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Post by chehystpewpur on Jun 23, 2014 15:23:23 GMT -5
Ok I read your thread and one thing I can say that could have something to do with it is the exhaust. I bought my bike non running and the oil pump was way out of adjustment about 1/4 the way open with throttle closed. It filled the case and exhaust up with oil. Completely ruined the exhaust. Bike would barely run and when it did it was hard starting and no power and would die when riding then start back up after about 10-15 mins and run crappy then die. Try starting without the exhaust and see if it runs as bad. If it doesn't maybe it plugged up with carbon or something else. I've heard that when ran too hot the insulation inside will melt and rattle around or plug the exhaust . Its atleast a thought because I had hell sorting mine out untill I tried the exhaust thing and low and behold it ran perfect. Also the reed blocks are known for leaking and leaning things out. What color is the plug?
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Post by 2TDave on Jun 23, 2014 15:47:19 GMT -5
Do Not start the scooter without an exhaust!
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t2no
Scoot Member
Posts: 55 
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Post by t2no on Jun 24, 2014 11:10:22 GMT -5
Spark plug is brownish/caramelish, I will take a picture later to show. With new carb I think it is starting ok now, but cant make it idle. I have ordered bigger pilot jets (45 and 50) cuz I end up with A/F screw all in and no slack in the throttle cable. And it revs quite a bit like this. I might check oil pump adjustment markings to see if it is adjusted correctly. But I doubt it is what you are saying, but who knows... I will check  |
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Post by chehystpewpur on Jun 24, 2014 14:48:44 GMT -5
Spark plug is brownish/caramelish, I will take a picture later to show. With new carb I think it is starting ok now, but cant make it idle. I have ordered bigger pilot jets (45 and 50) cuz I end up with A/F screw all in and no slack in the throttle cable. And it revs quite a bit like this. I might check oil pump adjustment markings to see if it is adjusted correctly. But I doubt it is what you are saying, but who knows... I will check Hmm brownish or caramelish is good it means the jetting is where it needs to be atleast. Thats weird it won't go. If there were leaks the plug would be a diff color due to being lean Most likely alot whiter. |
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t2no
Scoot Member
Posts: 55
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Post by t2no on Jun 28, 2014 7:47:46 GMT -5
So yesterday came my 45 pilot jet (50 will come next week since the shop didn't have it in stock). Today installed it and didn't go far with my main jets, even 80 was too big. So I bought 70 72 74 and 76. went with 74 since with 70 and 72 runs similar. Starts, drives but still A/F screw only 1 turn out with snorkel, without only half a turn out. Top speed 55 km/h w/o snorkel, 48-50 km/h with snorkel. Gonna wait for bigger pilot jet and see what happens. From about 3/4 to WOT not so much response and difference. Noticed that exhaust fumes are very hot, cannot hold hand over fumes closer than 2 cm. Is that normal? Needle clip set to middle grove. Almost no smoke. Any ideas suggestions?
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Post by chehystpewpur on Jun 28, 2014 15:42:40 GMT -5
So yesterday came my 45 pilot jet (50 will come next week since the shop didn't have it in stock). Today installed it and didn't go far with my main jets, even 80 was too big. So I bought 70 72 74 and 76. went with 74 since with 70 and 72 runs similar. Starts, drives but still A/F screw only 1 turn out with snorkel, without only half a turn out. Top speed 55 km/h w/o snorkel, 48-50 km/h with snorkel. Gonna wait for bigger pilot jet and see what happens. From about 3/4 to WOT not so much response and difference. Noticed that exhaust fumes are very hot, cannot hold hand over fumes closer than 2 cm. Is that normal? Needle clip set to middle grove. Almost no smoke. Any ideas suggestions? No smoke and hotter than usual sounds like back go an oil problem. Or something else is making it overheat. Does it sound more hollow or a bog? Hollow is lean and bog is usually rich. Try the clip one notch in either direction and see if there is a difference in the sound. It might be more obvious and tell you up or down on the jets its what I usually do. Obviously keep an eye on plug color it usually takes 30-40 miles for me to get a color difference starting on my plug if I use the same one. Sometimes though too rich makes a white plug like its lean but the extra fuel is just washing out the plug so you can't completely rely on that. |
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t2no
Scoot Member
Posts: 55
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Post by t2no on Jun 30, 2014 10:31:13 GMT -5
I am thinking here, when I changed pilot jet to 45 (bigger) I am leaning out the mixture, correct? could that be a reason why its overheating?but then why it revs like crazy with smaller pilot jet?I am with almost all A/F screw in. :/ Couldnt be air leak, cuz with old carb it was not doing that.
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Post by 2TDave on Jun 30, 2014 12:35:40 GMT -5
Larger jet = more fuel = richer. That is a large pilot. If the a/f screw is all the way in then you are probably compensating for the pilot being to large.
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Post by chehystpewpur on Jun 30, 2014 14:11:33 GMT -5
I am thinking here, when I changed pilot jet to 45 (bigger) I am leaning out the mixture, correct? could that be a reason why its overheating?but then why it revs like crazy with smaller pilot jet?I am with almost all A/F screw in. :/ Couldnt be air leak, cuz with old carb it was not doing that. Man just bring your bike down to fl and bring a 6 pack well get it right or claim faulty wiring out in the barn... |
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t2no
Scoot Member
Posts: 55
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Post by t2no on Jul 1, 2014 14:49:31 GMT -5
Today found out that throttle cable was too short and that was the reason it was revving like crazy. Fixed that and of course had to step down with pilot jet size. Installed smallest that was around - 34. Was playing with main jets and end up putting biggest around - 94. Cannot idle with the snorkel properly and it bogs a lot with the snorkel. Without the snorkel it drives ok, but still max speed like 45km/h. WTF?  ?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here? |
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Post by chehystpewpur on Jul 1, 2014 19:22:07 GMT -5
Today found out that throttle cable was too short and that was the reason it was revving like crazy. Fixed that and of course had to step down with pilot jet size. Installed smallest that was around - 34. Was playing with main jets and end up putting biggest around - 94. Cannot idle with the snorkel properly and it bogs a lot with the snorkel. Without the snorkel it drives ok, but still max speed like 45km/h. WTF? ?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here? From my understanding a stock main jet is fine up to most big bores. Some of the wild ones need more fuel. I've used the stock pilot with 2 bbks and not had an issue and thats with zx-r exhaust and always snorkel out. The extra noise is good for alerting people and not loud enough to really bother ppl. main jet with that setup is 75-80 and 80 was in the winter and about 30-60 degrees daily. I use Mikuni 19mm but that would put me a hair leaner than ur set up id expect. More air and same amount of fuel. Bbk I'm using around 80-85. When I had some issues with one and it was losing comp it was about 90 main jet. What are the temps there in morning and the night? What about the hot part of the day? Where I'm at we get 40-60 degree temp swings sometimes and well I doubt a tune will perform good like that no matter what. Is there any way u can get a video ? Snorkel out please. It will make the sound more obvious. If it just flat out falls on its face but doesn't have the lean or rich sound it could be the rings or the rollers/slides for the variator. Bad cvt can mimic bad carb tune along with no compression lol I've found out the hard way. |
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Post by TruseiC on Jul 2, 2014 3:09:50 GMT -5
Today found out that throttle cable was too short and that was the reason it was revving like crazy. Fixed that and of course had to step down with pilot jet size. Installed smallest that was around - 34. Was playing with main jets and end up putting biggest around - 94. Cannot idle with the snorkel properly and it bogs a lot with the snorkel. Without the snorkel it drives ok, but still max speed like 45km/h. WTF? ?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here? Im running 74 on my 16.5Mikuni on 50cc. Try something like 74-80 or smth |
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t2no
Scoot Member
Posts: 55
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Post by t2no on Jul 3, 2014 12:31:34 GMT -5
Today found out that throttle cable was too short and that was the reason it was revving like crazy. Fixed that and of course had to step down with pilot jet size. Installed smallest that was around - 34. Was playing with main jets and end up putting biggest around - 94. Cannot idle with the snorkel properly and it bogs a lot with the snorkel. Without the snorkel it drives ok, but still max speed like 45km/h. WTF? ?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here? From my understanding a stock main jet is fine up to most big bores. Some of the wild ones need more fuel. I've used the stock pilot with 2 bbks and not had an issue and thats with zx-r exhaust and always snorkel out. The extra noise is good for alerting people and not loud enough to really bother ppl. main jet with that setup is 75-80 and 80 was in the winter and about 30-60 degrees daily. I use Mikuni 19mm but that would put me a hair leaner than ur set up id expect. More air and same amount of fuel. Bbk I'm using around 80-85. When I had some issues with one and it was losing comp it was about 90 main jet. What are the temps there in morning and the night? What about the hot part of the day? Where I'm at we get 40-60 degree temp swings sometimes and well I doubt a tune will perform good like that no matter what. Is there any way u can get a video ? Snorkel out please. It will make the sound more obvious. If it just flat out falls on its face but doesn't have the lean or rich sound it could be the rings or the rollers/slides for the variator. Bad cvt can mimic bad carb tune along with no compression lol I've found out the hard way. You are talking about main jet size. I am curious about pilot jet size Smaller size (4mm)? in my carb sits next to main jet. Morning and night now I would say about 13 degrees Celsius. Actually I think it runs slightly better in cooler weather. I changed recently contra spring to red one 32 kg, 5 gram rollers new belt, changed o rings on the torque drive re greased everything. New variator. I am starting to think maybe this contra spring has something to do with it. How to check these rings on the crank for air leaks? I end up putting 100 main jet and there is no difference between (I have tried 80, 88, 90, 94 96 and now installed 100). No smoke. engine is still getting to worm in my opinion. Should I go even higher with the main jet? Maybe I should mention that I live in Copenhagen, Denmark and its quite humid here. Altitude according to wikipedia 31m (only about 100 feet) above sea level and some other website, Copenhagen is only 6m above sea level. Donno if that is helpful. back to tuning the carb, when trying to adjust idle, after turning out the A/F screw 3 turns out, no change in the engine sound. What could that mean? I tried to take of the air filter box and noticed that the carb is spitting petrol/oil dust (small drops) into the air box. Is that normal? When I tried to rid it without air box it just bogged down on me. Also after riding the scooter when I was changing my jets I noticed that when I took of the carb from the stud, there was small amount of smoke/steam coming out from the stud, is that normal on the hot engine? I made a video but I doubt you will be able to see anything. |
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t2no
Scoot Member
Posts: 55
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Post by t2no on Jul 3, 2014 12:32:12 GMT -5
Today found out that throttle cable was too short and that was the reason it was revving like crazy. Fixed that and of course had to step down with pilot jet size. Installed smallest that was around - 34. Was playing with main jets and end up putting biggest around - 94. Cannot idle with the snorkel properly and it bogs a lot with the snorkel. Without the snorkel it drives ok, but still max speed like 45km/h. WTF? ?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here? Im running 74 on my 16.5Mikuni on 50cc. Try something like 74-80 or smth What about pilot jet? |
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Post by chehystpewpur on Jul 3, 2014 14:17:00 GMT -5
Where I'm at is about sea level as well and believe it or not humidity actually helps with the engine running more efficiently just a hair but it does. I've never changed a pilot jet due to always having it be too rich at low rpm anyways. Pilot jet is for the bottom 1/3 of throttle the needle position is for the middle 1/3 and main jet is for the last 1/3 more or less. Being about sea level should give you a hair more air than most people get and make slightly more power. Maybe you just need a larger carburetor to accommodate for more cooling. And fuel coming out of the carb on the air filter aide is normal along with the steam its actually the air oil and fuel mixture which is a vapor. And get the video somewhere so I can see it. The visual I don't need really just the sound. If that's there I might be able to hear something thats out of whack. You would have to do a leak test to check if their leaking. Or visually u might see a little oil coming from the seal where the crank is my guess though you wouldn't because it would most likely get shot out of it and not just drip down. I put an air scoop on mine for the cooling fan because it gets to over 100 degrees Fahrenheit here in the summer so it was a just incase. Maybe that would help you if its actually getting too hot.
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?? And sounds loud a bit. I should install even bigger main jet now? I am so confused.. This carb tuning is driving me crazy. And engine is still hot, exhaust fumes a bit cooler though. What to do? What pilot jets guys are running on 50 cc engines with 17.5mm carbas here?