JTH's HD 883 Dual Sport'ster conversion

how much are you going to lengthen the swingarm or should i say how much do the extensions add.

The extensions are installed and looks like a ~4" increase in swingarm length feels & looks about right. Wheelbase will be ~64" when suspension is fully extended. I'll take some pictures this weekend and post them.

Next step is select rear shock and begin new swingarm design.... Any sugestions on a rear shock ? Im considering a Progressive 465 series but need to make sure spring rate and travel are adequate.

we are tracking about the same I am having a swingarm built for mine. I have the shock location figured out and will be using a single shock. I am working with Rick at motocd.com on the shock. It will be a one off build, unless we end up with the same swingarm design then it may work on yours too. My swing arm will be 2" longer, I am trying to keep it no more than 62" WB. No good reason for that wb other than the longest of the ADV bikes is the KTM ADV and the 800 gs both right at 62" That is not to be a negative on 64" as that is what the HPN air head conversion bikes end up at.

enough rambling on your thread

Sounds good. I had the Cogent Moab shock on a KLR from motocd and liked it. I'll check them out - thanks.

It will be interesting to see how close our designs get to each other. I'll post some pic's as I get into it.

Very interesting project. Never seen a dual sport sporty. You might be on to something here. Can't wait to see how this project ends. So far it is looking pretty trick.

i responded to the pm, I think we can work something out. there is two pm replays

Installed the swingarm extensions and looks like +4" extension is about where I i'd like it, but still need to do some cad layout on the geometry and swingarm / shock to make sure all the dim's work out.

With 4" extension and the KTM front end w/ 21" wheel - new wheel base is ~64". A bit long, but should help with stability at speed. We shall see

Swingarm geometry mockup ....

A better view from side....

did you go with PBI sprockets?
what chain length?

Sprocket Specialists 530 x 51 tooth, and the chain is 120 links shown, but final length is TBD. Probably +/- a few links. Looks pretty close as is.

i hope mine is the right length when we get through, i ordered a conversion but they didn't provide chain length.

I started the geometry layout to determine the swingarm length, shock length & spring rate, and shock position. Im considering a monoshock mounted either Left Side (thanks john - good idea) or Center.

Here are the layouts - work in progress....

Left Side Shock - Neutral (no load) & Compressed:

Center shock - Neutral & Compressed:

Heres a side by side of each...

what length from swingarm pivot to shock mount did you use

Here are the dim's... Swingarm is shown at ~20 degrees from flat...

thanks, I like the adjustable shock mount. With the measurement does that give you room to clear the break caliper?

Yah - that position will hit the caliper. Im trying different geometries to see what looks best - and learning in the process. As I mentioned in your thread, the ATK mounting looks best so far, but will require a frame mod to add the attachment bracket plus some stiffening. This is still close to the caliper, but I think it may be do'able. Detail design of the swingarm will
tell.

How do you plan to mount your shock ?

Here is the geometry:

ATK style - Neutral and compressed: