Suzuki Bergman 400 2008 - Engine bogging down - mss1tw
Mods, would you mind leaving this here for the evening to get a few views and hopefully comments? Bike is a fuel injection model so some comparable tech to cars.

Basically even in this cold snap, it starts and runs fine but the last third of the the throttle travel causes the engine to bog down, losing speed even on downhill sections.

I wondered if the tank was vacuuming but opening the cap briefly didn't make any difference.

As I've only just bought it, it's going back to the dealer tomorrow but I need it for work so anything sensible I might be able to suggest would be handy. I wonder if if it's a faulty throttle position sensor.
Suzuki Bergman 400 2008 - Engine bogging down - focussed

Suspect fuel filter getting blocked or the gauze screen on the inlet to the fuel pump obstructed - usually both inside the tank, usually a real swine of a job getting to.

Also worth checking is are the battery terminals tight and clean.

There are onboard diagnostics in Suzuki FI systems which display error codes on the dash display but you need to know where the diagnostic plug is, the diy method is to use a paper clip to short two of the pins to get the display into dealer mode to display the codes, but you need to know which pins if it's a multiplug. The dealer should have a diagnostic tool which just plugs into the diagnostic plug, and a box with a switch on it.

Suzuki Bergman 400 2008 - Engine bogging down - mss1tw
Thanks focussed!
Suzuki Bergman 400 2008 - Engine bogging down - craig-pd130

Does it recover and run normally again if you roll the throttle back to halfway, after it has bogged down?

It could be fuel flow, it could be a badly-fitted airfilter, or the inlet snorkel of the airbox could be partially blocked. I would strongly recommend checking the air filter snorkel, airbox and filter just in case. Ask me why I recommend this :-)

As Focussed said, a look on the Bergman forums will probably show you where the connector for the 'diagnostic special tool' is (I have a Suzi SV650 which uses the same method).

I'll take a stab and say it's unlikely to be a faulty TPS - if it works fine for the first half of the throttle travel, it's probably OK.

Suzuki Bergman 400 2008 - Engine bogging down - mss1tw
Thanks craig - you were right about the TPS

Turns out the clutch and flywheel are knackered. As I have no interest or passion for automatic scooters I've never learned anything how an auto scooter trans works, I don't know if they're CVT or some sort of torque converter, so I'll have to take their word for it. Ultimately if that doesn't fix it they can have it straight back!

Apparently the parts come to £450 - for once I'm glad I bought from a dealer!
Suzuki Bergman 400 2008 - Engine bogging down - focussed

Someone has just told me there was or is a service campaign on burgman 400 s - (not a safety recall - a Suzuki recall for updated parts) to do with the charging regulator or similar.

Put your VIN in here to find out -

Suzuki Bergman 400 2008 - Engine bogging down - SteVee

Scooters use a CVT type transmission. Some bigger bikes use a DCT (Dual Clutch) like VW's DSG but less troublesome. Never seen a Torque converter on a bike - though the Boss Hoss might be an exception.


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