[Fixed] Will not rev past 8k - Printable Version

[Fixed] Will not rev past 8k - Printable Version

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[Fixed] Will not rev past 8k - positron - 11-06-14

Hi,

2003 Fazer is my main commuter and I do about 60-70 miles a day. It was restricted to 33 bhp up until March, so it didn't revv past 7-8k, so I assumed it's the restriction. However, since the restriction washers has been removed, I can feel the overall power has gone up much higher, but the bike seems to struggle when it reaches around 7-8k rpm on the motorway. When it reaches this rpm range, it feels as hesitant to go forward, as if someone is applying and releasing the brake rapidly. This is the case in 6th, 5th and even 4th gear. I can take beyond 8k on 3rd gear if I remember correctly, I will confirm later. Over all fuel consumption has shot up since derestriction. And especially when I take the bike to this 'boggle zone', I can almost see the fuel needle moving! I have checked the exhuast headers and all four seems to hot - meaning all four cylinders are firing. Bike is serviced every six-nine months (6-9k miles)

What could this be? Where should I start? I should add I don't really know much about the inner workings of the bikes - but I am ready to invest some money and time and keen to learn.

Thanks a million!

Re: Will not rev past 8k. - His Dudeness - 11-06-14

I'm only guessing here I don't know for sure but it sounds a bit like it's still restricted. There's two types of restrictor kits for the carb fazer the washers type and the type that uses different springs and needles. Maybe your bike was already restricted with the springs and needle kit and you then put in the washers

[img height=545 width=730]http://i.imgur.com/MXYe06W.jpg[/img]

[img height=546 width=732]http://i.imgur.com/fLknPjM.jpg[/img]

Re: Will not rev past 8k. - positron - 11-06-14

Thank you so much. This might very well be the case - I bought the bike off a dude who said he bought it off a Driving School. He said it's not restricted, so I assumed that's right and got it restricted with washers. Oh dear!

Anyway, I tried to get it to rev past 8k in lower gears today on the motorway, and it won't. Say I am going as far as 6th will take me (hitting the 8k limit), I pull the clutch, and the bike free revvs to 10-12k, but as soon as I let off the clutch and put load on the engine, it goes brrr.. brrrr.. holding back and serious engine braking. This was the case even when I took it all the way down to 2nd gear! Finally back in 6th, I pulled the clutch in, let it revv to 12k, and let the clutch out and the RPM dial starts going from 0 - 4k - to real RPM I am doing - back to 0 - 4k - like that 2-3 second each at each position. It reverted back to normal once I stopped, turned the bike off and back on again.

If it is indeed restricted with the spring / needle mechanism, is that something I can DIY, or would I need to bring it to my mechanic?

Re: Will not rev past 8k. - thunderpantz - 11-06-14

Check the air intake seals around the carbs and also the timing?

Re: Will not rev past 8k. - unfazed - 12-06-14

Always start with the simple things and rule them out.
You try running it with the tank filler cap open rules out a partially blocked breather (when tank is less than half full of fuel stops it spilling)
Is the fuel tap turned on fully
Check the fuel pipe to ensure it is fitted correctly and not flattened. The pipe to the tank is routed under the frame cross link, many route it over it and the tank flattens it.
Check the fuel filter and change it if unsure.
Check the Air Filter is it badly clogged, I have seen many a DIY mechanic strip the carbs when all it needed was a new filter.
Since the tank is off
Remove top of one Carb (right side is easist) to see if it has factory restriction (His dudeness pictures show you what you are looking for on the cover)
Drain the carbs could be dirt being sucked up
Check the float heights with a plastic hose attached to the the drain hole.
Check for loose spark plug caps.

If all these check out come back to the forum and we can suggest other options

These are all easy thing to do before you start stripping anything

Re: Will not rev past 8k. - positron - 26-06-14

Thank you for the comments, and apologies for the delay in trying the steps out.

I tilted the tank up and checked the fuel tap and fuel pipe routing. Fully on and pipe not flattened out. I checked the breather pipes (the two things that open up at the bottom of the tank, and they look okay, and they are sitting into a little rubber cup thingee, so I assume they are not blocked. I couldn't try riding with the tank filler cap open as I couldn't get the key out of the tank filler cap when it's not closed (It just occured to me that I could have used my second key... doh, will try that soon).

Air filter was replaced within last six months or so, I don't know about fuel filter though. I don't have these handy, so I will order them in and try changing them. Last week the bike felt really clunky in the front and felt as if there is massive engine braking as soon as I let go off power. Turns out that the front wheel bearing was badly shot. I got that replaced by my mechanic, and it feels better now, but the 6.5k/7k issue is still there. My mechanic reckons it might be carb related, but he can't be sure unless he starts stripping the bike to have a good look (which sounds expensive...)

Thanks again, I'll report back when I have done some more work.

Re: Will not rev past 8k. - reddave101 - 27-06-14

After you have tried the things unfazed has suggested, try looking at your clutch. Open up the clutch cover and look at the torques for the outer pressure plate cover and also the see if the springs have worn and gone soft. You can also check on the clutch plates and steel pressure plates to check for blueing? Just another thought as the engine will clearly go past 8k when clutch is in but when the clutch is released it bogs down, maybe clutch isn't engaging properly to get the torque needed. You may also check the crank case breather? Now and again I kept getting the slight bog down but wasn't all the time, after a few investigations I did notice the crankcase breather was filling with a creamy sludge and was filling into my air box. A simple and free alteration soon cured this and now get no bog downs and actually get better acceleration and higher revs, think I've actually hit just over 14k.

Re: Will not rev past 8k. - positron - 06-07-14

Massive respect for your knowledgible foc'ers, the problem has gone away! Big Grin

Over the week the bike was running even weaker and poorer and I was finding it hard to keep up with the traffic. I had started avoiding motorways and had to sit back behind the traffic on B roads as the bike was not accelerating past 5.5 - 6k, and as soon as it hits that particular rev spot, bike actually slows down equivalent to going couple of gears down and it was altogether getting a bit too dangerous for everyone.

Over the week I tried riding it with tank lid open. It didn't improve the situation.

Today after scanning thru this excellent forum for details, I carefully removed the tank, and peeled back the big rubber cover over the air filter box thingee (I had to remove the bracket where tank attaches to, and the two black plastic panels on both sides of the bike), and took out the air filter. This doesn't look too bad, does it?

[Image: IMG_20140706_172943.jpg]

I didn't have a new one to replace it with, so I cleaned it from inside with the hoover, and put everything back in (didn't forget to turn the fuel back on, thanks to my overly excited three year old girl reminding me), and rode out to nearly open stretch of road and as the rev went past the 7k and then 8k mark I was so delighted it's as if I won a race or something! Big Grin

Now I don't know if it was cleaning the filter that did the trick OR (embarrassing part) that I noticed the female connector part of the gerbings heated gloves connector lead that I had folded back under the seat had slipped under and was sticking into one of the three air intake squares.... it probably was blocking some of the air going in..!!

Thanks again for the pointers folks, they were all certainly in the right direction. I am considering splashing out on a K&N air filter with the money I saved today (had I got to the local mechanic who said he will strip the bike to see what is wrong).

I have more issues with the bike - idle running is too low and it cuts out all the time, it needs a new right side mirror, main stand, main light is pointing to the left and too high etc etc. I will give it my best shot reading and learning from here. So much fun! Smile

Re: Will not rev past 8k. - unfazed - 06-07-14

What mileage is on the bike?
The filter is bad, have you seen an new one Smile

Re: Will not rev past 8k. - positron - 07-07-14

(06-07-14, 11:03 PM)unfazed link Wrote: What mileage is on the bike?
The filter is bad, have you seen an new one

Bike has done around 70k miles. I haven't seen a new filter, so that's the reason then? I thought the filter was replaced within last year, bit may be not. Thanks again!

Re: Will not rev past 8k. - unfazed - 07-07-14

That filter does not look like it was changed last year. Smile

When the bike is at full temp, set the tick over by turning the black knob on the bottom left of the carburettor bank
Clockwise increases the tick over speed
Anti Clockwise decreases the tick over speed
Set it to around 1100 to 1250 rpm

New OEM filter is white and you can see light through it :lol

Re: Will not rev past 8k. - darrsi - 07-07-14

Put a K&N in there and you'll probably hear the bike take a deep breath. :lol

Re: Will not rev past 8k. - positron - 07-07-14

(07-07-14, 11:50 AM)unfazed link Wrote: That filter does not look like it was changed last year.
....
New OEM filter is white and you can see light through it :lol

Wow. I have a note here from February this year saying the mechanic changed air filter. That's just crazy. Is he duping me? I thought he's a nice honest lad. I will have to pull out the receipt and double check. I really hope it was a mistake from my part.

Seeing bike has already done 70k+ miles, would a K&N air filter be kinda aspirational? Def not getting hiflow air filter based on the experiences here Big Grin

Re: Will not rev past 8k. - noggythenog - 07-07-14

Here's an old filter that has been lying in my garage for 2 years....i replaced it with a K&N

Ok so this filter didn't see many miles but demonstrates the difference.....it is a genuine yamaha part.

Re: Will not rev past 8k. - positron - 07-07-14

Thanks a million noggy, mine looked dirtier I rekon. Here's one more photo that I had taken yesterday.

[Image: IMG_20140706_172909.jpg]

I guess I will follow the good advice here and go for K&N air filter. And possibly a new mechanic may be... Sad

Re: Will not rev past 8k. - noggythenog - 07-07-14

Doesnt look like a yamaha oem one either....i cant see the serial number.

Look at mine and the serial number is clearly visible.

You wont go far wrong with a K&N.

Re: Will not rev past 8k. - andybesy - 07-07-14

K&N recommended. Condition of old filter depends a lot on how dusty it is where you're riding of course!

Andy

Re: Will not rev past 8k. - darrsi - 07-07-14

(07-07-14, 02:10 PM)positron link Wrote: [quote author=unfazed link=topic=13563.msg157591#msg157591 date=1404730207]
That filter does not look like it was changed last year.
....
New OEM filter is white and you can see light through it :lol

#

The said note I had somewhere (it's not much, but may be you guys get a laugh out of it, figures are in EURO not Sterling)

4 new spark plugs.
new oil and filter.
new air filter
new front brake lever
new rear break pads
new rear piston seals etc, piston & calipers serviced and reconditioned
33 bhp RESTRICTOR WASHERS taken out from the carb intake - FULL POWER NOW.
3 hours of labour x 50.
+ VAT brought it to 340.
[/quote]

Are you saying that's also a Hi-Flo filter?

If so they have caused a few of us problems before, including me, they are cheap rubbish that simply don't let in the normal amount of air needed.

Go K&N, it'll feel like a new bike. Smile

Re: Will not rev past 8k. - unfazed - 07-07-14

There you go Noggy a sale for your K&N :lol

Re: Will not rev past 8k. - noggythenog - 07-07-14

(07-07-14, 06:02 PM)unfazed link Wrote: There you go Noggy a sale for your K&N :lol

It was sold long ago Smile

Actually pretty much the whole bike is sold in theory...it seems that it pays to plan ahead with dibs......will i make more money than if i just sold the bike......hmmmmmmmmmmmm.....im not sure yet........but I've enjoyed the strip & if i ever get another fzs600 ill have a bit more knowledge about where things are and how difficult they are to get at/off/on........plus ive got a bag of bolts n bits......you just cant put a price on a bag of bolts n bits :lol