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Post by aeroxbud on Mar 26, 2014 6:29:45 GMT -5
Making good progress  Sounds like it wont be long before you have it dialled in. |
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Post by Upgrayedd on Mar 31, 2014 21:44:22 GMT -5
Well... me and my carb did a little bit of battle the last few days. I've been trying to get my jetting right. Long story short, that 33# pilot is almost too tall for this thing and with having limited room on the low side with it.. what was really throwing me off was the accelerator pump. The setup on that pump is not ideal by any means. There is no adjuster screw to dial it in like some setups have. Just a springy lever that seems to adjust itself with the weather, engine temps, phase of the moon. So after 2 days of trying to get my pilot, jet needle, and pump to all play nice together, I decided to just disable it and dial my pilot and jet needle in without it. Success. Took only a few adjustments with it disabled, and the last of the weird spots that seemed to move around my throttle with the weather and engine temps, are gone. Needle is 1/2 a slot leaner than stock (clipped 1 slot leaner, shimmed halfway back), fuel screw around 3/8 - 1/2 turn out. I'm not out to race, there's no shifting taking place, and for a daily driver/grocery getter/joyrider, the throttle is plenty snappy enough without that pump in use. Getting that odd size pilot I had to dance well with the jet needle setting came quick without it. I left the forward facing tube with the cap on my stock airbox so I'd have more consistency overall, but even with the inside snorkel gone and mount slots/tabs cut out, it was still a little more rich than I wanted at WOT. So that forward facing tube had an unused vacuum line port that was plugged off. I removed the plug that was in there, and took another plug I already had that fit the hole, drilled a small hole in it and with that, the main jet feels and looks right on the plug - just a little toward rich. I like this setup, it gives me an easy way to adjust the airflow.. especially if I move somewhere at a lower altitude. And I like the stock airbox.. its really a pretty good design, and handy for keeping a filter dry and free of mud slings. I ordered a BANDO CVT Belt and a KOSO 1.5K Torque Spring today. They'll take a couple few weeks to get here, but that's okay - I saved a bit ordering them from overseas  I decided on the Bando after some feedback from others, thank you USMCDOC for helping me verify what size belt I needed, and the info on the different brands. Most all the sites say if you have 12" rims you need the longer belt... mine's a short case though. I decided to try out a 1.5K spring.. i have a lot of hills here, and as is with stock weights and spring, once it heats up, my shift range drops from 6,700-7kRPM down to under 6,500RPM, and lower when already moving and coming up on a hill. Still not sure what my stock weights weigh. Gonna pull them out and weigh them when I put in the new belt and spring. My scooter came with 100/60-12 tires, I forget the brand - Bob's Tires or something. They didn't want to hold air, especially the back one, kept dropping to 20# after an hour of riding. I added 6 ounces of Tire Slime to both tires. I am a big fan of the slime, I use it in all my tires. Haven't had a flat in years. The stuff really works for me. Happy to say, the scooter tires now hold their air. I still think I may move up to 110/70-12s when it comes time, there's room for em, and it'd give me a little more tire under there too. |
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Post by Upgrayedd on Apr 2, 2014 15:27:42 GMT -5
Yesterday I pulled that partially open plug I'd made for the unused vacuum port, and ran her with that port all the way open for less restriction. Went 1/2 a slot richer (back to stock) on my jet needle, and down to 3/8 turn out on fuel screw, to smooth out my throttle.
Spark plug is now showing a hint of dark dark brown on the electrode and strap, vs black. Nice color on the ring, no more soot. I think I have found a good balance of jetting and airflow.
Just a little bit more power now too. These little suckers got some kick to em, I am surprised. Bikes and scooters out in full force around here with the warm weather. All the other scooter bugs in town have been real cool - most of em dig my new wheels.
There's one guy in town here who has an older Kymco with the 2000k contra and clutch springs and I forget what all else he said hes got in it, but that sucker will MOVE up a hill and it's still stock 49cc displacement. Impressive.
I changed the oil again yesterday. Wear metals are really lightening up, along with the used oil color. I've changed it at roughly 25, 50, 100, 200, and 350km this last time. Going to do one more change with conventional at 650km, then switch to Rotella T6 Synthetic 5w40 at 1000km.
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Post by dan50 on Apr 3, 2014 7:26:42 GMT -5
Glad to see you have a good setup going.
If that guy can move up a hill with a scooter, he doesn't have a stock 49cc. All 3 of mine slow down going up hills. That's why I need to save for BBK's and performance stuff. I have a need for speed!
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Post by Upgrayedd on Apr 5, 2014 20:45:37 GMT -5
Glad to see you have a good setup going. If that guy can move up a hill with a scooter, he doesn't have a stock 49cc. All 3 of mine slow down going up hills. That's why I need to save for BBK's and performance stuff. I have a need for speed! He may have some hidden displacement indeed Yeah the engine's smoothing out nicely. I did make a gasket and completely block off the accelerator pump on my carb days ago, but no more tuning, been running well. She's shifting at lower RPMs than I would like.. my new belt and 1.5k torque spring should be in next week, then I can figure out what weight sliders/rollers I need. I did another motor & gear oil change at 650km.. and I have enough regular oil left for top off if needed. Switching to synthetic next oil change. I've removed several little odds and ends that were unnecessary too, and I have one of those collapsible crates coming to add to my back end for groceries and stuff. Ah.. my fuel mileage has crept up a bit, getting closer to 70mpg now. I LOVE THIS FUEL MILEAGE!!!! |
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\\-olf
Scoot Enthusiast
Iowa
Posts: 304
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Post by \\-olf on Apr 5, 2014 21:15:24 GMT -5
My now 2 year old TT50 has plenty of power on hills and always has, there is a real steep one near me that it will maintain at least 20 or so all the way up, I don't know what the grade is, but it's quite steep.
I never really bothered much with the stock carb, I simply pulled it out and replaced it with an unsealed one and rejetted it.
I would suspect your jetting and throttle issues are connected to the carb on these scooters being pretty crude, when you can buy a whole brand new one for about $30 that doesn't inspire much confidence on it's quality!
I think the much better built keihin carburetor might be the best money spent over trying to toy around with a cheap $30 stock carb.
Oddly enough MY TT50's speedometer was almost exactly right on the money, I timed a run of about 2 miles with a known distance and at a set speed the whole way on the flat road, and I was about 100 feet away from the end point when the 120 seconds elapsed, that's about as close as you can expect. It will do 40 mph on the flat with no problems and without WOT if there's no headwind- there's still a little more throttle travel it can go, I seem to remember taking it to about 45 briefly.
I have not modified the ignition in any way, it's all factory installed-stock, the rollers and variator were replaced last summer with the same ones.
I think the keihin carburetor would start it easier in the cold and idle more smoothly but I haven't bought one yet.
My windshield does make a difference as well, withthese small engines any wind resistance or head winds are going to be noticeable, the windshield was a cheap aftermarket add-on that more than saved it's cost and helps get more speed and power out that otherwise would be wasted.
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Post by dan50 on Apr 5, 2014 22:20:06 GMT -5
My SunL will go 44mph GPS, my DongFang will go 42mph GPS, flat road and no wind. Both stock but I need to tune the CVT on the DongFang. Going uphill they slow down, not enough power for hills. A couple of hills around here they slow down from 35mph to 20-25mph fairly quickly.
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