Skorpion 660 Lightweight Build

[breakwellmz]

So the new plug helped the low speed hesitation, but did not cure the current problem. bike ran great until it got up to temp, about 6 mins this time and the problem happened again. Looking at the AFR gauge when its happening, it seems like its just slowly going lean/not combusting (a misfire also looks like a lean mixture since the oxygen is still present). I felt the coil and it seemed not too hot, but playing with the connections on it seemed to help temporarily. I have replaced those spade connectors once before when they were slipping off, but I will inspect them again.

I have the nicer CDI ignition system coming from bill in germany, but the package tracking says that it is held up in NY right now for some reason. It, along with the new rectifier, will essentially just have a new electronics system.

Also when I installed the new plug I went back to the base level jetting (40, 155, EMR needle at clip 5 from bottom) and the AFR readings were better. I can still go leaner, which is interesting. But I don't really want to keep pushing the bike home, haha

Hi.
You havn`t disconnected the coil terminals and re-connected them the wrong-way-round?

[jpmsteadi]

I will check again, but I don't think so.

The bike will run until its hot, I think it would be unhappy all the time if it were backwards.

[breakwellmz]

It`s a new one on me.
Just the other day a mate was telling me about how it had happened to him, the bike ran fine until it got hot with coil terminals reversed.

[jpmsteadi]

huh. Yeah, I will check them today. Hopefully thats it!

[jpmsteadi]

I went out to a local junkyard today and picked up a pretty nice front end off of a 1999 Yamaha R6. Came with everything I need to convert it over. I am going to freshen it up with new seals, bushings, rebuild the brake caliper, and see if I need new springs (which I assume I will).

Everything is so much lighter on it. Its pretty crazy.

The steering stem and lower triple seem to weight half as much.

the brakes are pretty nice too. Going to convert over to a single rotor. I don't think I need both.

Measured up the steering stem bolts. The random blog I found awhile ago was right: DRZ400 bearings will work well. 30mm ID, 52mm OD, and 16mm height. It is very strange that the MZ uses just ball bearings for the steering stem as opposed to tapered bearings.

Not a bad haul for 300 bucks I don't think.

[jpmsteadi]

And here are the forks, though already stripped down:

The forks are right side up cartridge forks, fully adjustable. Plus parts and things for them are super easy to find.

[breakwellmz]

What`s not to like?
Is the wheel a lot lighter as well?

[jpmsteadi]

I measured some weights this morning:

Item MZ R6
axle 653g 364g
caliper 930 966
lower triple 1333 1153
top triple 1259 823 (this is with the handle bar risers still on the MZ and the stock key setup still on the R6)
forks 8.7 kg 7.53kg
wheel 11.6kg 11.6kg (this is with an old tire and both rotors on the R6 rim. I will weight them on more equal footing when I do the tire swap. I think the R6 will be slightly lighter.)
fender 625 505


Looks like I will be able to save at least a couple of pounds off the whole ordeal while also getting much better suspension. Can't complain about that!

[Puffs]

That seems like a worthwhile visit!

On using both disks/rotors: if you use only 1, all the torque from the braking will only be stopped by 1 single fork leg. That may cause extra wear, as well as torsion in the forks. Sometimes you see a brace between the 2 legs to combat that.
It's your bike, but I would very much prefer using both disks. Even though it's a bit of extra weight.

[breakwellmz]

Here is one more picture closer of where the thermostat ends up.

The attachment IMG_20200626_120354.jpg is no longer available

Initially I was thinking I would need to build or 3d print a bracket for it, but it seems to be very well held in by the hoses, the oil return line from the head, and the clutch cable.

I received this via Ebay today but think it`s final resting place will be a bit different to yours due to the hi-level header pipes on mine, we shall see. -
https://www.ebay.co.uk/itm/Ktm-RC-390-R ... 2749.l2649

[jpmsteadi]

That seems like a worthwhile visit!

On using both disks/rotors: if you use only 1, all the torque from the braking will only be stopped by 1 single fork leg. That may cause extra wear, as well as torsion in the forks. Sometimes you see a brace between the 2 legs to combat that.
It's your bike, but I would very much prefer using both disks. Even though it's a bit of extra weight.

That makes a lot of sense. I will look into either using them both or at the very least making a fork brace. I think it would be pretty simple.

Perhaps I will start with both and see how I like it. I don't think there is a huge weight penalty, I just don't know if for the speeds I am going having two discs is needed for a 350 lbs motorcycle. Something to think about!

[jpmsteadi]

Here is one more picture closer of where the thermostat ends up.

IMG_20200626_120354.jpg

Initially I was thinking I would need to build or 3d print a bracket for it, but it seems to be very well held in by the hoses, the oil return line from the head, and the clutch cable.

I received this via Ebay today but think it`s final resting place will be a bit different to yours due to the hi-level header pipes on mine, we shall see. -
https://www.ebay.co.uk/itm/Ktm-RC-390-R ... 2749.l2649

Nice! It looks like yours didn't come with a t- pipe for the water pump side of the routing, but that should be pretty simple to solve. I bet it works well!

[breakwellmz]

No it didn`t but Ebay to the rescue again! - https://www.ebay.co.uk/itm/T-Piece-Hose ... 2749.l2649

[jpmsteadi]

Got the lathe in last week and got around to continuing the intake manifold project. Did a lot of work on it today and got very close. a couple more small bits on the mill to clean up some bolt mating surfaces and some more time with the dremel to make the inside a little better and it should be good to go. Not the prettiest thing in the world as it is manually machined, but as long as it works. I built it long with the idea that I can always make it shorter, but its harder to make it longer.

[Puffs]

That looks suitable & beautifully machined!

You probably said so somewhere, is it stainless steel or alu? Regardless, me being old school, I'd put a file to it and thin the walls down, from the outside.