Triton # 2 (T2) 49cc to 110cc & Nearly Everywhere In Between

[billwill]

Jun 3, 2024 12:51:44 GMT -5 90GTVert said:

Jun 3, 2024 8:51:00 GMT -5 billwill said:

Got a link for that clear bowl? I've been thinking about trying one myself but haven't been able to find one with a confirmed fit specifically for the Polini PWK.

amzn.to/4aLe4oj

There are more on there. There are some that don't have the power jet barb that you need to cap if you don't have one. Some have a drain. This one worked and had residue in it for a month and hasn't deteriorated that I can tell so I just reordered it.

Jun 3, 2024 8:51:00 GMT -5 billwill said:

Very intrigued in this whole problem and following closely since I have a Polini PWK30 that seems to make my bike run hotter than it should. Also dealing with the mysterious lack of ceiling for main jet. This thing keeps taking more and more of a main jet and gobbling them up. It ran (very lean) with a 128 main and I've since upped it to a 148 where it was still running clean and crisp, though just a bit hot on sustained WOT runs.

I installed the MVT dd over the weekend and that seems to have cooled things down a bit, interestingly enough. Going to try a 154 main next and see how that takes but it seems awfully large for my setup.

Considering most with a 34mm are 175-195 MJ, 150 doesn't sound crazy to me at all on a 30mm. My 28mm VHST is currently liking 140-ish, but used a 150 for most of it's time and that's what Malossi sends it with. Not sure what everyone else uses with a 30mm PWK though.

Right on, thanks man. Going to give it a go and mount my phone focused on it like you did with the GoPro.

I went even higher on my main and its still running a bit hot for sustained WOT. 154 main now and still no sign of sputtering. These polini PWKs gobble up fuel.

And oh I thought I remember you saying that RC-ones are taking 165 with the 34. But 175-195 makes more sense.

[90GTVert]

The replacement cheap bowl seems even slightly cheaper. Exact same link I posted and ordered from both times. Nothing major, but the barb that I have to block for power jet is smaller on the new one. The adapter ring has some sharp edges and the bowl has some sharper spots. Again, not a problem, but I wanted to make you aware. Oddly enough, if you mix and match the old bowl with the new ring and the other way round, they match color like it seems like they should.


First kit on top.


Mixed and matched.

[90GTVert]

I spent quite a while working on the piston’s ring land. I tried to sand just the top of the ring land the best I could with 400 and then 220 grit once I realized how slow the process was. I used a feeler gauge with sandpaper folded over it at one point, which sped the process up.

I started by just getting the ring to fit without binding. Luckily, I measured the ring land of a new piston at one point and got 0.033” with feeler gauges, so I kept working on it till feelers fit well all the way around. This is not the sort of thing I’d recommend, but if it saves a piston enough for more testing… I’ll take it.

It’s mostly together and leak tested. I’d still like to do a compression test.


I want to use the larger plastic float bowl, but it can’t sit on the fender or it’s gonna wear through in a hurry. I rotated the intake more and got enough clearance that it should be OK. The line is aligned with the L in Italy for reference.




I looked at the clear bowl and it seems like more fuel would be more useful if I could put the main jet nearer the bottom of the bowl.




I had some brass hex bar and used it to make an extension for the main jet. It’s M5x0.8 thread.








Now I’m hoping it’s not too close. There’s maybe 1/8” clearance between bowl and jet. I’m also not sure if the extension will change flow and screw something up. It’s 2.5mm all the way through, which is larger than many jets at their largest point and then 4mm on the end toward the jet.

[90GTVert]

I checked compression (150psi) and took it for a 25 mile easy ride this morning. Can't say I can tell any issue with the main jet extension so far. I only got into it for a few seconds a couple of times though. I can tell that the needle is wrong. The JJK raised even 1 position makes it sputter and buck at some low throttle positions. Real fun when you hit the wrong spot and it struggles to make it through an intersection.

Next up will be setting the ignition curve to a flat 16 degrees to see what I read. Pretty sure it won't be 16 degrees anyway because I had to either alter my curve (the easier way and what I did) or go back and set the stator different to see the numbers I wanted.

[tysta]

Jun 3, 2024 7:41:42 GMT -5 90GTVert said:

Jun 2, 2024 18:29:16 GMT -5 190mech said:

Looks good! Wobbly post # 39439 (team ESE thread) shows his setup on the TM kart engine, also tells how the sensor works..
I might have asked this before, does that pipe use a tailpipe nozzle/restrictor? If so what is it's ID in relation with the stinger ID?

Thanks.

This one doesn't. It's a welded on stinger. I did have one comment on YouTube tell me I should try a pipe with a larger stinger because it may be that moving more volume with a larger carb has put me just over the edge. It could again go back to Ryan, the local and countless others running 34mm carbs with the same setup without issue and would a stinger size make the plug look lean? When I have had an obviously too small stinger on something in the past (I think I tried the 70cc MRP exhaust on a 90cc) it clearly damaged the piston from the exhaust port side. This doesn't look like signs of that. Seems like detonation indication all the way around the crown rather than heat coming from one source, but I guess if it were a mild sizing issue it could be enough to heat the mixture overall and make that more likely. Just not sure that's the most likely candidate right now.


My thought for post-re-assy is to use the clear bowl. Possibly alter how the carb sits if I can get it to not hit the fender so it won't rub the bowl and wear through the plastic quickly. The plastic bowls may hold up well enough at $12 that I could replace periodically if needed as long as there's no contact.

I checked the plastic bowl and the aluminum original bowl by letting them fill at different angles and draining them. Original holds ~30cc at a 30 degree angle and ~35cc flat. Plastic bowl holds ~50cc either way. I retested the plastic because it didn't make sense how 1 changes with angle and the other doesn't really, but it came out the same. It may be a cc or 2 more fuel flat, but I'm not using a super precise method because within a few cc is close enough for this. Only thing that sucks with the plastic bowl is that there's no easy access for jet swaps. If I ever get it to work though, I don't typically have to swap jets a lot.






I'll also probably do the flat timing curve to see how my numbers match with what it's supposed to be.

Why your main jet is sitting so high?!!!

[aeroxbud]

Jun 9, 2024 14:37:27 GMT -5 tysta said:

Jun 3, 2024 7:41:42 GMT -5 90GTVert said:

Thanks.

This one doesn't. It's a welded on stinger. I did have one comment on YouTube tell me I should try a pipe with a larger stinger because it may be that moving more volume with a larger carb has put me just over the edge. It could again go back to Ryan, the local and countless others running 34mm carbs with the same setup without issue and would a stinger size make the plug look lean? When I have had an obviously too small stinger on something in the past (I think I tried the 70cc MRP exhaust on a 90cc) it clearly damaged the piston from the exhaust port side. This doesn't look like signs of that. Seems like detonation indication all the way around the crown rather than heat coming from one source, but I guess if it were a mild sizing issue it could be enough to heat the mixture overall and make that more likely. Just not sure that's the most likely candidate right now.


My thought for post-re-assy is to use the clear bowl. Possibly alter how the carb sits if I can get it to not hit the fender so it won't rub the bowl and wear through the plastic quickly. The plastic bowls may hold up well enough at $12 that I could replace periodically if needed as long as there's no contact.

I checked the plastic bowl and the aluminum original bowl by letting them fill at different angles and draining them. Original holds ~30cc at a 30 degree angle and ~35cc flat. Plastic bowl holds ~50cc either way. I retested the plastic because it didn't make sense how 1 changes with angle and the other doesn't really, but it came out the same. It may be a cc or 2 more fuel flat, but I'm not using a super precise method because within a few cc is close enough for this. Only thing that sucks with the plastic bowl is that there's no easy access for jet swaps. If I ever get it to work though, I don't typically have to swap jets a lot.






I'll also probably do the flat timing curve to see how my numbers match with what it's supposed to be.

Why your main jet is sitting so high?!!!

That's the million dollar question. 🤔

[tysta]

Jun 6, 2024 21:29:13 GMT -5 90GTVert said:

I spent quite a while working on the piston’s ring land. I tried to sand just the top of the ring land the best I could with 400 and then 220 grit once I realized how slow the process was. I used a feeler gauge with sandpaper folded over it at one point, which sped the process up.

I started by just getting the ring to fit without binding. Luckily, I measured the ring land of a new piston at one point and got 0.033” with feeler gauges, so I kept working on it till feelers fit well all the way around. This is not the sort of thing I’d recommend, but if it saves a piston enough for more testing… I’ll take it.

It’s mostly together and leak tested. I’d still like to do a compression test.


I want to use the larger plastic float bowl, but it can’t sit on the fender or it’s gonna wear through in a hurry. I rotated the intake more and got enough clearance that it should be OK. The line is aligned with the L in Italy for reference.




I looked at the clear bowl and it seems like more fuel would be more useful if I could put the main jet nearer the bottom of the bowl.




I had some brass hex bar and used it to make an extension for the main jet. It’s M5x0.8 thread.








Now I’m hoping it’s not too close. There’s maybe 1/8” clearance between bowl and jet. I’m also not sure if the extension will change flow and screw something up. It’s 2.5mm all the way through, which is larger than many jets at their largest point and then 4mm on the end toward the jet.

Yap seems better like that with the extension

[90GTVert]

I did the 16* flat timing curve observation with the $15 no frills Trisco timing light and the $110 Innova Pro Digital timing light.

RPM	Trisco	Innova
2,000	19	19
3,000	17.5	17.5
4,000	16.5	16.5
5,000	16.5	16.5
6,000	16.5	16.5
7,000	16.5	16
8,000	16	15.5
9,000	15.5	15.5
10,000	15.5	15
11,000	15.5	15
12,000	16	14.5
13,000	16	Cuts Off

I still get higher than designed timing at 2,000-3,000RPM. The Andromeda software manual that comes with the Stage6 PVL does say that it operates at whatever the mechanical timing is at very low RPM. It should be around 30* mechanical normally, a 3.59mm BTDC setting for my engine. Mine was actually set to 5.1mm BTDC, 36*, after seeing my observed curves about 6* shy of programmed. Not sure why that is, but it may be that there's a downward slope from mechanical timing and not a drop off right to desired timing at 2,000RPM.

Both lights have the same results to 6,000RPM and after that they deviate. I think this is where you start to see the delay of different lights. Less advance means more delay and delay is what I'd expect at high revs. From the changing advance and the light cutting out earlier, it shows that the full featured light can't keep up with the cheap no frills light. We already knew this and that's why cheap lights were suggested to me long ago, along with the fact that it works with ignitions when some of the fancy stuff doesn't work at all.

It throws things off seeing that advance rises again with the Trisco light. I don't think advance is actually increasing. Not totally sure what it's doing and it's also tougher to keep RPM stable up there and advance fluctuates slightly as RPM is changed, so it's better if you can hold it stable at a desired reading point... but it's very tough to hold it stable at high revs. At 12,000-15,000RPM, we're talking about 200-250 sparks per second (assuming no misses and 1 spark per revolution) so things are tough to keep up with.



None of this tells me 100% what my timing is. My assumption is that a good bet would be to assume 4,000RPM to be a good checking point. If I cross my fingers and hope the ignition works well and otherwise matches the programmed curve, then if I get 4,000RPM where I intend it to be then the rest should be correct or nearly correct. Malossi advises checking timing at 4,000RPM with their MHR ignition. I suspect that's more related to it being in what is typically a flatter spot of the curve with less fluctuation though.

It's still odd that I have to advance 6 degrees on the stator to get things to match up, at least quite close, to expected results. No idea what that's about, but I'm not gonna stress over it since I can seem to get basically what I am looking for. Seems like at this point, leave it at 5.1mm BTDC and program the curves 0.5* lower than where I want the timing. That's the very easy way. I could reset the stator to 4.95mm BTDC and that should match up to the programmed numbers... but moving dots on a PC is easier.

Again, my ignition gets set up using a camera zoomed in on the stator and rotor with a degree wheel on the engine in addition to a dial indicator just for that extra verification. I use the camera because line of sight deviation can greatly alter where it looks like marks align so the camera on a tripod aimed straight at the mark should be about as reliable as most of us are likely to get. I do the same when the timing indicator is setup. I do not move the camera between timing indicator setup and checking timing so the camera is essentially zeroed with the timing indicator at that point to eliminate another potential point of error. Just pointing this out because I know my methods have been questioned, but I'd bet you'll have a tough time finding many people that go to the effort that I do when setting up and checking ignitions. You know damn well the vast majority are eyeballing the stator setup, assuming it's right, and carrying on with life. Most of the through folks will add a quick timing light check at some selected RPM or watch it retard as revved prior to moving on. Not many people will spend hours to check timing. I'm not saying that anything that I do is spot on, but I am saying that I give it a good effort and put a lot of time into the process.


I'll probably stick a 15.5* flat curve in there, which should be the actual 16* that Malossi specifies, and try it with the 205 MJ and jet extender just to see how it runs. I had 13,500RPM set at 15* in my modified MHR curve though, so it should have already been very close at an actual 15.5* around peak power if all of my above assumptions are correct.

[sinfull]

Brother, I do hope you actually figure it out soon. Don't give up on the 2 stroke like I and many others have. But you do have a great 4 stroke bike that runs to ride around with. So at what point do you just scrap the 2 stroke and give your self fully to the dark side 🤔 😉

[90GTVert]

I did some tests today with the flat 16* timing curve, main jet extender, larger clear bowl and different main jets.

Main Jet	330ft	1/8 Mile	EGT @ 60MPH	30-60MPH RPM
205	6.43@54.31	10.09@65.29	1,212	13,785-13,995
210	6.30@54.15	9.98@64.83	1,183	13,610-13,790
215	6.19@55.26	9.81@65.47	1,227	13,755-13,915
220	6.21@54.80	9.85@65.34	1,196	13,663-13,908
210 Redo	6.29@53.90	10.00@64.12	1,162	13,578-13,775

It didn't lean out with bigger than 205 jets this time. Far left is a BR10EG from break-in riding. The others are BR9EG and just test runs.

L to R : Break-in, 205, 210, 215, 220, 210 redo.



The 210 seemed like an outlier with it's colder EGT and lower RPM, which is why I re-tested it. Basically the same results though.

It's rich now somewhere at low-mid part throttle. Breaks up, bucks, bogs and so on. Not sure if that's related to lazier timing at lower RPM, big jets, jet extender... The good news is that I haven't felt or heard the RPM drop at the end of any runs. Other good news is that it equaled it's quickest 1/8 single run and the RPM is higher than it should be so it's probably got more in it and it's not pulling MPH as well up top.

[90GTVert]

I switched back to the timing curve that I was using, a modified version of MHR's curves. I put the 215 main jet back in because it gave me good results with the 16* curve and wound up trying a 220 as well because of higher EGT. The advance below peak power cleared up the bogging and bucking at some throttle positions and made it more responsive. On the 16* flat curve, I could get into the throttle more quickly on launch.

I found that the MHR-ish curve raised EGT by roundabout 20F at 60MPH for both jets. The 215 now averaged 1243 and the 220 averaged 1221. Both were very near 1300 by the time I let off in the high 60s to 70MPH, also about 20F hotter than with the flat curve. Can't say that I'm thrilled about that, but they can make it through 1/8 mile runs at least. Not sure how well it would go if I tried to hold it longer or tried a top speed blast. I really just do 1/8 mile most of the time and screw around with little power wheelies so practically this may work. I'm kinda back to where I started way back though, with requiring huge jets if I want it to cool. As long as it will run strong, it wants what it wants... but it's pushing EGT where it wants to run strong right now. I didn't try the next size up (230) or larger, because I can see that RPM drops a little going from 215 to 220 and I expect I'm gonna get slower.


Here are plugs from 16* (left) and MHR-ish (right) curves side by side with the same jetting.






I hope I’m done with plug chops. At least I can see that it’s putting fuel on them now. I just got an order in f plugs and I’m already almost out. I’ve chopped up ~$120 worth of plugs in the last 2 weeks. I removed the carb cam too after seeing that there’s still plenty of fuel in there even when it’s getting hot at the end of runs.





I decided to move on from the carb, at least for a bit, to see if I could get RPM in the usual range of best results for me. It was around 13,650-13,900 with the 220 and about 150RPM higher with the 215. I moved from 5.25g to 5.75g sliders and RPM dropped to 13,150-13,300. I only did 2 runs, because when I saw it in the 13.1k range I figured it wasn't going to do well. I got back and checked the dragy and it actually averaged 9.78 so it was pulling pretty well for being below what usually works.

I swapped to 5.5g, assuming this would be about right. The first run was 13,470-13,710 between 30 and 60MPH. The second run was 13,280-13,530. On the third run, I let out around 60 because RPM dropped and I wasn't sure if it was blowing up at first. RPM for that run was 13,300 @ 50 and dropped to 13,150 by 60MPH. EGT wasn't alarming so I did a 4th run and RPM ranged from 13,140-13,380... pretty much where it was with the 5.75g.

Of course it couldn't just cooperate and do what I expected... or it did for 2 of 4 runs and then changed totally. The higher RPM on the last run was at 60MPH, so it's dropping RPM. That is often a sign of not enough shimming... but it's usually not a sudden change in the middle of a group of runs if it's shimming. I'll probably try a little more shim thickness and see what happens, largely because I don't have a better idea ATM and I'm hoping it's just an adjustment that it wants with more weight.

The other issue is that, while heavier weights improve cruise EGT with lower RPM and the tuning seems mostly OK... it still wants to hang at idle. Did it with either needle that I've used and even with the flat 16* curve. On top of that, on the last run the idle quality wasn't as good. Seemed like it wanted to die and I turned the speed screw in very slightly. Died when I came home and let it coast down the driveway at idle. That makes me hope I haven't hurt the engine again... but it was still pulling hard. I may check compression anyway. Humidity and heat are coming in so that may be a factor. I think it's supposed to get into the low-mid 90s for a bit with "oppressive humidity" by the beginning of next week. Has been in the 80s with pretty low humidity lately.

After twice prior thinking I've finally got this thing working and then eating pistons, I've given up on too much optimism. It feels like it's close to a working setup, but EGTs are still troubling at the end of runs and now the (I think) CVT issue. 🤷‍♂️

[90GTVert]

Compressing m test shows a little over 125psi. It was 150 on reassembly.

I put the bore scope in there and there is damage to the crown. I’m thinking the ring locator pin may have came out and bounced around a few times, plus now the ring could be clocked anywhere.





Gonna have to pull it apart again. Also curious if maybe the ring moved when RPM dropped suddenly during a run or some other damage occurred right then or if it’s coincidence and is the CVT.

If I need a piston, then the next fun thing is do I just get an A for my AA cylinder or spend more and wait for who knows how long for AA or B. That’s if there’s no major cylinder damage. Like I said in the previous post… whenever I think I’m right there, everything crumbles.

[aeroxbud]

I can't believe how this is going. With the old Dellorto it ran great for ages. Then the carb we dare not talk about. Now this carb is becoming a nightmare too.

[tysta]

Yap crazy but I still think there's more than one problem
For example you just mentioned the idle whants to hang usually that's a sign of being lean (pilot jet)
Know this problem that small debris you still have some knocking.

[90GTVert]

Jun 13, 2024 17:36:03 GMT -5 aeroxbud said:

I can't believe how this is going. With the old Dellorto it ran great for ages. Then the carb we dare not talk about. Now this carb is becoming a nightmare too.

The Lectron was on the 86cc. lol I don't think flat slides like me. IIRC, I could run the Lectron on the TPR OK WOT. That one I just couldn't get to work part throttle without eating pistons. After a bunch of metering rods, Lectron couldn't come up with anything either other than to tell me to install a power jet for mid throttle or that the engine was too small to handle a 30mm, which they say flows way more than other 30mms... and then I gave up on it and went back to a round slide and carried on with life again.

The RC-One has only had the VHST, then the PWK. I had problems with running out of fuel on the VHST, which turned out to be fuel supply. That's when I found out that it works way better having the same size hose on both sides of a fuel filter. Worked fine after. About a year and a half of that. Wore pistons out purely from mileage.