Isn't that just rich...

[swooshdave]

Took a longer ride today, bike seems to be running really rich. Pops several times when you close the throttle. I get some surging when I try to hold a steady speed.

PO had installed K&N pod filters, I assume that when that was done the jets were changed (bigger) to accomodate the assumed extra air flow. Why I suspect that is that there is a package in the spare parts marked "stock jets". Regular Sherlock you're dealing with here...

Of course I don't want to tear apart the carbs yet, so I come here and ask questions.

Is my assumption that most people rejet when using pod filters?
What is the recommended jetting for the carbs when using pod filters?
Are there any external adjustments on the carbs to lean them out a little? Or is the only way via a jet change?



I looks at the carbs and they appear to be the stock but now I can't remember if they are 32 or 38 (32 being stock).

[BevHevSteve]

Makes a difference if you want to know what jets came stock, so please go have a look at let us know what carbies are there and please be specific and write all the info that is on the side of the carb..

[swooshdave]

Makes a difference if you want to know what jets came stock, so please go have a look at let us know what carbies are there and please be specific and write all the info that is on the side of the carb..

Writing stuff down is too difficult for me.





I hate the cloth covered fuel line. The rubber inside deteriorates and you don't know until it leaks. I prefer Tygon as it's both fuel resistant, translucent and yellow.

What I need to do next is to confirm that the package of "stock jets" are actually the stock ones.

Can you confirm that rejetting is common with filter and muffler changes on Ducs?

What are the common air leak points on the intake side? How about the exhaust side?

[BevHevSteve]

your intake manifold insulators are crushed from being over tightened and tey are often a source of leakage which netts burnt valves (bad) so take off the intake manifolds and make sure the faces are FLAT then get some intake manifold insulators (measure the stud distance center to center (52mm or 58mm) then order 2 of the right size. Those PHF32AD (front) and AS (rear) carbies are stock.

Stock Jetting

needle = K6 middle position
Main = 122
Idle = 60
Slide = 70/2
Atomizer = AB265
Pump = 35
Starter = 75

Often mains and idles are change, needle clip changed. But not by much.

Remember also that today's gas calls for larger jets. FYI I went to 268 atomizers and up a couple main jet sizes after pulling a bevel of mine out of hybernation after 5 years.

You will need to rebuild the carbies, replace in man insulators and maybe ex rings as well. I do stock everything you will need, order online I ship it out asap. Make sure to sync the carbs correctly after rebuilding - long writeup on how to do it right here on this forum in the fuel section.

[wdietz186]

+1 What Steve said but as for the popping,The ign syst on the 860 is pretty crude being as it is a one step advance at about 1200 rpm. With the Conti pipes and the fact they run better a bit rich you will get some popping on decel. It all serves to make bystanders aware that you are astride a ripsnorting,uncivilized beast! Even Harley riders notice it sounds more menacing than their flatulent rumblers.
The ignition is a weak point on the early 860 so don't be suprised if it takes a dump on you. The most common symptoms are losing one cylinder when hot and it can be total or intermittant and can sometimes mimic carb problems. To minimize the load on the system it is advised to run the plug gap down to .020" which reduces the voltage requirement to jump the gap.

[swooshdave]

I'm going to take down one of the carbs today to see what kind of shape it's in.

The Ducati does not like to start cold or warm and sometimes when hot. Not sure if it's ignition or carb. I'll start with the carbs. $75 for a rebuild kit (ea) is a little bit of sticker shock when you're use to Amal kits.

[swooshdave]

your intake manifold insulators are crushed from being over tightened and tey are often a source of leakage which netts burnt valves (bad) so take off the intake manifolds and make sure the faces are FLAT then get some intake manifold insulators (measure the stud distance center to center (52mm or 58mm) then order 2 of the right size.

Dunno, I think this looks serviceable!

So I dug into my Amal spares and found some o-rings to put on each side of the insulator, assembled it back together as a temporary hack. Of course now the ignition is dead so off to the electrical forum.

[machten]

They're screwed. Replace them. You'll be glad you did!!!

Kev

[swooshdave]

They're screwed. Replace them. You'll be glad you did!!!

Kev

Yes, I know.

[BevHevSteve]

As important as replacing those rubbers, make sure you get the face of the intake manifolds that sit against the rubber flat as well as the ends are obviously bent from over tightening. If you don't do that you will never get a good seal.

[swooshdave]

As important as replacing those rubbers, make sure you get the face of the intake manifolds that sit against the rubber flat as well as the ends are obviously bent from over tightening. If you don't do that you will never get a good seal.

After dealing with Amals for many years I'm quite familiar with the not so flat face issue. Thanks.