Wed Aug 25, 2021 9:21 pm

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Wed Aug 25, 2021 9:21 pm linkquote
whodatschrome wrote:
And just to be clear, i currently have a 128 main in my 200. I do have the heart drilled into the air filter, flowed the carb and carb box to the case, and matched the cylinder transfers to the case as well, but the engine is still bone stock.

Doesn't the Malossi 210 kit come with a 130 and or a 135 main jet included?
It came with a 130 and a 120. My mechanic stuck .128, but it was four stroking, or at least that's what I think it was doing. I don't know why my spark plug is so dark with a .125. That's why I'm on here. Hopefully someone with insight might be able to help and with the four stroking around 4000 rpm.
Wed Aug 25, 2021 9:53 pm

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Wed Aug 25, 2021 9:53 pm linkquote
Hey now, some things:

1. That plug is dark as dark can be. On the other hand a 125 main jet is very much on the lean side for a port matched malossi 210. When dialled in you'd likely end up at about 128 with the 160/be3 stack.

2. When you took that photo was it after running WOT under load for a minute or so and then killing the engine? Or was that just after general usage?

3. If it was the latter, put that 127 (or even the130) back in and do the former. And If the plug is then still black, I'm at a loss to explain what's happening. But it shouldn't look like that at 125. The ceramic should be white as the driven snow, and the CHT would go north of 300F.

4. My best guess, assuming that photo wasn't the result of a WOT run, is that you've got a very rich idle circuit going. I understand you haven't installed that slightly fatter idle jet though. How many turns out is the mixture screw?

5. Slightly O/T: total elimination of four-stroking at low RPMs on these engines is a fool's errand. You'll never get rid of it entirely. I mean you can come close, with leaner idle circuits and less overlap with the MJ, but then you start courting disaster when you're rolling off a long WOT run. That gurgly, rough patch is a small price to pay for not seizing.
Wed Aug 25, 2021 10:41 pm

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Wed Aug 25, 2021 10:41 pm linkquote
Hey now, some things:

1. That plug is dark as dark can be. On the other hand a 125 main jet is very much on the lean side for a port matched malossi 210. When dialled in you'd likely end up at about 128 with the 160/be3 stack.

2. When you took that photo was it after running WOT under load for a minute or so and then killing the engine? Or was that just after general usage?

This was after riding for about an hour of general use.

3. If it was the latter, put that 127 (or even the130) back in and do the former. And If the plug is then still black, I'm at a loss to explain what's happening. But it shouldn't look like that at 125. The ceramic should be white as the driven snow, and the CHT would go north of 300F.

I don't really have a chance to ride WOT much that's why I figured I should ride it the way a normally would. The speed limit any where near me is around 50km and I usually do 60-70km. Also my kit came with a 120 instead of a 127. I can't seem to find a 127 or 126 any where. Even if I did, the shipping cost is $30.

4. My best guess, assuming that photo wasn't the result of a WOT run, is that you've got a very rich idle circuit going. I understand you haven't installed that slightly fatter idle jet though. How many turns out is the mixture screw?

I'm not sure how many turns out the mixture screw is out. My mechanic did the initial tuning. It idles perfect though. I'll ask and sees if he can remember. I know I have to do it, but I really hate messing with the mixture screw because of the starter motor, even with an angled wrench.

Is there a ratio that you can recommend for the idle jet?


5. Slightly O/T: total elimination of four-stroking at low RPMs on these engines is a fool's errand. You'll never get rid of it entirely. I mean you can come close, with leaner idle circuits and less overlap with the MJ, but then you start courting disaster when you're rolling off a long WOT run. That gurgly, rough patch is a small price to pay for not seizing.

That's what I got after watch misterfreaks videos, but it was four stroking pretty bad. Enough were first and second were not fun.
Thu Aug 26, 2021 1:50 am

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Jet Eye Master
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Thu Aug 26, 2021 1:50 am linkquote
If it gets hot quickly soon after opening it up, it's way way too lean. Should take a few miles of WOT in 4th, at full speed, before it even gets to 300F.

160 air correctors are for near stock cylinders. Anyone who puts one in a Malossi 210 has too much money to burn.

Tuned road going 2 strokes should almost splutter or feel like they are near splutter all the time.
Thu Aug 26, 2021 2:48 am

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Thu Aug 26, 2021 2:48 am linkquote
Jack221 wrote:
If it gets hot quickly soon after opening it up, it's way way too lean. Should take a few miles of WOT in 4th, at full speed, before it even gets to 300F.

160 air correctors are for near stock cylinders. Anyone who puts one in a Malossi 210 has too much money to burn.

Tuned road going 2 strokes should almost splutter or feel like they are near splutter all the time.
Any recommendations on where to begin? Don't want have money to burn, so it would be awesome if you can set me the right direction.
Thu Aug 26, 2021 4:12 am

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Thu Aug 26, 2021 4:12 am linkquote
Hey so, Phangtonpower -- just some points:
Quote:
2. When you took that photo was it after running WOT under load for a minute or so and then killing the engine? Or was that just after general usage?

This was after riding for about an hour of general use.
So yeah -- the plug only reflects what the engine was doing most recently. It gets 'painted' relatively quickly, after a minute or so of use. So, if you want to see what's doing at WOT, run it at WOT (under load) for a minute and then kill the engine. For the same at midrange, same deal -- run it along at 1/3 throttle for a minute or two and kill the engine. And of course the same for idle.
Quote:
I don't really have a chance to ride WOT much that's why I figured I should ride it the way a normally would. The speed limit any where near me is around 50km and I usually do 60-70km. Also my kit came with a 120 instead of a 127. I can't seem to find a 127 or 126 any where. Even if I did, the shipping cost is $30.
Not sure what's going on with your engine but I'd recommend against running WOT with a 120MJ on a malossi 210 that's using a 160 AC. More on that further below.
Quote:
I'm not sure how many turns out the mixture screw is out. My mechanic did the initial tuning. It idles perfect though. I'll ask and sees if he can remember. I know I have to do it, but I really hate messing with the mixture screw because of the starter motor, even with an angled wrench.

Is there a ratio that you can recommend for the idle jet?
Well, you've got the stock 55/160 idle jet in there, which is apparently a bit lean for the Malossi 210. I've put in a 50/140 which is slightly fatter. Re the mixture screw, yes that's a gigantic pain in the ass b/c of the starter motor. I had one of those once. But you'd do well to make sure it's 2.5 turns out from fully seated, at least.
Quote:
That's what I got after watch misterfreaks videos, but it was four stroking pretty bad. Enough were first and second were not fun.
From the sounds of it this isn't just some mis-jetting with the mixture screw. Any chance you could upload a video?

On to the next section, which is a bit of a thread hijack but Phangtonpower asked so....

@Jack221 - I've been reading about this mythical JackStack (tm) here and there for some time now and I'm thinking it's time to take the plunge. See what life is like there with the smaller air corrector and a BE5. But I can't find any single cohesive JackStack source anywhere explaining what's going on in terms of theory etc. So, here goes -- I don't have a 120 AC, but I do have a 140 lying around. Would playing with that get me anywhere with this Malossi 221 setup? Get me "halfway" to a JackStack at least? And would the 140 play well with the BE5?
[/i]
Thu Aug 26, 2021 4:39 am

Moderibbit
1980 P200E - "Old Rusty", 1976 ET3 Primavera
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Thu Aug 26, 2021 4:39 am linkquote
I don't know what your bike needs, but I totally agree you shouldn't go down to a 120. A completely stock premix P200 runs a 118. You're asking for trouble if you go that low.
Thu Aug 26, 2021 4:42 am

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Thu Aug 26, 2021 4:42 am linkquote
xantufrog wrote:
I don't know what your bike needs, but I totally agree you shouldn't go down to a 120. A completely stock premix P200 runs a 118. You're asking for trouble if you go that low.
I never said 120. I said for some reason malossi sent me a 120 and 130. I have a 125 right now and I even think that's low, but is running better than the 128 I had before.
Thu Aug 26, 2021 4:56 am

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Thu Aug 26, 2021 4:56 am linkquote
For whatever it's worth, Malossi's recommended jetting for this kit depends on whether you have modified the intake timing on the crankshaft. If you have, Malossi recommends a main jet between 125 and 130. If you haven't, Malossi recommends a main jet between 120 and 125. Based on that, it is plausible that the 125 is too rich.

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Thu Aug 26, 2021 5:04 am

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Thu Aug 26, 2021 5:04 am linkquote
Kowalski wrote:
For whatever it's worth, Malossi's recommended jetting for this kit depends on whether you have modified the intake timing on the crankshaft. If you have, Malossi recommends a main jet between 125 and 130. If you haven't, Malossi recommends a main jet between 120 and 125. Based on that, it is plausible that the 125 is too rich.
Intresting... My crank is stock and the reading I have done, most have used 126-128.

One thing I noticed though is that my temps did go up about 30 degrees going up a short incline. Jack mentioned it should take a while. I don't know if a 5 second incline going 60km would raise it that quick?

Do you guys know what a good temperature would be going 60km most of the time?
Thu Aug 26, 2021 5:16 am

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Thu Aug 26, 2021 5:16 am linkquote
Kowalski wrote:
For whatever it's worth, Malossi's recommended jetting for this kit depends on whether you have modified the intake timing on the crankshaft. If you have, Malossi recommends a main jet between 125 and 130. If you haven't, Malossi recommends a main jet between 120 and 125. Based on that, it is plausible that the 125 is too rich.
That's with an unmodified bike otherwise, though. The OP has a Polini Big Box, right?

My otherwise stock P200e with an SIP Road 2, 1st oversize, carb box milled to match base, runs a 125 MJ, and that was dialed in with the help of SF Scooter Centre. It's not unusual to see 120-122s on more-or-less stock P2s with a simple Sito or Road pipe.

*edit* not that the OP is planning on going down to a 120, as they've clarified
Thu Aug 26, 2021 7:43 am

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Thu Aug 26, 2021 7:43 am linkquote
xantufrog wrote:
That's with an unmodified bike otherwise, though. The OP has a Polini Big Box, right?

My otherwise stock P200e with an SIP Road 2, 1st oversize, carb box milled to match base, runs a 125 MJ, and that was dialed in with the help of SF Scooter Centre. It's not unusual to see 120-122s on more-or-less stock P2s with a simple Sito or Road pipe.

*edit* not that the OP is planning on going down to a 120, as they've clarified
Yes sir, I am running a Polini.

With my sito I was running a 122 and B6ES(recommended plug for Japan) and it ran lean. Before I had the Malossi installed, I drilled the main to float chamber in the carb and ran the polini with that setup. I knew it would run rich. It four stroked, but not as bad as it did with a 128 and 210 installed.

I'm not sure how to proceed next. I don't really have the space to do WOT testing and I'm not sure if I should be looking at the Idle jet or air mixture. I talked to my mechanic and he had the mixture screw turned out 2 turns for a spaco.
Thu Aug 26, 2021 8:25 pm

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Thu Aug 26, 2021 8:25 pm linkquote
Doing more research, I found this thread on an Italian site with the same issues I have. Setup is almost exact except I doesn't mention what kind of exhaust he is using. He ended up using a 120MJ...Scary.
https://www.et3.it/topic/71799-malossi-210-sport-problemi-carburazione/
Thu Aug 26, 2021 11:17 pm

Jet Eye Master
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Thu Aug 26, 2021 11:17 pm linkquote
Phangtonpower wrote:
Any recommendations on where to begin? Don't want have money to burn, so it would be awesome if you can set me the right direction.
AC120 BE5 130MJ 50/100 pilot. This main jet should be too big, if your fuel flow is enough. Check the carb is drilled out to over 2mm also.
Thu Aug 26, 2021 11:31 pm

Jet Eye Master
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Thu Aug 26, 2021 11:31 pm linkquote
JimVanMorrissey wrote:
I don't have a 120 AC, but I do have a 140 lying around. Would playing with that get me anywhere with this Malossi 221 setup? Get me "halfway" to a JackStack at least? And would the 140 play well with the BE5?
[/i]
An AC140 BE5 combo go really well in a stock 125cc motor. These are not going be rich enough to cool a 221cc at max rpm.
SI carbs only look simple. Is hard to find any real information about them.
Fri Aug 27, 2021 5:25 pm

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Fri Aug 27, 2021 5:25 pm linkquote
Jack221 wrote:
AC120 BE5 130MJ 50/100 pilot. This main jet should be too big, if your fuel flow is enough. Check the carb is drilled out to over 2mm also.
Thanks Jack!!
I can't seem to find a 50/100 pilot. Would you pick a 55/100, 48/100, or get both and see what works best?
Fri Aug 27, 2021 10:49 pm

Jet Eye Master
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Fri Aug 27, 2021 10:49 pm linkquote
55/100 might be slightly too much but this is better than not enough.
Sat Aug 28, 2021 10:17 pm

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Sat Aug 28, 2021 10:17 pm linkquote
Jack221 wrote:
55/100 might be slightly too much but this is better than not enough.
Thanks for the help Jack!! I'll give it a try.

Today I went out for a long run. Installed the 128 back. It runs ok. The carb bolts were a little loose. Re torqued it. I need to check the spark plug again.
Sun Sep 05, 2021 9:12 am

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Sun Sep 05, 2021 9:12 am linkquote
Jack221 wrote:
AC120 BE5 130MJ 50/100 pilot. This main jet should be too big, if your fuel flow is enough. Check the carb is drilled out to over 2mm also.
I finally got everything together this weekend exactly as you mentioned including the 50/100. First run tried a 130. Way too rich. Worked my way down from a 130>128>125>122. I feel the 122 works best so far, but at the same time is it too small?

As I mentioned I really don't have a stretch to do WOT runs and do plug
chops. I could do quick burst for maybe 10 seconds at the most. I'm still getting a flat spot/sputtering around 4000 5000 rpm

Temps are cooler then the stock set up by 20F to 30F.
Sun Sep 05, 2021 1:55 pm

Jet Eye Master
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Sun Sep 05, 2021 1:55 pm linkquote
WOT doesn't actually mean full speed in 4th gear. Wide open in 2nd gear is actually the best.
Ride along at 3000 rpm in 2nd, then suddenly go full throttle until max rpm and hold it there for a few seconds.
Two things should happen when jetted correctly. It should accelerate immediately without bog or splutter. Also it should achieve max rpm without any splutter and hold full rpm steady.
Try this and see how you get on.
Mon Sep 06, 2021 12:01 am

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Mon Sep 06, 2021 12:01 am linkquote
Jack221 wrote:
WOT doesn't actually mean full speed in 4th gear. Wide open in 2nd gear is actually the best.
Ride along at 3000 rpm in 2nd, then suddenly go full throttle until max rpm and hold it there for a few seconds.
Two things should happen when jetted correctly. It should accelerate immediately without bog or splutter. Also it should achieve max rpm without any splutter and hold full rpm steady.
Try this and see how you get on.
Ah ok good to know!! I actually have been doing that usually in 2nd and 3rd. Can't remember where, but it does splutter a little around the 4000/5000 rpm. It does take off smoothly. I can't recall right now as I have another issue, but do you think a 122 is too small?

Anyway today went for a ride of easy riding, and the clutch went out. I was stuck on the side of the road till I had it towed back home, but I haven't had a chance to really look at it.

Cable feels like it's adjusted properly with a little amount of play. When I disengage the clutch the rpms drop and it stalls out unless I give it gas. it also has a loud raddle sound. I rebuilt a little bit before the kit was installed with a SIP banded 16 spring clutch basket using only 12 of the medium springs and honda corks. I hope it's not the seals!! Are there anything to look for when I take the clutch apart?
Mon Sep 06, 2021 3:02 pm

Jet Eye Master
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Mon Sep 06, 2021 3:02 pm linkquote
First thoughts are the clutch nut has come undone. Heavy rattle and stalling are usual. Take it out and see.
Tue Sep 07, 2021 6:16 am

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Tue Sep 07, 2021 6:16 am linkquote
Jack221 wrote:
First thoughts are the clutch nut has come undone. Heavy rattle and stalling are usual. Take it out and see.
Good call. Torqued down and loctited still got this.
Still wondering if 122 is to small a main jet? I feel I could go down one more.



Sun Sep 26, 2021 6:43 am

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Sun Sep 26, 2021 6:43 am linkquote
Jack221 wrote:
First thoughts are the clutch nut has come undone. Heavy rattle and stalling are usual. Take it out and see.
Finally got my clutch all sorted, but here is where I am with my jetting.

I went back and tried the 128 way to spluttery.

The 125 accelerated smoothly from WOT, but it was spluttery and 4 stroked from 1/4 to 3/4 throttle.

Back to the 122. It feels the best so far, but I'm not really sure if it's too small. I still feel that I can go down one more.

If the 122 is too small, can there be another issue I should be looking at?
Sun Sep 26, 2021 9:28 am

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Sun Sep 26, 2021 9:28 am linkquote
Phangtonpower wrote:
Finally got my clutch all sorted, but here is where I am with my jetting.

I went back and tried the 128 way to spluttery.

The 125 accelerated smoothly from WOT, but it was spluttery and 4 stroked from 1/4 to 3/4 throttle.

Back to the 122. It feels the best so far, but I'm not really sure if it's too small. I still feel that I can go down one more.

If the 122 is too small, can there be another issue I should be looking at?
I suspect the BE5 mixer tube is too rich for your setup. Try a leaner mixer tube--a BE1 if you can find one or go back to the BE3.
Sun Sep 26, 2021 7:44 pm

Jet Eye Master
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Sun Sep 26, 2021 7:44 pm linkquote
So to confirm, you are running AC120 BE5 122MJ 50/100 pilot? And on a Malossi 210 Sport with a 24/24 and box pipe?

When you did the holding wide open in 2nd gear the 128 spluttered badly, 125 not so much and 122 was ok?
Sun Sep 26, 2021 10:54 pm

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Sun Sep 26, 2021 10:54 pm linkquote
Jack221 wrote:
So to confirm, you are running AC120 BE5 122MJ 50/100 pilot? And on a Malossi 210 Sport with a 24/24 and box pipe?

When you did the holding wide open in 2nd gear the 128 spluttered badly, 125 not so much and 122 was ok?
Yes sir. Went for an hour long ride today with that set up. Just a cruise, no WOT. I'm still noticing 4 stroking at around 4000rpm. Temps were at about 250F when going about 60km/37mph.
Mon Sep 27, 2021 3:24 am

Jet Eye Master
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Mon Sep 27, 2021 3:24 am linkquote
A lot of peoples 4 stroking is actually not. Sometimes it feels just like it and sounds like it but really its lean.
I think this could be the case here. Try a 55/100 pilot or a BE4 (or both), whichever you have. If the initial pull away seems clean and sharp then bogs, the BE4 is probably more important.
Mon Sep 27, 2021 7:54 am

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Mon Sep 27, 2021 7:54 am linkquote
Kowalski wrote:
I suspect the BE5 mixer tube is too rich for your setup. Try a leaner mixer tube--a BE1 if you can find one or go back to the BE3.
Jack221 wrote:
A lot of peoples 4 stroking is actually not. Sometimes it feels just like it and sounds like it but really its lean.
I think this could be the case here. Try a 55/100 pilot or a BE4 (or both), whichever you have. If the initial pull away seems clean and sharp then bogs, the BE4 is probably more important.
Looks like I have some mixers to try out. Thank you both!

Jack I'll try the 55/100 first since it's already in.
Tue Sep 28, 2021 5:17 am

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Tue Sep 28, 2021 5:17 am linkquote
Jack221 wrote:
A lot of peoples 4 stroking is actually not. Sometimes it feels just like it and sounds like it but really its lean.
I think this could be the case here. Try a 55/100 pilot or a BE4 (or both), whichever you have. If the initial pull away seems clean and sharp then bogs, the BE4 is probably more important.
So today and went and tried a BE4 with the 55/100 pilot. It felt the same as before with a 128/125/122 but it did pull a lot cleaner at WOT with the 125. It was still spluttery below. For some reason the temps seem little hotter by a few degrees. The four stroking/splutter around 4000rmp has cleaned up a lot to. Another thing I'm noticing is that it will stutter a little around 1/2 throttle and below especially in second and sometimes 3rd. This is with a 122MJ.

It feels like I'm getting there. maybe the idle jet?

Edit: I just realized I still have the 50/100 in it. I'll give the 50/155 a try when I get a chance.
Tue Sep 28, 2021 9:31 pm

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Tue Sep 28, 2021 9:31 pm linkquote
Today I gave the 55/100 pilot a try. With the 125 it felt too rich. The 122 feels a little richer and four strokes a little more. If a kitted bike is supposed to four strike a little maybe this is the setting? The 122 does run a little cooler than before.
Tue Sep 28, 2021 10:52 pm

Jet Eye Master
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Jet Eye Master
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Tue Sep 28, 2021 10:52 pm linkquote
Now is AC120 BE4 122MJ 55/100 pilot? And with a stock drilled air filter and bellows?
Is the 4000rpm issue any better? Whats the 50mph steady cruise temperature?
Tue Sep 28, 2021 11:01 pm

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Tue Sep 28, 2021 11:01 pm linkquote
Jack221 wrote:
Now is AC120 BE4 122MJ 55/100 pilot? And with a stock drilled air filter and bellows?
Is the 4000rpm issue any better? Whats the 50mph steady cruise temperature?
Yes it's a AC120 BE4 122MJ 55/100 pilot. The air filter is stock pre-drilled. The bellow is stock. The 4000rpm issue does feel better. As far as cruising at 50mph. There are no roads or space in Japan, or at least in my prefecture, that you can cruise at that speed unless your on the toll ways, so I haven't tested it. I have taken it up to that speed, but it's rare that I do and I can only do it for a few seconds. I usually ride half throttle at most and really only use WOT for passing cars, or if I need to going up hill.
Tue Sep 28, 2021 11:28 pm

Jet Eye Master
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Tue Sep 28, 2021 11:28 pm linkquote
UK is not so far behind with the amount of speed cameras and unmarked cars everywhere. Still manage to get some fast runs though. There's always a way.

If the 4000rpm is now better with it much richer, its probably still not rich enough. The filter will be half the issue. This will keep the main jet smaller. Vortex, T5 filter or nothing are the best options.

What makes you think the 125MJ is too big? Maybe a sound recording would help.

When a 2 stroke is jetted well, one thing you notice is that, almost all general riding can be done using less than 1/4 throttle.
Wed Sep 29, 2021 2:01 am

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Wed Sep 29, 2021 2:01 am linkquote
Jack221 wrote:
UK is not so far behind with the amount of speed cameras and unmarked cars everywhere. Still manage to get some fast runs though. There's always a way.

If the 4000rpm is now better with it much richer, its probably still not rich enough. The filter will be half the issue. This will keep the main jet smaller. Vortex, T5 filter or nothing are the best options.

What makes you think the 125MJ is too big? Maybe a sound recording would help.

When a 2 stroke is jetted well, one thing you notice is that, almost all general riding can be done using less than 1/4 throttle.
The speed limit of 99.5% of the roads I ride is 50km and below. 50km for half the drivers here means 40km. I'm already "that guy" that passes people. I don't even see other motorcyclists pass people often. Plus I don't trust the drivers here at all. Sure I can cruise at 80 km, but probably a minute at the most.

This video is not me, but similar roads I ride.
I'll try and get audio, but I don't know how to post it on here. I think the 125MJ with the 50/100 pilot pulled the cleanest at WOT, but any other throttle position and in almost all RPM range in 4 stroked. The 55/100 felt more boggy.
Fri Oct 01, 2021 8:35 pm

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Fri Oct 01, 2021 8:35 pm linkquote
Jack221 wrote:
UK is not so far behind with the amount of speed cameras and unmarked cars everywhere. Still manage to get some fast runs though. There's always a way.

If the 4000rpm is now better with it much richer, its probably still not rich enough. The filter will be half the issue. This will keep the main jet smaller. Vortex, T5 filter or nothing are the best options.

What makes you think the 125MJ is too big? Maybe a sound recording would help.

When a 2 stroke is jetted well, one thing you notice is that, almost all general riding can be done using less than 1/4 throttle.
Here's a recording with AC120 BE5 125MJ 50/100 pilot. I took it up to 80km for a little bit. Temps went up to 245F. I'm sure it would have went up more if I could run it longer, but it is running a lot cooler. Also I'm wondering if the flat spot I'm getting at 4000rpm is the exhaust. I was warned earlier in this thread that the polini has less top end compared to others.
https://soundcloud.com/phangtonpower/recovery-20211002-1116031

I'm starting to understand when you said "Tuned road going 2 strokes should almost splutter or feel like they are near splutter all the time." I'll keep it with jetting for a while and see how it goes, but please give it a listen and tell me what you think.
Fri Oct 01, 2021 9:48 pm

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Location: London UK
Fri Oct 01, 2021 9:48 pm linkquote
Phangtonpower wrote:
Here's a recording with AC120 BE5 125MJ 50/100 pilot. I took it up to 80km for a little bit. Temps went up to 245F. I'm sure it would have went up more if I could run it longer, but it is running a lot cooler. Also I'm wondering if the flat spot I'm getting at 4000rpm is the exhaust. I was warned earlier in this thread that the polini has less top end compared to others.
https://soundcloud.com/phangtonpower/recovery-20211002-1116031

I'm starting to understand when you said "Tuned road going 2 strokes should almost splutter or feel like they are near splutter all the time." I'll keep it with jetting for a while and see how it goes, but please give it a listen and tell me what you think.
First impression is its not running terrible. When over rich they can be much worse and this is more obvious. Still sounds like it could be lean.

If you are actually running AC120 BE5 125MJ 50/100 pilot, then you need to fit the 55/100 pilot. There is quite a difference between the two. When on the 55/100 give the sound recording another go. Keep in 2nd gear all the time and ride from zero to WOT and everything inbetween. Although will probably do 70km/h in 2nd, so even that might be a speed issue in Japan.

The other thing is the air filter. If its still a stock P200 filter its too restrictive. It will eventually jet in with the stock filter but will always feel a bit flat.
Fri Oct 01, 2021 11:42 pm

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Fri Oct 01, 2021 11:42 pm linkquote
Jack221 wrote:
First impression is its not running terrible. When over rich they can be much worse and this is more obvious. Still sounds like it could be lean.

If you are actually running AC120 BE5 125MJ 50/100 pilot, then you need to fit the 55/100 pilot. There is quite a difference between the two. When on the 55/100 give the sound recording another go. Keep in 2nd gear all the time and ride from zero to WOT and everything inbetween. Although will probably do 70km/h in 2nd, so even that might be a speed issue in Japan.

The other thing is the air filter. If its still a stock P200 filter its too restrictive. It will eventually jet in with the stock filter but will always feel a bit flat.
If I can find a T5 air filter and taller carb box cover, I would have to rejet right?
Sat Oct 02, 2021 3:50 am

Jet Eye Master
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Sat Oct 02, 2021 3:50 am linkquote
Yes. But only the main jet. A less restrictive filter (or none with a vortex) would need a bigger main jet as the air flow would increase. Air flow then leans out more at lower rpm, while the top stays richer due to the bigger jet.
Do a ride without the filter and feel the difference.
Sat Oct 02, 2021 9:08 pm

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Sat Oct 02, 2021 9:08 pm linkquote
Jack221 wrote:
Yes. But only the main jet. A less restrictive filter (or none with a vortex) would need a bigger main jet as the air flow would increase. Air flow then leans out more at lower rpm, while the top stays richer due to the bigger jet.
Do a ride without the filter and feel the difference.
Here's where I'm at today.
https://soundcloud.com/phangtonpower/carb-2?si=cb5757e29b00474c94c9c1589cc111d2

With the 55/100, I can't adjust the idle. I have the idle screw all the way in and will sometimes stall out. It idles between 900-1200 if it doesn't stall out. A few times the it actually went up pretty high coming to a stop and went back down after blipping it. Maybe not enough gas?
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