Fuck Fuck Fuckety Fuck

[jim.cox]

First kicking of the New Year and with fresh fuel the old Ducati started easily enough, idled even.

So I tried taking it out for run.

Bad bad bad bad BAD Idea.

Under load there is a huge hesitation and misfire until you hit about 4k rpm. Horrible pulling up out of the end of the driveway.

Tried fanging up Hackthorne hoping it might clear - sadly not

But worse - on the way home I stalled half way in. No way to restart, just a hillside of nasty slippery rounded river gravel that rolls under your feet and tyres.

We ended up hauling out my rope gear and practicing crevasse rescue, dragged it to the garage on a Z-pulley.

Bonus: my son also managed to start the bike himself for the first time.

It is absolutely, definately time to take a closer look at that front carb me thinks

[Grumph]

The one way valves on the accelerator pumps fail after standing for some time. Always worth installing new. If you can find them.

[Laava]

Not that bad dude, you didn't drop it!

[jim.cox]

The one way valves on the accelerator pumps fail after standing for some time. Always worth installing new. If you can find them.

Thanks for that - will add them to the list of suspects

[F5 Dave]

Obvious answe, ride all year.

But otherwise, end of year run out of gas. Or invoke carb clean every winter.

[toycollector10]

I had a similar problem today...

[jim.cox]

The one way valves on the accelerator pumps fail after standing for some time. Always worth installing new. If you can find them.


You would be meaning part #64 in the attached diagram - yes?

352270

[Grumph]

I think so. They have a tiny plastic ball in them which develops flat spots over time. Once it's not round it won't seal so won't hold a prime. Once it can't prime the accelerator pump won't work. Then you get the off-idle flat spots.

[jim.cox]

Then you get the off-idle flat spots.

Thanks

I've got a huge misfire under load up to about 4000 or 4500 rpm.

Feels like the front carb is not delivering sufficient fuel as it goes from the idle circuit to the needle & slide delivery.

Gowanloch have a pretty good range of Dellorto service parts...

[BMWST?]

Not as bad as having the hall sensor fail abot a km from home. I tell ya pushing a R100gs uphill for about 4 or 500 m is a very bad idea

[F5 Dave]

You would have preferred to be 1/2 way around the Coromandel when it happened?

[jim.cox]

The one way valves on the accelerator pumps fail after standing for some time. Always worth installing new. If you can find them.

I think you are onto it, Grumph

Finally got around to rebuilding the carb this evening.

Found that one-way valve to be a zero-way. It is completely blocked.

Which would explain the symptoms I've been having.

With luck, this weekend, I should get that carb back on the bike and be able to test it.

Thanks for your help.