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Post by ashdump on Sept 4, 2008 13:04:10 GMT -5
Hey Earl! Rejetting may be a winter project. The performance problem is only a problem when I want to get out on the highway in heavier traffic (which is almost never). I live in a rural area and my drive to work is rural. All-in-all, it has worked out very nicely for me. I like to cruise at a comfortable speed of about 40mph. Virtually no traffic, so I can run it just about however I please. I think the old vacuum petcock was probably loosing a little vacuum against the diaphragm under high revs, but the new solenoid took care of that. I did notice a slight but noticeable difference in performance. BTW, why do most of the folks here recommend the looser valve settings? I checked them and they were between .002-.0025" before I adjusted them to .004". The tappets were noticeably loud. I went ahead and put them back to the factory setting. No noticeable difference either way in performance. When I take off, I can feel the vibration from the slop in the belt, but just for a second or two.
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Post by earlwb on Sept 4, 2008 13:19:54 GMT -5
The GY6 manual suggested .004" settings. So everyone more or less copies it. If .002" works for you, go for it.
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Post by ashdump on Sept 4, 2008 13:28:37 GMT -5
The GY6 manual suggested .004" settings. So everyone more or less copies it. If .002" works for you, go for it. I read somewhere that the manufacturer recommends .05mm which is just a smidge under .002". I just prefer it because it is nice and quiet. It's been raining here the last two day's, so I've been 4 wheelin it. |
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Post by earlwb on Sept 4, 2008 21:18:33 GMT -5
Darn it all. My scooter was handling weird today. Sure acted like it had a loose steering head or something, then when I got home, I got to checking it over closely and I discovered a serious notch in the steering, when you turn thr wheel slightly left or right. The notch is right at center position for riding straight ahead.
On the way into work the engine ran fine, but on the way home it acted like the ignition coil is going bad again.
Oh well, something to play with for the weekend. The notch in the steering head bothers me, I may not be able to fix that. Hopefully it is something else when I get the front panel off.
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Post by earlwb on Sept 11, 2008 10:46:17 GMT -5
I thought I would measure some of my coils around the home.
Coil resistance, using a good ohmmeter, the primary should measure 300 to 400 milli-ohms and the secondary should measure around 8k to 10k ohms. Usually measurements on the secondary come out around like 9k. As the coil windings short out over time, the resistance gets less and less, where you wind up measuring like 3k ohms on the bad secondary windings.
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Post by bigluelok on Sept 22, 2008 16:26:23 GMT -5
great thread Earl
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Post by mx5tc on Sept 23, 2008 2:34:10 GMT -5
The GY6 manual suggested .004" settings. So everyone more or less copies it. If .002" works for you, go for it. Yikes, this has to be the most quoted/misquoted/unknown/what the heck it is really??? spec there is! First, I think the ScootDawg "Manual" is wrong on this spec; it states 19/10,000 (.0019) Intake and 24/10,000 (.0024) Exhaust! .002 thou for a COLD lash spec on an all aluminum engine!! What's the spec going to be hot running; -.0005?  ?? The Kymco 125cc GYG manual states .12mm cold (.0047), the Arrow 150cc manual states .08mm to .12mm. The generic 50cc GY6 manual and the generic Tank 50-150cc manuals both show the .05mm/.00197 valve lash spec. I think it is wrong and too tight for a 150cc GYG, YMMV, Mitch |
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Post by anhoa on Sept 23, 2008 11:35:38 GMT -5
Manual is for reference. If you don't like what's in the manual, you can pick your number or from other people who had done the valve adjustments. Not all manuals are the same for GY6 150cc engine.
Anhoa
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Post by earlwb on Sept 28, 2008 19:09:28 GMT -5
I got around to hooking up my oscilloscope to a COP coil as connected on my scooter. It uses a CDI module to fire the coil via high voltage pulses. Due to the low ohm resistance of the primary coil windings, there is a fair amount of current there too. In the annotated pic, I have the O-scope set for 5 volts per horizontal graduation, but the o-scope probe is a 10:1 probe so it divides the voltage by ten as well. So from the scale the CDI is providing approximately 135v per pulse to fire the coil with. A standard CDI puts out about 80 to 100 volts per pulse and the NCY racing CDI I used puts out about 135 volts per pulse. Some high-performance CDI's can put out more than 200 volts per pulse. Anyway, you can now see why the small COP design ignition coils would be susceptible to failure if the spark plug wire is loose or the spark plug cap comes loose. The output voltage would go to over 100,000 volts causing the wires inside the coil to short out or go open. They really need a good tight connection all the way to the spark plug.   |
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Post by earlwb on Sept 29, 2008 5:41:33 GMT -5
One of our illustrious forum members did this diagram of a CDI and its pinouts.  One note, the pickup coil is typically one of the stator coils under the flywheel. It is shown separate here. So don't be surprised if you don't see a outside pickup coil like the diagram shows. |
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Post by cathouse on Sept 29, 2008 16:37:10 GMT -5
You must remember that your settings will tighten up some when your motor heats up, a little loose is a lot better than a little tight on your settings.
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Post by Kaos on Sept 29, 2008 18:15:27 GMT -5
"here is how I handled the rear view mirror wiring color codes. I don't know what the third wire is for, it only needs two wires, ground and power." On my '08 there is a little red led inside each turn signal, thats what the 3rd wire is for. My wiring diagram calls it a "night light"...how considerate!  |
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Post by trigger on Nov 3, 2008 19:06:53 GMT -5
I just want to thank Earl for such a dedicated effort in putting together this post. It has surly saved me many hours of guessing, and effort.
I now have 2300 miles on my Tahiti 150 and it has ran like a top since day one. I have only replaced the intake and muffler straps, and elected to replace the valve stims on the tires for safety.
I made my muffler straps out of aluminum purchased from a farm store (TSC) and they are holding up great. Easy to make with a drill and hack saw. I used 1"x1/8" by 72" stock.
I bought my scoot from dirtcheapatv here in Indiana. Out the door with tax and title for $950.00 USD. So far that is the best price I have seen but I didn't have to pay shipping.
Well we are being blessed with 74 degree weather here, so I will delay Winter maintenance until the weather changes for the worst.
Happy scooting.
Trigger
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Post by scox on Nov 5, 2008 18:35:03 GMT -5
Quck question...... Just got my Roketa Carpi this summer so I am a real newbie. Is it completely necessary to run premium gas in these things? My son and I rode quads for years and just used reg.
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Post by earlwb on Nov 6, 2008 6:58:27 GMT -5
After you break it in good, try some regular and ride around a while paying attention to the engine foe detonation pinging sounds etc. If it runs OK, don't worry about it.
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Post by lumberjack on Nov 1, 2010 13:18:24 GMT -5
Fun read, Earl! Where is the scoot today? Do you still have it and how many miles?
I've got a Roketa Maui 49cc 4T with 315 miles on it. So far it's running good although a carb clean seems to be in order (it's bogging down a bit but not too bad!)
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Post by fuwad84 on Nov 1, 2010 18:54:39 GMT -5
Hi Earl, Actually I wouldn't mind a status update...and mabe a lil advice as well seeing as how I just purchased the same exact scooter only in black.
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