Sumotrack rebuild

[Ratranger]

That Champion seat/tail section really looks great!

Thanks, when I originally built the bike I ended up spending a while figuring out the bend angles, lengths and offsets to make the seat tube. I tried to be lazy and email/call multiple places that sell frames that use the seat, but no one would sell just a seat tube. I still haven't heard back from any of them and it's been atleast 6 years.

 

[Ratranger]

I think I got all the life out of the belt on my lathe.

Also finishing up some new intakes, I want the carbs to have a little tilt and didn't want to pay $80+ for intakes. So $10 for the rubbers and scrap bin for the aluminum.

 

[Ratranger]

Took it for a ride today. I'll probably add some more foam to the seat, you end up sliding forward too much and I could stand a little more room to the pegs.

 

[zrx1100]

Took it for a ride today. I'll probably add some more foam to the seat, you end up sliding forward too much and I could stand a little more room to the pegs.

Build of the year! The exhaust sounds great. Also seems nothing major missing in carburation. Looking forward to updates.

 

[Ratranger]

Build of the year! The exhaust sounds great. Also seems nothing major missing in carburation. Looking forward to updates.

I'm pretty sure it's lean, so I'll start by raising the needles a clip.

 

[zrx1100]

I'm pretty sure it's lean, so I'll start by raising the needles a clip.

Since you are planning on EFI later, can’t you use an oxygen sensor for tuning?

 

[Ratranger]

Since you are planning on EFI later, can’t you use an oxygen sensor for tuning?

I got lazy and didn't install the bung for it.

 

[Ratranger]

Ok so amazon pertronix clones aren't the way to go. The ignition worked, but the ignitor forthe right cylinder kept failing. 1st one lasted a few short rides and quit 9 miles through a 10 mile ride. Installed a spare and it made it about 3 miles, but would work again if given time to cool off. 3rd was DOA. So now I installed a trispark, easy install and with a degree wheel was within 3* of the max advance I installed it at. Since it started and idled so well I'll leave it at 35* max until I ride.

 

[Ratranger]

Gotta give a thumbs up for the trispark. Just did a 20 mile ride with no issues. Feels a little lethargic so I will add a little more advance to the ignition, currently at 35 so I'll set it to 38 or so and give it a go.

The lean feeling was fixed switching to 130 mains from 125.

Seat still needs attention. Stiffer foam and a grippy seat cover will fix that. Right now you slide too much and just end up against the tank, and the foam is soft enough you feel like you are just sitting on the seat pan.

 

[Ratranger]

Off work today so I got an early morning picture by a lake.

 

[Ratranger]

Apparently the X-rings I used to seal the clutch slave are too old, or the wrong type. Rode almost 100 miles today and the slave was leaking when I got home. Since I still have more of the x rings I swapped them for new ones, but have actual brake seals coming. I'll modify the body and make a new piston if needed.

 

[Ratranger]

Not much to look at but I replaced the foam in the seat. It's 4 layers now, bottom layer is 8mm "cosplay" foam, next layer is blue sleeping mat from walmart, and top 2 layers are 1/2" extra firm upholstery foam. Just sitting on the bike this feels much better. It's firm but with good cushion and the stiff foams down lower will prevent you from ending up on the seat pan. Picture is the finished seat and the original foam.

I also swapped the x rings in the clutch slave for EPDM ones. As a backup I'm making a new slave to fit proper brake seals from brakecrafters.

In my possession, but not installed I do have a lighter throttle spring. Right now I don't feel like dismantling the carbs to swap it.

 

[Ratranger]

The new seat pad is way better. It wasn't uncomfortable at the end of my 14 mile commute.

And just for fun a comparison between the XS and my DRZ.

 

[Ratranger]

Lighter throttle spring is on. Looking closer the throttle cam, and AP arm are held on with roll pins. So rather than have to re sync the carbs I knocked the throttle cam roll pin out. The new spring is only .2mm smaller wire, but it significantly lightens the throttle. Still going to do new grips soon, but it's nice to know I won't be fighting the return spring constantly.

 

[zrx1100]

Lighter throttle spring is on. Looking closer the throttle cam, and AP arm are held on with roll pins. So rather than have to re sync the carbs I knocked the throttle cam roll pin out. The new spring is only .2mm smaller wire, but it significantly lightens the throttle. Still going to do new grips soon, but it's nice to know I won't be fighting the return spring constantly.View attachment 332906

when is the dyno run?

 

[Ratranger]

Lol, no idea. I still haven't gotten the DRZ back to the dyno since adding the stroker crank, fcr41, and extra open intake.

 

[Ratranger]

Noticed a slight leak around the countershaft/clutch pushrod area today. Pulled the cover to look and found the sprocket nut a little loose. So now that is properly torqued to 84ft/lb. Hopefully that solves the leak. Pushrod seal looked dry, but I could see some streaks on the sprocket. So hopefully tightening that solves it.

 

[zrx1100]

Noticed a slight leak around the countershaft/clutch pushrod area today. Pulled the cover to look and found the sprocket nut a little loose. So now that is properly torqued to 84ft/lb. Hopefully that solves the leak. Pushrod seal looked dry, but I could see some streaks on the sprocket. So hopefully tightening that solves it.

I saw 84 ft/lb and thought, dayum! And then I read you are not taking about dyno numbers…

 

[Ratranger]

I saw 84 ft/lb and thought, dayum! And then I read you are not taking about dyno numbers…

Lol, I don't think anything short of a full on euro/aussie/NZ sidehack build could get close to that. They go all out for those things, 800cc+ stroker big bore etc.

 

[Ratranger]

I'm the only non harley guy at work.