Wildguzzi.com
General Category => Bike Builds, Rebuilds And Restorations Only => Topic started by: guzzista on October 14, 2022, 07:16:11 PM
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Just became the proud owner of a V7S frame,( dated Dec 1972 timing gears engine, Cr-Mo frame) crankcase and gearbox. Already have a well sorted out 850T based 750S tribute bike , so many (correct) items can find their way on the V7S chassis, and the 850T can return to its original form.
As for the V7S motor, I am pondering between a 78mm stroke with ex Rennsport 89mm bores cylinders with forged Arias pistons ( items already in my stash) , or perhaps do a HMB 88mm bore kit with the (70mm) V7S crank. Either way still lots of work to be done. Will post pics
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Very cool. It will be great to rehome those special parts….
My vote is to retain the short stroke V7S crank configuration. The way these special 750 Sport engines rev and turn on at higher rpm is part of the magic of the package.
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I’ve never done what you are embarking on so kudos to you. :bow: :thumb:
I would advocate avoiding chasing performance at the expense of everyday rideability and liveability.
You want to be out and about on it, before the electric bike, sword of Damocles breaks the thread and drops.
Nice and calm power that starts easily.
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First pics of assessment. Frame appears straight as the lower rails bolt up and holes center up front and rear. It did take a hit on the left downtube but the straight edge shows no bends and the same as the right side downtube . The front timing cover fits with only slight gapping (1.1mm) per side which could be due to the lower frame rails being tensioned before offering the timing cover or?...
Perhaps when a front end gets mocked up I may find more surprises.
The tubular end extension at the rear of the lower rails do make it a V7S from what I gather
With a 70mm crank in place for mock-up the piston is about 4mm below deck, something that I was expecting.
A few pics below , feel free to comment
(https://i.ibb.co/1Lj5kZS/IMG-1286.jpg) (https://ibb.co/1Lj5kZS)
(https://i.ibb.co/FwCtQNz/IMG-1287.jpg) (https://ibb.co/FwCtQNz)
(https://i.ibb.co/rZbd0yV/IMG-1289.jpg) (https://ibb.co/rZbd0yV)
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Looks like wrong pistons. V7 sport pistons are 4mm higher.
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Curious as to what markings you find near the headstock of the frame. :popcorn:
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Looks like wrong pistons. V7 sport pistons are 4mm higher.
I mentioned that I was considering a short stroke (bigger bore) engine in my original post.The pistons in the pic are Arias/ Rennsport 89mm
forged pistons originally for 78mm cranks bolted to a 70mm ( (V7S crank) and that is why they are 4mm below deck. The next step is to either fit 144mm rods as in Griso/ Stelvio/Norge, or bite the bullet and do a HMB kit with specific pistons.
Curious as to what markings you find near the headstock of the frame. :popcorn:
The marking below the headstock is from an impact, but so far, the timing cover and lower rails bolt up OK, the headstock shows no buckling or visible bends and the straight edge is good on either downtube...When the triple trees and a wheel gets mocked up, I hope there will be no surprises . Pic pf the dent below
(https://i.ibb.co/NY5C0pj/IMG-1288.jpg) (https://ibb.co/NY5C0pj)
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I mentioned that I was considering a short stroke (bigger bore) engine in my original post.The pistons in the pic are Arias/ Rennsport 89mm
forged pistons originally for 78mm cranks bolted to a 70mm ( (V7S crank) and that is why they are 4mm below deck. The next step is to either fit 144mm rods as in Griso/ Stelvio/Norge, or bite the bullet and do a HMB kit with specific pistons. The marking below the headstock is from an impact, but so far, the timing cover and lower rails bolt up OK, the headstock shows no buckling or visible bends and the straight edge is good on either downtube...When the triple trees and a wheel gets mocked up, I hope there will be no surprises . Pic pf the dent below
(https://i.ibb.co/NY5C0pj/IMG-1288.jpg) (https://ibb.co/NY5C0pj)
Interested about the Griso, etc. rods. I'll file that away for future reference.
I don't see a steering stop - is that intact?
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Should have been more clear... What stamped markings are on the right side of the steering head, if any?
My U.S. model, December '72 build date has DGM .....and VK * * - no numbers in between the stars. Euro models will have the frame number between the **
CrMo frames are pretty rare...
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Should have been more clear... What stamped markings are on the right side of the steering head, if any?
My U.S. model, December '72 build date has DGM .....and VK * * - no numbers in between the stars. Euro models will have the frame number between the **
CrMo frames are pretty rare...
The headstock would be for a US model as there are no numbers between the "star" markings.
As far as the Chromoly being rare, Beretta ( the Boiler makers, not the gun ones) ran out of CrMo at some point so (thicker wall ) mild steel was used. As actual dates and numbers were not kept in terms of frame steel type, it is hard to say. This frame, however rings differently ( higher pitch) than the T3 one I had in bare form so the possibility is pretty good. Cannot do a weight comparison at this point, but I will soon .
Now for the seized/ snapped off shock bolts in the frame bosses , then it's time to get is blasted and decide whether to cerakote, paint or powder coat
(https://i.ibb.co/DkWRSjD/IMG-1293.jpg) (https://ibb.co/DkWRSjD)
t (https://freeonlinedice.com/)
(https://i.ibb.co/txdrmBL/IMG-1292.jpg) (https://ibb.co/txdrmBL)
I don't see a steering stop - is that intact?
I don't see a steering stop - is that intact?
No, the steering stop was broken, just finished welding on a new tab
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The headstock would be for a US model as there are no numbers between the "star" markings.
As far as the Chromoly being rare, Beretta ( the Boiler makers, not the gun ones) ran out of CrMo at some point so (thicker wall ) mild steel was used. As actual dates and numbers were not kept in terms of frame steel type, it is hard to say. This frame, however rings differently ( higher pitch) than the T3 one I had in bare form so the possibility is pretty good. Cannot do a weight comparison at this point, but I will soon .
Wow, congrats on the frame score! Agreed that there is no clear line between production dates for CrMo/ Mild steel. I would be verrrry careful to preserve those stamped marks on the headstock during the stripping and re-coating. :thumb:
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personally i would retain the short stroke engine, just keep/make it stock.
the V7sport engine has a unique character.
going oversize pistons does not gain much, you will find the original carbs are too small ( they limit the v7sport engine in standard trim a 32 mm PHF is a nice improvement )
bigger carbs will need serious head work.
the stock V7sport engine is hard too improve without completely changing everything , at which point it stops being a V7sport engine.
make sure to check the front downtubes for cracks around the bottom engine mount.
they tend to break there.