Go Go Sundiro! 70cc Stage6 Sport Pro MKII build

[90GTVert]

Jul 2, 2018 10:51:45 GMT -5 lordverminaard said:

Still have some issues with the tach, it sorta does whatever it wants and I really have no idea if it is accurate or not.  It's the type where you wrap a wire around the spark lead.  Anyone have advice to make them work better?

Try different amounts of wraps and see if it improves.

[lordverminaard]

Thanks for the tip Brent, I will mess with it more once it is running again.


So my new belt came, decided to tear back into it and go for a ride now that the 100+ degree weather has stopped for the time being. Took my CVT cover off to find all kinds of carnage:






Wrecked my sliders, variator guides, and what you can't see is the internal bushing in the variator was also out of round.  It probably would have been fine but I didn't want to take any chances.  I rooted through my "box o parts" and found the stock variator.  I have a press, so in a few minutes I popped the bushings out to take a closer look and do some measuring.




Koso Variator on the left, stock on right, and the Stock bushing is on the left and Koso bushing on the right.  The stock bushing was longer so I would probably have to modify it, otherwise they were the same inside and outside diameter.  Also the stock bushing is a nicer smoother quality material than the Koso so it sounds like an upgrade to me.





Spent a long while carefully filing down the stock bushing to match the Koso.  Also found out that I can fit the stationary half of the variator in my grinder, made cleaning it up easy:







Pressed the bushing back in with the clip, and ordered a new set of sliders and guides.  Cleaned up the other half of the variator, and I didn't take any pics of it but I took apart the clutch end and sanded down my homemade "torque controller" as thin as I can get it so that should allow the variator to work all the way now.  I also went with a slightly wider belt in hopes that it could allow the final 2 or so mm of belt travel to get me MAXIMUM VELOCITY.  And, it's a Gates belt, quality looks better than the Bando that was on it:





As usual, waiting for parts yet again.  They are supposed to both be here this week so hopefully by Friday I can test it again.





Until next time!

[lordverminaard]

It's amazing how much time you can spend working on something so simple.

All my parts came last week so I decided to finally wrap this thing up. I didn't take any pictures because I just wanted to get it done and what I thought was going to be a quick job ended up taking me all day.

I first pulled panels so I can access the airbox and CVT cover easier, and while I was in there, I swapped the 97 main jet for a 93 since it was sputtering on the top end. Put the new sliders and guides in, and found out that the new belt was just a bit shorter than the last one even though they are rated for the same length. It was actually pretty tough to get it on the first time. After assembling, noticed that the belt was again riding a little too high at rest for my liking, so I fabbed up a shim out of a washer (which was a job in of itself) and shimmed out the variator halves. Better belt position, so I started it up and ran it to see how far it would go. Found that the contra spring was still coil-binding, so I pulled that apart and removed my homemade torque controller once and for all and re-assembled. Tested again and the belt wasn't going high enough for my tastes, so I took it back apart, removed the shim from the front of the boss and instead put it behind the ramp plate to see if I could get it to go higher.

I should add that my ramp plate has always had an extremely tight fit on the shaft, so much so that I usually have to grab it with a big pair of channel locks to take it off. When I was putting the variator back on, I somehow knocked loose some of the starter clutch bits which fell behind the starter clutch, and when I torqued the CVT back on, it bent the starter clutch plate. Pulled it all back off, and straightened the plate as best as I could in my press. Re-assembled, tested again, and the belt didn't go any higher than it did before, plus it had worse belt position at rest. Pulled it apart AGAIN, re-assembled with no shim, and it was not as good at rest and didn't go any higher (or lower) at full travel. Pulled apart AGAIN (see a pattern here?) and assembled back with the shim on the end of the boss for best belt position at rest, and at full travel it was still where it was for all the other tests. I assumed that over time the belt will stretch a bit and eventually ride up the variator a little more so this seemed the best place for me to leave it. One issue with this was that there was not any splines left on the shaft for the kickstart washer to engage on, so I had to eyeball the position and center it that way instead. It is working fine though.

I put the bike back together, and had issues with getting the airbox back on (as always when the panels are mounted) and was frustrated enough that I didn't want to pull the panels yet again so I fitted a cone filter with a homemade adapter on to the original snorkel. Much easier to fit and there is more space to access the CVT without pulling panels. Fired it up and it was running really well but I didn't ride it.

I basically didn't even look at it for the whole week but I had time yesterday to go for a quick test ride, so off I went. The combination of cone filter and 93 main jet transformed this thing, no sputtering, no dead spots, and full throttle is nice and crisp. No oil dripping out of the pipe anymore either. It will still bog a little if I snap full throttle from a stop but I can live with that. There is also a little muddy feeling at low rpm\low throttle position and the pilot is probably still a tad too rich but I am good with how it is running now.

The 4g sliders were probably too heavy, it shifts earlier than I would like but I am not ordering a 3rd set of sliders and honestly for putting around the city it is probably better. I know there is more acceleration with a more aggressive clutch setup and lighter weights but then it would be pretty obnoxious to ride. I still was able to get to 50+ mph without much problem.

As usual with most of my projects, once I get the bugs worked out I tend to sell stuff. That's what I am doing with this too, I will post an ad on Craigslist today. I like it, but I don't love it, and I really need the money for other projects and most importantly, I need the garage space. I want to focus my time on my Scirocco this year and I need cash and space (both mental and garage) to make that happen. I also have my KZ400 to work on and once I get that going I will decide to keep it or sell it and move to another scooter project. There are a ton of scooters that I still want, haha. Time will tell. Thanks for following along.