Phase 1 complete and looking to phase 2

[zrx1100]

I believe in the middle. Check with XRZ1100, I believe he did a similar build.

here is my dyno vs the original stock configuration

you can find the long story here: https://www.xs650.com/threads/700cc-kit-with-a-shell-1-cam-in-a-78xs650e.65405/

I very much like the power output as it is, though it has two features: torque peak at 4K rpm and a dip at 2500rpm. I beleive that is from 1 3/8" TPOs (torque peak optimizers https://www.xs650.com/threads/torque-peak-optimizer-tpos-performance-dyno-charts.66469/) that I am using to make the 1.75" headpipes work. If I were to go with 1.5" headers, I expect my torque curve would have flattened and the 2.5k rpm dip greatly reduced or disappeared.
On a twisty mountain road, though, this motor is an absolute gem.

 

[Slowshed]

Thank you. That would make a great addition to my bike.

 

[Kevin Werner]

With 18/42 final drive you will be real buzzy at 50 and above. Keep the notion of going to a stock hub so that when one come available cheap you shelf it in your shop. Some poster here did some dyno work on his build and showed results of stock and a couple of stages. I seem to remember the stock had a very flat torque curve. edit (as seen above)

 

[Kevin Werner]

If you stretch your drum actuator arm you can shorten your brake pedal.

My current peg placement has me very happy. Feels like an old enduro. The old brake lever (beta prototype) is shortened approx 4", With the extended actuator arm and shortened pedal arm the feel is pretty good.
Here with the early peg placement. Certainly not an off roader but the current peg placement (above), 31 inch wide bars with some pull back it is a 750 cc delight to ride.

 

[Slowshed]

View attachment 340274If you stretch your drum actuator arm you can shorten your brake pedal.View attachment 340275My current peg placement has me very happy. Feels like an old enduro. The old brake lever (beta prototype) is shortened approx 4", With the extended actuator arm and shortened pedal arm the feel is pretty good.
Here with the early peg placement. Certainly not an off roader but the current peg placement (above), 31 inch wide bars with some pull back it is a 750 cc delight to ride.View attachment 340276

That is very cool!

I need to shorten both my shifter (peg mounts I built move the pegs back a few inches) and the brake lever (same issue).

The shifter is just a matter of getting a shorter one, but the brake level I’ll need to section out a piece.

I already had to section out a piece to bring it closer to the frame. That allowed it to fit in between the frame / exhaust and the foot pegs.

I’ll see if I can find some old photos of some of the build highlights. Getting the mono shock mounted and the linkage to actual properly was the hardest part.

 

[Kevin Werner]

That is very cool!

I need to shorten both my shifter (peg mounts I built move the pegs back a few inches) and the brake lever (same issue).

The shifter is just a matter of getting a shorter one, but the brake level I’ll need to section out a piece.

I already had to section out a piece to bring it closer to the frame. That allowed it to fit in between the frame / exhaust and the foot pegs.

I’ll see if I can find some old photos of some of the build highlights. Getting the mono shock mounted and the linkage to actual properly was the hardest part.

I purchased rear sets from the classifieds. A member sells a kit there, https://www.slipstreamcycle.com/products/yamaha-xs650-rear-sets. I made new peg hanger brackets and used the supplied linkage for the shifter as seen in the picture but the geometry for the brake did not work. That is why I sectioned the brake pedal and stretched the actuator arm.

 

[Slowshed]

With 18/42 final drive you will be real buzzy at 50 and above. Keep the notion of going to a stock hub so that when one come available cheap you shelf it in your shop. Some poster here did some dyno work on his build and showed results of stock and a couple of stages. I seem to remember the stock had a very flat torque curve. edit (as seen above)

This is the setup with the 18/41 sprockets. You can see that the chain is very close to the rear hub. We can turn about if clearance there and I can run the 40t rear.

I’m thinking that the 40 and the high ratio 5th gear might get me into a comfortable range.

Already did a 530 to 520 chain conversion. That helped fit the 18 on the front.

 

[Kevin Werner]

View attachment 340373
This is the setup with the 18/41 sprockets. You can see that the chain is very close to the rear hub. We can turn about if clearance there and I can run the 40t rear.

I’m thinking that the 40 and the high ratio 5th gear might get me into a comfortable range.

Already did a 530 to 520 chain conversion. That helped fit the 18 on the front.

Let us accept that it is an ongoing project. I was just recommending you keep you options open as you finish and start developing your cool ride.

 

[Ratranger]

One option would be high ratio primary gears. They aren't exactly cheap, but they really expand the gearing options. I'm running 18/44 with a 150/70/17 rear tire and with the high ratio primary gears it's basically the same as stock. Add the taller 5th and you could run a bigger rear sprocket to gain clearance and get better overall gearing.

Edit: rephase still has vibration. Mine is rephased and it'll get uncomfortable at 75, much happier at 55-65. I don't want to go taller than stock on the gearing since 1st feels tall compared to other bikes I've had. I don't have the OD 5th gear, but might tear my bike down to re powder the frame, so I might add it then.

 

[Kevin Werner]

One option would be high ratio primary gears. They aren't exactly cheap, but they really expand the gearing options. I'm running 18/44 with a 150/70/17 rear tire and with the high ratio primary gears it's basically the same as stock. Add the taller 5th and you could run a bigger rear sprocket to gain clearance and get better overall gearing.

Edit: rephase still has vibration. Mine is rephased and it'll get uncomfortable at 75, much happier at 55-65. I don't want to go taller than stock on the gearing since 1st feels tall compared to other bikes I've had. I don't have the OD 5th gear, but might tear my bike down to re powder the frame, so I might add it then.

What does the high ratio primary gears do to first gear? I would think @Slowshed needs some low medium speed grunt while still riding some roads.

 

[Ratranger]

The high ratio primary gears spin the whole transmission faster. So to keep the overall stock gearing you have to run a larger rear sprocket. stock is 17/34, with high ratio primary gears you have to run 18/44 to have the same overall gearing. A different back wheel/tire combo will change that.

You can play with the number of gearingcommander.com and see what works. Stock primary is 2.66, Ivan's high ratio primaries are 2.16.

 

[Slowshed]

The high ratio primary gears spin the whole transmission faster. So to keep the overall stock gearing you have to run a larger rear sprocket. stock is 17/34, with high ratio primary gears you have to run 18/44 to have the same overall gearing. A different back wheel/tire combo will change that.

You can play with the number of gearingcommander.com and see what works. Stock primary is 2.66, Ivan's high ratio primaries are 2.16.

I’ll look at the Ivan’s options. I was going to ask where the high ratio primaries were available. I hadn’t heard of them before.

Thanks

 

[Ratranger]

Ivan Hoey is the main guy for high ratio primary gears. You'll have to email him and see if he has any, or is going to do a run soon. here's his email ltr.management@bigpond.com

 

[Slowshed]

Found some old pics of this build. The hardest part of this build was converting the stock dual shock swingarm to the mono shock YZ490 swingarm and getting the linkage to work through the full range.

I suckered myself into this project because the YZ490 swingarm fit right in place of the stock XS swingarm. That is where the similarities ended.

The swingarm fit easily. I just had to remove the passenger peg mounts. Then I cut the linkage frame mount from the YZ frame and welded it to the XS frame.

The frame geometry is clearly different so I needed to find a way to figure out what the transfer link shape would need to be. I used an aluminum flat bare cut into pieces and bolted together in different configurations until I got full travel of the swingarm and shock. (PS before I did this I welded a brace on the top of the frame for the upper shock mount. I made the shock as vertical as possible to get the highest possible spring rate. That gave me the maximum spring compression for a given amount of swingarm movement.)

Once I found the 3 hole locations that allowed full travel I went to a local machine shop and had them convert it to a cad file and mill it out.

Then it was time to install it and hope it works

Fortunately it worked well and had been effective both on and off road.

 

[Raymond]

That's some impressive engineering.

 

[Slowshed]

That's some impressive engineering.

More patience than skill