Malossi 210 build thread - PWK30 tuning / bypass sorted!
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Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Location: London UK
Wed Jun 26, 2019 9:38 am quote
Yeah. The check on the stand is for checking WOT jetting. To check WOT jetting, it has to be at WOT. If its at half throttle, then you are checking half throttle jetting.

Half throttle should also get to 10000 rpm. I would hope you can get somewhere approaching 9000 rpm in gear. That means half is too rich as well but this will come down as you reduce the main jet. So, still too rich.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Wed Jun 26, 2019 1:14 pm quote
i might need new trousers if i get to 10000 rpm....
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Wed Jul 24, 2019 8:46 pm quote
At 150 main, 3/4 now goes to 7800 RPM, solid progress.

Will have a look at the plug this weekend along with moving down to 148 main most likely.

I think the bypass for the fuel pump may still be on the small side. If I ride for a long while and then do an extended downhill, the running gets rich at idle and I have to keep revving it to clean it out. The filter doesn't seem loaded, and it cleans up again afterward. I think I'll probably have to open up my restrictor by 0.5mm diameter again. I'm smaller than most of you with the spark plug nipple.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1629
Location: London UK
Thu Jul 25, 2019 6:57 pm quote
I think once you sort the richness at 3/4 and WOT, the whole throttle range will lighten up. Sounds like its getting closer though.

Do a very long WOT run before checking the plug. Holding the throttle pinned wide open for a long time can end in disaster, keep listening for pinking and watching CHT.

If the main needs to be richer for WOT and 3/4 is still slow and heavy, then you have the wrong needle.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Thu Jul 25, 2019 8:03 pm quote
WOT is always richer/lower RPM than 3/4 so far. It seems ok for needle yet. Random plug check says we are not in crazy territory. It isnít the wot check you mention but I still think we have room based on it and the max rpm at 3/4 and WOT.

C657A5C2-EE79-4BAC-A7D1-57F86EE9036C.jpeg

Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Thu Jul 25, 2019 8:04 pm quote
Main jet reduced to 148, will report back.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1629
Location: London UK
Thu Jul 25, 2019 9:33 pm quote
oh As I understand it now, the main jet is way too big. If 3/4 revs to 7800 and WOT revs less, drops and gets colder, then still over rich. And quite a lot over rich at that. Could skip 148 and go straight to 145. I think you'll end up at 140. You might need to up your pilot jet once at 140 but it's going to be obvious.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Fri Jul 26, 2019 6:03 am quote
it's only taken a few years but I think we are close now
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Fri Jul 26, 2019 2:48 pm quote
I wish I had a dollar for every time you thought you were close now!!!
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Fri Jul 26, 2019 6:48 pm quote
Yeah me too Ginch!
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Sat Jul 27, 2019 11:05 pm quote
I'm about to spring for one of these

https://www.ebay.com/itm/Knock-gauge-for-detonation-sensor-klopfsensor-NEW-with-output/183855557123

still not convinced that the knocking really really was knocking.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7214
Location: Victoria, Australia
Sun Jul 28, 2019 12:06 am quote
oopsclunkthud wrote:
I'm about to spring for one of these

https://www.ebay.com/itm/Knock-gauge-for-detonation-sensor-klopfsensor-NEW-with-output/183855557123

still not convinced that the knocking really really was knocking.
Looks interesting. Is there a sensor? Ah, just saw you need a knock sensor to connect it to. Where do you connect a knock sensor?
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Sun Jul 28, 2019 6:45 am quote
Ginch wrote:
oopsclunkthud wrote:
I'm about to spring for one of these

https://www.ebay.com/itm/Knock-gauge-for-detonation-sensor-klopfsensor-NEW-with-output/183855557123

still not convinced that the knocking really really was knocking.
Looks interesting. Is there a sensor? Ah, just saw you need a knock sensor to connect it to. Where do you connect a knock sensor?
You put the sensor on the end of one of the studs. The one that holds the shroud on would be ideal, with the sensor on the outside.
Ossessionato
1963 GL, 1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
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Sun Jul 28, 2019 7:38 am quote
Haha, love the idea of a knock sensor but imagine getting one to actually work on these noisy engines would be a bit of challenge. Mounting it in some meaty part of the cylinder below the head seems like a logical place for it, but Iím sure it would take some experimenting with different sensors, different placements and different noise filters to get it to pick up actual detonation vs other ďfalse knockingĒ signals. A perfect engineering task for you, Patrick!
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7214
Location: Victoria, Australia
Wed Aug 07, 2019 1:22 am quote
John I tried to work out what your current setup is but got confused. Can you please enlighten me as to which needle & jets you have in there?
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Wed Aug 07, 2019 7:58 am quote
HKJ needle on clip 4
main 148 is next trial, 150 was still rich
42 pilot
18 hole atomizer

I had to look it up myself
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Wed Aug 07, 2019 1:57 pm quote
sdjohn wrote:
HKJ needle on clip 4
main 148 is next trial, 150 was still rich
42 pilot
18 hole atomizer

I had to look it up myself
Ha ha! Thanks for that!
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Thu Aug 08, 2019 2:34 pm quote
John, how much difference is there between the 18 and 20 hole atomiser? Kyajet doesn't include them... what effect do they have on the system? I assume they don't exist in the Keihin OEM world?
Ossessionato
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Fri Aug 09, 2019 6:48 am quote
It's hard to say. I've not run the 20 hole. It has 2 more holes but all of the holes are smaller diameter, so I'm guessing it will end up richer than the 18 hole. They help to significantly lean out the middle to top end of the jetting range, particularly at higher RPM. The 18 hole is OKO, the 20/30/40 are Polini, and yes I think you are right that they don't exist in the OEM world. The 30 was way too much atomization, driving me to crazy needles. You are right, Kyajet treats all RPM equally, but this is really an item that changes low RPM vs high RPM. For any given atomizer, kyajet should still show an appropriate change in fueling, but it is not possible to use it to compare across atomizers.

Left to right:
18 hole OKO atomizer from treatland, 20 hole polini, 30 hole polini, 40 hole polini


Last edited by sdjohn on Fri Aug 09, 2019 6:50 am; edited 1 time in total
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
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Location: Victoria, Australia
Fri Aug 09, 2019 6:49 am quote
Thanks. Seems like the 18 hole is a special OKO thing.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Tue Sep 17, 2019 6:22 am quote
148 main = 7960 RPM on the flat. 146 main is next. Haven't been riding much but each time we get closer! It feels clean on average driving, getting pretty dialed in.
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
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Tue Sep 17, 2019 6:37 am quote
John, I truly admire your courage and patience. I'm fed up with mine. After the new piston, for some crazy reason my engine runs shittier and richer than before (no air leaks of course). I'll probably go for a PHBH or similar Delly or eventually burn it
Ossessionato
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Tue Sep 17, 2019 9:31 am quote
Maybe your air leak was before and it runs richer now that youíve sorted it....
Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
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Location: Veria, Greece
Tue Sep 17, 2019 10:06 am quote
sdjohn wrote:
Maybe your air leak was before and it runs richer now that youíve sorted it....
The culprit was probably the needle I had on clip 1 in my efforts to lean it down low and not an air leak. I even tried your current combo, still rich as hell till 1/2. I even dropped to 132 main and it's bogging like crazy (previously, I was running a 145 and it was OKish). Everywhere I asked, people told me the same thing. These carbs are crap and this is their main problem. They run rich as hell down low...
Ossessionato
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Tue Sep 17, 2019 12:52 pm quote
well if they were easy I'd have finished about 7 pages ago
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
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Tue Sep 17, 2019 2:36 pm quote
Vader talked me into one because he said they were easy to set up. I just live with it being very rich down low (currently on the smallest idle jet available), runs quite smoothly otherwise. Although, I do have the bits together now to duplicate your jetting John, so I'll be interested to see what difference it makes.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1629
Location: London UK
Tue Sep 17, 2019 7:10 pm quote
40 pages but no incidents. nothing wrong with that.

Sounding like its all working out. If all smooth from zero to WOT, then quite an achievement. Before dropping the main anymore I would want to know the sustained WOT CHT (at plug) temperature and that the plug colour could take a another drop.
Was that 7960rpm in 4th? I'm guessing 3rd and that is plenty.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Tue Sep 17, 2019 7:17 pm quote
Yes thatís 3rd gear. It still falls off going from 3/4 to WOT, I think itís got at least one more drop in there.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Tue Oct 01, 2019 6:23 am quote
a crisp morning + 146 main jet = 8500 RPM in 3rd with 3/4 throttle!

3/4 and WOT no longer feel different, I think we have found the proper main jet

I still have a problem where on one hill of my commute, a long downhill, it floods every time. Otherwise, though, I have no flooding issues. The idle jet seems to be otherwise OK, so I'm thinking float issues or I need to open that bypass up a bit. I'm going to try the bypass, I think.
Ossessionato
1963 GL, 1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
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Tue Oct 01, 2019 6:34 am quote
Time for some speed runs. Letís see what itíll do.
Ossessionato
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Tue Oct 01, 2019 6:56 am quote
SoCalGuy wrote:
Time for some speed runs. Letís see what itíll do.
It's pretty healthy, I was letting loose a bit this morning.
Ossessionato
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Tue Oct 01, 2019 6:57 am quote
... and?
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Tue Oct 01, 2019 7:01 am quote
You want top speed? I need more road!
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Tue Oct 01, 2019 12:19 pm quote
72MPH in 4th at 7000ish RPM is when I chickened out. That's indicated, but this speedo tracks dead on at 50MPH and the rev calculation seems about right using the scooterhelp calculator (actually scooterhelp says the MPH may be reading low). I don't think I want to go much faster on 10's
Molto Verboso
One or two fun scoots....nothing too precious
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Wed Oct 02, 2019 12:56 am quote
John, I see you are looking to sell the P. Has it got the better of you after 40+ pages? I was just starting to pay full attention to your exploits to help me get mine sorted.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Wed Oct 02, 2019 5:14 am quote
I donít know that Iíd say itís gotten the better of me, but rather that I think itís basically done and that for some strange reason Iíve still never really bonded with this bike. Iíve got my eye on some other bikes and thereís only 3 spaces in the garage and they are currently filled. Iím still plugging away at it for now. Iím going to put a float needle in and open the bypass to try and sort my rare random flooding next (at least I have one hill where it happens regularly to evaluate progress). Itís not over till itís over.
Molto Verboso
One or two fun scoots....nothing too precious
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Wed Oct 02, 2019 9:08 am quote
What is the flooding symptom, and what difference do you see with a hill? Reason I ask is that mine will splutter and cough up a certain hill at 3/4-full throttle. It seems just to be an oversized main jet. However, once I've reached the top of the hill and have covered a flat 300 yards, I come to a T junction. When pulling away, I get splutter at 1/4 and 1/2 throttle, which wasn't the case before the hill. It's as if the hill has upset the flow or float chamber or something. Feels like it's flooded.
Ossessionato
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Wed Oct 02, 2019 11:47 am quote
My deal is this:
Coming down a big hill at very light throttle, then coming to a stop light. The hill is long, and at the end you pull the clutch in and you can hear it is rich and going to stall. You can try a few throttle blips, but often on this one hill, it is too late for that even. I usually know it's coming and then put it into 2nd and dump the clutch to restart it and clear it out. There are other big downhills on my usual route but none that are this severe. Those others usually end in a rich idle. This has me thinking the bypass isn't big enough and the fuel pump is overcoming the float needle and filling the bowl extra high. Thus, the new float needle and the need to drill open my bypass restrictor to the next level (currently 2mm I think, will try 2.5). There may be a bike angle thing that comes into play here otherwise it wouldn't be limited to downhills. If I modify my route slightly to avoid this intersection, I'd never even know there was an issue .
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7214
Location: Victoria, Australia
Thu Oct 03, 2019 4:36 pm quote
So your "final" jetting is what again?

Keen to try out your jetting, I've collected the bits but didn't want to do it just before the Mille... I've learned some lessons about last minute changes before a big ride!

Yep sounds very much like too high a pressure from the pump, I had similar issues some time ago. I'm using the top off a spark plug in the bypass and I see a number of others have as well.
Ossessionato
2015 GTS300, 1974 Primavera, 04 Ninja 250
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Location: San Diego, CA
Thu Oct 03, 2019 5:04 pm quote
When I used the top of a spark plug it was too big, the bowl would run dry on light throttle. Something in between is what Iím after.

Jetting same as above but 146 main.
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