Slides and ramps.

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BevHevSteve
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Re: Slides and ramps.

Post by BevHevSteve » Fri May 24, 2013 6:45 am

You will ruin the slides if you try the lathe route. It just isn't possible that way. Be very careful not to remove too much material. You will also need to replace the slide screws and most likely cut down the springs on them as well.
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Ray O'Donohue
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Re: Slides and ramps.

Post by Ray O'Donohue » Fri May 24, 2013 7:08 am

When I had a set of Dellorto bodies bored (and THAT was tricky),I also had to have the tops of the slides turned to trim off just a bit of material.There was a Swiss machinist who handled all this for me-VERY carefully no doubt. I didn't see any of the work done.

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Re: Slides and ramps.

Post by bobnorton » Fri May 24, 2013 7:47 am

Hi Steve and Ray, A mate has just machined the stops ramps leaving them slightly thicker than std which allows a bit more metal for wear, the slides fit perfectly all for the cost of a packet of fags!!,i will check out the springs situation. I will let you know how they perform although i have never ridden a twin , The Guy has been an engineer all his life and is making engine parts for a vintage Henderson as i type.

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Re: Slides and ramps.

Post by bobnorton » Thu May 30, 2013 5:24 am

No reliable idle so the carbs will be cleaned in an ultrasound bath tomorrow, sorting out the tiny "O" rings is fun as there does not appear to be any info on these.

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Re: Slides and ramps.

Post by machten » Thu May 30, 2013 7:09 am

Are your carbs PHF32 A or PHF32 C series? It will be marked on the carb.

Kev

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Re: Slides and ramps.

Post by bobnorton » Thu May 30, 2013 10:42 am

Hi KEv , they are 32A s and 32A D,

machten
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Re: Slides and ramps.

Post by machten » Thu May 30, 2013 11:00 pm

OK. If they were C series, i was going to suggest you check that you have the correct (different) idle mixture screws in them, but as they are A series, the question is moot.

regards,

Kev

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Re: Slides and ramps.

Post by bobnorton » Wed Jun 05, 2013 4:19 am

Could not get the new 60/1 slides to lift on the idle screws, was thinking Steve 's prediction was right, then noticed that the DPO had fitted stainless idle screws, wrongly made with sharp long points and not enough shank before the threads, a bit of hand file work and thats sorted.Screws are a bit naff though, what screws would you recommend for this combination of bits Steve?.

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Slides ... continued

Post by herbg » Sun May 25, 2014 11:45 am

Not quite the same question but related ...

While trying to get the 900SS to idle, I decided to embark upon the carb sync procedure.

When backing out the throttle cables to establish the right amount of free play, I noticed that the rear carb slide was sticking.
It's very subtle but - with no tension from the cable and thottle on the slide - and the idle/slide screw completely backed out, the slide "sticks" a bit when trying
to lift from the bottom most position.

When I try to lift with my finger - ever so slightly - it is definitely binding. Conversely, the front carb lifts effortlessless with just the slightest, tiniest bit of finger pressure.

Only if I add the slightest bit of tension on the slide, by tightening the cable screws at the top of the carb, will the slide lift smoothly without sticking. But by doing that, I don't leave enough slack in the cables.

In my opinion, the carb slides should lift easily and effortlessly without cable tension but I'm open to advice here.

So, before I start ripping the carb apart to see what's going on, I'm wondering if I anyone has any experience with this. I'm hoping that I don't have a "defective slide".

A bit of background ...

This bike has not run since 1988 as it's been a very long restoration project. I am now at the stage where I can get the bike fired up and tuned to idle but it has not cooperated.
The carbs were re-freshed with new gaskets, seals, etc. But the slides and other main components are originals (PHM 40's).

Thanks,
Herb...
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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Re: Slides and ramps.

Post by BevHevSteve » Mon May 26, 2014 11:43 pm

To modify the back of the ramps on new style slides to fit the older style carb bodies you can not use a lathe as gripping the slides is impossible without distorting them as well as the cutting tool will chatter like hell as it bumps each ramp sending said slide across the shop and ruining it. As me how I know..

I use a cylinder shaped carbide deburring bit in my drill press and put the slide on the table working it carefully cback and forth to keep things square etc.

It's a long tedious process and entirely possible with patience.
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Re: Slides and ramps.

Post by bobnorton » Wed May 28, 2014 11:13 am

Hi Steve. My guy did the job in no time and did not distort the slides, However we are talking a pro machinist of 50 years (or more) practice,who also makes his own engine parts for 4 cylinder veterans when he's got a break from production runs .If only i had his talents!!.

herbg
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Re: Slides and ramps.

Post by herbg » Sat May 31, 2014 5:58 pm

Any thoughts on my sticky slide issue?
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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BevHevSteve
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Re: Slides and ramps.

Post by BevHevSteve » Sun Jun 01, 2014 5:59 pm

Hi Herb, I will assume that you have completely cleaned the varnish & crud from your slides as well as the bore they slide in.

Things to check:
is the slide round or did it get dropped and is now oval?
Is the pump diaphragm miss adjusted (sticking out into the bore)
Is the throttle cable frayed or bent causing the hangup?
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Vince
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Re: Slides and ramps.

Post by Vince » Sun Jun 01, 2014 11:57 pm

Its surprising how much friction goes with a bit of lube on the accelerator pump ramp.You could try painting bits with Engineering blue and seeing what rubs but lots do rub and there supposed to rub,rub yes,bind not so much.Good luck.BTW I used to get a horrible jerky throttle response on my 92 Husky 350 with Del carb,BUT only when riding when it was wet weather.Little twist,nothing a tiny bit more and it would surge forward as the slide was released.Never fixed it,bike long gone.

machten
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Re: Slides and ramps.

Post by machten » Mon Jun 02, 2014 1:10 am

Have you tried swapping the slides and see if the problem moves to the other carb?

Kev

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