My (wife’s) Genuine Buddy 50 build...

[lunatuck]

Jun 3, 2020 20:22:09 GMT -5 Zino said:

The Yasuni R is a fun pipe it has that wide band but still has the hit your looking for .
Most medium springs in the clutch will work with that pipe Unless you really want it to launch higher in the power band .

I’m sure it’ll perform once I get the clutch worked out. Until then, its not really rideable. Cant get it to move on an incline.

[aeroxbud]

Sounds like you could do with stiffer springs, and lighter rollers.
It's going to be fun to ride when sorted.

[lunatuck]

Update:

I removed the snorkel on my airbox. I had a feeling it would balance the mixture at different throttle positions and it did. I did a jetting run with a 90 jet and it feels perfect. But I was planning on doing a plug chop, so I got all setup. Warmed it up and parked it on the side of the road. Switched the pkug and it wouldn’t start. I quickly realized that I bought the extended plugs. :foreheadslap:.

So I’m stuck trying to jet via gps. The original plug looks ok, maybe a touch rich. But I didn’t do a true plug chop so I’m not sure. Its basically the average position. I will do a chop when I get some more plugs.

For now, the GPS top speed was 49MPH on my same slight uphill. This makes me think it’ll go 53-55MPH on the flats. It has great acceleration throughout the range and very nice top end.

The only little thing I noticed is it’s slow to downshift. I think this means contra spring, but it’s not that bad. Just nitpicking at this point. Going to try GPSing a 92 jet. Maybe pickup some plugs if I have a chance today.

I also installed a temp gauge, so I have some insurance.

[Zino]

If you have tuned dirtbikes in the past .
You can hear real rich and real lean just listen for zingy lean or deep and rich

Take a road and go wide open down it take the richest jet that gives you the best top speed .
You should hear the exhaust tone change .
You can plug chop the fastest jet .

[lunatuck]

Upjetted to 92. Oddly, the idle seems to hang slightly when coming to a stop but the bike sounds richer at above 1/2 throttle. Top speed was 51MPH on same jetting run.

I took it to town for a quick run, and the temp hit 325F on my return trip. Big uphill, but I passed some cars that usually pass me on the way up. I was basically trying to see the max temp I could hit, but gave up at 325F because the bike seemed to slow a bit. Could’ve been the contra spring and uphill,, but I didn’t want to push it too hard at that point.

Not going to get plugs today and I’m working the rest of the week, so we’ll see. Probably going to take it to work.

[lunatuck]

I brought the scoot to work this morning. I have one bridge that's flat, mostly strait and about 1/4 of a mile long and ends with a banking left turn at a stop light. I decided to GPS the route because I was curious about my top speed on that particular section. It hit 51MPH easily and had a lot more to it. I think I'm underestimating the top speed. Maybe by a lot.

I am searching Google Maps for flat roads, because now I'm really curious. I also have some RPM gains to be had if I lighten the rollers. I haven't worked on them since I installed the exhaust and rejetted. I still haven't fully put the RPM into the cylinder and exhaust's best power range which is about 9250RPM.

I have plugs showing up tomorrow and once I am 100% confident in my jetting I'm going to give it a good test. The only thing that makes me apprehensive is that my temps seems to be a bit high. I can hit 300F easily. On my ride home, up a big hill where everyone drives fast; it has hit 325F. I'm concerned about what it would hit if I just stayed on it for a long time.

[lunatuck]

New update...

I was able to upjet to a 94 jet without losing anything.  It sounds very rich on the bottom end, but still pulls fast.  I'm hoping that keeps the temperature down a bit. 

I also realized that I'm now pushing 9250 RPM.  Higher on over-rev downhill which may also partly explain why my temps were getting high quick on WOT runs.  It also explains why I'm going considerably faster then I expected.  I don't think I'm far off from 60MPH, but don't really want to push it that far.  I'm going to do chops tomorrow, and decide the path forward. 

Wondering if I should de-tune it slightly to maintain reliability.  I'm not sure about the stock crank, and there are no other options if I mess it up. 

[Zino]

The malossi kit peaks low 9000-9300 on all 3 of my scoots .
Being a sport kit it is designed to be run on a stock crank .
The genuine crank holds up well to 10,000 ish rpms
Now if you were living high 10,000 rpms then a Crank swap starts to make sense.

Jetting is the biggest thing to get right.

[lunatuck]

I installed a 1000RPM contra spring and it totally fixed my hill climbing acceleration and gave me much better mid end acceleration.. I can pull uphill right up to 55mph indicated, or can just accelerate out of turns.

I also installed a new pilot jet one step up because I have a hanging RPM when coming to a stop. I still have to tweak that. I may remove it because one other thing popped up and I want to be sure I know where it’s coming from. I have a slight lag in acceleration from a start. If its not the jetting, I may then try the new clutch springs.

The stock contra spring was so weak. I could see why it wasn’t keeping my in a lower gear. Its probably fine for slow cruising, but I like the feel of always having the acceleration there when I hit the throttle. If I’m rolling and hit the throttle, its accelerates immediately. Now I just need to find out what’s going on with the lag on takeoff. Then I can retweak the rollers. One thing at a time. Lol.

[Zino]

Good to hear the Contra Fix is In .
My bet is its clutch springs if the contra was that shot.
You should feel power when you hit the throttle.

[lunatuck]

Dropped the pilot jet back down to 40 and put the 1500RPM clutch springs in. Now it takes off with barely any lag. 0-35MPH is about 5s indicated.

I was apprehensive about installing them, but it really only raised my takeoff RPM by about 3-500. Just enough to get it closer to a spot the pipe/engine likes. I think it could use 2000RPM springs, but not going to change them yet.

The persistant issue now is a hanging idle. But an odd one. Doesn’t happen all the time. Seems to only happen when the engine is warm. But, it hangs around 3200RPM and idle is 1500RPM. It will hang for as long as 20s and only when coming to a stop. I can’t reproduce it by reving. I need to go for a decent distance.

Everything seems airtight. The only hint of anything wierd was that the bottom of the spark plug temp sensor had a bit of oil on it. But, the oil looked dry. Like from last time I did a plug chop. It’s wierd. No oil leaking. Intake is tight. Air box boot is tight. Propane around the carb didnt change idle. Scratching my head here.

[Zino]

I just fixed a hanging idle today only when warm
The main jet is right on .
I just had to raise the needle 1 clip rich.
With your non adjustable needle if you could get a very thin washer under the clip to raise it up.

When you dropped the pilot down you altered the mixture .

[lunatuck]

I was getting the hanging idle before I increased the pilot jet. I increased it for exactly this reason, but it sounded gurgly rich at idle with the larger jet and continued to have the hang. I'm looking for some sort of air leak because I'm 99% sure the idle was very rich with the new pilot jet. It's not what I typically think of as a hanging idle. Normally, you can blip and hear the slow return. This is as if the throttle cable is getting stuck, but its not from what I see. If that makes sense.

I do need to drill out the epoxy plug at the air/fuel mix screw so I can test, but I'm really thinking its coming from somewhere besides the jetting.

[lunatuck]

Finally the weather is getting better! Thinking through this years goals. I’d love to pickup a used Zuma or similar that I can really go crazy on, but until that happens I’m just going to keep optimizing this scoot with reliability being a primary focus. So... The plans seem to be as follows...

New clutch - I did a lot of clutch tuning last year, but the Stage 6 adjustable really seems like it’ll make everything easier. It pulls very well from the start, but its not a wheely scoot. While thats not my goal, I think it demonstrates that there is low end gains to be had.

New carburetor - The more I’m thinking about it, the more I believe that the stock carb is limiting performance. An 18.5 or so should give me gains, but more inportantly, I need the adjustability that my oem doesn’t have. No air/fuel screw and non-adjustable needle is too limiting.

Gear up - If I want to hit 60mph, I think I’ll need a gear up kit. I’ve never done any gearbox work, so its new to me. Also, theres not a ton of info on what will work, but I may be willing to take a chance and try to go to 9.9:1 from the stock 11.5:1. That should put me into 60mph territory easily. My hopes are that if I upgrade the clutch, I can do the gear up kit and get back some of the low end gains I’ll sacrifice with the gear up kit. I kind of look at the gear up and clutch upgrades as going hand in hand. I don’t want any clutch slip. I also like the idea of keeping the rpms lower, though I’m willing to optimize to 9500rpm.

Or, another scoot will pop up used and I can make wifey jealous. She refuses to drive the Tao Tao. Lol.

[lunatuck]

Ordered the Malossi Dellorto 19mm carb. Jets are out of stock, so hoping that I have the right size at home. I think I have the mains, but don’t think I have the pilots. May have to try and find them because I’ll be anxious to start the tuning process all over again.