Vespa subframe repair kit for Grande and Bravo
I have owed several Vespa mopeds, both the Grande and the Bravo and one thing is certain. With all the city riding I do the subframe is going to crack and break. Always on the front right hand side. Doesn't matter if it's bone stock or mildly kitted. I have early on just tried to sew up the cracks with welds only to have a new crack form next to my repair Here are a few cracked sub examples.
New crack on a Grande frame
This one I recently discovered on my daily rider.
Here is a pic if the first Grande I had. Note the scabby weld stitches.
Now I have found a great solution the breaking subs in the form of this reinforcement plate offered by Treats. I have installed this repair plate on two of my bikes and it is more that enough bolster up the weak frame and ward off any more cracking. Here is a link to get the plate https://www.treatland.tv/vespa-piaggio-sub-frame-reinforcement-plate-p/vespa-subframe-reinforce-plate.htm
The following is a picture tutorial of my installation process. The first is on a bare subframe but it is not necessary to remove the subframe frome the bike as I will later show.
First I like to rough up the side of the plate that will be touching the inside of the subframe with sand paper. It is this side that will accept the "spot weld" so I want it to be clean.
A quick test fit shows me that all the holes will line up nice with their parent holes in the subframe.
Now the easy task of placing the spotweld holes in the subframe using a drill and a 1/4" bit. The pattern is totally random except I like to place three in a row at the back of the plate and at the front of the plate near the slotted motor mount holes. Note how I position the bit to penetrate both layers of steel so that the weld will also include the X member layer that will be covered with the reinforcing plate. I drill three holes vertically in this area.
A block of wood to support the front will help in drilling the front three.
These front three are important as they will include three layers of steel when welded.
After all the spotweld holds are drilled I like to de-burr the backsides of the holes to assure the reinforcing plate will sit flat against the sub.
This next few steps are for Grande subframes only as the coil is bolted through the sub and it is therefore necessary to spotweld the coil mount bolts permanently in position.
You could always use a Bravo style, or make a separate coil mount bracket and skip this step.
Drop the Grande coil mount bolts through their holes
Now put a couple of healthy burns on them till you are confidant the will stay in position forever.
Quick note: this long notch is for the stock choke lever clearance.
Now lets slide the plate in and clamp it for welding.
Three clamps should be enough as you can move them around to the particular hole you will be welding.
Ah, the love of spot welding. I would have to say that if you did all the drilling, cleaning and prepwork, then went to a body shop and said "can anybody spotweld these holes?" They would do it in a minuet just to show off their skills, which in the case of "spot welding" It takes no skill and always turns out prolike even with a newb. You can see the other holes waiting to be welded.
I do this area last as you have to firmly clam a little harder to get the metal to meet flush as it is shaped different in this area. Will you just look at the spotwelding skill this guy demonstrates.
As I said earlier, you do not have to totally tear down your bike to install one of these kits. Here are some shots of my daily rider that I did the other day.
"If you don't know how to remove your motor or carb look here"
Drop out the motor and coil. It is wise to remove the fuel line all the way to the pet cock and maybe wrap a water soaked rag around the cock itself if you are worried about sparks.
Here the coil studs are spotted in.
Now drill the spot holes and clean off any paint
I did not have a lot of clamps when I did this bike so I used the motor mount bolts to hold the plate in position.
My favorite part.
Before I reassembled I tried to float on some cheapo white paint to cover up the burn carnage.
I recommend getting this reinforcement plate as an alternative to just stitch welding on cracks. This repair mod has not failed.
If you have any questions about the installing tips I suggested, or are having trouble with the install contact