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:

http://cbrforum.com/forum/archive/in...p/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

I also found this ...Restrictor in Speedo ?

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 )

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.