Yep, 8CR weights are your factory weights.
Good to hear it ran ok for you, and were able to enjoy it!
Good to hear it ran ok for you, and were able to enjoy it!
supercharged111
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8300 is where peak power is stock, but it's a pretty broad peak and mine definitely seemed happier at 8500 than 8100.
morecowbell
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@MURDER YAMAHA it was kick ass. Keep the old sled dream alive.
I ordered a set of adjustable weights that indicated they'd fit the 8mm pins on the primary with a 50g base weight, I'll play with it until we're in that 8500 range.... it's peaking at like, 9700 right now
I ordered a set of adjustable weights that indicated they'd fit the 8mm pins on the primary with a 50g base weight, I'll play with it until we're in that 8500 range.... it's peaking at like, 9700 right now
morecowbell
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The longer 151 track length might have something to do with it b/c I didn't swap gearing or the track drivers etc... I would think I'd feel that more as bogging down / loss of RPMs on those steeper hill climbs
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supercharged111
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Oof, I think I'll be under 50 on mine even after I get the rivets in. Is that the Thundershifts? They used to make lighter ones.
morecowbell
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Lightest ones I could find that explicitly said they'd fit the 8mm pins for the primary but i'd order something else if y'all have a recommendation. They're the STM Supertip Trail Cam Arms.
9gr difference between them and current arms but I dont have a way to add weight and I'm way, way above the RPM goal. ....
Secondary position is 6/1 with a green spring, btw.
9gr difference between them and current arms but I dont have a way to add weight and I'm way, way above the RPM goal. ....
Secondary position is 6/1 with a green spring, btw.
supercharged111
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9700 RPM is nuts, I wonder when they go boom?
morecowbell
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Update. The 50gr weights felt a little bit sluggish for power. But the Tach was topping out. So I began to suspect the tach itself. The dash pod is ported from a 1998 MM 700.... the original dash with the two separate round pods was trashed when I got the sled. So I grabbed one of those cheap "tiny tachs" from amazon that you wrap a little interference cable around a spark plug wire.
Turns out there is a pretty significant difference between that tach and the one in the dash. When the tiny tach reads ~1500 at idle the dash says ~2500.
So now we get to try again and see what the tiny tach tells us
'Course now all of the dash pod indicators are suspect, lol. The fuel level, speedo, brights indicators all seem to work. I've never tried to trigger the water temp indicator or the oil level indicator lights.... i put new sensors in during the overhaul and have always treated it mostly nice.Not sure how I would test those realistically. Can I just unplug the clips and complete the circuit?
EDIT: Yes, you can short the sensor plugs and it will make the dash pod lights work. So everything but the Tach is happy. Now we just need to dial it in!
EDIT: After some Google-fu it looks like the 1999+ has a 12-pole stator but the 1998- had a 6-pole. So the tachometer for that older sled is reading basically double the real RPMs which sorts explains everything. I'm also gonna find some kind of frequency step-down unit.... and it should get the original tach working right again... Because, nerd sh*t I guess
Turns out there is a pretty significant difference between that tach and the one in the dash. When the tiny tach reads ~1500 at idle the dash says ~2500.
So now we get to try again and see what the tiny tach tells us
'Course now all of the dash pod indicators are suspect, lol. The fuel level, speedo, brights indicators all seem to work. I've never tried to trigger the water temp indicator or the oil level indicator lights.... i put new sensors in during the overhaul and have always treated it mostly nice.
EDIT: Yes, you can short the sensor plugs and it will make the dash pod lights work. So everything but the Tach is happy. Now we just need to dial it in!
EDIT: After some Google-fu it looks like the 1999+ has a 12-pole stator but the 1998- had a 6-pole. So the tachometer for that older sled is reading basically double the real RPMs which sorts explains everything. I'm also gonna find some kind of frequency step-down unit.... and it should get the original tach working right again... Because, nerd sh*t I guess
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morecowbell
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@MURDER YAMAHA @sideshowBob -
Back in Cooke. Having this one side-by-side with the other MM 700 here and the highway to blast full throttle up to compare is helpful but is revealing this sled still has more demons.
Long story short - she starts just fine after a few pulls with choke. Idles fine at 1500rpm forever once its warmed up. Seems to be plenty happy at low-to-medium RPMs but the top end just is not there at all. The other MM 700 is straight up scary to full blast on the highway and has noticeably more power at the top end when blasting hills.
Mine almost feels like it's running insanely rich when you got WOT, and it won't rev past maybe 6000 (hard to tell with the sh*t tach the way it is).... It just does not scream the greasy triple scream the way the other one does.
The sled is as described above, #135 main jets, #55 pilots, 2 screw turns out. Maybe a touch rich on the jetting chart all the way up this high but no way it should stumble the way it is on the top end. Brand new WSW main spring with stock 41gr 8CR weights in there. Brand new green secondary spring set at stock 3/3 settings.
The engine has those replated cylinders, brand new pistons, rings....
What we've done:
- New in-tank fuel filter / line
- Moved secondary preload around
- Swapped clutches completely between the two sleds
- New belt
- Full tank of pure give you cancer immediately mineral 2 stroke oil
- Deep cleaned the carbs (incl needle)
- Cleaned / new BR9ES plugs
- Moved the position of the spark plug wires to each cylinder (no difference)
- Confirmed each cylinder has spark (and actually will run with the other two unplugged with a bit of throttle)
- Confirmed throttle position at WOT is in fact pulling the throttle to the WOT position
- Confirmed the choke is NOT too tight (or stuck)
- Blipping the choke at WOT adds too much fuel and it stumbles more (no improvement)
These have produced at best very minor improvement...
Do not have a compression gauge with me or a way to leak-down test but we cannot for the life of us think of anything else to try? You Yammie warlocks have any bright ideas??
Back in Cooke. Having this one side-by-side with the other MM 700 here and the highway to blast full throttle up to compare is helpful but is revealing this sled still has more demons.
Long story short - she starts just fine after a few pulls with choke. Idles fine at 1500rpm forever once its warmed up. Seems to be plenty happy at low-to-medium RPMs but the top end just is not there at all. The other MM 700 is straight up scary to full blast on the highway and has noticeably more power at the top end when blasting hills.
Mine almost feels like it's running insanely rich when you got WOT, and it won't rev past maybe 6000 (hard to tell with the sh*t tach the way it is).... It just does not scream the greasy triple scream the way the other one does.
The sled is as described above, #135 main jets, #55 pilots, 2 screw turns out. Maybe a touch rich on the jetting chart all the way up this high but no way it should stumble the way it is on the top end. Brand new WSW main spring with stock 41gr 8CR weights in there. Brand new green secondary spring set at stock 3/3 settings.
The engine has those replated cylinders, brand new pistons, rings....
What we've done:
- New in-tank fuel filter / line
- Moved secondary preload around
- Swapped clutches completely between the two sleds
- New belt
- Full tank of pure give you cancer immediately mineral 2 stroke oil
- Deep cleaned the carbs (incl needle)
- Cleaned / new BR9ES plugs
- Moved the position of the spark plug wires to each cylinder (no difference)
- Confirmed each cylinder has spark (and actually will run with the other two unplugged with a bit of throttle)
- Confirmed throttle position at WOT is in fact pulling the throttle to the WOT position
- Confirmed the choke is NOT too tight (or stuck)
- Blipping the choke at WOT adds too much fuel and it stumbles more (no improvement)
These have produced at best very minor improvement...
Do not have a compression gauge with me or a way to leak-down test but we cannot for the life of us think of anything else to try? You Yammie warlocks have any bright ideas??
Plugs appear rich?
May be time for new needle and seats?
May be time for new needle and seats?
I agree...also the rubber O ring under the float needle seats can deteriorate, leak, and cause rich running conditions.
morecowbell
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@MURDER YAMAHA @sideshowBob Plugs do kinda look dark and oily over time. Particularly the driver's-left. And they seem to foul up worse over a longer ride. Here they are after the carb cleaning / fresh oil / fresh cleaning the plugs and then blasting it up the highway plus some mid-RPM cruising. Driver's side wet. Center plug looks fine, right side rich but not wet....
I swapped in buddy's carb and tried it on mine. Just to see... I don't know what his jetting etc is but man it rips. It hill-climbed like a demon yesterday riding two-up. Which is epic because his machine has been living outside in Cooke for like 6yr with zero TLC and is a total greaseball. His carby did not make any difference in my machine.... But that sorta rules out carby issues as the root cause? Took a picture of the reeds while I was there, they aren't chipped or anything and seem to seal.
Since my tach is dead right now and the cheap interference tach doesn't work very good.... Based soley on the sound of his MM, mine sounds like it is capping out around 6750/7000rpm. Wont even think about climbing up toward 8000. And it revs up really slow by comparison to the other one.
But it starts, idles fine, and runs in that 3500-5000rpm range just like the other one. And it doesn't cut out, or stutter or anything up high. It just doesnt want to scream.
At this point - we ruled out clutching and the carb - just about the only things that haven't been replaced on this machine are:
- Fuel Pump
- Plug wires / CDI
- Oil Pump
- Reeds
- Gearing
Would this happen if the oil pump was toasted (the cable is set to that 22mm stock play) and just blasting a ton of oil into the mix? Or maybe the fuel pump isn't metering right? I'll pull on it with the compression tester when we get home but I am not certain what else to try
I am already planning to swap gears since I went from a 141 to 151 track which I am sure is not helping the equation. Was thinking 19/40 or 19/42... current is the stock 21/40.. It's on the stock 9 tooth drivers. I have a hard time believing that's the root cause though
Pics of plugs in order drivers left/middle/right. I pulled them after trying the other carb and results were similar, I had put the cleanest one back in the left cylinder and it came out wet but not too dark.
And a pic of one of the reeds; they all look the same.
I swapped in buddy's carb and tried it on mine. Just to see... I don't know what his jetting etc is but man it rips. It hill-climbed like a demon yesterday riding two-up. Which is epic because his machine has been living outside in Cooke for like 6yr with zero TLC and is a total greaseball. His carby did not make any difference in my machine.... But that sorta rules out carby issues as the root cause? Took a picture of the reeds while I was there, they aren't chipped or anything and seem to seal.
Since my tach is dead right now and the cheap interference tach doesn't work very good.... Based soley on the sound of his MM, mine sounds like it is capping out around 6750/7000rpm. Wont even think about climbing up toward 8000. And it revs up really slow by comparison to the other one.
But it starts, idles fine, and runs in that 3500-5000rpm range just like the other one. And it doesn't cut out, or stutter or anything up high. It just doesnt want to scream.
At this point - we ruled out clutching and the carb - just about the only things that haven't been replaced on this machine are:
- Fuel Pump
- Plug wires / CDI
- Oil Pump
- Reeds
- Gearing
Would this happen if the oil pump was toasted (the cable is set to that 22mm stock play) and just blasting a ton of oil into the mix? Or maybe the fuel pump isn't metering right? I'll pull on it with the compression tester when we get home but I am not certain what else to try
I am already planning to swap gears since I went from a 141 to 151 track which I am sure is not helping the equation. Was thinking 19/40 or 19/42... current is the stock 21/40.. It's on the stock 9 tooth drivers. I have a hard time believing that's the root cause though
Pics of plugs in order drivers left/middle/right. I pulled them after trying the other carb and results were similar, I had put the cleanest one back in the left cylinder and it came out wet but not too dark.
And a pic of one of the reeds; they all look the same.
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