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Post by 90GTVert on Oct 27, 2023 13:22:54 GMT -5
I went to a JJK needle with the clip in the middle and that didn’t work at all. I could only use idle or just barely above or 3/4 to WOT. Otherwise it was sputtering and bogging and jumping around generally not going anywhere.
I had an area in the throttle where it wanted to act up a little with the JJL too, so I may need to figure something else out for needle selection than the JJs.
Better news is that RPM looked better when I attempted an acceleration run so the CVT should at least be closer.
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Post by 90GTVert on Oct 27, 2023 17:13:53 GMT -5
I decided to try the JJK with the clip at the top to lean it out. Needle position on this carb seems more drastic than what I’m used to. I usually think of clip position on the Dells as a bit more fine tuning where it feels like it’s more drastically altering the fuel delivery in the PWK.
It didn’t really seem different from the JJL. Idle still hangs when I come to a stop.
OK. Let’s try the bigger pilot like Keihin’s guide says. I went up from a 52 to a 58; the largest pilot jet that I have.
Now it feels soft off idle. Not crisp like it was. It still hangs a little, so I’m thinking maybe if I ever get a big enough main jet it won’t hang. Prob going down to a 55 or back to a 52 next time.
Even overheating, and it’s getting pretty hot again today, times are right around where the 28mm was that was in a decent state of tune. I’ll prob struggle again to be consistent because it wants to pull up if I give it much gas now. It’s easier to handle when slipping, but has more potential if I can deal with it this way.
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Post by oldgeek on Oct 27, 2023 17:45:18 GMT -5
I decided to try the JJK with the clip at the top to lean it out. Needle position on this carb seems more drastic than what I’m used to. I usually think of clip position on the Dells as a bit more fine tuning where it feels like it’s more drastically altering the fuel delivery in the PWK. It didn’t really seem different from the JJL. Idle still hangs when I come to a stop. OK. Let’s try the bigger pilot like Keihin’s guide says. I went up from a 52 to a 58; the largest pilot jet that I have. Now it feels soft off idle. Not crisp like it was. It still hangs a little, so I’m thinking maybe if I ever get a big enough main jet it won’t hang. Prob going down to a 55 or back to a 52 next time. Even overheating, and it’s getting pretty hot again today, times are right around where the 28mm was that was in a decent state of tune. I’ll prob struggle again to be consistent because it wants to pull up if I give it much gas now. It’s easier to handle when slipping, but has more potential if I can deal with it this way. I made identical observations, with the same needles trying to tune my 28 PWK on the 120cc. Ordered the Polini needle set to give them a try, they are supposed to arrive Monday finally. I have another set on PWK needles from a different source, but none of ones I tried worked. Also noticed the low speed screw seems to have little effect so it is usually 1/2 turn out for me.
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Post by 90GTVert on Oct 28, 2023 6:04:57 GMT -5
Also noticed the low speed screw seems to have little effect so it is usually 1/2 turn out for me. Mine seems to really only affect the idle or some area very very close to it. I'm used to possibly being able to eliminate lean hang by just mix screw richening, but this doesn't do much of anything for that right now. Then again, neither does a smaller needle diameter or any needle setting that doesn't make it way rich or a big pilot jet. It does change idle speed and how it idles so it's working. No drastic change though. The difference in about 1-1.5 turns out and 3.5 turns out was maybe 100-200RPM so I had to spend some time and watch it closely to tell that it was going the right way.
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Post by 90GTVert on Oct 31, 2023 6:29:27 GMT -5
200, 205, 210, 215, 220 and 230 main jets arrived from Niche Cycle yesterday. I overlapped with a 200 jet just in case the size/flow is any different from Stage6 jets. Also got a 175 and 178 from treatland that I ordered when I first realized the gap in S6 jet kits. Don’t like to mix and match, but don’t really wanna buy another entire set of jets. Naturally just in time for the weather to change. It was 80 yesterday, but very windy… blew some siding and a vent off of the house. I attempted test runs with the 52 pilot before the jets came just to see how bad it hangs, but the wind felt like hitting the brakes at times. Today the high is 53 with morning rain and wind gusts. By Thursday morning it may hit the 20s.
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Post by 90GTVert on Oct 31, 2023 18:11:46 GMT -5
The afternoon looked better than expected today. No rain and not windy, still cold enough at 50F exactly when I did a couple of test runs.
I tried a 215 main jet first. Still hot, but performance picked up. It's doing similar to the best times I've ever ran.
I tried a 230. Biggest commonly available jet for this carb. Still hot. Still performing well.
It averaged 1339 EGT at 60MPH with the 215 and 1294 with the 230. I need it to drop another 70 degrees consistently to match previous results, so that would mean probably a 250 or larger I'm guessing. 250 is the biggest jet I've ever seen for a PWK when I searched and not even available from Keihin or well known manufacturers from what I've seen.
I would like to say the EGT is just wrong since it's new... but the damn thing is running harder now with the big jets so there's at least some merit to all of the others being too small.
My question now is; what am I gonna do about this? I can trust Chinese main jets up to 250... which may not be big enough still. I can start trying to buy drill bits to go bigger. But why is my setup needing gigantic jets? I'm now almost 50 jet numbers above where Ryan is. It's still lean hanging. Is the bellmouth and giant filter so effective that jetting is not even in the same ballpark as just clamping a more standard UNI on there? Doesn't seem likely to me. Do I need a thinner needle and/or shorter? It looks like I have a 2.6mm needle jet, while some smaller versions of the PWK have larger. Is that too small... especially if paired with something like the filter setup that may want a bit more fuel? Ryan has ran an open bellmouth on his carb before though, and I don't recall him saying it needed a big swing in jetting. I don't think it should be fuel supply related. It never tries to die like I've seen with starvation in the past... it just gets hot. Plus it doesn't get worse with larger jetting, which tends to happen if the fuel supply is the problem. I'm not exactly sure where to go from here.
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tysta
Scoot Member
Posts: 74
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Post by tysta on Oct 31, 2023 22:33:05 GMT -5
I guess the internet will be happy now you have a bigger carb? 🙈 Let's hope so. lol I'm truly curious if there will be any difference as I've always been happy with carbs on the small side of suggestions and the only flat slide I've used is the Lectron. I used an OKO as the first carb that I ever put on my first Triton, but didn't like it. To be fair, it was too big for my setup (though part of a full performance package that I bought) and I wasn't very good with carbs at that point so I don't count that. IIRC it was a 28mm for a sport 70cc setup. well nothing wrong using a bigger carb. but down side is the intake speed is reduced alot. but in your case you should be ok after 10k rpm usually you need to make changes on intake and cylinder to work with bigger carbs. i run a 35mm on mine
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tysta
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Post by tysta on Oct 31, 2023 22:40:52 GMT -5
Here’s the Bonneville X360 intake installed. I have the other Malossi intake for 30-34mm carbs as well, but didn’t want to try it after Ryan’s recent experiences with the carb popping out. Fits OK. Didn’t even have to mod my seat bucket for it to clear the cable. I did swap to a 90 degree adapter vs the standard straight adapter that the PWK comes with. The filter is pretty huge, but so far so good. I fired it up for the first time yesterday. Idled and revved well enough with a quick adjustment that I took it down the road to see how it runs. It seemed to run well cruising down back roads and EGT looked good. Didn’t sputter as much as I’m used to at low throttle. I stopped to try a quick acceleration test but EGT hit 1402 by 60MPH so I let off. Tried again and I let off in the upper 1300s. Idle hangs and richening the mix screw makes it not want to idle so it prob needs a needle adjustment. I think I’m gonna start with a bigger main jet first because it’s way hot and I’ll see how much that changes low throttle. I’m glad Ryan had posted his tune, because the 122 MJ that it came with would have been light years off. so i noticed you didnt modify your sub frame. can actually gain 100% clearance for your intake and even install a spacer to gain some crankcase volume. i can send you some photos. hum i never liked those carbs but if you want to try a 35mm or a 33 mm keihin let me know i will send them over for a few so you can try them
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tysta
Scoot Member
Posts: 74
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Post by tysta on Oct 31, 2023 22:46:03 GMT -5
So far not so good with tuning. Moved up to a 195 MJ. Still too hot. Moved up to 205. Still too hot in 1/8 mile runs. That’s the largest jet that I have and that is found in Stage6 and Polini kits… at least what’s on ScooterTuning. I moved the needle up to see if that did anything at all to WOT since it seems to need more fuel down low anyway. Plug is fouling and I couldn’t do a run, but it still got hot if I held it WOT. The S6 filter is not oiled and I just left it that way. I guess I’m gonna oil it and see if that changes jetting after talking to Ryan about it. I don’t recall seeing a big swing from oiling, but foam should generally be oiled for better filtration so I’d expect it could make some change. Nothing to lose by trying at this point. If that doesn’t work, then I either need to buy a bunch of bigger jets or try the UNI that Ryan uses instead of the S6 with the bell mouth adapter and see if jetting changes. dont restrict the carb with a air filter just use the jets. if you very small metric drill bits you can make your jets since those numbers should match the metric system. "mikuni carbs are different measurement"
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tysta
Scoot Member
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Post by tysta on Oct 31, 2023 22:51:16 GMT -5
I’ve got the CVT apart, so here’s some fun stuff. 1300 mile drive belt is about 18.95-19.15mm, depending where I measure. One new belt is about 19.25mm. Another new belt, same thing, is around 19.4mm. New spec is 19.5mm. I’ll prob clean up the old belt and take some shims out. See if I can get a little more out of it. Gonna sand the vari faces at least to try for a little grip. When I took the variator off it was sticking a little. Opened it up and the steel o-ring is pinched. Can’t push the boss back through it, and shouldn’t anyway. No spare so I found a high temp o-ring and I guess I’ll find out if that’s a bad idea. I’ll be trying to get some replacements though. on mine even with 16.5mm belt wont slip. but iam also lighter than you. it actually makes a little bit more speed since it goes more down on the torque drive. how many kg is your contra spring?
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tysta
Scoot Member
Posts: 74
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Post by tysta on Oct 31, 2023 22:57:41 GMT -5
I decided to try the JJK with the clip at the top to lean it out. Needle position on this carb seems more drastic than what I’m used to. I usually think of clip position on the Dells as a bit more fine tuning where it feels like it’s more drastically altering the fuel delivery in the PWK. It didn’t really seem different from the JJL. Idle still hangs when I come to a stop. OK. Let’s try the bigger pilot like Keihin’s guide says. I went up from a 52 to a 58; the largest pilot jet that I have. Now it feels soft off idle. Not crisp like it was. It still hangs a little, so I’m thinking maybe if I ever get a big enough main jet it won’t hang. Prob going down to a 55 or back to a 52 next time. Even overheating, and it’s getting pretty hot again today, times are right around where the 28mm was that was in a decent state of tune. I’ll prob struggle again to be consistent because it wants to pull up if I give it much gas now. It’s easier to handle when slipping, but has more potential if I can deal with it this way. those carbs are kinda a replica of the keihin and some of their components are made to spec the diffuser and the piston valve most the times are wrong
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tysta
Scoot Member
Posts: 74
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Post by tysta on Oct 31, 2023 23:06:37 GMT -5
The afternoon looked better than expected today. No rain and not windy, still cold enough at 50F exactly when I did a couple of test runs. I tried a 215 main jet first. Still hot, but performance picked up. It's doing similar to the best times I've ever ran. I tried a 230. Biggest commonly available jet for this carb. Still hot. Still performing well. It averaged 1339 EGT at 60MPH with the 215 and 1294 with the 230. I need it to drop another 70 degrees consistently to match previous results, so that would mean probably a 250 or larger I'm guessing. 250 is the biggest jet I've ever seen for a PWK when I searched and not even available from Keihin or well known manufacturers from what I've seen. I would like to say the EGT is just wrong since it's new... but the damn thing is running harder now with the big jets so there's at least some merit to all of the others being too small. My question now is; what am I gonna do about this? I can trust Chinese main jets up to 250... which may not be big enough still. I can start trying to buy drill bits to go bigger. But why is my setup needing gigantic jets? I'm now almost 50 jet numbers above where Ryan is. It's still lean hanging. Is the bellmouth and giant filter so effective that jetting is not even in the same ballpark as just clamping a more standard UNI on there? Doesn't seem likely to me. Do I need a thinner needle and/or shorter? It looks like I have a 2.6mm needle jet, while some smaller versions of the PWK have larger. Is that too small... especially if paired with something like the filter setup that may want a bit more fuel? Ryan has ran an open bellmouth on his carb before though, and I don't recall him saying it needed a big swing in jetting. I don't think it should be fuel supply related. It never tries to die like I've seen with starvation in the past... it just gets hot. Plus it doesn't get worse with larger jetting, which tends to happen if the fuel supply is the problem. I'm not exactly sure where to go from here. ok like i said before you can use metric drill bits will match the numbers. but ear me out. looks like the intake speed dropped alot. my first question did you inspect the plug for color? which reed valve are you using alot of this can be corrected with reed valves. reeds and intake it self affect this alot. the thickness of the reeds and also their design affects the intake speed another thing is the mvt ignition seen this problem before and soon changed to a pvl or another good one problem is gone
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Post by 90GTVert on Nov 1, 2023 6:13:30 GMT -5
so i noticed you didnt modify your sub frame. can actually gain 100% clearance for your intake and even install a spacer to gain some crankcase volume. i can send you some photos. This seems to work quite well as-is concerning installation and service. The bowl clears the fender, throttle cable clears the seat bucket, can be rotated to swap jets and carb seems secure. That said, I'd gladly check out pics of a modified subframe. It's something I've considered in the past as well as more recently considering a very mild stretched version to try to gain a slight advantage for launch control without sticking the tire way out of the back. on mine even with 16.5mm belt wont slip. but iam also lighter than you. it actually makes a little bit more speed since it goes more down on the torque drive. how many kg is your contra spring? It's a 28kg Polini contra spring. I'm sure I could up the pressure and slider weight to reduce the likelihood of slip. Right now it's not slipping though and belt wear has been excellent. Probably a combination of too much shimming and glazed stuff. It would probably slip if I could use the throttle off the line, but there's no chance of me trying to twist it open quick when it's trying to wheelie with just slow opening. looks like the intake speed dropped alot. my first question did you inspect the plug for color? which reed valve are you using alot of this can be corrected with reed valves. reeds and intake it self affect this alot. the thickness of the reeds and also their design affects the intake speed another thing is the mvt ignition seen this problem before and soon changed to a pvl or another good one problem is gone No. It's been a long time since I've done plug chops. I rely on acceleration testing because my goal is quick acceleration, so whatever works best there is what I want in it. I've never had a carb that needs jets larger than what is made for it before though. Regardless, if it's picking up performance as temps drop closer to what typically works, that should be telling me that I indeed need to keep trying larger jets. It's the reed block and reeds that come with the RC-One. Same ones Ryan uses with his more "normal" jetting. I checked them over while swapping carbs and they still look like new. I have had so many people tell me the MVT sucks. I can't say that I get it. Granted, I've never tried another high end ignition. Had MVT on this and the TPR 86. With a 28mm VHST, Malossi pipe and MVT I've been within 0.5 seconds of Ryan's best times using a 34mm, 8.1 exhaust, Malossi/Selettra ignition. Him and his MetRuck are at least 150 pounds lighter than me and T2, punch a much smaller hole in the air, and I lose time taking off because I can't grab much throttle right away. He does experience some wheel spin on the street or belt slip on a prepped track though. I just don't think mine's that weak. I'm not saying that it definitely isn’t the problem, but there's gonna have to be a lot more testing before I buy a different ignition to try to solve this. Drilling to make larger jets does seem logical. I think I have a 2.5mm bit and possibly a standard that comes in that range somewhere. Doesn't seem like you need really small steps with these giant jets. But with a 2.6mm needle jet, it makes me wonder if you can really get anywhere with a main jet that's as big as it is.
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tysta
Scoot Member
Posts: 74
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Post by tysta on Nov 1, 2023 12:42:18 GMT -5
You should be using at least a 32kg contra and then match the weights. If you lean foward you should be able to control the wheelies no problem. your weight should be enough to keep it down.
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Post by 90GTVert on Nov 1, 2023 13:00:37 GMT -5
If you lean foward you should be able to control the wheelies no problem. your weight should be enough to keep it down. 🤣 You’ve obviously never rode this thing. I sit all the way up on the seat, lean forward and get the front suspension compressed from my weight and when it’s right just rolling in too quick makes me get back out of the throttle. I know it ain’t the fastest scooter around, but when the tune is working I have had to get out of it because it would loop itself from a 25MPH roll. I don’t like big wheelies and usually don’t get the wheel up more than a foot because I find it scary even at that, but I have accidentally done them before. Granted, I’m usually in my normal riding position on the back of the seat when I’m doing 25-30MPH power wheelies but I’m not even using all of the throttle before I get back out of it sometimes (with the 28mm… haven’t really tried with this). I believe ryan_ott could vouch for me on this. If not, I’d gladly let him hop on it next time he’s around and find out how easy it is to keep down. He rode it with the 86cc and the wheel would come up a little with that and I could launch that most of the time with quick WOT no problem as long as I kept my weight up front.
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