Slides and ramps.

Post your 'Carburettor & Fuel System' FAQs, comments & questions regarding Ducati motorcycles here.
bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Slides and ramps.

Post by bobnorton » Thu May 16, 2013 9:30 pm

My 76 GTs has 70 slides.I'm thinking of fitting 60's, what suffix number should i be looking for? and is there much difference between a /1 and /2.

machten
MHR / S2
Posts: 480
Joined: Sun Oct 29, 2006 8:37 am
Location: Perth, Western Australia

Re: Slides and ramps.

Post by machten » Fri May 17, 2013 5:45 am

Yes. A lot of difference in effect of both slide cutout height ("a" of "a"/"b") and ramp length ("b"). Some description here...

Image

Don't be fooled into thinking that because the numbers are close, the effects are close.

Kev

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Fri May 17, 2013 6:31 am

I strongly suggest you install 60-1 slides,and set your pumps to 5cc per 20 squirts.

bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Slides and ramps.

Post by bobnorton » Sat May 18, 2013 3:15 am

Thanks guys, Every part of this bike is a minefield!, lots to learn and lots to do.

machten
MHR / S2
Posts: 480
Joined: Sun Oct 29, 2006 8:37 am
Location: Perth, Western Australia

Re: Slides and ramps.

Post by machten » Sun May 19, 2013 1:50 am

lots to learn and lots to do
I've got some bad news, Bob. Even after 35 years of bevel ownership, nothing changes ;) . Hang in there though, get it sorted and ride it through the twisties, and it does repay you!!!

Kev

bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Slides and ramps.

Post by bobnorton » Thu May 23, 2013 6:20 am

I bought the pair of 60/1 slides that were on E-Bay, and am fitting them, no idea if they will improve anything as i have not ridden the bike at all. Whats the best method of checking the pump output?.Have to say i like Ray's" empherical" attitude!, I'm a bit like that myself and get a bit grumpy if i have to explain my decisions!(cave man attitude) :10-HUT:

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 6:34 am

Squirt the fuel into a container 20 times,allowing plenty of time for float bowl refill. 5cc total for twenty full squirts is what you want.

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 6:48 am

The result will be the delivery of the needed (but very minute) amount of extra fuel at the earliest throttle opening,and you will notice the improvement. Also:you may find your needle setting is now a bit rich,due to component overlap from the richer #60 slide but I am not sure about that. See how it goes!

bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Slides and ramps.

Post by bobnorton » Thu May 23, 2013 7:32 am

HI RAy, the 60 slides are for a later carb and need a little machining of the screw ramps to clear the base to drop right down. The diaphrams look sound if a little baggy, can the pump be tested with the carb off the bike?

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 7:39 am

Have you got a left/right slide mixup,or something like that?The carbs of course must be off the bike to set that pump volume! How else would you catch the gas to measure? I just held them up against a small glass jar,and measured the collected gas with a syringe. Seems to me mine were just about correct already,but that was 35 years ago.

bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Slides and ramps.

Post by bobnorton » Thu May 23, 2013 8:22 am

Slides are not handed but are for later carbs and need a little mod to fit, Think i must be stupid, can't see where the pump sprays but managing to get well wet!!, sprays from the brass tube near the bell mouth?, Carb needs working over full range of throttle? Pump piston is set back from slide barrel by a mm or so ,probably needs adjusting, previous owner was a total berk so every thing needs checking.

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 9:02 am

I would give it one full twist,but it's actually all over after the first little bit of twist. The little plunger/arm,etc.,of course need not to be gummed up,etc. I would wait just a moment between twists.

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 9:03 am

Whoops.Make that "the little plunger/arm,etc.,needs to be clean,not gummed up,etc."

Ray O'Donohue
Parallel Twin
Posts: 119
Joined: Tue Oct 13, 2009 8:11 am

Re: Slides and ramps.

Post by Ray O'Donohue » Thu May 23, 2013 9:08 am

Here's a good diagram if you enlarge it: http://www.ducatimeccanica.com/dellorto ... o_3_7.html

bobnorton
860 GT / GTS
Posts: 281
Joined: Wed Jan 16, 2008 2:18 am
Location: bromley kent

Re: Slides and ramps.

Post by bobnorton » Thu May 23, 2013 9:50 am

Thanks Ray, I get the picture!, Having fun replacing the "o" rings and seals, lots of small stuff all very similar but no sizes to work out which is right, not impossible if the old ones are in fair nick,but mine have dissintegrated. I did get the thing running after a fashion ,lots of pops and bangs but happily no Knocks!!.(yet).I can colourtune the idle mixture ok but will borrow mercury guages for the cable sync.Need to get a mate to modify the slides on his lathe.

Post Reply

Return to “Carburettor & Fuel System Shop”