Hey Pantah Good, doesn't your 851 have aluminum spacers at the swingarm?

Yes, they're just fat aluminum washers.

Does the F1 chassis fit onto an 1100 motor? Well, No. Not without a small amount of trimming here and there.

The front engine mount in the valley of the motor is 5mm too wide, but fortunately it is easy to get to with a hack saw and a quick and simple job to trim it.

But before I did any trimming I thought it prudent to check that the throttle bodies weren't fowled by any part of the chassis, say by 5mm!



With the front engine mount trimmed by 5mm the chassis dropped in easily, with only the top shock absorber mount resting on the cylinder head. Trimming the cylinder head and chassis by about 1mm each would allow the chassis to meet with the two rear engine mounts.

Plenty of room for the belt. Rear engine mounts miss by only a fraction. With a bit of persuasion they could have met.

I am confident now that the Verlicchi swing-arm is more likely to be off a later model bike - probably a 900, as it too wide to fit the F1 chassis
This is the biggest hurdle so far. Does anyone have any suggestions?

You could probably flatten the inside of the frame tubes at the interference points or cut it out and weld flat plate where you ground the tube. That part of the frame doesn't do too much in the way of rigidity other than support the seat area. The muffler hangers can be moved or removed. I think you may have an interference issue at the top shock mount with the valve cover/cyl.head,it looks pretty tight there.

Hi Mike, wdietz is right get rid of the muffler hangers. Never liked them anyway. I would also cut and weld in flat stock where you need the space. The shock mount looks like a real problem, although it is difficult to see, maybe a picture from above? Lou

You could also get rid of the third engine mount/center stand mount, and do something like this.
Bill

The swing-arm is still too wide for the suggested mods below to accommodate it. So each different way I look at it, I have to accept that I will need to take the hack saw to it
My current thinking is to cut the entire rear sub-frame as in the pic below, then size/line up the swing-arm in its correct place before welding the rear sub frame back on again... At least that is what I am thinking tonight And yup, I am still worried about the top shock mount... I am tied up for the next two weeks so 'won't get to take a closer look at that until then...

I love this thread! You 'da man.

My old 853 F1 used 900SS cases and a '94 900SS swing arm. We ditched a good chunk of the rear sub-frame, welded on a couple of mounting points for a footpeg hanger plate and life was good.

Matt Spencer at Salt Lake Motorsports has some velocity stacks that can be used with small K&Ns and work really well with those motors.

Thanks for the compliment Steve!

My mechanic delivered the engine and chassis to a welding/aircraft fabrication mate of his who built from scratch his own 851 chassis! (that's cred. enough for me!) this week for his input for the best way forward and implement that solution.
His brief is to (take lots of pictures) maintain the "look" of the stock frame:
1. which means leave the centre stand mounts and both rear passenger foot peg hoops in place, while making the rear sub-frame wider to accommodate the new swing-arm.
2. let us know if the shock absorber has any chance of clearing the rear cylinder head.
3. drill out the frame's engine mounting holes to accept the 1100's larger diameter (12mm) engine bolts.
4. modify/fit a set of 2007 Monster 695 exhaust headers (symmetric 2 into 2) to match a PAIR of NOS Ducati Paso Conti Corsa exhaust mufflers.
You now understand why I am keeping the foot peg hoops The Monty will have classic 1980s symmetric exhausts hanging off the both footpeg/exhaust mount hoops.