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Post by scooter on Oct 11, 2014 21:11:24 GMT -5
A very popular saying during the Dark Ages.  |
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Post by scooter on Oct 11, 2014 19:44:27 GMT -5
The only thing I tried was cut down a BOSS and put in a different belt but that caused loss of rpms and lower top end speed. Used the original belt but due to the shorter boss the belt climbed to fast up the variator and caused loss of rpms as well as top end speed. Used a longer and smaller width belt and that raised the rpms but loss of top end speed. Alleyoop  I see. It looks like you ended up geared a little too high in the first two setups. I'm guessing the second boss is 1/16" to 3/32" (0.063-0.094") shorter than the first one, making the belt go approximately 1/8" to 3/16" (.125 - .1875") higher on the pulley. A substantial jump. The shims I have seen start at .1mm (0.004") and go up to 1mm (0.039") which would raise the belt by .008 to .08 inches on the variator. On the third setup you caused the belt to ride lower in the pulley, so it could not open as much at top speed, and I guess it was not enough to offset the difference in your boss length? |
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Post by scooter on Oct 11, 2014 19:03:49 GMT -5
I think what you are asking is a little more advance than what most are comfortable with doing. These variators only have so much metal and machining them down risks messing with something that has to spin at several thousand RPMs. Then add to that the availability of different angles provided by different manufacturers and then the ability to change how they perform by simply changing the weights of the rollers of sliders, making doing the mods you are talking about out of the realm of common sense for most; But having said that..if you want to be the test bunny by all means go for it! lol Thanks. It's not all that complicated to trim a boss. I believe you'll get almost 2 units higher on the variator for every one unit you close the distance between the two sheaves. Trimming 1mm off of the boss will make the pulley go almost 2mm higher on the pulley, adding almost 4mm to the effective outer diameter of the variator where the belt rides. Some people sell shims to lengthen the bosses but if they are too long then you have to cut them or buy them shorter. Ideally a boss would be too short and come with shims. A few thousandths of an inch can make a difference in performance. People spend a good deal of money just to get that edge. Unlike weights, the length of the boss sets the starting and ending diameters of the belt on the variator, given the variator angles available. A perfectly made custom variator could keep a scooter at maximum torque and speed from start to top end. This would be very useful for racers and people who just like performance. I would like to find out how much I can cut off of a variator face without weakening it too much. That would be good to know, and setting custom shift points by adjusting the inner ramp faces would be especially useful. Like yourself, I have done a little sewing among other things. It's not for everyone but if you're adventurous then it can be rewarding to go beyond buying things off the shelf. An online community may attract adventurous people such as you and I and we can share information. |
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Post by scooter on Oct 11, 2014 14:46:14 GMT -5
In regards to the valve problem, seems to me the easy choice would be to just buy a better head with better valves installed. I mean on the expensive side we are only talking about 100 bucks. I think you are right. It appears to be made of very soft metal. I already had to drill out the exhaust stud holes and re-tap them because they were stripped, and I personally stripped two valve cover bolt holes, and I'm pretty experienced with tightening things without damaging them. I can't remember the last time I stripped a thread. Been many years I am sure. |
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Post by scooter on Oct 11, 2014 14:21:59 GMT -5
I was breaking your balls , the difference between the cranks is longer and shorter stroke . If the stroker is going to be put in the engine let that be the first mod you do . John HAHAHA I was going "Whuuuhh?"  |
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Post by scooter on Oct 11, 2014 14:18:48 GMT -5
I do like what you are thinking as this would give you a larger fuel capacity...It kind of sucks having to stop for gas every 60 or so miles. That's no fun. I see a lot of people saying they have one gallon tanks. Mine holds three gallons and goes right at 300km, or 186 miles, on a tank. |
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Post by scooter on Oct 11, 2014 13:27:22 GMT -5
Some time back I wrote a post about oil getting all over my engine bay. itistheride.boards.net/thread/6402/blowing-oil-messThank you all for your replies.  I wanted to update you on this because I think I may have found the problem. You be the judge and tell me if you agree or not.  Using gasket sealer really helped a lot, and really reduced the amount of oil leaking, but my valve cover always started leaking again, not as bad mind you, after a bit of running. I replaced all of the hoses and made sure nothing was clogged.  This last time that I checked the valves, the exhaust valve was too tight AGAIN. I have adjusted the valves at least 4 times since I got the scooter in June.  This last time, the little vent hose on top of the gy6 150cc was blown open, ripped at the outlet, perhaps indicating pressure issues. So, in an effort to reduce the time between valve clearance adjustments, I opened up the clearance on the exhaust side to .007 and I think .005 on the intake side. Now it's clicking as the rockers slam into the valve stems BUT, even after a week of running, I finally see NO OIL LEAK! Woohoo!  I did some reading and found this scooterbbs.net/board/DCForumID11/6779.html where they discuss just such issues. "I have recently had a suspicion of mine confirmed by an independent source regarding a particularly common problem with many if not all, chinese GY6 125 and 150cc motors.
I have seen in the last year that a very large number of cases coming in for repair had problems related to the exhaust valve on these 2 valve 4 stroke motors. It has been extraordinarily common to have to adjust the exhaust valve in the first 5000 miles. We have seen it so frequently, we have become expert in finding they problem by looking for key symptoms.
First, loss of power over 35 mph, or the motor simply wheezing and acting like it had shut off, only to return to power once you release throttle, but again losing power at above 35 mph.
Second, really dirty plugs very early. This is also frequently accompanied by oil leaks under the bike, or more commonly, oil on hte floorboard or underfloorboard areas. This is from back pressure blowing oil out of the top vent on the valve cover."So I'm thinking this may have been the problem.  Exhaust valve not closing properly, blowing air into the valve cover, blasting oil out of any place it could get out. What do you think? Sounds reasonable?  |
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Post by scooter on Oct 11, 2014 12:58:08 GMT -5
UPDATE 1 10/11/2014Today I gathered my variators and ramp plates and bosses and took a bunch of measurements. I ran the following two sets with 14g rollers. With my new variator I was getting about 6300 wot rpm at 35mph which ain't bad and 7500rpm at 50mph which is horrible, so I took all of the parts that would make my variator width as thick as possible to drive the belt higher while using a very slightly shorter (-0.004") boss as well. I am now getting 5300 wot at 30-40mph which is too low, BUT I am getting 6500rpm at 50mph and I'm doing 57mph at 7500rpm, instead of 50mph. With a reduction of pulley separation of only 0.037" I was able to make the belt ride about .070" higher on the variator by using my old variator with my new ramp plate and boss. It's not much of a modification but it's effective.
The next step will be to drop the weights some.  UPDATE 2, 10/11/2014 10:15 pmSwitched out the 14g weights for 10's, the lowest I have handy. 6100 WOT @ 35mph 6500rpm @ 50mph 7500rpm @ 56mph These are pretty satisfactory numbers. If I drive the belt any higher, I won't have enough power to push it any faster and my acceleration will suffer. I'll lose both acceleration and top end speed. If I make the belt go lower, I'll get better acceleration but I'll rev higher at high speed. I'll gain top end but at the expense of possibly damaging the engine by running it at too high an RPM. Dropping the weights to 8's should bring my WOT up even more while not affecting my top end. I want a sustained speed of at least 55mph without blowing the engine up. Without adding more power to the engine, this is about all I can do. Another variator may have a better power curve but so far I am not getting any measurements with these variators. I just get a variator in a package and a "let's see what happens this time" approach to performance. My ebay KOSO variator had a similar power curve to this setup, with 8g weights, but suffered a catastrophic failure ending in a distorted variator bushing, chewed up rollers, and a mulched Gates Powerlink belt. UPDATE 11:45PM 10/15/2014Ordered some DrPulley 8g sliders. My first set of sliders. I just put the Dr Pulley 8g sliders in my scoot and measured the plate/roller/sheave assembly. The new slider assembly width measures .010" less than the roller assembly, when the rollers/sliders are at the bottom, meaning my belt radius should drop 0.020", increasing off the line torque slightly, BUT, from what I can read of the "marker test", the DrPulley sliders raised the belt radius at top end by about 0.075". That's a huge jump that will lower top end rpm, but also pushes the limits of the engine's ability to move the bike faster. (I'm geared about as high as I can be without losing top end speed.) This setup is giving me 7500rpm@55mph and 6800rpm@WOT(at35mph*).These weights with this current variator are in my sweet zone, as I do most of my driving at 55-60mph. The acceleration rpms rise so fast that the digital tach struggles to keep up. *( I chose 35mph at random because the WOT-RPMs rise, the faster I go, so I had to pick something to use as a baseline to compare different variator setups. I have been using MPH@7500rpm, WOT-RPM@35MPH, RPM@50MPH, and RPM@top-speed as references). I COULD fine tune this with shims, if I wanted to, but really this is an excellent setup. I have the lightest weights I can find, for the best acceleration I can get, and the belt is so high on top end that going any higher would probably net a loss. I will likely try some shims just to get more readings anyway. A small shim could push my WOT toward 7000-7500rpm and might even give me more top end speed at the cost of having to rev the engine faster. But we're probably talking fractions of a mph at this point. Even at high rpms, 60-62mph seems to be about all it's got. Before anyone poo poos the shims, I will leave the following notes. On top end and RPM: Two limiting factors. 1)The first limiting factor is how hard the engine can pull. If the engine is struggling to reach 7500 rpm at top end, then the engine can't handle more load, and making the belt ride even higher, by cutting the boss or unshimming, will actually cause the bike to lose top end. If you are in fifth gear, to use an analogy, and you can barely keep the rpm up to 7500, then shifting into sixth gear is going to lose you even more rpms and speed. 2)The second limiting factor is redlining. If you are struggling at 55mph@7500, and you lower the belt, by widening the variator with shims, your rpms will go up. You will now be able to go faster BUT your rpms will go higher, and you have to decide how many rpms you think the engine can take. Let's say you moved to 55mph@8000rpm and have more throttle to go. Do you really want to wind the engine up to 9000rpm to go faster? You could, but do you want to risk it? At some point, raising the RPMs won't help any more. Even at full throttle, you'll be geared so low that the engine just can't rev any higher or has blown up. Lowering the RPMs won't help either because you won't have the power to push higher gearing. At this point, you are done tuning your variator with weight and shim exchanges.
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Post by scooter on Oct 11, 2014 5:04:14 GMT -5
How important is exhaust back pressure? I cut off the back end of my muffler and removed a loose piece of metal tubing that was rattling around in the muffler. I like the sound of the bike with the back end open but I am concerned that back pressure may be an issue.
What are the effects of running a muffler with the baffles removed and/or the back end open?
How much back pressure does the engine need and how does it affect performance? (I didn't notice any improvement in performance but it sounded nice, and not too loud with most of the baffle still in it.)
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Post by scooter on Oct 9, 2014 1:36:12 GMT -5
Yeah. You're not selling me on either the wrestling or the olive oil. And it's still EEEEWWWWWWWWWWWWWWWWWWWWWWWW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I mean, honestly, WHAT is his hand doing in there, out on someone's yard?!! COVER YOUR EYES, AGNES!!  Btb, don't tell kev'. He'll make it the next Monday Macho question. Which is machoier--Turkish wrestling, or something else? (sorry, I'm not kev', I can't think of a comparable activity to that) >'Kat HA! Great idea! |
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Post by scooter on Oct 8, 2014 15:26:11 GMT -5
There's only one way I can reply to that, scooter-- EWWWWWWWW!!!!!!!!!!!!!!!! >'Kat Don't worry. It's all very macho. Oil wrestling (Turkish: yağlı güreş), also called grease wrestling, is the Turkish national sport. It is so called because the wrestlers douse themselves with olive oil. The term "güreş" is shared with other forms of wrestling practiced by Turkic-speakers across Europe and Central Asia, such as the Uzbek kurash, Tuvan khuresh and Tatar köräş. The wrestlers, known as pehlivan Persian: پهلوان meaning "hero" or "champion") wear a type of hand-stitched lederhosen called a kisbet (sometimes kispet), which is traditionally made of water buffalo hide, and most recently has been made of calfskin. Unlike Olympic wrestling, oil wrestling matches may be won by achieving an effective hold of the kisbet. Thus, the pehlivan aims to control his opponent by putting his arm through the latter's kisbet. To win by this move is called paça kazık. Originally, matches had no set duration and could go on for one or two days until one man was able to establish his superiority, but in 1975 the duration was capped at 40 minutes for the baspehlivan[clarification needed] and 30 minutes for the pehlivan category. If there is no winner, play continues for another 15 minutes—10 minutes for the pehlivan category, wherein scores are kept to determine the victor. The preparation H is for if you strain yourself and get a hemorrhoid. hahaha |
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Post by scooter on Oct 7, 2014 21:58:29 GMT -5
I know it's normal to spot vehicles like your own when you get a new one, but I swear I see scooters everywhere! It seems I spot a new one in town every day or two. Now I'm seeing them in music videos too.
Check out Ariana Grande and her dancers at 1:07 in this video.
Where do you see scooters? Are they becoming a new sensation in America or am I just noticing them all the sudden because I own one now?
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Post by scooter on Oct 7, 2014 21:03:21 GMT -5
I have tried several variators on my scooter and not surprisingly, they are all a little different.
My original gave me somewhat high rpms at top speed, running the motor over 8k a lot, even with 14g weights.
My performance variator gave me low rpms, leading to shaky starts off the line but good overall acceleration, yet too low rpms on top, even with 8g weights. It was hard to get it up to 7,500 rpm. I bought spacers for it but have not used them. Not even sure the variator is okay after using it for a few hundred miles and having a belt failure with mangled rollers but that's another story.
My last purchase is giving me very high rpms, 7500 at 50mph with 14g weights, and I hit 9,000 rpm the other day by accident. I need to close it up. I'm ordering another boss to shave down. I have a little room on the variator diameter, to move up, so I'm going to see what I can do with it. Alternatively I could shave a hair off of the front of the drive sheave where it meets the boss but the boss will be easy to toss in a lathe and face without any hassle.
One thing is for sure, these variators are not all the same at all. It's understandable since quality can vary and a few thousandths of an inch can change performance, but it seems clear to me that modding variators would be a nice way to fine tune them.
If I knew it wouldn't break, I'd like to machine the surface of my sheaves for a custom rpm curve, to get the low end I want and the top end I want too. I could even add a nice top angle to set the limit of how high the belt could go. I believe someone on here mentioned that as a feature found on Dr Pulley variators.
So far, weight changes have been less than satisfactory and are a trade off at best. I figure some of you have modified your variators in some way, by adding shims, shortening bosses, cutting sheave faces, doing custom ramp surfaces, or maybe even bending your steel back plates.
How about it? Any V-Mods going on here?
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Post by scooter on Oct 7, 2014 2:02:16 GMT -5
OK Motor home won't start. Walt curses. Jesse; "What's wrong? It's turning!" Walt; "There's not enough amperage to turn the engine fast enough to allow it to fire." Jesse; "Well how about my robot idea?" Walt: "No Jesse, I can't build a robot that will rescue us." Jesse; "Well make the engine turn faster then, so it will start." Walt; "The compression won't allow the crankshaft to turn any faster, using this battery." Jesse; "Well lower the compression then!" Walt: "Yes, Jesse, I'll design a new engine with low compression & we'll leave the plans next to our bodies, so this never happens to anyone again. I CAN'T lower the compress....... Walt leaps to his feet and shoves aside the Preparation H & the olive oil setting in the toolbox and grasps their single tool, the pair of pliers. Jesse follows him as he runs outside, yammering excited questions a mile a minute. Walt traces two of the distributor wires and removes them from sequentially firing cylinders. Walt grips the tips of the spark plugs with all his strength and twists and loosens them. He removes the plugs and runs back to the cockpit. He pauses and then pumps the fuel and turns the key. The engine spins faster as it gets to the two empty cylinders and the momentum gets the next cylinder in line to fire. The beast coughs and sputters and manages to keep running but sounds even worse as it begins to run on just 4 cylinders. They let it run until the original battery is charged enough to start the engine with the spark plugs replaced. Jesse says; "Yes BlTCH!" I don't remember them having olive oil and preparation H, but it sure sheds light on the true nature of their relationship. Too bad our guy wasn't driving an RV. He could have tried that too. |
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Post by scooter on Oct 7, 2014 1:56:58 GMT -5
See? You didn't specify anything else, like nobody else around or anything. I would argue that my solution would work as well as whatever mechanicky one would. And the real question is, why is anybody driving around with a gallon of olive oil and a tube of Prep H in their trunk? >'Kat Maybe he's into Turkish wrestling.  ![]() |
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