lockhead83]

I talked to Sam yesterday.

I talked him out of tearing down the carbs (for now) - he does not have a garage etc to work in and the street is no place for that kinda job PLUS I really think he should just change one thing at a time and not potentially cause issues where there are none.

As a side note - I think Sams a recent arrival to our shores - he seems like a nice chap so lets make him welcome ;-)

Thanks Paul for your help the other day.... It was precise and pretty accurate. N after that day, i didn't bother to look at the carbs or anything as the bike was going really nice.

Update 2: The bike broke down last night RIGHT OUTSIDE THE ferry terminal when I was about to head of for the rally... :facepalm:.. life is a bitch and I learned it the hard way...

What I did and all of you shouldn't. If everything is fine, don't be a superman. A day before I added the remaining carb/jet cleaner to a full tank of gas and took the bike out for a spin. What happened then: I was riding and felt like the bike was cutting down on power. So I pulled over and waited for 10 as this has happened before (couple of thou kms back when I added the first half of the bottle :innocent:) After 10 she popped up fine and saw some white smoke out of the exhaust. After few more Kms, it stopped again n then again. Now it started worrying me and I thought just a bad day ,better go back home .Finally when i decided it's time now, I must have ridden 3-4 kms and got stuck again on the motorway. This time she just wouldn't pop up. I was stuck there for 3 hrs and after numerous attempts, I killed my new battery. So had to get my bike towed and blah blah blah. It's sitting with Boyle Kawasaki and they'll look at it on wed. So fingers cross.

And all of you guys who passed by me the other day doing :bleh: , SEE YOU IN HELL...... lol

Tk fellow riders. Might see you next wed.

Cheers!

[lockhead83]

All sorted now!
clogged valves n fuel supply with some crap....