750GT Rolling Basket Challange

Post pictures of your twin cylinder Bevel Drive Ducati (pre-1985) along with a description here.
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BevHevSteve
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Re: 750GT Rolling Basket Challange

Post by BevHevSteve » Thu Oct 10, 2013 9:26 am

never any problems believe me I have done every color under the rainbow...

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Thu Oct 10, 2013 7:55 pm

BevHevSteve wrote:never any problems believe me I have done every color under the rainbow...

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Excellent, then JB Weld it is. I have the family size in the bench drawer.

GD

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Fri Oct 18, 2013 1:26 pm

Repairing the rusted seat pan. It was first garnet blasted to get all the old paint & rust off. Then used JB Weld to bond some thin doublers to the sides where the metal was a little thin to support the upholstery when it's wrapped over it and glued. Also epoxied fender washers to the breather holes where they had been rusted through. The whole thing will be powder coated and then foam and seat cover.

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Last edited by geodoc on Sat Dec 29, 2018 11:34 pm, edited 1 time in total.

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Fri Nov 08, 2013 1:29 pm

The load of plating came back from the electroless nickel shop. I'm big fan of electroless nickel rather than cad or zinc - very tough and only about .0005" thick. No need to run a tap or die down threads. Nice look too, the slightest gold cast to it.

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I got a set of Race Tech Gold Valve Emulators for the fork dampers along with generic adapters & .9 kg. /mm straight wound springs. The adapters won't work in this installation, so it's going to be a home-rolled adapter. The end caps will have to to be machined off and then the adapter installed as a tight fit on the damper rod "stub" where the cap was previously located. Pondering whether to make the adapter out of Delrin or aluminum.

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Last edited by geodoc on Sat Dec 29, 2018 11:53 pm, edited 1 time in total.

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Wed Nov 13, 2013 5:49 pm

Prepping the damper rods for the Race Tech Emulators. The page on Race Tech's site that shows how an Emulator instllation works on Ducati 38mm Marzocchis shows heating the end caps to remove. Didn't work for me - they were really tight. Chucked them up in the lathe and turned the caps down to just an RCH bigger than the stubs they fit over and then with a twist, they were off.

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Enlarged the existing holes to 1/4" and added 4 additional holes above them (towards the damper rod upper end) with the orientation shown. De-burring the insides took some fiddling.

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Terry, the tech I've been talking to about the adapters shown on their page above, rooted around in their archive and found the information notes. He said that since I had already bought a pair of adapters that were supposed to, but didn't work, he would machine up a set and send to me no charge. Kudos to Race Tech! Really nice to deal with people that go an extra mile to help. When I get the adapters, I'll measure and put a drawing up for others to make.

Race Tech's Marzocchi Emulator installation:

http://racetech.com/page/title/DRod%202 ... %2074GT750

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Last edited by geodoc on Sat Dec 29, 2018 11:55 pm, edited 1 time in total.

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Fri Nov 22, 2013 3:39 pm

Just got the emulator adapters and damper rod replacement seals from Race Tech.

I expected the adapters to be a slight interference fit on the damper rod, but they are actually a slightly loose fit. Probably not a big deal. They are slightly different than the ones shown on the Race Tech adapter page (above) and more closely, though dimensionally not exactly the same as the "mounting spigots" shown on the Laverdamania Forum page here:

http://www.laverdamania.net/emulatorgb.htm

The adapter part number, if you want to get a pair from Race Tech is:

FPEV AD3807 P

$50.00 / pr.

If somebody wants to make their own, I'd be happy to provide the dimensions.

They also included a pair of blue-colored seals (seen in the upper picture below) to replace the nylon ones with expander rings that were on the original damper rods. As you might be able to see in the picture, they are a little loose in the seal ring "land", but I figure they are close enough to do what they need to do and certainly better than the worn out originals.

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Last edited by geodoc on Sat Dec 29, 2018 11:57 pm, edited 3 times in total.

Vince
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Re: 750GT Rolling Basket Challange

Post by Vince » Fri Nov 22, 2013 4:18 pm

I ran into Mr Race Tech at Wakefield Park in OZ a couple of years back.Paul does suspension seminars here.Anyway he was talking about a mod they do to Emulators,but after ringing them a couple of times from OZ at his request and not getting anywhere I went to Terry Hays,the Race Tech agent in Sydney and had it done.The mod involves a Teflon sealing ring attached to the outer of the Emulator that forces all the oil through it and not past it.It took a few attempts to get a good seal and no drag.Try asking at Race Tech HQ if its available now.BTW some of the fitting info posted here was done by a couple of the Sydney Laverda Club members,Chris P and Doug H quite a few years ago.Both hard to keep in sight as riders

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Mon Dec 02, 2013 3:17 pm

A bit diverted from the Ducati project. A customer that just acquired a "restored" Laverda 750SF is having a variety of issues that I'm sorting out for him. Electrical gremlins, fork stiction & correct wt., front disc fiddle, timing, valve clearance, starter died, carb sync., bent rear rim, eat-up sprocket carrier and so forth.

Just got a new rear rim from Wolfgang in Nakusp as well as sprocket carrier.

More parts due to be picked up in Point Roberts WA this week as well as get the frame back fro Paul Brodie after various welded bits. Should have all parts requiring powder coat ready to go next week, then get into some re-assembly!

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Got a little time squeezed in to lace up the rear rim that was polished & had tire lever dents fixed. Straightening the flat sports apparently requires that the rim be laced to the hub. So it's laced and will go down to Green's Wheel Shop tomorrow on the way to pick up the frame.

Busy, busy, busy.

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Last edited by geodoc on Sat Dec 29, 2018 11:59 pm, edited 2 times in total.

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Re: 750GT Rolling Basket Challange

Post by GeoffW » Tue Dec 03, 2013 2:16 pm

geodoc wrote:Just got the emulator adapters and damper rod replacement seals from Race Tech.

I expected the adapters to be a slight interference fit on the damper rod, but they are actually a slightly loose fit. Probably not a big deal. They are slightly different than the ones shown on the Race Tech adapter page (above) and more closely, though dimensionally not exactly the same as the "mounting spigots" shown on the Laverdamania Forum page here:

http://www.laverdamania.net/emulatorgb.htm
Hey Geo, I'm part way through fitting the gold valve mod to my Marzocchi 750GT forks - turning up adapters to fit tight on the top of the damping rods for the gold valves to sit on is no problem having seen yours and other example. However, the spacers mentioned in the laverda page above will need to be made next, for the fork springs to sit in. I found my fork spring internal diameter was 15.1mm whereas the emulator plate valve diameter is 15.7mm - so it won't work without making a spacer to create clearance for the plate valve to lift under fast compression and to allow the fluid to flow unimpeded. The tricky bit will be getting these spacers to sit centrally on top of the gold valve so that neither the spacer nor the fork springs scrape inside the fork tubes. I can't see how the spacers suggested in the laverda pages locate - at 31mm OD with no positive location on the gold valve, they look like they will just scrape inside the fork tubes, i.e. unnecessary friction and wear.

Thoughts, comments?

Geoff

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Tue Dec 03, 2013 6:15 pm

GeoffW wrote:
geodoc wrote:Just got the emulator adapters and damper rod replacement seals from Race Tech.

I expected the adapters to be a slight interference fit on the damper rod, but they are actually a slightly loose fit. Probably not a big deal. They are slightly different than the ones shown on the Race Tech adapter page (above) and more closely, though dimensionally not exactly the same as the "mounting spigots" shown on the Laverdamania Forum page here:

http://www.laverdamania.net/emulatorgb.htm
Hey Geo, I'm part way through fitting the gold valve mod to my Marzocchi 750GT forks - turning up adapters to fit tight on the top of the damping rods for the gold valves to sit on is no problem having seen yours and other example. However, the spacers mentioned in the laverda page above will need to be made next, for the fork springs to sit in. I found my fork spring internal diameter was 15.1mm whereas the emulator plate valve diameter is 15.7mm - so it won't work without making a spacer to create clearance for the plate valve to lift under fast compression and to allow the fluid to flow unimpeded. The tricky bit will be getting these spacers to sit centrally on top of the gold valve so that neither the spacer nor the fork springs scrape inside the fork tubes. I can't see how the spacers suggested in the laverda pages locate - at 31mm OD with no positive location on the gold valve, they look like they will just scrape inside the fork tubes, i.e. unnecessary friction and wear.

Thoughts, comments?

Geoff
Heh Geoff,

I don't have to make spacers like the Laverda article specs out since I'm using Race Tech springs (.9 kg. /mm) that are much wider than the stock units and fit on top of the Emulators w/o impeding the flow. Since using them doesn't necessitate a special spring adapter then there is no extra stiction from them too. They were about $90 for a pair.

GD

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Re: 750GT Rolling Basket Challange

Post by GeoffW » Tue Dec 03, 2013 6:42 pm

Thanks for the reply Geo - I'll just keep the springs I have, and machine a slight recess into the gold valves for a spacer to locate I think…I don't like the idea of more metal scraping inside the fork tubes than is necessary.

Geoff

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Thu Dec 05, 2013 2:39 pm

Having fun with the front rim. Wolfgang in Nakusp BC provided me with what he was fairly sure was 19" X 40 hole Borrani WM3 rim that fit a 750 GT. I laced it up finger tight and it looked OK so sent it to the polishing shop. Got it back and laced again, but when tightened it became apparent that half the holes were off far enough that the spoke nipple flanges didn't seat completely in the cup sections of the rim. Close, but not quite. Maybe it's for a hub with inner and outer spokes rather than straight pull? I donno.

Anyhow, Wolfgang also has a MORAD 19" X 40 that is specifically drilled for the 750 GT so the Borrani goes back to him and he's sending me that MORAD.

The rear rim that ended up having some flat spots that were apparent when laced and the truing process was started has gone to the wheel shop here that did the tire gouge repair and polish. Brad, the owner is confident he can massage out the flat spots with the wheel laced up (not able to do it with rim alone). Heatin the rim is apparently a necessary part of the process too. Hope this works or there may be a MORAD in its future too.

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Last edited by geodoc on Sun Dec 30, 2018 12:01 am, edited 1 time in total.

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geodoc
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Re: 750GT Rolling Basket Challange

Post by geodoc » Wed Dec 18, 2013 2:32 pm

Slowly the project crawls forward. Got the chrome back fro the plater. Seems like a nice job. Had to heli-coil the threads for the pinch bolt and machine the upper retaining collar to fit the post above lever. The New collar I got from Bevel Heaven had a 12mm hole & it needed a 15mm.

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Triple clamp / steering stem assembly is all together. The stem that I got to replace the bent one didn't have a slot for the steering lock, so machined one in there.

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I wanted to get shock bolts that would have a 30mm shank length so there would be no threads in bearing. Best I could come up with in stainless was 40mm shank so as soon as I pick up a new / sharp 10 X 1.5mm die, these bolts will get threaded down to suit and than length trimmed.

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Seat attachment tab was not there at all on the rear from hoop. One is now welded on. The dimpled upper seat pan is from a steel pan that apparently sat outside with its foam acting as a sponge and corroding the upper surface badly. The underside is fine and structurally, it's OK.

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Settled on aluminum seat trim fro Wolfgang in Nakusp. It's actually for some sort of Laverda Triple. The attach bolts will be from Z1 Enterprises for a Kawasaki H1. Their oblong heads should fit perfect.

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All manner of parts are waiting for the assembly process to begin in earnest - headlight reflector, tail light , battery strap, rear sprocket, petcock gaskets, tubes, rim strips, etc, etc. The last of the pieces to powder coat are waiting at the mail box place in the US and after those are prepped, the whole powder coat load can get sent out. Then the actual assembly can start.

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Last edited by geodoc on Sun Dec 30, 2018 5:16 am, edited 2 times in total.

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Re: 750GT Rolling Basket Challange

Post by geodoc » Thu Dec 26, 2013 11:44 am

Not much shakin' in the shop - holidays, waiting for parts, etc. Modified the new swing arm spindle from Syd's. It is much thinner wall (and I assume stronger material), but will not allow installation of the plastic caps. To fix that, I machined the O.D. down from the ends of the original spindle to make a light press fit into the I.D. of the Syd's spindle and then cut them off to a length of about 3/4". The ends have the correct groove necessary for the plastic caps to snap into place.

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Also needed to make a driver to install & remove the spindle since the clamp collars on the frame that hold the spindle are not 100% parallel and the spindle binds a bit.

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Last edited by geodoc on Sun Dec 30, 2018 5:18 am, edited 1 time in total.

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Re: 750GT Rolling Basket Challange

Post by geodoc » Sun Jan 12, 2014 4:05 pm

Guy Martin in Montreal has been busy with the engine overhaul and sent some photos of how it's going.

The crank was pressed apart when I got it, so it had to be re-assembled with a slightly undersized crank pin to allow alignment marks to be scribed in to allow accurate re-assembly when the actual pin & rods are installed and the unit pressed together. Included are improved thrust washers.

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Alternator cover is machined out slightly to accept the ST2 stator. ST2 rotor will be installed too.

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An oil drain with magnetic plug is installed for easier and cleaner oil changes.

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Another mod being incorporated is replacement of the rubber oil transfer collar that apparently tends to perish after time with an aluminum collar. the mod also requires that a squarecase screen tube replace the roundcase one:

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All the lower bevel gears are now shimmed to correct lash. Having no place to start (the whole thing was disassembled when I got it with shims were loose in various bags) so Guy had to start the process from scratch. He told me it too about six hours. The oil pump is a high capacity item bought from Back to Classics in Holland (310 Euros) and has a much better pressure relief valve set-up then the original.

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Both case halves had new, heavier main bearing support bushings installed along with new main bearings.

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With the Dyna-S ignition, no need for condensers, so a couple plugs fill the holes.

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I asked Guy about additional holes in the sump baffle, but he doesn't feel it's necessary. Likewise, I asked about an oiling mod I had seen to provide additional lubrication to layshaft 3rd gear. He tells me that he incorporates a mod to the gear that enhances lubrication and makes any additional feeds unnecessary.

Hopefully the crank goes together this week and the cases get mated, then on to the top end.

Just got the frame, swing arm, center stand, back from the powder coater today. Photos coming up.

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Jan. 16 -

Unscheduled defugalty. On inspection after getting the frame back from the powder coater, it looked as though a bunch of grit had blown onto it before it was baked. Sand / grit was baked into the finish in various places ...................... not good. The powder coat place at least admitted their screw-up and is in the process of a re-do. We'll see how that goes. Always something right?
Last edited by geodoc on Sun Dec 30, 2018 5:30 am, edited 1 time in total.

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