Restricted???

[Silverlegacy]

Has it had an oil change recently ie with car oil?......just curious if it could be the clutch slipping at higher revs if it has the wrong oil in..........or was it running well before & then started doing it without any changes ie services?

Its had an oil and oil filter change about 5 months ago at a motorcycle dealer.
Its been running like it pretty much since ive owned it, I left it at the garage and the mechanic took it out and said its fine and nothing wrong with it mechanically? so would like to think that hes given me the right advice, rather than making up a list of things that could be wrong just to make money off me.


I will give the air filter thing a try, i did check it the other day and seemed clean enough, but my clean and other peoples clean might be two different things.
Dont have any other biker friends local who could at least take it out and give me there opinion and trying to find a big enough section of road to at least try and push bike a little

[Ruby Racing]

Just a thought. There might be crap in the fuel tank blocking the fuel tap slightly so the bike isn't getting enough fuel to the carbs. It would be OK at low rpm as there would be enough fuel, but at higher rpm's it would struggle. Not had experience of this self, just read about it. So I may be wide of the mark.

[noggythenog]

Just a thought. There might be crap in the fuel tank blocking the fuel tap slightly so the bike isn't getting enough fuel to the carbs. It would be OK at low rpm as there would be enough fuel, but at higher rpm's it would struggle. Not had experience of this self, just read about it. So I may be wide of the mark.

Good call


Also the fuel pipe that goes from the underneath of the tank could be kinked etc but if youve been doing carb balance etc then youve had the tank up and down so not likely.

[Silverlegacy]

Just a thought. There might be crap in the fuel tank blocking the fuel tap slightly so the bike isn't getting enough fuel to the carbs. It would be OK at low rpm as there would be enough fuel, but at higher rpm's it would struggle. Not had experience of this self, just read about it. So I may be wide of the mark.

I will have a look into this also, typical that i filled up the other day so still loads if fuel in there, once i have ran it down a bit i will try and drain the fuel tank and give it a good clean out.

[Silverlegacy]

Air filter looks ok to me? What you think??

[darrsi]

Fuel filter could also be blocked, only a few quid to replace.


I could be off the mark here, but writing on parts indicates second hand to me?

[Silverlegacy]

I took the fuel filter out and gave it a good blow through, so hopefully dislodged any junk in there, although looks in reasonable condition.
hard to tell what the numbers are on the air box, but like you say it might very well be a second hand one, although not sure how big the second hand market is on used generic air filters??
Running out of things to try that are with in my technical limits, i think checking carb rubbers for washers is beyond me looking at how they are attached and how to get to them.
Might be another trip to my local mechanic

[Paulfzs]

what air filter is that?


mine looks nothing like it.

[noggythenog]

If you wanna lose 15 minutes of your life then heres a vid i did on my 600 when i got a new camera.....ok the video is crap and the camera wrong way round but anyway it does illustrate the rev needle climbing way beyond 5k, shame you cant see 5 k on the vid but i reckon i was probably cruising around there as i like to hold gears a bit.


My engine needed a carb balance but was still powerful way beyond 5k

[bigbluebear]

Why don't you get it Dyno'd, that will tell you plenty with what's maybe wrong with it.....will cost you £30-£40 and stop you second guessing and fannying around.

[Jules-C]

It sounds to me like it is restricted either in intake or exhaust. Since either severely restricts the airflow it stops it revving out even in low gears.  Only way to tell would be removing carbs and exhaust to check

[Silverlegacy]

No idea what air filter it would is, whether it's a standard on or cheap replacement?
Might look into dyno if I can find somewhere local.
Hard to know much more about the bike as bought it as a part ex from a dealer so didn't speak to original owner and dealer knows very little about the bike.

[Punkstig]

Good call with checking fuel lines, don't forget the fuel tap under the tank too- is that properly open?
Seems strange that a mech took it out and said it was fine, pop to another bike shop for a second opinion, just ask someone to take it for a quick ride!

[Silverlegacy]

Cheers for all the help and info guys.
Bearing in mind i have been riding on and off for nearly 15 years i still dont know much mechanically about bikes.
Will try and take it to another bike mechanic and see what they have to say, it just doesnt feel right and its niggling at me as i really like the bike and its ok at the lower end, i just want to open it up sometimes.

[darrsi]

Why don't you get it Dyno'd, that will tell you plenty with what's maybe wrong with it.....will cost you £30-£40 and stop you second guessing and fannying around.

Make that £50 or £60 in London.

[fazersharp]

your filter look like OEM and ok to me heres my old and new one

[Silverlegacy]

your filter look like OEM and ok to me heres my old and new one

Maybe mine isnt too old then? i gave it a hoover out and cleaned inside the air box.
Waiting to hear from the dyno place now to see what they can do.

[fazersharp]

Just an advisory---------- my yellow one was 16 years old (only 16k miles of air through it though )

[odbguy]

5k buzzing happens with all fazers.

Can I just jump in on this one.
Iv experienced a buzzing/vibrating noise with my fazer but not at 5k.
It starts at 2.5k and stops soon as it hits 3k.
Happens in every gear and at whatever the speed ..

Iv had a quick look thru old threads and there's very mixed opinions from needing to rebalance the carbs too cam chain rattle ..
Not many that say it's normal but is this possibly the case or should I look further into the issue?

[fazersharp]

I have a buz at a certain RPM but I only hear it at standstill without me lid on, and only if i keep the revs there, I think its the indicator storks on the fairing. But when moving I dont hear or feel anything

[odbguy]

Iv had a word with my dad and were going to give the bike a once over and he's going to show me how to balance the carbs  ...

Hurrah for Dad's!  Lol never thought I'd say that at almost 30 !! Haha

[Silverlegacy]

Iv had a word with my dad and were going to give the bike a once over and he's going to show me how to balance the carbs  ...

Hurrah for Dad's!  Lol never thought I'd say that at almost 30 !! Haha

I sync'd my carbs last week and the bike did seem to run a little better, but they wernt that far out so think the problem with mine lies elsewhere.
I did all the normal stuff first to eradicate the vibrations and noises, like the headlight mod and securing indicators, pretty much stripped off the whole front and put new washers and stuff on the secure any loose bolts or cure and free play in the fairing.
Ive checked as many mounting bolts as i can find and tried everything else i can think of at the minute.

[darrsi]

I have a buz at a certain RPM but I only hear it at standstill without me lid on, and only if i keep the revs there, I think its the indicator storks on the fairing. But when moving I dont hear or feel anything

Indicators can cause a buzzing on the fairing.


Headlight bulbs can cause a buzzing on their housing, which i sorted with self amalgamating tape.


Also had a buzzing from the plastic glass panel on the fairing, which i sorted with strips of soft sided velcro.


Not had it on this bike, but glass in wing mirrors can buzz too.

[JoeRock]

Sorry, Darrsi, got to disagree.

The kit in my ZX4 made it pull OK, but ran out of puff top end. Best thing to do is find an open "private" road, take her up to a ton. If it still pulls, all good. If not, check your carbs.

It was just a theory,  I've never actually ridden a restricted bike before.

You're right Darrsi - they don't accelerate at all hard through the gears. if you're accelerating from a start the best way to put it is they go like normal to 5k revs or so, but then you just don't get any more oomph!

[Millietant]

Silverlegacy, what you're describing sounds pretty much exactly like my son's Fazer 600 when we had it restricted to 33bhp for him.

The restrictors are 4 big steel "washers" which just slot in the carb mouths - so that when the throttle is wound fully open, there's only the hole in the middle letting air through, and it's only about 1/3 of the size of the carb mouth.

This means that no matter how far you wind the throttle open, things happen slowly after 5k / 6k RPM's, especially in the top two gears.

Cruising on the motorway at 70 didn't leave much in reserve for instant overtaking.

If, when you're riding it, the bike performs reasonably well on part throttle, but it just doesn't seem to do anything more when you wind the throttle past halfway, I'd say your bikes restricted - as long as it runs cleanly and doesn't misfire.


Maybe just take off (or pull back) a carb inlet rubber and you'll soon see if there's a washer stuck in the carb mouth - the aperture left open on our sons bike was probably less than about 20mm diameter.