fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 14, 2018 12:57:12 GMT -5
Thanks tocoo for a bunch of great info! I think everything is original on my scoot though, at least before i started tampering with it. ~2400km when i bought it, ~2800km now. Some girl had it since new, and she or her dad never touched it. I don't think it is pulley or transmission-related on mine. It sounds like engine is starved of either fuel or air. I should record audio for you guys! Could the engine stutter because of transmission/clutch/pulley? Hmm maybe if the resistance is too great from standstill, for some reason. Interesting thought. Unfortunately, i have almost no experience of transmission/clutch/pulleys on scooters. Not 100% sure that we have the exact same carb or same revision of the same carb. They might have changed something from 2014 to 2016. Mine came with 78 main jet, and there are only three slots for needle clip, not four. Because i unrestricted airbox, i can't de-unrestrict it and get it exactly as original, only close. Therefore your jets and needle clip positions might not translate perfectly to my scoot. I think next step would be to drain the tank, drill hole in vacuum petcock (thanks for tip!), and plug the vacuum connector on manifold. Could it be that it draws too much air that way, via my semi-broken petcock? Valve clearance adjust i should also do... but need to lay low for a while. Ppl are staring at me for working on my scoot all the time. It is gettin embarassing. + i need to do some fixes on my electric bike again. Its a shared, ill illuminated parking garage that i'm workin in, so must be very careful not to spill fuel.
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 14, 2018 14:49:43 GMT -5
I have a new great idea, LOL. To remedy the derestricted airbox, and to be able to fine-tune AIR instead of fuel, i came up with this idea. It is basically a 2-3mm thick plastic slide that restricts airflow, and is "easily" movable. I say "easily", because it needs some resistance so it stays in place for a short testrun without securing it properly. If i put it close to where the restriction was, the slide should be accessible without the need to remove saddle, for very easy adjustment.
EDIT: Could secure it with an L-shaped thing with two holes in it. L-thing secured by screw through airbox, other side of L has hole that slide screw goes through. Then slide can't move in any direction.
All i need to do then is put back the original carb and manifold, 78 or 80 main jet, and adjust slide until it runs great. If still hesitating despite that, then i'll look into other things. I could combine the above with drilled vacuum petcock and plugged vacuum hole in manifold too. What you think?
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 14, 2018 15:09:08 GMT -5
Hmm i have an even better idea! Drill a hole straight through, and make something that reminds of the "butterfly" in the carb. Then just a knob on the outside, with markings.
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Post by tocoo on Oct 15, 2018 2:06:14 GMT -5
yes I think the original carb has a needle with 3 grooves, not 4. I think the main jet was 78 too. I think you worry too much about the restriction of air, because whatever air flow you have with the stock airbox, you will adjust the mixture screw and as long as the mixture screw is between 1,5 and 3 turns, then it would be fine for idle and half opened throttle. What matters with the airbox is that it dried of water, so that no water enters the carburetor. Can you say how many seconds it takes for the scooter to react from idle to wide open throttle ? How high is your idle now ? does it idle well ? if it idles well and the enricher works well, then the transition form idle to wider opened throttle is about the needle. THere are diagrams here 49ccscoot.proboards.com/thread/23542/cv-carburetor-adjustment-progression-portsthere is a tutorial to set the carburetor www.49ccscoot.com/faq/carbtune.htmlYou can buy a tachometer on ebay or aliexpress too for 20 USD i will check my original carburetor too. I wait for the cold temperatures to come to set the carburetor for winter.
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Post by tocoo on Oct 15, 2018 2:57:57 GMT -5
I just checked = original main jet = 78, original needle clip = middle out of 3 grooves this is how my spark plug looks like for the setting for summer, idle jet = 33 , main jet = 82, mixture screw = 2,75 turns from screwed position, idle RPM = 2000 or 2100, everything original on the scooter, but not the CDI or the orange coil. I will try to see the ring at the base of the ceramic as explained on this tutorial 49ccscoot.proboards.com/thread/1727/spark-plug-reading-tuning-info
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Post by GrumpyUnk on Oct 15, 2018 14:44:01 GMT -5
fhol, have you looked at the accelerator pump shaft on the right rear corner of the carburetor? There should be a flat 'blade' that smushes down onto the shaft to operate the pump. It should start to push on the shaft as soon as you move the throttle control off of the hard idle stop. Open the throttle, and watch the pushrod. If you can open the throttle without the pushrod being pushed for some degrees of opening, try bending the flat metal arm down on the rearward end while holding the forward end in place. That should take care of any delay in the pump delivering the 'squirt' when you first open the throttle. tom
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 15, 2018 15:48:26 GMT -5
Thanks tocoo and @grumpyunk once again for very good feedback! Much appreciated. tocoo : It idles perfectly once the mix screw is set. But unrestricted airbox is a nogo for me. Solution in next post. @grumpyunk: Now that i have an accelerator pump on new carb, i will look into that.
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 15, 2018 15:56:10 GMT -5
EDIT: If anyone is stupid enough to try this, make sure to put the slide in the max restricted position first, then gradually increase opening if needed. Don't do it the opposite way. If so you risk running lean which can cause permanent engine damage.
I have now made a new mod - adjustable airbox restriction! Because trying with various amount of tape in front of airbox inlet makes a huge difference in how engine runs. This mod seems to work good (haven't tested it on scooter yet), and can give me more, equal, or less restriction than original box. The little plastic thing has a very tight fit so it should not be able to move unless i do it myself. Can't wait to try it! Too late tonight. EDIT #2: I ended up drilling tiny holes in the slide, to be able to secure it with cable ties (just in case) and also get some sort of a reference when adjusting, counting the visible holes on the outside.Will use cable ties shown in stack in above pic when completely satisfied. They are small enough that i can squeeze one through the hole in the slide.
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 16, 2018 15:20:36 GMT -5
Small victory today! The adjustable slide did wonders! Using 20mm Keihin carb with 84 main jet and 32 pilot jet, air/fuel mix screw 2 full turns out (thats when idle revs at max), i ended up with the adjustable airbox slide in hole 7 (more open than original, but not fully open) for the least amount of hesitation from standstill, but it is still noticeable. Here is what it sounds like. I'm sitting on the scoot, accelerating from standstill twice, recording with my mobile phone. AUDIO:www.dropbox.com/s/daz7pkjq02z6jkk/kisbee_hesitation-2018-10-16-20-47-41.wav?dl=0EDIT: To clarify, hesitation periods in red The second acceleration in above sound recording is spot on. If i restrict airbox more, it is kind of the same sound but for a longer period. If i let it run lean instead, it hesitates (dies) but the sound is a little less stuttering. So the victory was really that the engine runs awesome except for hesitation. Never had this much power and acceleration and top end. Up the hill to where i live, i reached 48 km/h!! Been struggling to get to 44-45 before. Rev limiter kicks in at 50 km/h. @grumpyunk: Also checked the acceleration pump carefully. It engages immediately when i touch the throttle, as it should. Any sane person would be satisfied with how the scooter runs now, and just forget about the hesitation. Still bugs me though, but i'm super happy with my adjustable airbox restriction and the power gain!
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 18, 2018 16:07:55 GMT -5
No one listened to hesitation-audio in last post, yet? Could it be too much or too little ignition timing advance on low revs? This page www.hotrod.com/articles/0604rc-ignition-timing/says "The basic rule of carburetor tuning is ignition first. Once the ignition advancing mechanism is correct, the air/fuel mixture can be tuned for improved power or fuel efficiency." V8 engine, but principle should be the same i guess.
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Post by tocoo on Oct 19, 2018 2:03:49 GMT -5
I listened to the sound recorded, but you do not tell when you open the throttle, so we cannot hear the delay in acceleration.
Before you turn the vacuum petcock into a manual petcock, can you tell me if you see a drop in RPMs [or even if the scooter dies] when you do the following -start the scooter on the main stand -let the engine run for 5 minutes to warm it up and let it idle -mount on the seat of the scooter -do not touch the throttle -still without touching the throttle, push with the feet the scooter forward to retract the main stand -still without touching the throttle, pull with the feet the scooter backwards over a few meters
at this point, either by pushing the scooter forwards or moving backwards with the feet, when I used the vacuum petcock, the RPM would drop, like form 2000 to 1700, sometimes the engine would die.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 19, 2018 9:16:27 GMT -5
As I read you post, it sounds like you have an after market CDI. So called “ preformance CDIs don’t retard the timing for low RPM running. I hate these things! I now have 7 of them in a pail in the corner of my garage. Since we have been building red bike and the earsplitingloudenboomer bike, I have become like the mr fix it of the 50 cc mo pod world. It seems like ever time someone brings me a “ hard starting” moped, I find one of these damn aftermarket CDIs and I fix their problem $15! (Stock cDI, new plug, and spark plug cap). I have no idea why the people that make these things think it’s an “improvement” to run fullbadvance all the time. And BTW, as close as I can tell with a timing light, there full advance is the same amount of advance I get with the stock CDI at higher RPMs
Ok, I’ll get off the soapbox now
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 19, 2018 16:03:50 GMT -5
I listened to the sound recorded, but you do not tell when you open the throttle, so we cannot hear the delay in acceleration. Before you turn the vacuum petcock into a manual petcock, can you tell me if you see a drop in RPMs [or even if the scooter dies] when you do the following -start the scooter on the main stand -let the engine run for 5 minutes to warm it up and let it idle -mount on the seat of the scooter -do not touch the throttle -still without touching the throttle, push with the feet the scooter forward to retract the main stand -still without touching the throttle, pull with the feet the scooter backwards over a few meters at this point, either by pushing the scooter forwards or moving backwards with the feet, when I used the vacuum petcock, the RPM would drop, like form 2000 to 1700, sometimes the engine would die. I haven't tried exactly that yet, but i have noticed a slight drop in RPM (idling) when i re-attach the saddle. Also small drop in RPM when i sit down on scooter. You could be onto something here! Didn't think much of it before because maybe slight change in angle of carb versus ground or something, could cause that, and that it could be normal. But maybe it is not normal. Please also re-visit my audio-post. I have added explanation of where i give full throttle and where it hesitates in that clip. It is quite easy to hear the stuttering sound it makes. ratdog: Yep, i have heard of those crappy aftermarket CDIs, but i'm pretty sure mine has the original one. I'm the second owner, and the first owner didn't touch anything on scoot. The too much ignition timing advance on idle is pure speculation from my side. Add to that, that i have seen and heard an almost identical Kisbee with the exact same hesitation sound as in audio i just posted.
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Post by tocoo on Oct 19, 2018 19:37:38 GMT -5
yes me too, it is the saddle that pushes on the enricher of fuel. go on the right of the scooter with a light and try to lift the saddle a bit [no fuel cap ON], you see the saddle pressing the enricher. the idle changes al the time: -the bike is on the main stand with no saddle -the bike is on the main stand with a saddle -the bike is on the main stand with a saddle+driver -the bike is not on the main stand and there is a driver I set my idle at 2000 RPM when the bike is on the main stand with a saddle. To minimize the effect of the enricher, you must push the tail of the enricher towards the air entry of the carburetor. But since you have the original enricher, which is tiny compared to the generic enricher on generic carburetor, you should not have problems like this with the original carburetor I found the 2 pictures illustrating the long needle of the original enricher int he original carburetor. The first picture is with a generic enricher and the second one is with the tiny original enricher. the tiny original enricher totally blocks the first hole
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fhol
Scoot Member
Peugeot Kisbee 4T 2016
Posts: 81
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Post by fhol on Oct 20, 2018 9:11:56 GMT -5
tocoo: I'll look into that. The Keihin carb is mounted a little lower than original carb because of slightly different shape on the 22mm manifold. I have drilled the darn petcock now. Turned out it kinda worked, but i had some troubles emptying the fuel tank. Had to remove petcock. The membrane in it was very stiff, so the turn on/off of fuel was kinda delayed for several seconds. Now it is drilled though, carefully cleaned of debris so there is nothing wrong with fuel delivery anymore. I also noticed petcock was fitted with a long filter sticking into the tank, so my manual shutoff is protected somewhat despite extra fuel filter mounted after it, very close to fuel inlet in carb. Tank and filter on vacuum petcock was clean. Couldn't find any gunk in the tank whatsoever. I also plugged vacuum hole in manifold and petcock using an inch long petrol line with a very tight fit screw, each. Going for a testrun in 30 mins... wish me luck!
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