Project 49

[90GTVert]

And for yet another bit of info I forgot to add... You can feel how weak the engine is down low when you rev it. Even revving on the stand it takes it a second to build up. I tried tuning the carb different ways and removing the snorkel and it seems to me that it's just how it's gonna be with the porting and pipe. Lightweight ign systems might really show a benefit on a 49cc since there's really no low end grunt to miss out on.

[90GTVert]

It's just so much quicker after initial launch that it annoys me I can't make it go immediately cause I'd really have some impressive times to share vs what we've been seeing.

[palezu]

I had the same problem, really annoying. Try a longer drive belt. Some guys say here that the stock 788 belt is too short, especially with aftermarket variators, and causes the belt to be deeper in the rear pulley than it should be. Piaggio typhoon 804x17,5 belt is suitable, buy one and see if it will help some?

[90GTVert]

First off, here are the pics I said I'd post. Before and after of the cooling mods today.






I happen to have a Malossi OR belt for one of my other scoots with the OR CVT. It's 815 17.5. Here's how it sits with the front pulley off so it can ride on the drive boss.




Here's how it sits when actually installed. I tried a couple configs of extra washers since it's a little wider (actually about 1mm wider).




That didn't do it. It still bogged and it didn't get any more belt travel. Odd, cause I would have thought just having the belt out farther should help. It didn't in this case anyway and the Malossi belt costs 3x the Bando, so I'll stick with the cheap one.

I left the cover off and launched it in the garage a few times after I had already test rode it with different setups. It seemed the clutch/belt position is not the whole problem. It would be nice if I could free up the belt from a stop instead of squeezing it in the pulleys, but that can't happen unless I wanna lose speed.

Then I started thinking about drive face setups. I have 3 other than stock. The modded stock I've been using, a Hoca, and a KRS (which is a Stage 6 replica).




The KRS and the Hoca are pretty similar. The KRS has no fins. The KRS also has a smaller flat center than the Hoca.




The modded stock face seems like it should be best for performance to me. It would let the pulleys close most at speed for with the most opening at rest.




I tried the other fixed halves anyway. Sure enough, the modified stocker worked best. Then I decided maybe I could make the modded face better. It's a bit round and I could also make it a little steeper angle still.




I filed and filed and was not getting the results I wanted. Then I did something stupid. It worked really well for me, but it was dumb. Don't try this at home. You'll loose an eye or some teeth or something if it goes wrong. Bad idea. Get the idea? Okay, so I used my drill as a lathe and redid the drive face that way. Again... bad idea. Don't do it. It's dangerous and stupid and stuff like that so don't blame me if you do it and get hurt. I do not advise using this method.






I took one test run and it seems to work better. It had cooled off a lot by the time I got to that point, so I'll mess with it when it's hot again and see if it still works. It's not great now even, but better.

[90GTVert]

I think it's the contra spring. When I leave the house it hits 9000RPM quickly. When I am coming back (3-4 mile test rides) it's not at 9,000 until near top cruise speed. I can put lighter sliders in and get the revs up faster, but then they are too light for anything but drag racing to 35MPH basically. I'd do that if I lived in a town and never passed 35. It'd actually be pretty quick for a 50 that way.

[90GTVert]

I worked the drive face a little more this morning. Sanded the center quickly then put it back in the drill with a smaller washer this time for less of a flat spot. I thought I would take off enough material to use .5mm more spacing, but I never measured and I didn't remove enough I suppose. I got sort of a faded line when marking the variator and using 2.5mm of spacing instead of 2mm. Went back to 2mm and I can't tell a difference in launch vs 2.5mm, but it does a little better at speed.



Current setup is the Hoca variator with 6g sliders, that modded drive face, 2mm of spacers, 2,000RPM contra spring w/torsion control, lightened stock clutch w/1,000RPM springs. That's giving me a pretty good result. Not perfect. I was just looking for a decent setup to test the pipes that would show off their potential better and be less annoying to ride by keeping it in the power more. I hope to just swap sliders on the other pipes. Prob won't work, but that's what I'm crossing my fingers for.

I'd like the wind to die down so I can get a better 0-35MPH run in. I've got some GoPro stuff loading from test runs. I might be able to show you the difference in cold and hot soon at least. Not sure if it will really show on the vid or not. I know in the past some things that seem obvious to me don't come out on video.

[90GTVert]

I'd say the fade I mentioned is pretty obvious on video. lol

[palezu]

Looks so familiar. Back in the time when I still had mine tuned (and I had stock 171 porting) with cold engine it took off like a jet plane but after 5 min I lost takeoff to stock scooters. Actually I'm currently having the same problem even with the stock pipe with restrictions (after I lost my registration plates I had to restrict it back to get them back :laugh: ) but it is not so bad it was with the tuned pipe. That is probably because the stock pipe has a way wider powerband, at a lower rpm. Should have mentioned earlier, but I'm the ASoftaaja guy in youtube who asked you about the problem in your video, and yeah I have tried almost everything ;D

At first I fought long with the CVT believing the problem is in the springs fading, tried a couple of different springs and everything and got frustrated and went to adjusting the carb believing that the problem is there (rich mixture sometimes causes poor performance when the engine is warm). After fighting with the carburetor with no result for months and months, I'm now here and saw your video about the problem and I think I agree now that the problem is in the springs fading, but how in the name of CVT inventor, the problem can be fixed??

[90GTVert]

I do know some of my springs fade worse than others. The stock stuff seems to work best, but I don't have sliders light enough to get revs where they'd need to be for me. It's not taking off that bad now. If you can manage to get the belt completely free at idle the clutching part will improve a lot.

[90GTVert]

I had a very mild headwind for the 0-35MPH run, but it's doing quite well compared to all past runs.

[90GTVert]

It's been windy here, which is a pain with the 49cc, but I've got the SP3 on and have messed with it a bit. It seems to make peak power in the mid 8000s, so I am using 6.5g sliders instead of 6g with the GP. Pulls a little better at lower RPM, but with the CVT setup right it's really not at a low RPM other than briefly at the initial takeoff. Same 85 main jet. Seems like I'll be able to get similar speeds out of it, but I don't think it's gonna be as quick, although there's not a huge difference I don't believe. Maybe a few degrees milder porting and it would be hard to go wrong considering I see these online for $120ish new right now. Porting, CVT tuning, carb tuning, $50 variator, $120 pipe... that's not bad for a 50MPH capable, mid 40MPH cruising, 49cc setup. I've always said a BBK is by far the best choice for a first mod (accompanied by matching the carb and CVT to it of course), but I'm starting to wonder if I'll think the same thing when I try the 70cc. I've always said the torque really makes the BBK superior... but then with some time and effort I've got this thing tuned so that low rev power is pretty much irrelevant... of course that includes a $50 variator and you need to do the porting yourself and the tuning is a pain at times. lol I dunno... I'm interested to find out in real world tests when the time comes.

[90GTVert]

I must have had the wind in my favor more than I realized last time. I've got my doubts about mid 40s cruising and 50MPH with the SP3 now. Seems more like low 40s cruise speeds now, mid 40s at times.... Back to BBK superiority. lol I'm not gonna try to stretch 50MPH out of it. I'm sure it could be done, but I have no great desire to ride around tucked. Still seems like a deal if you need a pipe that is pretty quiet and doesn't look like a performance pipe and keeps a little more low end power, but it wouldn't be my choice of the two tested so far.

[90GTVert]

[reveeen]

I've always said a BBK is by far the best choice for a first mod (accompanied by matching the carb and CVT to it of course), but I'm starting to wonder if I'll think the same thing when I try the 70cc.

This is where you and I have always differed. I believe the best mod for a "new person" to be a LV ZX and kit. You end up with a pipe that will grow with you, and although there are better pipes, the included kit will give you the fundamental transmission tuning skills (if you pay attention) that you will need later.

[90GTVert]

When I did a BBK on a Beamer with carb tuning and he already had a Hoca variator I was very impressed. 50MPH, all stock appearance and pretty much same sound as stock since it was the stock pipe. With light rollers it would yank the front wheel up a little (deep gears I assume, my Tritons sure never did that)... but I didn't like that tune for speed so I sent it back to him with rollers that gave good speed and takeoff. Every time I hear about it (now 2-3 years later) he's been so happy with the scooter. He's done nothing else because it beats all of his riding buddies scoots, including the ones with pipes. He even asked me about a pipe with the big bore before deciding on the big bore. I coulda made more money from it, but I told him I'd advise trying this first and seeing if you're happy before spending more. Felt good to be right for a change. lol

I never liked mine with only the BBK that much... but I bought a power pack so I had the pipe around and got used to the pipe and the kit. I just pulled the pipe off at times cause between the MRP pipe and the open filter I literally used to make people jump when I revved it up in towns and I didn't always wish to have everyone stare when I rode around. Had I not known what I was missing, I probably would have been happy... well... as happy as a gearhead ever is with an engine/trans. lol

It makes it kinda tough to say what works best where too, because not all scoots are equal gearing and weight and riders like different things and so on.


I put the ZX on this morning, but I can't get anything accomplished. It seems weak. I've swapped sliders, but I think it's the stupid weather again. Instead of being windy today, it's raining off and on and very humid. It's running just a bit cool with the jet I think is probably right (85) and I can hear a faint sputter at WOT. Same symptoms I usually get out of an engine that normally runs well but when it's this humid. I see no point in trying to tune it when it's like this. I could swap to a leaner jet, but next time I try to ride I'll prob have to change back.

Riding long distances has been a good learning tool for me regarding this. It's the only way I've got to watch and listen first hand as weather changed from a humid morning to a normal day and a scooter went from low power and sluggish to running great. Seeing and feeling it is worth more than reading about it ever will be. Everybody that wants to learn about tuning should leave on a cool damp morning before the sun comes up and ride till at least noon. At very least, it's an excuse to ride.