Occasional loss of power

grichards · Post by **grichards** » Mon Oct 03, 2011 12:56 pm

Hi all,

Went for a bit of a spirited ride earlier, and noticed early on that it was popping and banging slightly more than usual and had a slight occasional stutter. Usually for me this means that one of the vacuum take-off ports isn't sealed properly, but there's nothing obviously amiss there, no hoses have popped off or anything.

Once I got to slightly higher speeds, about 120-130... I mean 12-13 mph

... I found the bike would suddenly stop pulling and start to slow down, throttle didn't seem to do anything. When I pulled in it would run and rev fine though, and it seemed to accelerate fine up to the red line through the first couple of gears, just after that it would lose power. Maybe it was only running on one cylinder at this point, hence not having enough power to pull me along at 120 ish?

Any thoughts? Plugs have been changed recently (500 miles ago), and not had any other issues apart from it being a bit reluctant to start up from cold. Fuel shouldn't be the problem, as this was happening at the end of the tank, and also 15 miles or so into the new one.

Cheers for any help!

stormingjoe · Post by **stormingjoe** » Mon Oct 03, 2011 3:43 pm

Have had the tank off?
Sounds like fuel delivery problem, check the fuel tap diaphragm and vacuum lines and check fuel line not kinked/pinched.

gilson · Post by **gilson** » Mon Oct 03, 2011 3:55 pm

Starting problems could mean a blocked pilot jet. I cleaned mine recently and it really improved the starting.

Whilst you are there clean the others too.

darkember · Post by **darkember** » Mon Oct 03, 2011 8:32 pm

Could be a coil breaking down as it heats up

grichards · Post by **grichards** » Mon Oct 03, 2011 10:49 pm

Thanks for the suggestions so far. I'll get the carbs off tomorrow and give them a good clean, they're probably overdue some attention anyway. I can check the fuel lines at the same time, but I've not had the tank off recently. Hopefully that'll solve it, don't want to have to pay for new coils!

benny hedges · Post by **benny hedges** » Mon Oct 03, 2011 10:51 pm

check the air filter's not choked with dead flies as well

darkember · Post by **darkember** » Tue Oct 04, 2011 10:59 am

grichards wrote:Thanks for the suggestions so far. I'll get the carbs off tomorrow and give them a good clean, they're probably overdue some attention anyway. I can check the fuel lines at the same time, but I've not had the tank off recently. Hopefully that'll solve it, don't want to have to pay for new coils!

You can check the coils using a multimeter. Primary will be an Ohm reading & secondary a kohm reading. Haynes explain this clearly. By checking them both you will be able to see any disparity.

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