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Post by dmartin95 on Nov 24, 2015 20:56:23 GMT -5
Yummy! I'll be in contact with you about that early next year, thanks! Your welcome.... I have been giving thought to ordering a few of the -3 type of crankshafts and just selling the entire stroker, instead of just the rod... Only problem is, I do not have a good connection on your style of crank.... Do you know how to change the rod? |
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Post by JerryScript on Nov 24, 2015 21:07:17 GMT -5
Yep, I take it to a shop. ;-)
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Post by rcq92130 on Nov 26, 2015 12:30:08 GMT -5
Excellent write up on a cheap O2 sensor solution! You should copy this to a thread in the Tips & Tricks section! Thanks, Jerry. Do with it whatever would be helpful to folks. |
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Post by rcq92130 on Nov 29, 2015 14:45:54 GMT -5
This is about CLUTCH TUNING (see below, at the bottom, for a link to a wonderful guide on how to select different parts of not only the clutch, but also the variator, so you squeeze the most performance out of your engine The scooter has a full NCY clutch. Like maybe some others, I had not before messed around with the clutch ... so maybe this little write up will help some better understand. CLUTCH OPERATION: The "clutch assembly" really has two functions: 1. An actual 'clutch' - that spins freely until engaged (as if you were in neutral gear), and then grabs for positive connection between the engine and rear gears/wheel assembly 2. A part of the 'transmission' that varies the gear ratio between the engine & rear wheel much as your car's stick shift. Clutch part: this part of the clutch assembly consists of 3 pads like a drum brake. Springs hold the pads tight against the spindle at low speeds, so the scooter acts as if it's in neutral. Then, at a certain speed, the centrifugal force overcomes the power of the springs and the pads expand outward, pressing against the inner surface of a drum (again, just like a drum brake). This causes a positive connection between engine and rear wheel. Transmission part: Your variator is only 1/2 of the 'transmission' in your scooter. In the 'clutch assembly" is another pulley that does the same basic job of the variator - squeezing against the drive belt causing it to move outward toward the edge of the pulley and thus acting as if a larger gear was being used (or vice versa, allowing the belt to drop down into a smaller diameter part of the pulley). But - while the variator accomplishes this with rollers or sliders, the rear pulley in the clutch assembly does so with a strong spring called the contra spring. It presses against the pulley, pushing the 2 halves of the pulley together and forcing the belt to ride high near the outer circumference of the pulley. As rpms of the clutch assembly increase, the contra spring is compressed - the pulley halves separate, allowing the belt to ride lower in a smaller arc within the pulley. This acts like a smaller gear in the rear, which is good for higher road speeds. CLUTCH ASSEMBLY PARTS. Here are examples of the parts of the NCY clutch assembly: The pulley itself, called the Torque driver - www.ebay.com/itm/SCOOTER-150CC-GY6-NCY-RACING-PERFORMANCE-SLIDING-TORQUE-DRIVER-PLATE-ASSY-/191740307239?hash=item2ca49ce727:g:p18AAOSwPhdVIFADThe pad assembly (which includes the 3 small clutch springs) www.ebay.com/itm/SCOOTER-GY6-150CC-HIGH-PERFORMANCE-RACING-NCY-CLUTCH-NEW-GENERATION-/191734914710?hash=item2ca44a9e96:g:SxwAAOSwx~JWFCXuThe clutch drum "bell", which is like a brake drum against which the clutch pads press: www.ebay.com/itm/SCOOTER-150CC-GY6-HIGH-PERFORMANCE-RACING-NCY-CLUTCH-DRUM-BELL-/172005115206?hash=item280c4dc546:g:hd0AAOSwEeFVGaO6The Contra (or torque) and clutch springs, which are available in different strengths: www.ebay.com/itm/SCOOTER-GY6-150CC-HIGH-PERFORMANCE-NCY-CLUTCH-AND-TORQUE-SPRINGS-1000RPM-COMBO-/181918400530?hash=item2a5b2e8012:g:SH8AAOxyRhBSvcjV&autorefresh=trueMY CLUTCH PROBLEMI received part of my NCY clutch from the most generous and helpful scooter guy on the planet - GEH - and got part new. Once I had all the parts, I took the old OEM clutch off and just put the NCY parts on without thinking about tuning. It turned out there was a fundamental mismatch between the "GEH parts" and the new parts because the clutch springs in the new parts were not correct for the Contra (torque) spring that came from GEH. Performance sucked. The writeup in the link at the bottom here made that clear. The new pad assembly came with "red" clutch springs - very high performance that delayed the clutch from engaging until a very high RPM existed, whereas the yellow Contra (torque) spring that came with the GEH-donated parts was only a modest RPM strength. This allowed the pulley halves to separate long before the clutch pads engaged. Bad. Springs, generally, are color coded by strength as follows (Note: not all spring suppliers use this color scheme): OEM >>>> Blue (1,000RPM) >>>> Yellow (1,500 RPM) >>>> Red (2,000 RPM) A "1,000 RPM spring" means it is designed to engage 1,000 RPM HIGHER than the OEM springs. I ended up using the NCY Yellow (1,500 RPM) Contra spring that came with the GEH parts, and removed the ultra-high preformance red (2,000 RPM) small clutch springs and replaced them with nice blue (1,000 RPM) springs. The result: nice, smooth pickup from start to high speed! Changing either the Contra or the small clutch springs is a little challenging simply because the nut holding the clutch assembly together is large, and you will need a large crescent wrench to loosen or tighten it --- BUT MORE IMPORTANTLY BECAUSE THE CONTRA SPRING IS IN THERE UNDER A LOT OF COMPRESSION, AND IF YOU ARE NOT CAREFUL ONCE YOU LOOSEN THE LARGE NUT THE ASSEMBLY CAN FLY APART AND INJURE YOU. By standing on the assembly while you remove the nut, and then lifting your feet off the assembly gradually, you can release the tension without it going "sprong!!!!!". Stepping on the assembly is also a good way to compress the Contra spring so you can get the large nut started back on. Just use reasonable caution. Anyway, as promised, here is a WONDERFUL writeup on the selection of both variator and clutch weights and springs (the author is "BLK8WDW"): www.dansgaragetalk.com/topic/366-cvt-breakdown/?page=1 |
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Post by rcq92130 on Dec 2, 2015 19:08:30 GMT -5
GEH George donated his prized K&S variator ---- the one that got him to 75MPH on his Blue Demon (with only a 58mm BBK!). So, this is a comparison of my Dr Pulley variator versus his K&S with different weights. NOTE 1: "accelleration" is subjective; a best guess. NOTE 2: The Dr. Pulley costs TWICE what the K&S does, so it had better be WAY better! NOTE 3: For those who don't want to read ahead, the K&S is at least equal to the much more expensive Dr. Pepper. This was done really to tune the variator. I decided to pull the K&S off and run the scooter under the same conditions with the Dr. Pepper installed just to satisfy George's curiosity. Weights ranged from 14 grams, to 13 grams, and finally 12 grams. The first 2 were with rollers, the last with sliders. Most people say a 2 gram heavier roller set is equivalent to a roller set 2 grams lighter. That was NOT the case here - with either variator. Also, performance was EXTREMELY sensitive to weight! Belt climb was measured by marking the variator, doing a high speed run, and then seeing how much of the original mark was left (measured in 64th's of an inch). I tried to compare (seat of the pants) off-the-line accelleration. Did the best i could w/o actually conducting a measure 1/10th mile spped run. I also compared top speed ... sort of. Both variators got me easily up to 80 chinaMPH, with a good deal higher clearly possible ~~~ and the retro scooter is UNSAFE at any speed above 65mph. Even the worst variator tuning got me to 75mph, which is still scary as on this scooter. BOTH THE K&s AND THE DR. PULLEY WORKED BEST, BY FAR, WITH 13 gr ROLLERS (actually, 3 12gr rollers plus 3 14gr rollers). The Dr. Pepper seemed to have a little advantage in top speed (but, again, I was not brave enough to try past 80mph), while the K&S seemed a little better at acceleration. GIVEN THE DR. PEPPER IS TWICE THE COST, THE K&S IS CLEARLY THE BETTER CHOICE !!!   Note: I may have mixed up the pix for the Dr. Pepper variator and am too lazy to fix the pic. but you get the drift. |
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Post by rcq92130 on Dec 8, 2015 16:09:48 GMT -5
One thing to add --- about max RPMs. Both variators reacted almost identically in terms of RPM versus weights. I am NOT interested in running at redline all the time ... and, in fact, really want to run comfortably BELOW redline so the engine is still around 5,000 miles from now. As I understand it, "redline" on a GY6 is somewhere from 8,000 to 8,500 RPM. Those interested in racing applications (not me, BTW) should know that a standard Gy6, or one with a BBK, will put out max torque according to the cam you have in the head. Most cams used by normal owners have a peak in their torque curve at about 7,500 to 8,000 RPM.  Thus, when you operate ABOVE this engine speed you hurt, not help, the cause. In my case, I'd like to operate normally in the 6,500 to 7,000 RPM range, and not see engine speed much above that even under WOT. Both variators easily went up to 7,500 RPM and slightly higher when using 12gr weights. Both variators would not climb much above 6,700 when using 14gr weights. Both variators gave about the RPM performance I was seeking with 13gr weights. It was a surprise to me that these variators were as sensitive to slider or roller weight as they proved to be. I have no idea if these are typical results for a standard GY6 engine (again, I'm running one of Martin's Taida "SuperEngines"). It would be interesting is others with a standard GY^ could add to these results. |
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Post by cyborg on Dec 8, 2015 16:42:50 GMT -5
I think the 8-8500 redline may be a tad conservative in your case,,,but i like to run comfortable at around 80-  % of max,,,,they last longer that way |
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Post by geh3333 on Dec 8, 2015 18:00:06 GMT -5
Yeh , honestly the new engine may be just fine running over redline , maybe even up to and over 9000 rpms , however I would never chance hitting 9k or even running at 8k for extended lengths of time . I'm curious how high the oil temps get at those rpms for extended periods.
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Post by cyborg on Dec 8, 2015 23:39:29 GMT -5
This is not a normal engine,, 9500-10000 is redline territory for this engine 7500-8500 is completely safe I would think,,, don't forget this is a handcrafted engine with premium parts,,,,,it is not the junk pile fodder Chinese mill,,,
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Post by geh3333 on Dec 14, 2015 20:15:11 GMT -5
This is not a normal engine,, 9500-10000 is redline territory for this engine 7500-8500 is completely safe I would think,,, don't forget this is a handcrafted engine with premium parts,,,,,it is not the junk pile fodder Chinese mill,,, I would go by a better brand like kymco and other quality made scoots . what's the redline for these brands ? I'll check. |
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Post by geh3333 on Dec 14, 2015 20:29:23 GMT -5
Looks as if the first couple kymco 150cc scoots I saw had a redline at 8000 rpm . this is what we need to consider:
The Chinese gy6 is a cheaper made scoot engine . did this engine take the normal redline of 8k and apply it to the cheaper made engine " which is what more then likely happened " or did they actually put the cheaper made China engine through a ton of tests and determine that 8k was the redline ?
Considering it is a clone of a better made engine , I'd say they stole the redline of 8k and figured they would slap it on their dash . I think I possibly might have seen a 9k redline before , but I'm not sure what I saw it on ?
When it comes down to it I don't think i would run any of these between 8-9k rpms for any real length of time . the redline is a warning that u are reaching an unsafe rpm for the engine.
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Post by JerryScript on Dec 14, 2015 23:02:52 GMT -5
There are really only three things to take into consideration when discussing redlining, piston+crank mass vs alloy strength, bearing limits, and valve float. On a gy6, the main issue is valve float up to redline, then crank mass, then bearing limits. If you want a super gy6 to redline regularly, you will need to have stronger valve springs.
Engine age and normal usage also are important factors. An engine that is babied all the time will suffer most when redlined due to a lip that forms at the end of the piston ring travel. An engine that is redlined, or close to it, often will not have such a pronounced lip edge. This lip edge can break rings when pushed on a babied engine.
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Post by ricardoguitars on Dec 14, 2015 23:36:32 GMT -5
Ride it like you stole it, bores and pistons are reasonably cheap on GY6 engines, you can treat them as consumables.
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Post by geh3333 on Dec 14, 2015 23:53:45 GMT -5
There are really only three things to take into consideration when discussing redlining, piston+crank mass vs alloy strength, bearing limits, and valve float. On a gy6, the main issue is valve float up to redline, then crank mass, then bearing limits. If you want a super gy6 to redline regularly, you will need to have stronger valve springs. Engine age and normal usage also are important factors. An engine that is babied all the time will suffer most when redlined due to a lip that forms at the end of the piston ring travel. An engine that is redlined, or close to it, often will not have such a pronounced lip edge. This lip edge can break rings when pushed on a babied engine. One other main issue is heat !! When u run these engines up past redline the oil temps rise and rise . I've done this on many ocassions. Heat is possibly the #1 killer when it comes to these engines and there is no temp gauge on these things. At least from the manufacturer. My oil temps at regular use ran between 160 and 212 f. When I would run near redline the temp would rise over 212 really quick . at 8000 rpms for only a few seconds would take the temps past 220 f . I'm guessing running over 8,000 rpms for any real length of time would take the temps up to at least 240+ , so u can imagine what 9-10k would do to the temps . That's just like my air cooled buell . it has an rpm limiter near 7k , and has no cooling fan . if the 500cc engine was able to reach 9k it would cook itself really quick. Its almost the same story with the air cooled gy6 . it being air cooled these babies have limits and heat is one of the main issues when running these engines. Yes they have a cooling fan and The oil cooler will def help the engine stay cool longer , but , I still don't see 9-10k rpm range . |
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Post by rcq92130 on Dec 15, 2015 0:33:26 GMT -5
Ride it like you stole it, bores and pistons are reasonably cheap on GY6 engines, you can treat them as consumables. My concern is throwing a rod, because of the damage it could cause. And I have no idea what and how the rod is made on these crank sets. And I have no idea what kind of valve springs Taida uses. The Taiwan 60mm head I had before supposedly had 12k stainless springs ... but who knows. This engine is only running at 190cc - which is 18% under the max they can handle. So, there is plenty of meat in the case and probably not very much movement. And the oil cooler keeps everything nice and cool. Even running at 75mph for a while the oil does not get up much past 150. I guess the main issue here is what the intended use is. 60 or 65mph top speed, for me, was just inadequate. It's not that I want to exceed this often - the scooter suspension isn't safe at higher speeds - but when the occasion arises i want to have the reserve. And i don't want to be slowing down to 50 or 45 going up hills. And, mainly, I want to be able to cruise along at normal speeds (60 or so) without the engine wailing like it's a jet taking off. So, even if 8K is safe for extended periods of time (I'm not yet convinced) I don't want that racket, vibration and irritation. Being ABLE to juice it is vital - but cruising at 6500 or 7000 is what I'm after. |
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% of max,,,,they last longer that way
