bike choking when revved hard and fast in neutral.... - SV650.org

03-09-05, 01:59 PM

ok, this is hard to explain.
when im at the lights at idle, if i give a handful of throttle to rev her up with no load, sometimes it 'chokes' a bit initially then revs up.
i dont know if you can understand that, i dont know if its normal for a carborated engine.
im on a 99 650.

was thinkin it may be the carb balancing? but the idle is absolutely fine.

any ideas appreciated!!!

Spanner Man · 03-09-05, 03:06 PM

Afternoon.
It's known as bogging down. This is more pronounced on engines with fewer cylinders, due to the size and consequent extra weight of larger pistons. They take a micro second or two longer to get moving than smaller pistons do.
Obviously valve clearances, carb balance, condition of airfilter & spark plugs etc will make this worse, as will running lean at idle. As a precautionary measure I would check all of the above just to be on the safe side.

Cheers

03-09-05, 04:39 PM

i think i need new plugs.
i also think i am running lean, i dont get good fuel consumption (presumed this was due to the 'open throttle' riding style

)
also i sometimes smell fuel when i stop at the lights.

how can i check my mixture?

Scoobs · 03-09-05, 05:57 PM

Quote:

Originally Posted by branny

how can i check my mixture?

Get it dyno'd

03-09-05, 06:00 PM

Bikes arent meant to be revved with no load anyways..specially with petrol so costly why bother?

03-09-05, 09:41 PM

try doing a snorkelectowhatsit, it solved my bogging

04-09-05, 01:09 AM

if you can smell fuel at the lights i would say that it sounds like someone has tried jetting it at some stage and totally gone overboard or your airfilter is disgustingly dirty

do what spanner man suggests its all good advice

04-09-05, 12:50 PM

Quote:

Originally Posted by zx6man

Bikes arent meant to be revved with no load anyways..specially with petrol so costly why bother?

thanks so much for your helpful advice

what a pointless post....

embee · 04-09-05, 04:52 PM

Sounds rather like your carbs could do with a clean out.

Has it recently started behaving like this or always been like it?

First thing , simply drain the carbs. Lift tank, airbox off, down between the carbs each floatbowl has an allen hex socket screw in the side, and just slacken these off a turn or so and the fuel drains out of the bottom.

Check the carb slides lift and drop freely and don't stick (the diaphragms offer a little resistance, but they should be smooth and not notchy).

Check the carbs are seated properly into the rubbers on the cylinder heads and the clips are reasonably tight (not leaking air).

Fit iridium plugs. They are worthwhile on a carb bike particularly. I get mine from here

http://www.spark-plugs.co.uk/
they will last a long time, so the extra cost is balanced out.

Non standard exhausts and air filters etc can/will affect how the engine picks up unless the fuelling is sorted out to compensate.

Check the choke plungers are returning properly and the cables are free. The cables tend to corrode near where they meet the carbs and the plungers attach. Back one you can get to easily, front one really needs carbs lifting off.

04-09-05, 06:17 PM

yeah, it seems to have started just recently. perhaps more so when engine is hot after a long run then idled at traffic lights...

cheers for that post, i'll have to have a go. i havent got any experience of looking into carbs though... theres no damage i can do here is there???

i think ill get myself some of those iridium plugs anyway.

03-09-05, 01:59 PM	#1
branny Guest Posts: n/a	bike choking when revved hard and fast in neutral.... ok, this is hard to explain. when im at the lights at idle, if i give a handful of throttle to rev her up with no load, sometimes it 'chokes' a bit initially then revs up. i dont know if you can understand that, i dont know if its normal for a carborated engine. im on a 99 650. was thinkin it may be the carb balancing? but the idle is absolutely fine. any ideas appreciated!!!

03-09-05, 03:06 PM	#2
Spanner Man Member Mega Poster Join Date: May 2005 Location: Sunbury Middlesex Posts: 1,396	Afternoon. It's known as bogging down. This is more pronounced on engines with fewer cylinders, due to the size and consequent extra weight of larger pistons. They take a micro second or two longer to get moving than smaller pistons do. Obviously valve clearances, carb balance, condition of airfilter & spark plugs etc will make this worse, as will running lean at idle. As a precautionary measure I would check all of the above just to be on the safe side. Cheers __________________ Spanner Man http://stewarts-motorcycles.co.uk/default.html

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03-09-05, 04:39 PM	#3
branny Guest Posts: n/a	i think i need new plugs. i also think i am running lean, i dont get good fuel consumption (presumed this was due to the 'open throttle' riding style ) also i sometimes smell fuel when i stop at the lights. how can i check my mixture?

03-09-05, 06:00 PM	#5
zx6man Guest Posts: n/a	Bikes arent meant to be revved with no load anyways..specially with petrol so costly why bother?

03-09-05, 09:41 PM	#6
svrash Guest Posts: n/a	try doing a snorkelectowhatsit, it solved my bogging

04-09-05, 01:09 AM	#7
Barty_b0y Guest Posts: n/a	if you can smell fuel at the lights i would say that it sounds like someone has tried jetting it at some stage and totally gone overboard or your airfilter is disgustingly dirty do what spanner man suggests its all good advice

04-09-05, 04:52 PM	#9
embee Member Mega Poster Join Date: Jul 2003 Location: Warwickshire Posts: 2,801	Sounds rather like your carbs could do with a clean out. Has it recently started behaving like this or always been like it? First thing , simply drain the carbs. Lift tank, airbox off, down between the carbs each floatbowl has an allen hex socket screw in the side, and just slacken these off a turn or so and the fuel drains out of the bottom. Check the carb slides lift and drop freely and don't stick (the diaphragms offer a little resistance, but they should be smooth and not notchy). Check the carbs are seated properly into the rubbers on the cylinder heads and the clips are reasonably tight (not leaking air). Fit iridium plugs. They are worthwhile on a carb bike particularly. I get mine from here http://www.spark-plugs.co.uk/ they will last a long time, so the extra cost is balanced out. Non standard exhausts and air filters etc can/will affect how the engine picks up unless the fuelling is sorted out to compensate. Check the choke plungers are returning properly and the cables are free. The cables tend to corrode near where they meet the carbs and the plungers attach. Back one you can get to easily, front one really needs carbs lifting off.

04-09-05, 06:17 PM	#10
branny Guest Posts: n/a	yeah, it seems to have started just recently. perhaps more so when engine is hot after a long run then idled at traffic lights... cheers for that post, i'll have to have a go. i havent got any experience of looking into carbs though... theres no damage i can do here is there??? i think ill get myself some of those iridium plugs anyway.