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Since my engine cutting out and hard starting has been the result of flooding, I'm not too worried.
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Just about done buttoning up everything and hoping to get back to jetting and riding.

The wiring detour took longer than expected, but I'm glad I did it. Lots of sketchy connections repaired, wires cut to length and installed with the proper bits, bobs and booties…mostly.

For the longest time, I couldn't figure out how the PO had hooked up the DC only conversion and relay once I pulled it all apart to put in a new stator. I was running it without the relay with direct DC to the headlight circuit and battery to the key on circuit.

Yesterday, I stumbled across a thread about DC conversions where he described how he did it. One sentence set me straight and I think I understand the voltage drop I was getting. Here it is, in case I can't find it again.

SIP Electronic Ignition Install + DC Conversion

I used to hate wiring until jetting became a thing. Now I like wiring a lot more.
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Yeah a lot of jetting issues are actually electrical/ignition problems.

I remember not being able to set up my phbh 30 properly for the longest time.

Set the ignition up correctly and the jetting falls into place.
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108 wrote:
Yeah a lot of jetting issues are actually electrical/ignition problems.

I remember not being able to set up my phbh 30 properly for the longest time.

Set the ignition up correctly and the jetting falls into place.
Very true. Ignition has been working great, but lighting needed some work. Fuel flow should be good now.
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Back in business. Went for a good ride and pushed it harder. Temps got up to 342F so I stopped for awhile. Not sure what's too much.

Jetting is 52-140 120/BE3/135

Just for fun, I tried running with the choke on. It sputtered a lot more, but temps went down.

I'm happy with the way it runs/rides but the temps seem high. I'm surprised that it does with such a big main jet. Fuel flow is good. No more flooding.

I'm going to go back up to a 138. Not sure about the temps. If not for the temps, I'd call it good.
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Those temps do seem very high. I thought over 300° was danger territory?
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orwell84 wrote:
Back in business. Went for a good ride and pushed it harder. Temps got up to 342F so I stopped for awhile. Not sure what's too much.

Jetting is 52-140 120/BE3/135

Just for fun, I tried running with the choke on. It sputtered a lot more, but temps went down.

I'm happy with the way it runs/rides but the temps seem high. I'm surprised that it does with such a big main jet. Fuel flow is good. No more flooding.

I'm going to go back up to a 138. Not sure about the temps. If not for the temps, I'd call it good.
Next time you get up there in CHT kill the engine and coast to a stop.
Take a pic of the plug.

If you want to play more:
1st (milder) play, put a drilled filter on.
2nd play, tape over the air channel that feeds the slide cut.
These should provide some clues.
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Ray8 wrote:
Next time you get up there in CHT kill the engine and coast to a stop.
Take a pic of the plug.

If you want to play more:
1st (milder) play, put a drilled filter on.
2nd play, tape over the air channel that feeds the slide cut.
These should provide some clues.
I will give it a try.

What is considered a safe CHT is all over the place. Also a big variation in what gauges will read. I'm also betting that the center mounted plug gives hotter readings. Gauges tend to most useful for trending, like x engine is running well when it's within y temps.

Max safe cylinder head temp

In my bus, which has aluminum heads and pistons with cast iron jugs, I try to keep CHT's at 350-375F. Temps might go a little over 400F briefly after pulling up a hill. I know it's a different animal, but cast aluminum all the same. The issue isn't seizing, but the valve seats loosening in the heads with repeated excessive heat cycles.
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orwell84 wrote:
I will give it a try.

Also a big variation in what gauges will read. I'm also betting that the center mounted plug gives hotter readings.
That could be very true!
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I tried a 138 main jet. It will rev out cleanly in second after some stuttering but is awful in third and fourth at WOT. A lot like my ride with the choke pulled. CHT's were better. 1/4-1/2 not too bad.

So that's where I am now.
Nice to be back on the road though.
Nice to be back on the road though.
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go back to the better main, then retard (move it closer to TDC) your timing a degree, like from 18 to 17. See what that does for the temps.
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chandlerman wrote:
go back to the better main, then retard (move it closer to TDC) your timing a degree, like from 18 to 17. See what that does for the temps.
Funny, I was thinking of things like that…some detuning…Maybe increasing squish?

I will retard the timing a bit.

Thanks.
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If the timing is accurate at 18 degrees that isn't the issue. Think you've found the main jet. If 138 is a little too rich and the temperature is lower, the 135 is low enough for now.
What's the rest of the stack and pilot at the moment?
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It's 120-be3
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orwell84 wrote:
It's 120-be3
Pilot?
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52-140
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orwell84 wrote:
52-140
Most likely way too small. When rich enough it doesn't get hot.
Try that 50/100. Will still be small but closer.
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Jack221 wrote:
Most likely way too small. When rich enough it doesn't get hot.
Try that 50/100. Will still be small but closer.
Will do.
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I tried the 50/100 idle jet and went back to 120/be3/135.

CHT's were much better. Highest was 323 uphill with a headwind, but mostly below 290. This was my longest fastest ride…since 1989…

But it splutters like mad until half throttle. Feels way rich. When stopped for a couple minutes, idle will drop until it stalls. It feels somewhat soggy at high throttle too. I will upload a video to make sure I am interpreting rich/lean correctly.
Plug at 1/2 way point.
Plug at 1/2 way point.
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Plug suggests your are interpreting just fine…

You're still in the "general" when looking at the plug without killing motor and coasting.

But generally - you are filthy rich.
Congrats.
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orwell84 wrote:
I tried the 50/100 idle jet and went back to 120/be3/135.

CHT's were much better. Highest was 323 uphill with a headwind, but mostly below 290. This was my longest fastest ride…since 1989…

But it splutters like mad until half throttle. Feels way rich. When stopped for a couple minutes, idle will drop until it stalls. It feels somewhat soggy at high throttle too. I will upload a video to make sure I am interpreting rich/lean correctly.
Too rich idle jet and the engine will try to die at idle when hot.
Too lean it will rev up.

Do you have a 140 ac?
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CM22: Wasn't a legit, cut clean plug chop for sure. Just having a look-see for generally rich or possible flooding.

Ray8: Yes, I have a 140AC. I found this great YouTube video on rich/lean that used a 2t leaf blower. Too rich off idle goes bluh before revs pick up and idle falls right off and lower…which is exactly what I'm getting.

With the leaner idle jets, I was getting a great return to idle.
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Also thinking about CHT's. For awhile now, I have been jetting based on CHT worries more than how the bike runs. There is info that suggests that a center mounted plug will read considerably higher, so it's possible my engine isn't actually getting that hot. It's just that finding out for sure means risking a seize.

Here's a short video.

So center mounted plugs DO give higher temp readings.
So center mounted plugs DO give higher temp readings.
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Its not awful. It is rich low down but most of that will be the main jet. Check the main jet at wot again. Before 138 was full splutter and 135 was ok. Now it will have changed. Might get down to 130 for full clean rpm.
Typically for a 26/26 50/100 is too lean. How many mix screw turns at 1200 rpm?
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Orwell - I've often made the point about temps dependent on type and location of sending unit.

That said, there's also been some discussion on timing here. Jacks point being, 18 should be okay.

Curious, how (exactly) did u measure 18 degrees. There are a number of variables. I'm wondering if perhaps you are a bit more advanced then you may think. (Insert dad joke here).
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charlieman22 wrote:
Orwell - I've often made the point about temps dependent on type and location of sending unit.

That said, there's also been some discussion on timing here. Jacks point being, 18 should be okay.

Curious, how (exactly) did u measure 18 degrees. There are a number of variables. I'm wondering if perhaps you are a bit more advanced then you may think. (Insert dad joke here).
I measured it with the piston stop/degree wheel method when I was running the old kit. When I put the new kit on, I measured with a degree wheel and a dial indicator on the piston, marked the flywheel and cover. Timed with a light at maybe 3k rpm. The stock marks on the cover were accurate. I didn't have to move the stator.

No harm in trying all of the above:

Retarding timing a bit (and rechecking)
Trying a smaller main
Throwing a 140/be3/big ass jet at it

Jack, I believe I was 2 turns out. Any more and smokey.
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Timing lights on these things are tough.
The parallax effect from flywheel to the cases can be significant.
Then there is the challenge of the thing moving all over the place if you have variable timing(?).
In any event - it is ALWAYS possible to accurately take a degree or two out relative to where you are now.

*too much retard (don't say it) can cause the heat to move to your exhaust port - and that's not desirable either - as its hell on the rings...
When that happens - you can see combustion carbonization occurring on bottom of exhaust port.
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charlieman22 wrote:
Timing lights on these things are tough.
The parallax effect from flywheel to the cases can be significant.
Then there is the challenge of the thing moving all over the place if you have variable timing(?).
In any event - it is ALWAYS possible to accurately take a degree or two out relative to where you are now.

*too much retard (don't say it) can cause the heat to move to your exhaust port - and that's not desirable either - as its hell on the rings...
When that happens - you can see combustion carbonization occurring on bottom of exhaust port.
The timing marks on the fan cover and flywheel are pretty good if they happen to line up. Taking off a degree-ish should be pretty accurate. Bus Type4 scales are pretty awful too.
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The Bad Timing Club is kind of like Amazon Prime. You think you've canceled your membership, but those fuckers keep right on chiseling away at your credit card.

Thanks for the gentle reminder to check my account.
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orwell84 wrote:
I measured it with the piston stop/degree wheel method when I was running the old kit. When I put the new kit on, I measured with a degree wheel and a dial indicator on the piston, marked the flywheel and cover. Timed with a light at maybe 3k rpm. The stock marks on the cover were accurate. I didn't have to move the stator.

No harm in trying all of the above:

Retarding timing a bit (and rechecking)
Trying a smaller main
Throwing a 140/be3/big ass jet at it

Jack, I believe I was 2 turns out. Any more and smokey.
Do anything but don't change the AC. Running weak feels lovely but does damage.
Even if the timing was at 20 degrees it would still be ok.

Main jet is still too big. Either you're not doing the WOT checks right, it's more powerful than a bolt on kit should be or something is up with fuel delivery. There are other possibles, like blocked exhaust, wrong air filter....long list....
Try the WOT runs again and try for a smaller main. Do some plug chops at WOT. That will help.
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Jack221 wrote:
Do anything but don't change the AC. Running weak feels lovely but does damage.
Even if the timing was at 20 degrees it would still be ok.

Main jet is still too big. Either you're not doing the WOT checks right, it's more powerful than a bolt on kit should be or something is up with fuel delivery. There are other possibles, like blocked exhaust, wrong air filter....long list....
Try the WOT runs again and try for a smaller main. Do some plug chops at WOT. That will help.
I agree that the main jet is too big. I will try working down. The splutter test has been confusing because in second, even large jets clean up at WOT. With a rich idle jet, they might not.
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The idle jet on SI carbs does way more than the idle. If on a needle carb the idle jet is dominant until 1/8 throttle, then on an SI carb it is dominant until around 1/3 throttle, whilst less than mid rpm. Or, where we all ride 90% of the time.
If the main jet really does need to be 132, I would be surprised.
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Jack221 wrote:
The idle jet on SI carbs does way more than the idle. If on a needle carb the idle jet is dominant until 1/8 throttle, then on an SI carb it is dominant until around 1/3 throttle, whilst less than mid rpm. Or, where we all ride 90% of the time.
If the main jet really does need to be 132, I would be surprised.
I'm thinking it will be lower, for sure. With the Polini kit, it was at 118. I know, different kit, bigger carb, but even so…

The richer idle jet really helped CHT's. Not a huge difference between 323 and 340F, but mostly it stayed under 300 and only got higher in expected conditions and back down again. With the leaner idle jet, it would just keep climbing.
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I stepped down jets, just to see how it would effect low throttle and CHT's. Last one I tried was a 125. Still spluttery low to mid range. Idle is hard to set and eventually drops to the point it stalls if I don't give it some throttle from time to time. CHT's we're not bad, hitting 315F after running at 55-60 indicated for awhile. Short video:

Title says 50-120. I'm still running the 50-100.
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It is too rich low down but not by much as you can actually ride it. Do you have any air filter on? I was thinking the carb was no filter on top and bellows to open frame.
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Jack221 wrote:
It is too rich low down but not by much as you can actually ride it. Do you have any air filter on? I was thinking the carb was no filter on top and bellows to open frame.
No filter, but running bellows.

The next size down I have is a 50-120.
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Not the air filter then. The mixture screw needs adjusting better next time.

Go back to the main jet test in 2nd. Still struggling to get it rich enough to fully splutter at max rpm? This is the issue.
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What I'm having trouble understanding is that to me, it seems puke rich down low. It seemed rich before with the 52/120. 2 turns out, it smokes like Bogart, stings my eyes and makes me cry 2t tears. I don't think I'm interpreting it wrong. I get that a large main will drown it and bringing it down will allow a richer idle jet. That's why I went with the 125. It helped, but still seems rich down low. I would think I would also have to go much larger on the main to make it splutter at WOT in second. I'm just trying to understand the the logic of how this works.
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Yes, the bottom end is rich, that's for sure. Why the main jet won't splutter at max rpm is the issue. Meaning really rich low down and really lean high up. The high cht confirms it's lean past mid. And the smoke confirms it's rich low down.
On a 190 perfectly set up, the cht would be under 250f most of the time and near 300f on a long wot run.
Put in a BE2 and do the 2nd gear runs again. The main jet must be a little under where it splutters or the piston will get damaged.

There's no air leak I can hear. Timing static 18 and verified? Check fuel flow at carb height.
Undo the banjo with a tray under the engine is the dirty way. 20oz a minute minimum.
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Thank you for taking the time to explain. It helps to know the reasoning behind the jetting changes. Sometimes a change will make it run like shit, but get closer to the goal. A lean engine sounds and performs great, but not for long.

When I was at 135 with the 50/100, it ran like crap under half throttle, but it was a nice ride…because CHT's leveled off and I could enjoy the scenery. I have been pushing it harder on flatter roads along the lake instead of up into the mountains. This riding really shows the weaknesses in jetting.

So the issue is that it's not getting rich enough at high throttle even with larger mains, which is why you aren't suggesting going leaner on the idle jet to make it sound nice.

So the next thing is to figure out why big mains aren't making it pukey rich like it should. Maybe I'm not doing the splutter test right. Maybe it has to stay at max rpm's awhile to let fuel flow catch up. The trend is for second gear to rev out clean now matter the jet, but for 3rd and 4th bog rich.

I will check for fuel flow, possible restrictions and intake leaks and try the BE2. Another suggestion was trying a drilled filter to make it richer (rather than no filter).
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