An ongoing job we have at present is the lengthening of a Moto Guzzi Frame for touring 2 up more comfortably.
Our customer has brought the frame, seat & tank to me to chop about.
Initially I had discussed with the customer his requirements and this guy really knew what he was after (a seasoned Guzzi fan), I had descriptions, drawings and pictures. It is actually very refreshing to have a customer that has thought so in depth about his requirements before even bringing the bike to me. I love customers like this. Since our real forte is offering custom modifications to customers cars / bikes / vehicles or parts very often a project starts as something and ends up being either far more work or ends up being something different to what was wanted at the start. However, this is usually because people have good ideas and yet in manufacture / set up / mocking the job up things have to change a little sometimes due to dimensions, parts clashing, not lining up or physically unable to make something as first thought or designed.
Nice to know though that we always take great delight in customers actually going away with something they love. Our enjoyment is very often seeing a customers face when they collect a part and we know they love what we have done. I for one love to be able to work through a project with customers and lovemaking something out of the ordinary. Very often nowadays this is is helped along by parts being modeled or drawn up on a cad system first whilst pulling the “look” or design of something together – people love to see what they are getting for their money upfront if its possible at all.
Any way here are the first pictures of the Moto Guzzi mods, I will update this blog as we go along with pictures and descriptions.
Seat roughly chopped and extended 3″
Showing gap between seat and tank to be filled up
I am not happy with the way the tank sits on the frame at present so I am going to have to have a jiggle about
Once I am happy with the tank position, I need to check swing of forks to ensure they dont hit the tank on full lock
The tank actually sits pretty parallel to the frame spars but I think I am going to have to extend the seam around the bottom of the tank to cover the frame more especially around the area shown above, I am also going to have to move the tank back about 10mm to give sufficient clearance on the forks as they swing to full lock.
FOLLOW UP
SEAT EXTENDED AND TACKED UP PROPERLY 2″
Seat fitted back onto frame and temporary mountings
Now I can see what gap I have from the new seat position to the tank – approx 10mm to move the tank back to clear forks on full lock.
OH DEAR. No going back now!
Tank end tacked back on roughly 75mm further back (just to give me an idea)
Tank back on frame with end spaced off and positioned to view the general look
Looking from above, again just as a rough idea we can see how the tank flows into the seat.
You can see from the picture above that I have dropped the tacked in position tank end down to try and get the top of the tank to flow into the seat nicely. This totally messes up the side of the tank in that the press lines in the tank sit approx 20mm lower on the end compared with the rest of the tank. Effectively the customer wants the back end of the tank to “flow” nicely along the frame rail so once I get the end in the correct position I will have to fabricate a “dummy” panel to make the tank flow with the bottom seam along the centre line of the frame top rail (if you understand ?). See the next picture to understand the flow of the tank lines.
From the above picture you can see that the lines in the side of the tank either need chopping and altering or we lift the chopped off end of the tank to get the lines level along the side view and then chop and lift the top of the tank to change the flow of the top of the tank.
All of the below pictures show you the issues we will have now we have extended the tank. The main tank will need slicing up and new material adding in to change the profile of the tank and ensure that the lines of the tank, position of mounting, bottom seam position are all aligned and “aesthetically pleasing to the eye”. This will be where the work starts!
Next step was to start slicing the tank to open out the taper to “flow” towards the front of the seat.
Slicing the tank is not for the faint hearted as once this is undertaken, the plunge has been taken and there is no going back.
So there you go – above, tank sliced and “tabbed”, you can see that I have cut along the natural form lines in the tank. Opening these out has the effect of smoothing the flow of material back to the re positioned end panel.
Due to the nature of the tank I have decided that we also need to almost “scollop” in 2 new sections along the length of the tank sides to get the material to shape and look right as it meets up to the bottom flange (shown at the top, tank is upside down).
You can see on this view that I have tacked in a brace plate to ensure that the tank “top” & “bottom” stay at the correct dimension, whilst manipulating the panels to fit.
As you can see above I have added small tabs to keep the sliced sections apart evenly, as now I have to start removing the longitudinal tacked plates off  a couple at a time to begin the infill process.
Above, 1st infill panel shaped and tacked in place.
Once the top infill panel had been tacked in I can now work opposite and start fitting some infill material to the underside.
Whilst tacking infill panels into the extended tank it is critical to keep checking the dimensions of the gap to ensure that the shrinkage of the tacks does not shrink the panels in too much and create distortion or twist.
A good “fit up” is essential to keep the tank even and aid the welding process.
A better view of the underside infills
Now you can see that the side infill panels will meet up with the top infill panel roughly on the centre of the sliced press lines in the tank. The idea being that the new infill for the longitudinal will have a pressed line in it meeting up with the joint position of the new top and side infill metal. You cant see in the picture below but I have put a slight radius on the ends of the top and side infill plates along the joint so that I dont end up with a sharp pointed joint line as this needs to be a smoother radius to match up with the re fitted end panel and new press line in the longitudinal infill panel.
And both side infills
FOLLOW UP – WELDING
Above – All joints taped up ready for purging the tank with argon to stop atmospheric attack on the back of the welds on the inside of the tank. Each seam was completed one at a time and tape removed as I moved around the joints to spread the heat to ensure I never allowed a build up of heat in one area, which will cause shrinkage and distortion.
Below, just to show that I have tried to complete all welded joints along an existing press line in the tank, therefore reducing chance of the welded joints shrinking and “sinking” if I chopped and joined the tank on a flat panel / slightly shaped there would be more chance of distortion / sinking where contraction has taken place along joint as it has cooled.
Common rule in engineering “majority of metals expand upon heating but, nearly always contract more upon cooling”. Using this rule of thumb a skilled engineer will be able to level a flat bar of solid metal e.g. a flange, by strategic pin point heating using an oxy-fuel gas torch.
Some of the welding does not look good as quite a lot has been welded using the “pull” mig welding method, or “stitch” welding method, and in some instances what we term “backstep” method. All of these methods are used in completing differing joints due to gap, thickness of metal, joint set up and various other anomalies.
Above a view on the underside of the tank
You can see above where I have seam welded the small lip where the edges join around the end
Cut out and patch in of new filler neck and cap assembly.
Mark up for chop out
Cut out and mark up for shaping and fitting into existing tank
Shaped panel with new drain pipe added before we graft in new filler cap
Tank cut out and panel shaped (bit of panel beating here to reshape panel), offered up for fitting
Better fit
Grafted in / welded and flushed in
From another view
Back end where welded flange has been previously repaired – not pretty
We need to do something with this and to fill the gap between the tank and frame spar.
Infil panel and scallop around head stock
From riders view
Front flange extensions to cover frame drops tacked on to existing tank.
Note these blend into new mounting bracket panels.
Scalloped out infil panel for lower rear of tank to blend in with chassis better
Welded / blended and reshaped front flange extension
Tacked on infil panel (looks better when side panels on)
Pressure tested and ready to fit properly. Now the whole set up wants to be fitted with all panels and motor / carbs / re-trimmed seat and new mounting rubbers to sit properly on the bike frame and then the work begins, skimming and paint prep.
Hopefully another happy customer ?
CUSTOMER FEEDBACK –
I was not fully sure this job was feasible until I visited Flash Customs for a consultation.
With a full discussion of what was wanted, I was assured it was and it was clearly described to me how it could be done.
I was pleased that I was kept informed every step of the way. The finished article is testimony to the bespoke services that Flash Customs can offer.I would not hesitate to recommend their services. Thank you.
Richard Cresswell
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