Running Bad at Full Throttle

[ColleyV12]

This is an open and shut case, already solved it but thought it useful to post it here anyway.

The bike has been running great for a couple of weeks since getting it on the road, gave it a wash on Sunday ready for the week and took it to work on Monday, had to fill up with fuel on the way but it felt peculiar taking it to the petrol station.

I put this down to low fuel so filled up and set off down the dual carriageway to work, this is when the problems started.

The bike was fine at low and mid throttle position, would idle fine and ran best when cold.

I had set the fast idle cam on Sunday as well so did not know if that was the problem because when you opened the bike up, it died. it surged and slowly came to a halt. If you let go of the throttle it ran great, even after the surging at full throttle.

I had the same problem when the bike was new, the fuel cap had been changed under warranty so thought it was air not getting drawn in to the tank that was causing the fuel starvation.

Checked the cap and it was working fine, checked the vent (small hole inside fuel opening that exits near the side stand) and it was blocked. quick shot with the air compressor and it was cleared out. Thought I had fixed it.

Took it for another run and it did the same thing, stopped, opened the fuel cap and tried it again leaving it open, same problems so not the vent issue.

Wed night, drained all the fuel (full tank) and removed the tank off the bike, removed the fuel pump and filter as per the workshop manual and looked for the strainer, couldn't see it for a large, what looked like, ball of mud. The entire filter and gauze was caked in slimy brown crud. The metal casing of the fuel pump had started to rust and bad fuel dealt the death blow to the running.

Cleaned it up with fresh petrol and the compressor, replaced the fuel pump and filter, bought good quality petrol not from a supermarket and the bike is running better then ever.

I'm amazed it actually ran at all looking at the amount of debris in the tank.

Live and learn, only buying quality petrol and changing the filter regularly from now on.

When the bike was running bad, I tried holding it at about 9000 rpm in second (I think about 90ish mph) and it didn't hiccup, only at full throttle opening and in any gear.

[snapdragon]

Useful info thanks ColleyV12

admit to rarely (if ever) using full throttle - also haven't checked the filter for ages

however I have bit the bullet and booked her in for a full service at a recommended Suzuki workshop (Crescent in Verwood) so am guessing they will check and replace if neccessary.

[Miz]

Useful info thanks ColleyV12

admit to rarely (if ever) using full throttle - also haven't checked the filter for ages

however I have bit the bullet and booked her in for a full service at a recommended Suzuki workshop (Crescent in Verwood) so am guessing they will check and replace if neccessary.

I would be very surprised if they checked/changed the fuel filter, they will "service" the engine, as in, change oil/filter and check clearances, but unlikely touch anything they are not familiar with.

[ColleyV12]

Nope, not on either the Cagiva or Suzuki service schedules

http://www.burniemorgan.com/cagiva_rapt ... nance.html

I still prefer external fuel filters than those in tank

Remember tough, my bike was stood up for a couple of years, may be more to note if reviving an old bike than those ridden daily.

[Miz]

I try to use this (or something like it) once a year.

http://www.halfords.com/webapp/wcs/stor ... yId_255221

Last winter I stripped the fuel pump out of the tank and although there was some corrosion, it was not bad.

I try to use the above only if I am going to use the bike a lot for a few days, so I can make sure I put a couple of tanks of fuel through after the treatment.

[dizzyblonde]

Where is this fuel filter?

As for the pump, when I swapped tanks last month, I was suprised that the pump was pretty clean. I expected that the horrendous 'chicken pox' may have been evidence towards a proper manky pump.....but no!

[shedmonkey]

There are 2 ish ,a strainer (nylon gauze on the pickup pipe ) and a metal canister filter .both inside tank on the mounting plate.

[dizzyblonde]

Still none the wiser. I am presuming 'mounting plate' means stuck to the big fuel pump jobbie, under that big rubber thing hiding all its insides

[shedmonkey]

yeah goldie coloured (or it should be) the main can measures about 60mm (2.5")long by 45mm (1.75")diameter with a pipe sticking out both ends and the strainer is white meshy thing on the back of the pump/motor itself .All fitted inside the tank on the plate with 6(correct me if im wrong) bolts.

[ColleyV12]

The bit on the left of the main pump with the two rubber pipes attached, not the larger separate bit, all under the rubber boot when in the tank

[weirdo]

No wonder ya can't get much petrol in the tank with that lot taking up all the space.


Sheesh !

[dtpeebles]

Hi,

I've just bought my mates 2000 Raptor 1000 and it has the "surging" problem !
Before I resort to the expense of a Power Commander I am checking everything else.
Just in case I need to clean out the filters etc inside the tank, where could I get a spare filter & pump if I need them ?
Cheers
Dave

[snapdragon]

not quite sure what you mean by 'surging' but if it's the one where you lose half then engine I'd check the front plug and cap and change 'em if damamged

If it's more general and the bike's been standing for a while I'd check any connectors you can find are clean and nothing is pinched or damaged, drain the tank and fill up with some super duper/V/opti quality fuel and see how that changes things.

If it's the 3000rpm 'it's built like that mister' issue then I just ride under or over it, change gear to avoid 3000rpm until the engine's properly warm, warm the engine fully before riding off.

But I'm certain that someone will have a more expensive option for you

[Miz]

, warm the engine fully before riding off.

But I'm certain that someone will have a more expensive option for you

If it is the 3,000RPM stutter, then the magic number is 83degrees, once over this temp the bike changes its fuelling/ignition map so runs better.

The idea of warming an engine before riding/driving is not really valid these days, tolerances in an engine are better machined, oils are better at all temps (hence multigrade), engines warm up quicker/better when ridden/driven gently until up to temperature.

If you are riding in cold weather (or only short journeys) you will get good results from masking off some of the radiator.

[dtpeebles]

Thanks for the advice and now I've got my service items delivered I will sort out asap ... hopefully running well for Spring !
After all, I live in the Scottish Borders so winter is here already