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Post by eclark5483 on Oct 8, 2018 14:50:12 GMT -5
Conventional thinking tells you that you are restricting air flow, but if you think of it more in terms of changing atmospheric pressure, then it's not really a restriction if what it is doing, is making the vacuum suction tighter. And again, as I told him before, the reason behind this, is to improve bottom end and get a cleaner burn. It's better to err' on the side of rich, but with too much free flow, you are over compensating with a bigger jet. In 4 stroke, the impact is not felt as much as 2 stroke, but whatever help you can give vacuum, the more to your benefit it will be to meet the basic theory of horsepower that throwing more air and fuel into the piston produces more power.
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Post by dexameth on Oct 8, 2018 15:00:14 GMT -5
Still, in my eyes, a motor is a pump and efficiency is key, so any of these restrictions to "add vacuum" is merely restricting the pump/motor from operating at its' fullest potential. Sure, with some tape and blocking you can create more "suction", but all you're really doing is adding a choke.
The way you explain it isn't wrong, it's just not the most efficient way for the engine to operate.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 8, 2018 19:45:58 GMT -5
Looks almost where you need to be. Don't jet higher (yet). Work on the back pressure on your filter. Can you snap a photo of it so we can see what you got going on. Will advise further WAIT! Do you see any color on that insulator? I see pure white! That is way lean, if we are looking at the same pic. To read a plug you look at the insulator, not the electrode.
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Post by katt on Oct 8, 2018 21:24:14 GMT -5
Looks almost where you need to be. Don't jet higher (yet). Work on the back pressure on your filter. Can you snap a photo of it so we can see what you got going on. Will advise further WAIT! Do you see any color on that insulator? I see pure white! That is way lean, if we are looking at the same pic. To read a plug you look at the insulator, not the electrode. This is the confusion i am having with reading plugs half guides online say look at insulator half say look at metal ring around thread and some guides say give opposite information about colors to look for etc this is why i were asking earlier what part of plug what to look at.
Example, nothing about insulator
then in same article they say talk about insulator again this is super confusing to understand.
so should i look at middle or button of ring on insulator then to see main jet work?
P.S. I almost take off and ride with WOT.
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Post by katt on Oct 8, 2018 22:09:37 GMT -5
Okay here is my plug with #110 main jet get major overheating today on a long trip first 5 miles it was okay was going WOT all time then remaining 3 miles oil temp were stuck at 98*C even holding steady 6000 RPM temperature would not go down and i felt detonation again!
However on the way back another 8 miles after it got cold outside i were pushing it 7000-8000RPM most all way and temp never jumped more than 90-95*C, perhaps it cooled more efficient on traffic lights when its cold outside. Three pictures of same plug different lighting. Look inside the insulator all white too.
I have put #130 main and see whats up next.
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Post by dexameth on Oct 9, 2018 9:19:32 GMT -5
Dang! That looks WAY lean still. Like really lean. I am at a 112 main at sea level right now, with a good coffee color to my plug. Wait, now that I think about it I haven't checked my plug in months... haha maybe I'll pop a new one in there and do a plug check. It'll have to be next week, I leave for Vegas for AIME tomorrow.
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Post by katt on Oct 9, 2018 17:11:37 GMT -5
#130 must be way too big i am getting some lag only at WOT when riding under load i get like 1 second burps very often during which all power is lost and it just shakes. On idle it looks like this i was holding throttle steady open at full its engine lags and i get gasoline smell, what exactly is mechanics behind this effect?
Okay i put #125 main jet still had rare misfires on WOT.
Next size down i had is #120 main jet this one have no misfires and i guess i will run this for now and see the plug.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 9, 2018 19:44:12 GMT -5
Well let’s think about this... white insulator, over heating, possible detonation,... what could it be...
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Post by gsx600racer on Oct 9, 2018 21:03:28 GMT -5
Well let’s think about this... white insulator, over heating, possible detonation,... what could it be... It's a new engine running condition called "denial".
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Post by katt on Oct 9, 2018 23:23:18 GMT -5
Well let’s think about this... white insulator, over heating, possible detonation,... what could it be... i have no idea vacuum leak?
Did a 20 miles run tonight on #120 still few misfires on WOT need to go to 115, but no overheats and power is decent.
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Post by diynuke on Oct 10, 2018 2:28:55 GMT -5
Well let’s think about this... white insulator, over heating, possible detonation,... what could it be... i have no idea vacuum leak?
Did a 20 miles run tonight on #120 still few misfires on WOT need to go to 115, but no overheats and power is decent.
Will inspect plug soon.
Just buy a tune kit.. you are all over the place. and don't look too much at the misfire's but at the spark plug color. ive had it with main 90 it didn't work great and it bogs a bit and with 88 it runs good all the way. so its just as simple as getting the right jet but don't do that with 5sizes up or down. that's way too much. so indeed go to 115 and then really fine tune it. (and never go for a long ride with an hot running engine..) and don't ask too much basic stuff that you kind of already know xD But yeah with the spark plug look at the insulator. not that ring. And I suggest you shouldn't run it too long when your tune is still really crude..just a few minutes is enough to tan the spark plug And gosh I can't believe ya took it for a ride. that oscillating rpm at full throttle is just that the main jet is so small that it gets so lean that it just doesn't run. and that's kind of the worst case scenario You should be happy you don't have a 2 stroke otherwise you would already have seized the fk out of her xD
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Post by katt on Oct 10, 2018 3:21:23 GMT -5
And gosh I can't believe ya took it for a ride. that oscillating rpm at full throttle is just that the main jet is so small that it gets so lean that it just doesn't run. and that's kind of the worst case scenario That was with too rich condition, not lean... since it got almost eliminated going from #130 main to #120 main and when i used #90-#110, i never had this issue at all.
Cannot afford no kits at moment need to make this work.
Perhaps internet is right top of insulator only shows idle since my idle is lean it will never change insulator top color, will cut the plug thread off tomorrow and see what bottom of insulator looks like.
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Post by diynuke on Oct 10, 2018 5:56:08 GMT -5
And gosh I can't believe ya took it for a ride. that oscillating rpm at full throttle is just that the main jet is so small that it gets so lean that it just doesn't run. and that's kind of the worst case scenario That was with too rich condition, not lean... since it got almost eliminated going from #130 main to #120 main and when i used #90-#110, i never had this issue at all.
Cannot afford no kits at moment need to make this work.
Perhaps internet is right top of insulator only shows idle since my idle is lean it will never change insulator top color, will cut the plug thread off tomorrow and see what bottom of insulator looks like.
Dude.. no need to chop the spark plug..... for that money you already can buy 2 jets if you are complaining about money.. just trust the guys here.. just run it at 7000rpm for a few minutes then turn the key OFF WITHOUTH letting it idle then pull it out and look at the color. (the top part.. this is the part which is effected with the last air fuel ratio. so that's why they would say its the pilot part however if you run it and not let It idle it will read the value which you ran it.. but honestly if you don't have enough money then just put on the stock 18mm carb and tune that then it will be way more reliable while still being faster than stock. But besides that. but yeah pick something between 110 and 120 then so were talking about 115 so try that first. and the top of the spark plug.. It really shows the color and if it just doesn't get brown well its just too lean.. you DO need to watch out that you are not reeding values like low throttle So do literly what I say.. start it let it warm up a little bit. then on the stand. let it rev around 7000/7500rpm do that for 1minute then HOLD the throttle then turn off the KEYSWITCH then slow down the engine as fast as you can and then pull the plug out. so you don't want it to fire at all when slowing down that's why you have to use the key switch.. This will be a very rough way of seeing the mixture but it does point it out.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 10, 2018 7:35:36 GMT -5
I just noticed in your bottom block that you list a “no rev limit cdi”. Does that mean you have one of the aftermarket “racing” cdi? Do you still have your orginal CDI? My experince with “preformance “ CDIs is that they run at full advance all the time. If you still have your stock cdi, it might be worth sticking it back in and seeing if the scoot starts better and runs better at low speeds. You didn’t, by chance, do the mod to the ignition pick up above the flywheel did you? I see a lot of stuff on YouTube about making the two mounting holes into slots so you can run more advance, I hope you didn’t do that.
I have to believe that you have an air leak. I just don’t see you running that lean with as big a jet ad you say you were running
Maybe it’s just my old eyes, but it looks like you are picking up Aluminum on that latest plug to me.
Do you have the stock air cleaner still? On the scoots I have worked on, there is a long snorkel like tube that goes into the air cleaner from the back of the carb. If you what to try something, you should be able to remove that tube, cut it to about 6” long then mount your cone filter on it ( that most likely will require some work with a file to take the ridge off the end. This would just be a temp fix to see if it had any effect, but you may find the long intake runner will let the engine “catch” some of the gas that’s being brown out the carb now
I’d still vote for investing in a new head gasket and pulling the head to see what the inside of that engine looks like, but ofcourse I tend to over react to stuff like this
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Post by katt on Oct 10, 2018 15:48:05 GMT -5
but honestly if you don't have enough money then just put on the stock 18mm carb and tune that then it will be way more reliable while still being faster than stock. But besides that. I had same exact problem with 18mm carb and stock air box, engine overheated on holding RPM in 7500-8000 even using size #98 main jet.
Can it be leaking in cylinder gasket area somewhere because i have checked the intake manifold it has no leaks.
My suspicion confirmed tip of the insulator only shows idle jet, mid shows mid range and bottom shows WOT.
Its tough to take picture with exact light of the insulator middle part, its something in between this two shots its black not brown.
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