Gone to the Dark Side - Ducati 860 GT

[Tusayan]

The ‘performance option’ with regard to non-Desmo bevel engines is not related to the springs, but the valve gear and adjustment: Sport and early 750 GT had shim valve adjustment, with adjustment of the later 750 GT and all 860s by lock nut and screw.

[canuck750]

The ‘performance option’ with regard to non-Desmo bevel engines is not related to the springs, but the valve gear and adjustment: Sport and early 750 GT had shim valve adjustment, with adjustment of the later 750 GT and all 860s by lock nut and screw.

I like things simple, lock nut and screw valve adjustment is fine with me!

Machine shop just called me, the valve seats are worn out and new seats need to be pressed in, machinist says someone has been in the heads before and the valve face cut was poorly done.... cha-ching   

[wicks]

Awesome bike!  I've always been a Ducati guy but became also a Guzzi guy about 7 years ago. Miss my 900ss should have never sold. Currently looking for a 750 Laguna F1 if anyone has a lead.

[jas67]

I like things simple, lock nut and screw valve adjustment is fine with me!

Machine shop just called me, the valve seats are worn out and new seats need to be pressed in, machinist says someone has been in the heads before and the valve face cut was poorly done.... cha-ching   

On the bright side, you'll know it's down right when it's down.

[SmithSwede]

I’m really enjoying your work on this project.  Please keep the photos and commentary coming.

[canuck750]

I bought a couple sets of five LED dash indicators for real cheap on Ebay, Chinese of course. The little coloured plastic lens inside each idiot light had clouded over or are missing. I replaced the 12v bulbs on my Benelli 650 Tornado rebuild with these and thought I would do the same for the Ducati. Some of the light sockets were damaged so just as well to swap out to LED.

These are real small, smaller than the 12v bulbs


The little LED bulb is just push fit into the metal bezel, I just pulled the bulb by the wires out the back


The bulb pushes into the back of the original screw in cap but the bulb will push right out the opening in the cap

So I just took my hole punch and punched out a thick clear plastic disc from some of that annoying packaging that is on most everything today

I pushed the clear disc in 1st though the back then the bulb

The wires on the LED are miniscule

I ended up pulling the original wires off the metal lugs on the back of the LED and then soldered some fine wires to the LED

Push the LED with new wires into the cap, feed the wires through the front and out the back, then I fed some black silicone into the back of each socket to keep the LED in place

From the front it looks stock but hopefully the idiot lights will now be visible in daylight

[canuck750]

Here is your chance to rebuild your own ugly duckling, on Ebay.

looks to be complete, better than what I started with, has the correct instruments, signal lights, exhaust and handlebar controls



https://www.ebay.com/itm/1975-Ducati-GT/193229666644?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

[jas67]

https://www.ebay.com/itm/1975-Ducati-GT/193229666644?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

The Hagerty valuation page he references is WAY off.   I double checked to make sure he didn't get the value on a 900SS instead.
Looks like Hagerty has bad data for this model and year.   I'd say the numbers they have for a 1976 860GTS are closer to real.

Hopefully he doesn't really think that it is worth what he is implying it is worth.

[canuck750]

The Hagerty valuation page he references is WAY off.   I double checked to make sure he didn't get the value on a 900SS instead.
Looks like Hagerty has bad data for this model and year.   I'd say the numbers they have for a 1976 860GTS are closer to real.

Hopefully he doesn't really think that it is worth what he is implying it is worth.

I think it’s a $4K bike but the seller probably thinks he has gem that’s worth 4 or 5 times that!

[jas67]

I think it’s a $4K bike but the seller probably thinks he has gem that’s worth 4 or 5 times that!

Currently at $3,950 with 5 days to go.

[canuck750]

Waiting for me at the office this morning my Smiths gauges restored by Vintage British Cables



Got them back in one week, amazing service and they look beautiful. Andy totally disassembles the gauges and replaces anything that needs attention, beautiful! $450.00 CDN for the pair

www.vintagebritishc ables.com

[jas67]

Wow, very nice Jim.
By the time you are done you will have the nicest 860GT in existence.

[canuck750]

Wow, very nice Jim.
By the time you are done you will have the nicest 860GT in existence.

Not sure about that but it will be a nice bevel, thanks for the support!

| finished off the rear sub harness, HVC Cycle sent me a selection of bullet crimp connectors and protective sleeves, signal lights and tail lights connected, grey wire with an eyelet is a separate ground I ran from the tail light / signals.



Last rear sub harness, the battery connections



In the front I made up bullet connectors to connect the dash idiot lights rather than trying to make the connections from the main harness to the light sockets, easier to assemble the gauges / plastic dash bezels and light leads then feed the dash sub harness into the headlight bucket. I soldered the resistor and diodes to the old fibre plate for the Engine Stop Relay, hopefully it works. Ducati Paddy in the UK has an old used one he is sending me to compare the components to what the electrical component shop sold me yesterday. I ran some dedicated ground wires from the signal light stems / headlight bucket bolts to a common ground tab, the factory relies on grounding signal lights through the frame / bolt connections but that seems suspect given the rear fender is isolated with rubber bushings and the headlight is isolated with rubber bushings around the fork tubes + all the new paint.

The horn relay and horn switch still needs to be hooked up - Bevel Heaven had a NOS horn relay so I will fit that.

That should only leave the headlight socket wires and the front signal lights / dash indicator light, I think I need to fit diodes between the Left and Right signal light leads that feed up to a common dash idiot light. I am figuring that if the diodes are not installed when the signal lights are on the power will run through the dash idiot light and power the opposite side signals???

Another head scratcher, getting the seat latch working, its a bit finicky getting the adjustable latch tightened in the right position to grasp the little lug on the frame, seems to be good now.

I need to find a little black plastic cap for the seat latch


I did find a source for a reproduction under seat decal in Australia, ordered a couple, I have the latter flat seat as well. Contact Phil Hitchcock - www.roadandrace.com .au - $20.00 AU each, postage included

Getting this spring in the right spot and tight takes a few attempts



A couple more little jobs done, going to get the dash finished next.

[canuck750]

I got the dash together today, a lot going on in a small space

rubber rings surround the instruments that then drop in from the outside of the top bezel section



Steel rings bolt to the underside of the instrument, then a large O ring fits around the tangs of the bracket

A second steel bracket with tabs that fasten to the underside of the upper tipple clamp shares the O ring joining the two steel rings together and allowing the instrument to flex

The bottom half of the bezel now folds over the upper half



Instrument running lights plug into the back of the gauges



The two plastic bezel sections sandwich the steel bracket but I don't like the idea of applying pressure to the plastic so I fitted these bushings I had from an old dirt bike side cover

On the upper half I reamed out the holes and then made up some nylon bushes to take the pressure of the through bolt mounts

All the electrical passes through the opening in the base

A couple self tapping black automotive trim screws fasten the two halves along the front lip

And its done



The tach and speedo cables I bought don't fit the mounts on the Smiths gauges, probably for Veglia instruments


Andy at British Cables is making up new ones from scratch to match the original cable fittings and lengths

Also fitted the Left caliper, used a steel insert to fit 10mm inserts into the caliper body, this caliper was not threaded like the right hand original, either from a Guzzi or Laverda, they use the same caliper but rely on bolts and nuts to secure the caliper to the fork leg


1st time I used these, easy enough to do but I had to get the right metric tap and metric drill bit

Insert just threads in with the bolt then drive the vertical tangs down into the threads and then file the top of the insert flush wit the caliper body


Some spare Guzzi LeMans front brake steel lines fit the purpose on the Ducati

[Tusayan]

Awesome bike!  I've always been a Ducati guy but became also a Guzzi guy about 7 years ago. Miss my 900ss should have never sold. Currently looking for a 750 Laguna F1 if anyone has a lead.

In your area...

https://classicavenue.com/1989-ducati-750-f1-laguna-seca/

[RinkRat II]

  Hi Jim,  Great stuff there.  I'm curious about the dimension between bolt centers on the caliper you added. Looks to be real close to the Brembos on my K75.
 If you have a minute to spare shoot me a dimension, Thanks.

       Paul B

[canuck750]

  Hi Jim,  Great stuff there.  I'm curious about the dimension between bolt centers on the caliper you added. Looks to be real close to the Brembos on my K75.
 If you have a minute to spare shoot me a dimension, Thanks.

       Paul B

Centre line spacing of Brembo caliper mounting holes is 108mm

Cheers

Jim

[RinkRat II]

   

Centre line spacing of Brembo caliper mounting holes is 108mm

 
  Very interesting tidbit for the archives, same spacing as on the K75 and probably the 100's as well. Fluid line in is the same, but my bleeders are right next to the line.
     
       Paul B

[jas67]

Is that caliper an F08?

[canuck750]

Is that caliper an F08?

Yes standard Brembo F08, dual bleeder type, pretty common 70's Italian bike fitment.

[jas67]

Yes standard Brembo F08, dual bleeder type, pretty common 70's Italian bike fitment.

Hmm, I actually have one left over from my Eldo.  When I put the second one on it, I bought a matched pair, but, this one is fine.
Only problem would be that my 750GT (should be the same calipers) has a single bleeder on on it, and this is a dual bleeder.   I like symmetry.
 

[canuck750]

Hmm, I actually have one left over from my Eldo.  When I put the second one on it, I bought a matched pair, but, this one is fine.
Only problem would be that my 750GT (should be the same calipers) has a single bleeder on on it, and this is a dual bleeder.   I like symmetry.

I agree, matching calipers are nice to have

The dual bleeders are getting harder to find, I bought one a couple weeks ago but it had the through bolts seized to the aluminum castings, I will need to drill out. If I see some original F08 dual bleeders on Ebay for a decent price I buy them.

[Antietam Classic Cycle]

I agree, matching calipers are nice to have

The dual bleeders are getting harder to find, I bought one a couple weeks ago but it had the through bolts seized to the aluminum castings, I will need to drill out. If I see some original F08 dual bleeders on Ebay for a decent price I buy them.

I may have a few, will send them to you once I remember to dig them out.

[canuck750]

I may have a few, will send them to you once I remember to dig them out.

Wow that would be great

[Kiwi_Roy]

I bought a couple sets of five LED dash indicators for real cheap on Ebay, Chinese of course. The little coloured plastic lens inside each idiot light had clouded over or are missing. I replaced the 12v bulbs on my Benelli 650 Tornado rebuild with these and thought I would do the same for the Ducati. Some of the light sockets were damaged so just as well to swap out to LED.
 

You really don't need sockets for your LEDs in fact they are more reliable without them, I just solder the wires direct to the LED base.

I buy these 194s by the hundred for a project and also use them inside the existing bezels of a bike, use the same colour as the lens
The nice thing about these is they are not polarity dependent as they each have a bridge rectifier inside, this is nice for a flasher circuit where you have one lamp for both directions.
Don't use a lamp between left and right if you are using LED bulbs in the turn signals, you need a pair or diodes with the lamp to chassis there otherwise you will get crosstalk.

I did buy sockets for these but I found if there was any strain on the wires they would lose contact so because the LED will pretty much last forever I elected to skip that item.

If you want to dim these down for a lamp like High Beam add a resiator like 56k or even 100k.

I have done several of the bezels like they use on the spine frame bikes where I simply glue the lamps into the existing fitting, they have a nice shoulder that makes this easy.

https://www.superbrightleds.com/moreinfo/wedge-bulbs/194-led-bulb-1-led-miniature-wedge-retrofit-car/197/   I have only ever bought the 90 degree ones

They even look ok if you just drill a hole in a plate and poke them through gluing them from behind, with 1/8" plate they end up flush.

[canuck750]

You really don't need sockets for your LEDs in fact they are more reliable without them, I just solder the wires direct to the LED base.

I buy these 194s by the hundred for a project and also use them inside the existing bezels of a bike, use the same colour as the lens
The nice thing about these is they are not polarity dependent as they each have a bridge rectifier inside, this is nice for a flasher circuit where you have one lamp for both directions.
Don't use a lamp between left and right if you are using LED bulbs in the turn signals, you need a pair or diodes with the lamp to chassis there otherwise you will get crosstalk.

I did buy sockets for these but I found if there was any strain on the wires they would lose contact so because the LED will pretty much last forever I elected to skip that item.

If you want to dim these down for a lamp like High Beam add a resiator like 56k or even 100k.

I have done several of the bezels like they use on the spine frame bikes where I simply glue the lamps into the existing fitting, they have a nice shoulder that makes this easy.

https://www.superbrightleds.com/moreinfo/wedge-bulbs/194-led-bulb-1-led-miniature-wedge-retrofit-car/197/   I have only ever bought the 90 degree ones

They even look ok if you just drill a hole in a plate and poke them through gluing them from behind, with 1/8" plate they end up flush.

Those LED bulbs look perfect, I will consider them for next time. I did hook up a pair of diodes between the L and R signal light leads that run up to the dash bulb to eliminate the cross current.

[canuck750]

The machine shop I use called to tell me the heads are done, four guides and pair of intake and exhaust valves and where back to good. Springs measured within spec.

The machinist who I have known for ages told me they where the worst set of heads he has seen, the valve seats where very poorly cut as where the valves, new seats installed and cut with a machine that cuts the three face cut in one pass matched to the valves. It pays to have professionals that really know what they are doing handle this work.

This is getting to be a habit, the Moto Morini 500 I just finished suffered at the hands of a botched cylinder rebore that resulted in replacement iron liners. You can't skimp on machine work and few people really want to take the time to do it right.

[canuck750]

Painter finished adding the black to the side covers, had to put them on with the tank to see what it will look like



I started to pull the pieces together to assemble the heads / cams etc, and on the rear cam bevel gear I found a couple teeth are missing the corresponding tower gear is fine, the other set is all good as well.

Do I risk putting it back together with this chipped gear or look for a new gear???

[dguzzi]

By looking at the other teeth....that gear is worn out!

[canuck750]

By looking at the other teeth....that gear is worn out!

Yeah figured so, the new ones come as a set and are damn expensive at $479.00

https://store.bevelheaven.com/Engine-Related/Bevel-Gear-Set-Upper-860-900/