860GT runs rich --- try smaller pilot????

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Tinkerbell
Mariana
Posts: 39
Joined: Sat Sep 05, 2020 3:57 am

860GT runs rich --- try smaller pilot????

Post by Tinkerbell »

Hi All,
I have bought some #55 and #52 pilot jets to try to cure rich idle. My 860 has the standard #60 jets installed at the moment ... Steve at BH says "just turn the idle screw in ..." So I am wondering why Dellorto has so many pilot jet choices if its just a matter of adjusting the screw?
Any Thoughts concerning the selection of pilot jets ?
Sincerely,
Kara
ducadini
860 GT / GTS
Posts: 278
Joined: Sat Jul 31, 2004 9:54 am
Location: Antwerpen

Re: 860GT runs rich --- try smaller pilot????

Post by ducadini »

Dell'Orto doens't just make carbs for Ducati :shock: ?
They've been busy for some time now and tried (not always succeeded) to keep things uniform, like pilot jets, usable in a wide variety of carbs.
And needles, also of different tapers, lengths and thickness.
Maybe the needle in Your carbs is just a notch too high ? Or (just the same) the clips is just a notch too low.
And then there is the mixture screw, also available in different types.
Maybe the airfilter is a bit too soaked in oil, or if dry it could be too clogged.
I Seem to remember Steve has a nice manual on his site about this.

ciao
ducadini
Nego i ricordi peggiori
Richiamo i migliori pensieri
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BevHevSteve
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Re: 860GT runs rich --- try smaller pilot????

Post by BevHevSteve »

Kara - I said to drop the needle 1 step (raise the clip).
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Tinkerbell
Mariana
Posts: 39
Joined: Sat Sep 05, 2020 3:57 am

Re: 860GT runs rich --- try smaller pilot????

Post by Tinkerbell »

Hi Steve,
I have not forgotten about dropping the needle, however people do talk about alternative pilot jets and I am trying to understand the principle , if one exists, upon how such changes were determined in an effort to comprehend my options. As I understand it , the 900 Darmah was standard with a #55 jet.
Sincerely,
Kara
ducadini
860 GT / GTS
Posts: 278
Joined: Sat Jul 31, 2004 9:54 am
Location: Antwerpen

Re: 860GT runs rich --- try smaller pilot????

Post by ducadini »

It could well be that the Darmah 900 has a #55 pilot, but I thought we were talking about a 860 GT ? :shock:
Well, nobody forces You not to try something that is easy do fix and could give results.

ciao
ducadini

sps : please keep us posted of the things You did and the results, even if they worked
Nego i ricordi peggiori
Richiamo i migliori pensieri
Tinkerbell
Mariana
Posts: 39
Joined: Sat Sep 05, 2020 3:57 am

Re: 860GT runs rich --- try smaller pilot ( #55 now)

Post by Tinkerbell »

Hi Ducadini,
I just put the #55 s in the PHF32 carbs which are fully rebuilt. My air filters are clean and valves adjusted etc. Sachse unit seems to be working well. In any case I started up with 1 turn open on idle screws and it idles nice. Was slightly spitty until it warmed up and then smoothed out well. No real farts going downhill with closed throttle--just a little burbling. I could increase rpm at idle by going in to 3/4 turn open on idle screws. Motor slows down at 1-1/2 turns open. Both carbs are about the same . Overall the bike seems pretty happy with the #55 jets. It certainly did not destroy the performance of the engine. I don't know how much real tuning I can do this season--out damp chilly weather is just about to close in .

I am having problems getting neutral when fully stopped. Clutch is smooth and seems to disengage well . Pulls easily. As soon as I shut motor off, I can snick neutral easily. So it seems to be a drag issue. Maybe I need to disassemble and clean clutch pack? As a starting point...
Sincerely,
Kara
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81mhr900ss
750 GT
Posts: 150
Joined: Tue May 31, 2016 3:49 pm

Re: 860GT runs rich --- try smaller pilot????

Post by 81mhr900ss »

Hi Kara: fiddly neutral is a very common problem; my old 860GT was more hit and miss than my MHR but I still try getting it in neutral before I actually stop.

A clutch pack inspection is really easy. What you may find is serrated slots on the housing where the steel clutch plate tangs have bitten into the sides of the housing slots. This hinders smooth operation of the clutch a little. If you have not already done so, I'd remove the whole pushrod assembly, clean out the main shaft hole it runs through, clean all the pushrod parts and reinstall with a light grease.

I set my clutch up with about 2mm of cable free-play when the engine is hot.

Good luck.
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