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Post by pistonguy on May 7, 2017 9:50:47 GMT -5
 Thats me from World Karting magazine 30 years ago, I have spent allot of time around Kart Racing and there is no such thing as a Two Stroke Expansion Chamber on a Four Stroke Briggs or any other Four Stroke. fyi "C Mod" is Piston Port light, 320 lbs Kart and Driver, Stock Appearing on the outside but on the inside anything goes (Porting, Crank Case stuffing etc.) keeping within displacement limits anything goes on the inside, Open Fuel, Alky/Nitro Methane, Gasoline is just for washing parts. Looks like now everyone knows my real name. |
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Post by pistonguy on May 7, 2017 9:44:55 GMT -5
 This is a friend Pat Dakin out of Dayton Oho, Top Fuel or Top Alky know one is or has wasted there time with a Two Stroke Expansion Chamber on one of these cars.  Local to me now Roy Hills Hemi Alky Pro-mod.  |
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Post by pistonguy on May 7, 2017 9:38:19 GMT -5
Friends, all I can say is that it works well for me, and has for a half-century. I'm beginning to wish I'd have not bothered re-posting these old 150 "how-to" tricks, and am glad I moved up to a larger-displacement ride that doesn't require more wrenching than riding... If it didn't work well, I wouldn't have wasted my time taking pix and making the post...While chamber pipes are not common or popular on 4-strokes, they are a proven success... A few years back, even top Alcohol dragsters were experimenting with chamber pipes on their engines with promising results. For over fifty years, I've run numerous chamber pipes on small 4-strokes with noticeable improvement in overall performance over stock-type mufflers and straight-pipes. I'm well aware of how a chamber pipe works on a 2-stroke...
A 4-stroke is totally different scenario with a much simpler "exhaust impulse" than a hot 2-T. What it is in effect, is simply an "enhanced straight-pipe" with a slight improvement in performance and a big improvement in ease of tuning and good all around running. It is not rocket-science... just a very good "muffler" for a 4-stroke... End of story.
Back in the 1960's when we had numerous chamber pipes laying around from experiments with Mac's, West Bends, Power Products and Homelite kart motors, we adapted them to Briggs, Tecumseh and other old-school 4-strokes on pit-bikes with great success. As I mentioned, some Vento Chinese 150 GY6's came factory-equipped with them, and I even have a NOS Vento chamber pipe laying around. The reason I did this conversion is simple... IT WORKS. Maybe on paper it isn't supposed to, but in my experience it works VERY well. Everybody is entitled to his/her opinion. I raced Mac-powered karts some, but was better in the pit than in the driver's seat... Just too big... LOL! I never did drag Harleys except for my own chopper... At Oswego Drag Strip"Old Blue" would run in the high tens/low elevens, at 130+ in street trim in 1962... (My 4'6" 76-pound gal friend could crank off a mid tens at 145+). I won enough street racing to pay the obscene cost of building that motor... You build 'em your way, and I'll build 'em mine and we'll both be happy...
Ride safe,Leo (some zip) in Texas PS: That's a nice exhaust setup on your red scoot. You found the same garbage fabrication on your stock pipe as I did. A full-sized header is one MAJOR improvement over the stock setup. The Engine will start, run and go down the road with a Two Stroke Expansion Chamber, That's all If you would put her on a Dyno you would clearly see it Does Not Work and Improve your numbers over Stock or Aftermarket Exhaust. I'm not much for opinions, the Dyno don't lie. If there was anything at all to Chambers on Four Stroke we would widely see them, there is no such thing. As a Profesional at a high level in the Motorsport industry know body in any market segment is installing Expansion chambers on Four Stroke's. I have worked very closely with many Pipe manufactures and none of them is wasting there time with Chambers on Four Strokes. FMF, Pro-Circuit, Yoshimura, and you have a Pipe God close to you David Rash aka the "Pope of Pipes" D&D exhaust in Fort Worth. Sure in the end its your Scoot you do what you want but your providing misinformation to others. The Pipe on my Scoot was not fabricated I purchased it from the GY-6 store out of Puerto Rico for $69. then Wrapped it. PS Id like to see those time slip's of mid tens at 145mph. Post em up! |
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Post by pistonguy on May 6, 2017 19:40:57 GMT -5
OK, for those interested, here's pix from the old post on the 2-stroke chamber-pipe adaptation for the GY6... (Note the cool chromed brake-caliper... LOL!) The old caliper went south, and the chrome one was CHEAPER than a stocker...  Onan, John Deere and other generators use headers that match the GY6 bolt-pattern. You need to cut off the stubs that protrude into the heads of those generator engines.
  That stainless flex-pipe is available at RV stores for generator motors. The factory strap-mounts for the stock muffler can be altered to fit a different type of exhaust...Instead of fabricating a headpipe from scraps like I did, it's better to just "pony up" a few bucks for a real, full-diameter high-perf header... Easier too! Simply discarding the factory header that is SMALLER inside than the EXHAUST PORT (EEEEWWWW! Major restriction right at the head where it causes the most problem!) and replacing it with a full 1" inside-diameter pipe will improve running noticeably! Even with a stock muffler... But STOCK stuff is no fun when you have a hacksaw and a wrench... LOL!Ride safe! Leo Ok understanding how a Two Stroke Expansion Chamber works I have no understanding why you or anyone would mount it on a Four Stroke. a HP killer The GY Like a HD likes to breath and the Stinger and Silencer on the end is like Farting thru a Cocktail Straw. the sounds waves working thru the cones will also jack up a four stroke scavenging, No Bueno! It still beyond my why some Zip adapted this System and even worse why anybody with a Four Stroke would actually buy one and mount it. I thought you mentioned somewhere that you raced two stroke Mac's then Drag raced HD's? |
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Post by pistonguy on May 6, 2017 19:32:08 GMT -5
  How a Two Stroke Expansion Chamber works. |
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Post by pistonguy on May 6, 2017 19:24:23 GMT -5
 A Proper Gy-6 150cc working Header System Correctly Wrapped. |
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Post by pistonguy on May 6, 2017 19:02:41 GMT -5
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Post by pistonguy on May 6, 2017 14:48:37 GMT -5
If you have cooling issues, this might help.In Texas, I often ride in over 100-degree weather. My original Chinese 150 did run a little hot, with the oil-temp approaching 200-degrees. I added one of those "fan scoops" which helped "slightly" lowering the temp a few degrees. I then made an extension from PVC pipe which moved the scoop outboard of the plastics. THIS lowered the oil-temp from 195+ to 170-175 on a 110-degree day. I believe the stock cooling-fan shroud is SO far "inboard" of the plastics that it suffers from starvation of fresh air, even at speed. Of course, heat will still be a problem when sitting idling. Any longer than a couple of red-lights and I shut off the motor, restarting when traffic in front begins to move. I do that even with my current water-cooled Kymco when the temp gauge gets near the top.
Here are some pix of the simple fan-scoop extension from my old 150 GY6. It's pretty simple to make, and really does lower the oil-temp a LOT on a hot day...    
Getting the "scoop" out past the plastics (which MAY produce a "votex" of "dead air") really worked for me. In temperatures below  -degrees, it may not matter as much, but the engine can use all the fresh air it can get... On my old 150, I replaced the black fan-shroud with a chrome one, and trimmed the extension with chrome mylar tape to make it all match. Strictly "cosmetic" but the whole assembly could be simply painted flat-black, or any color. It's the function that matters... LOL!Ride safe,
Leo in Texas Ok I just can't get past the Two Stroke Expansion chamber on a Four Stroke, Its a Mind Blower...  |
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Post by pistonguy on May 6, 2017 14:21:43 GMT -5
This is a hot topic however plugging a motorcycle or scooter tire is a temporary fix to get you to the tire shop for a replacement tire or at least a patch installed by removing the tire, grinding the area around the puncture from behind and cold vulcanizing a patch on from behind. The issue is not in the 50% that will have no problems but becoming one of those few among the other 50% that have a catastrophic failure afterwards instead of just an irritating slow leak. Are you willing to risk life to save the cost of a scooter tire. You mention Bible Study so you should be aware that Safety Regulations started there with laws even covering the need to have a safety rail around a raised terrace or porch to prevent injury or death. Even causing the death of another in an accident would require fleeing to a city of refuge because a life had been lost due to your actions and staying there until the death of the current High Priest which could be a very long or very short time off depending on the age and health of the High Priest. We are not under the old law code but it shows the high value of life that was held under that law and is something to consider when taking risks that could harm ourselves or others. You may want to consider this at a future study session but refrain from continuing it in any depth here. 50/50 odds really ?!  % of home patch jobs last longer than the tire and the other 9.9% fail as a slow leak and are do to improper application the plugs don't fall out. In fact it is a pain in the ars to remove a plug at all after the glue sets. So 0.1% is left over for complete idiocy like trying to plug holes Bigger than the instructions recommend or not cleaning the tire as instructed. But even with complete plug glue failure the tire is still not gonna explode it's just going to go flat. In the back tire it's a minor inconvenience. In the front tire? Well then yes it can be a little hard to stay upright if you're tire is flimsy. On my scooter I have lost pressure due to a lost valve stem. It was little more than something to be mad about. That hole is 5/8th of an inch that is a BIG hole. hmm ok you can have the .005% that's left for your explosive tire of doom Amen Chewy!!! |
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Post by pistonguy on May 5, 2017 15:26:35 GMT -5
i tried an oil filter wrench, didn't work. the variator on my ride had little vans around the outside circumference, not the cooling vanes on the outside face. the design of my CVT case allowed me to fashion a wedge of hard rubber to hold the variator. another thing i noticed was that 2 variator halves, vane to vane, interlocked perfectly. an old variator vane half can serve as a holding tool if the center hole is bored out to accept the socket, and a handle attached. another thing, i didn't torque the nut. i got it as tight as i could with just my hands, then gave the wrench handle 5 or 6 whacks with a hammer. no thread lockers either, but i GOTTA remember that zip tie trick. that one deserves a bone. Ya the Human Impact Wrench of a few whacks will work I also like your idea of melting some of the plastic from the Zip-Ty onto the Threads, I carry a lighter and a bunch of spares. I coulda found a plastic bottle on the road for sure and melted it on the threads to get me home. I knew exactly what I was buying in my Sunny 150 Hunter/Phantom style scooter, cost $749 + $120 freight brand new in 2013, its a Light duty ride and I have very much enjoy doing upgrades and tuning, Im that type of guy, Its as much fun as riding one to me, a hobby if you will. |
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Post by pistonguy on May 5, 2017 10:30:23 GMT -5
about the rope thing, it's simply not the right thing to do. the rope wraps around one of the open valves, holding it open. the piston moves up. one of the following will happen: 1. due to close tolorances the valve punctures the piston. 2. the valves doesn't puncture the piston but warps the valve stem instead. 3. god comes along, issues a miracle, and you are able to complete the task with no ill effects. also, do not try the screwdriver in the variator fins trick either. Exactly, and I should add I would suggest that while the Piston may be coming up to TDC if one of these fools is not paying attention the Engine is Not on the Compression Stroke but the Overlap Stroke were both valves are slightly open and the Rope would be pressing against the Open Valve and they may bend a Valve Stem. on larger engines like Industrial Diesels they have very large diameter Valve stems and would be less likely to bend but I still would never be shoving rope down a bore for any reason. I suppose one could use a oil filter wrench or even your leather belt to hold the Vari, I just bump mine with a impact, that maybe Not the thing to do if one has Never had any experience with a impact. |
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Post by pistonguy on May 5, 2017 10:13:18 GMT -5
The wear yo see is with just a few hours run time. I can hardly imagine what this would look like in a challenging climate like in the Tropics were these Scoots ar ridden everyday thru wet sandy salt water mixed roads. A modern O ring chain will win every time. And again I'm sure this has to do with me using a impact on my Vari nut. just plain silly to imply such a thing Mine variator does not look like that even after 12,500 miles on a set of rollers and currently has 30,000 miles overall on it and is on the second replacement set of rollers/sliders. And yes you could have flipped some of the sliders over while rattling them about with an impact wrench however most times people are going to mess up the splines on the ramp plate or damage the drive face introducing som wobble using an impact wrench to install. You still have too much trouble for all the effort and expertise you claim. Showing a close tolerance brand new race piston has no bearing either on shoving a rope down a bore with some miles on it and enough wear to start developing a ridge. Forum advice on best practice has to be tempered by the fact that most folks here will be working on bikes with some miles and wear on them and possibly be in the hands of the second or third owners. We all don't have MegaBucs and money to burn on the best race tech on the market. If you don't/won't do it yourself then don't encourage others to do it either. I encourage all to go by the book and take the safe route when it comes to maintenance. It cost less in the long run and greatly lowers the failure rate. This has become comical. lol! First remind us what Scooter you own, make model year displacement. How about posting up some pictures of the damaged pistons from rope and Your Vari and Scooter? My Vari assembly was held firmly in place with one hand as the other hand bumps the impact wrench, the notion that the impact rattled the slider to roll over is ridicules and just plane silly. If someone is jacking up there threads and busting off the end of the crank with there impact they shouldn't own one to begin with, Im no rookie with a impact, lol The 150cc Vari's are inexpensive to buy and I'm getting just what I paid for, The NCY Coated Vari pictured has a very low end coating I never expected it to last any amount of time, The Coating coming off and turning into powder has impeded the Rollers from Rolling and caused the Flat Spots, its just junk product thats all, and its so convenient for all these manufactures and retailers to sell the product as "High Performance" and provide no warranties or returns. One could manufacture a very nice Forged Vari, Shot Peened then a high end polish or Micro-Finish but the mostly entry level consumer who is now used to all the cheap prices for junk product will never pony up the money for it. I try to be humble and not get on a Scoot board with mostly entry level people to belittle them with who I am and what I do and have done braggadocios crap. A bore has been long wore and piston has long been worn out long before a ridge forms. I wonder if you actually have the proper measurement equipment and know how to read it. There must be some sadist in my because its got to the point with you I post a stupid question to just get a laugh from your response. itistheride.boards.net/thread/9919/velocity-stack-improve-filter-performanceThe notion that there was the level of engineering you suggest in the design and production of a Scooter Air Box is ridiculous, news flash, Its Not a Working Resonant Air Box, The Scooter Air Box is in no way Restrictive, It Far Outflows what the Engine Demands, however it Is a Velocity Killer and that is were the Gains are made by ditching the Box and installing a Uni-Filter or Short Stack with a Filter on the end of that. |
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Post by pistonguy on May 4, 2017 19:57:33 GMT -5
 Ya Im not ashamed nor embarrassed to admit I did what I did to get her home. I don't care if it was duct tape and bubble gum. Was so funny watching the Clutch Bell pass me up as a Dodge Ram pick-up was coming the other way and I was waving this guy off as to not run over my Clutch Bell. I used correct torque with some loctite and have no issues. Yes I do now keep a spare Vari and clutch nut in my tool kit along with a belt etc. |
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Post by pistonguy on May 4, 2017 10:08:05 GMT -5
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Post by pistonguy on May 4, 2017 10:02:27 GMT -5
 Ive been running this Ankle Biter set-up since last September. I have encountered no such "O" rings on my 150 Vari's, there simply nothing to keep the grease in the Vari. I used a High Temp Synthetic grease. I have no knowledge or experience with the Honda vary you mention to comment on it. And Yes that is a Zip-Ty in place of the Clutch nut holding it on, I was to ginger tightening up the Clutch Bell nut and after a couple hours I chopped the throttle and the Bell slid half way off. I knew if a tapped the breaks the Bell was going to come off, It was comical I tapped the brakes and the bell came off and passed me up going right down the middle of the road. I limped her home with the Zip-Ty |
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-degrees, it may not matter as much, but the engine can use all the fresh air it can get...
% of home patch jobs last longer than the tire and the other 9.9% fail as a slow leak and are do to improper application the plugs don't fall out. In fact it is a pain in the ars to remove a plug at all after the glue sets. 
