why does my bike surge???

[spready]

can anyone give me advice on what to check to find out why my bike surges? it seems to happen at 3000rpms, but i think it starts when i keep the throttle very steady. it never stalls, backfires, splutter or loose power at any stage, it just has these little surges at a steady rev. i hope someone can enlighten me
thanks <i></i>

[GDYUP]

I've found my bike surging at speed limit speeds a while back.

Turned out the be rooted cush drive rubbers.

Grab your rear sprocket and see if there is any movemnet back and forth. If there is play. They're rooted!

My Red/Black 99 used to surge at low speeds going through roundabouts. It was a bad map due to the 4 into 1 Yoshi system. But they were the early days...

Don't know if this helps? There are some clever Busa owners in the Club. I'm sure you'll get the right info when they see this post.

Cheers, Phil. <i></i>

[BUSGO]

My 99 Red/Black surges at low speed when I don't have the baffles in the Staintunes. I think GDY is on the money again with the mapping issue.
When the baffles are in, it never does it.

<i></i>

[spready]

should i replace sparks and clean fuel filters? would that help? <i></i>

[BUSGO]

It depends how bad a surge it is Spready.
I have new plugs and clean filters a month ago and it still surges when hot and no baffles in the cans. If I put the baffles back in, it does not surge.

If the bike hesitates under power or acceleration, you need to clean the regulator screen in the fuel pump.
<i></i>

[spready]

there only very minor surges at low revs. i give it a handful, nothing but smooth power <i></i>

[rev 01]

Internal or external fuel pump ?

ie: what year is it ?

<i></i>

[spready]

its a 2000 model. how can i tell if in or ex fuel pump? <i></i>

[rev 01]

Pretty sure the 2000's have the old style pump (external).

It's bolted to the rear of #3 & 4 cylinders & has a large rubber heat shield around it & sits inside a yellowish cad plated mounting bracket.

This type of pump needs regular TLC (tender loving care )

The filters in this pump are prone to blockage especially the ************fuel pressure regulator filter*************
This filter is located on the pump body under the pressure regulator itself. I'll bet any money it's blocked if it hasn't been checked within the last 10,000 k.

*Hot weather will always accentuate any restrictions within the fuel system. *

The plastic gauze filter in the rear end of the pump can also clog up completely if not serviced properly.

The pressure filter doesn't seem to cause any trouble.

The fuel supply & return lines are moulded rubber and are prone to shrinkage & twisting, further restricting fuel flow.

All these things need to be in order for best performance under all conditions.
<i></i>

[spready]

geez, thanks very much for that info, will have a go at the filters tomorrow i hope. in Rockhampton it has been hitting the high thirty's. <i></i>

[BUSGO]

Spready,
If you haven't done so, Check my additions to the thread regarding fuel senders etc further down the tech thread. It has everything you need to know about the 99/00 fuel pump.
Here is a shortcut.
p083.ezboard.com/faustralianhayabusaclubfrm11.showMessage?topicID=226.topic Rgds BUSGO
<i>Edited by: BUSGO at: 23/1/06 5:02 pm
</i>

[spready]

is there an additive i can put in the fuel that might help clear the filter area. it looks like a friggin big job getting to the filter <i></i>

[Geribusa]

It's not a big job to pull off the pump and clean the filters on an external pump bike. I can do it start to finish in under an hour easy. Petes turbo project<i></i>

[WARD P]

If you're lucky it'll be the little return screen under the vaccum thingy- check this first as it is usually the cause of surging, and dying when backing off, and you can actually get to it without taking the pump off.

But it's allways better to clean all 8 filters. Yes 8
1 in the tank
4, 1 on each injector
1, above return screen

and the 2 buggers in the pump itself.
1 is the $50 paper filter
the other is the screen in the back of the pump - which takes a certain amount of brute force to get to.


To open the pump-
It is an easy job, but watch the cheesecake screws that hold the pump together. Get them off and throw them away - replace with allenheads. You'll also have to be carefull of the odd shaped o-ring under this, as it will expand if let dry out, and can be a bugger to get back right.



Or do what I did . . .
I got the shits with the pump about 60,000km ago, so I put in an inline filter(about $2 worth) and threw the $50 suzuki part away. Then I simply cut the screen out of the back of the filter. Haven't had a problem since, just replace the $2 inline filter with each service. and check the others every 20,000km.

If you go back through old threads of 3-4 years ago there's books been written on this.

cheers,

WARD




<i></i>

[BUSGO]

Would you believe I have to clean the regulator screen again after only 2,500 klms since the last clean?

I am certain that I got another bad batch of fuel from BP.
I have been using BP Premium 95 oct for the last couple of fills and suddenly as soon as the bike gets down towards empty the bloody filter blocks up again.


The bike ran perfectly on Caltex Vortex till nearly empty since the last pump service and then bugger, 2 tanks of BP and its blocked again.
Maybe its coincidence but the regulator screen is coming out for good this time.

Anyone have anymore thoughts on this, I know Rev recommended it last year.
Rgds BUSGO
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