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Post by oldchopperguy on Jul 3, 2013 1:13:35 GMT -5
There seemed to be some interest in my home-made 50cc GY6 "chamber" exhaust, mated to my GY6 150. After 500 miles, I can say WHOO-HOO! It runs GREAT!!!Pix shown below: how to take screenshots lightshot free downloadThe one concern I had however, was that the fat, 1 1/8" O.D. header wrapped in heat-wrap was "shoehorned" between the frame and engine SO close, that it might really roast the crankcase.I just got a good "instant-read" thermometer for monitoring deep-fry oil (50 to 500-degrees) and checked the oil temp... I rode in the 100-degree sun HARD for several miles, then immediately checked the oil temp. It was a comfortable 204 degrees!All I can say is: "That heat-wrap REALLY works!"So I can happily report that the oversized header, tightly fitted did NOT transfer any serious heat to the crankcase oil.The 1-inch inside-diameter header runs GREAT on my 150, and seems to be OK residing tightly in the same place as the original undersized steel factory header. Just a quick update for those wanting to try this setup...Ride safe! Leo in Texas PS: The glass-packing in the little "stinger" after-muffler must be settling a bit. The exhaust note, while still quieter than stock at idle, is developing a little bit of a bark under hard throttle application. Nothing objectionable, but sounds ALMOST like a proper internal-combustion engine, rather than a kitchen appliance... 
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Post by newbscootdude on Jul 3, 2013 2:04:55 GMT -5
wish i could help you out. But your scoot looks badass dude!
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Post by oldchopperguy on Jul 4, 2013 0:57:07 GMT -5
wish i could help you out. But your scoot looks badass dude!
Thanks for the compliment on the scoot... It'll look a lot better once I get it cleaned up some... Sat too long, got too gritty!It's running great now, so I hope I don't need much more help. I'm looking forward to another four years of riding, not wrenching... OH, RIGHT... In my dreams... LOL! Ride safe,Leo |
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Post by oldchopperguy on Aug 4, 2013 1:27:56 GMT -5
I've had a few members asking about this exhaust, so I'm adding a reply to move it up where it can easily be found...
Leo
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Post by skuttadawg on Aug 4, 2013 10:32:18 GMT -5
Interesting a 2T exhaust on a GY6 50 hmmmm . How would you say performance and MPG were compared to the stock exhaust ?
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Post by oldchopperguy on Aug 4, 2013 12:52:59 GMT -5
Interesting a 2T exhaust on a GY6 50 hmmmm . How would you say performance and MPG were compared to the stock exhaust ? It runs slightly richer than the stock muffler (plug was light-tan with the stock muffler, now it's slightly sooty-black). I can live with a little rich in this HOT area... LOL! Idle is smoother, and throttle-response is better. (After "never-ending" carb-tuning with the stock muffler and small I.D. header there was still a slight hesitation upon quick throttle application.) That's gone now. AMAZING! Gas mileage is about the same as always (around 75 - 80 mpg).Also, removing about 10 pounds of un-sprung muffler weight from the swingarm improved handling over "washboard" surfaces like multiple railroad track crossings. After about 500 miles it's "all good". The only problems I can foresee would be the very lightweight stainless can, or my home-made flex-tubing header burning out prematurely. I don't think this will happen though, with the can being a well-made unit, and the flex pipe being commercial RV grade. These GY6 engines seem to run "OK" to "REALLY GOOD" with an endless variety of exhaust systems. I think the 2-stroke "chamber" style is one of the better ones. However, I also think increasing the header diameter is a BIG part of the "secret". Please see pix below for comparison... screencast screenshot captureFor anyone wanting the full-size header however, I would recommend buying one of the nice factory-made ones. They run about $50 but look great and eliminate a LOT of home-made effort. I hope this info may be of help to anyone wanting to try something similar. Ride safe, if not loud... LOL!Leo in Texas |
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Post by jerseyboy on Aug 4, 2013 15:34:49 GMT -5
Very cool Leo,,
Glad you made a thread on this!
I always learn something really cool from you!
Tom
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Post by oldchopperguy on Aug 4, 2013 21:39:12 GMT -5
Very cool Leo,, Glad you made a thread on this! I always learn something really cool from you! Tom I did complete thread on this a while back, but then, nobody was much interested. Now I'm glad I took pix, and now have enough miles on it to have some conclusive facts and opinions. With so little displacement, and so little horsepower, these scooters are MUCH more of a challenge to "get right" than a big bike, with power to spare. Lots of fun trying though!Leo |
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Post by jerseyboy on Aug 5, 2013 7:31:56 GMT -5
[replyingto=oldchopperguy]oldchopperguy[/replyingto]Yes sir,, Mine definetly goes better than a 10 hp briggs,,thats for sure! Guess Im on the right track  |
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Post by robrun on Aug 11, 2013 7:37:57 GMT -5
Where did you get the flange?
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Post by oldchopperguy on Aug 11, 2013 21:46:02 GMT -5
Where did you get the flange? They have shanks that went inside the flathead motor, which I cut off. Then, I notched the inside of the bend, bent it tighter to match the scooter header curve and had a muffler shop weld it up. The tubing is RV commercial-grade aluminized steel flexible exhaust tubing (fused to the steel shorty flange with "INFERNO" a SUPER-HIGH TEMP. exhaust-manifold repair material from Auto Zone). The flex-exhaust is 1 1/8" I.D. which is a perfect fit over the steel tube header-flange, but sort of hard to find. It's made for RV's, farm-implements and generators. You can find it on eBay if you search enough. You might find it at a well-stocked RV supply store too. Here are the headers before modification: click image uploadHere is the much-cut-n'-bent shorty flange before welding up: image hosting imgurThis setup works great, but the negatives are; 1. It still costs around $35 to make. 2. It takes some time to assemble. 3. You have to fiddle with it some to get it properly in place, and, get it connected to whatever muffler you use. If I do it again, I'll just pony-up $50 for a chrome or stainless factory-made 1" I.D. header that fits right up to the engine. Then, connecting to the muffler is somewhat easier, AND the assembly looks great... If you DO get a factory pipe, please remember these GY6 150 heads have at least 2 different angles to the exhaust port. You can probably check pix in the listing compared to your old header to be sure it's right. The one other BIG advantage to the home made flex-header however, is that you can adjust it to fit any head. I believe, but am not sure, that Onan and John Deere flathead generators use the same headers. These that I got are a PERFECT match to my head's exhaust port. They are also INCREDIBLY durable! They were cheap, I took a chance, and got lucky. Check out Jeepsteve's setup to see how nice a factory-made one-incher can be...Hope this may help... Sincerely, Leo |
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