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Post by kevin55950 on Sept 14, 2012 0:24:22 GMT -5
Maybe it's because gas mixture is richer because of less oil. Main jet might be a little too big.
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Post by 90GTVert on Sept 14, 2012 7:31:44 GMT -5
I originally tuned with 50:1 and an 85 main, so I got an 84 and 86 to use whatever is closest. Can't be exact, but that's about the best I can do. The thing is, RPM was highest at 40:1, lowest at 100:1. Steady decline, no up and down that I would think may be associated with differences in jetting solely.... BUT, I also went from 40-100 so if something else were getting worse it would work that way too. I'm gonna try a different oil mixed more rich soon, so I'll see if the RPM comes back. If not, the testing may only be good for the pics I'll be sharing, eventually, to show differences in wear and carbon with each. It seems that every time I try anything where consistency is important, something on the scooter acts up.
What I've been doing is just noting my average WOT cruise RPM. Where I can expect it to be most of the time WOT. My notes for the AMSOil tests are...
40:1 = 8800-9100RPM
50:1 = 8700-9000RPM
80:1 = 8500-8800RPM
100:1 = 8500-8800RPM
There has also been a small loss of speed, but that could be only associated with lower RPM. It's not much different anyway. About 1 to maybe 2MPH on average best to worst. Again, best being 40:1. Worst being 100:1.
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Post by stepthrutuner on Sept 14, 2012 17:27:26 GMT -5
Your results pretty much line up with the findings of Jennings, Bell, etc. Anxious to see your final report on wear and deposits. To me richer oil makes for cleaner piston tops, heads and exhaust ports. Probably tends to keep the parts "wetter" thus not allowing deposits to stick in the first place. This is not to mention more power from better piston ring sealing with more oil.
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Post by 90GTVert on Sept 15, 2012 16:38:27 GMT -5
I rode 98.81 miles last night on Havoline TC-W3 at 40:1. I don't think the RPM drop was all in the CVT. Without touching anything but the top end, and the main jet back to 85 to match 40:1 better, RPM last night was 8700-9000 again.
I had a quart of Maxima Scooter 2T around as well, so it's all cleaned and back together with that in the tank at 40:1. No one else will be around for granny till late tonight. Not sure if I'll feel like leaving for a 3+ hr ride if no one is home till near midnight. If not, maybe early tomorrow. That'll be my last chance to ride much for a few days.
Sorry, but there won't be any 100:1 long term tests. The cylinder didn't look that bad, but not after seeing RPM come back with a different oil/mix. Once I'm done with this and get pics up, I'm looking forward to riding a 103cc again. I've basically spent all of the good riding weather this year and last year doing projects. It'll feel good to ride a setup I really wanna ride again. Nothing really wrong with the little 49cc, but I miss half my engine. lol
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Post by reveeen on Sept 15, 2012 16:38:58 GMT -5
It would also follow that RPM would be higher @ 32:1 (just like Honda recommends in their 2 cycles)
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Post by 90GTVert on Sept 15, 2012 16:43:06 GMT -5
My main reason for not mixing more is carrying. Granted, I don't do it often, but it's hard enough for me to carry enough oil for 50:1 under the seat with tools and stuff on really long rides. Also, doing the other oils at 40:1 will at least give something to compare on buildup and such.
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Post by 90GTVert on Sept 16, 2012 8:55:12 GMT -5
I rode 80 miles last night on 40:1 Maxima Scooter 2T. I wanted to do 100 miles, but it was 50 degrees and I ran into an irrigation system at about 1AM that never rotated out of the road. I was shivering after that. Finished up the ride this morning, totaling 100.25 miles. RPM went back to match the highest at 8800-9100RPM.
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Post by 90GTVert on Sept 16, 2012 11:20:44 GMT -5
Now that that's done, I just need to start going through "a few" pics...  |
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Post by 90GTVert on Sept 17, 2012 21:46:13 GMT -5
I'm gonna start throwing bits and pieces of info and pics up from time to time. Eventually, I'll group it all together in one post somewhere. The oils tested and a little info from their manufacturers...  AMSOil Saber Professional 100:1 SyntheticSynthetic : Yes Current Price : $10.75/quart From AMSOil : " AMSOIL Saber™ Professional is formulated with exclusive AMSOIL synthetic base oils and premium additives. Designed for lean mix ratios in two-cycle motors, Saber 2-Cycle Oils have excellent lubricity and cleanliness properties to control friction and help prevent wear, plug fouling, ring sticking and exhaust port blocking. Saber 2-Cycle Oils also feature an anti-rust formulation to counteract the damp environments often encountered in two-cycle applications." Havoline TC-W3Synthetic : No Current Price : $? From Havoline/Chevron : " Havoline 2-Cycle Engine Oil TC-W3 is a high quality two stroke engine lubricant that delivers excellent performance in water-cooled and air-cooled
applications. It is formulated to provide excellent lubrication and deposit control in a wide range of applications.
Havoline 2-Cycle Engine Oil TC-W3 contains a special ashless detergent designed to help keep piston rings from sticking promoting smooth and efficient engine operation. Havoline 2-Cycle Engine Oil TC-W3 will help
keep the engine clean of deposits and will also protect the pistons from scuffing and preignition problems." " Havoline 2-Cycle Engine Oil TC-W3 is well suited for engines using oil injection systems with fuel/oil mixture ratios of up to 150:1." Maxima Scooter 2T
Synthetic : No Current Price : $8.50/liter From Maxima : " Premium quality low-smoke 2-cycle engine lubricant for both premix and oil injector use in scooters and mopeds. Clean burning while providing excellent protection to all engine parts. " |
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Post by 90GTVert on Sept 18, 2012 7:25:52 GMT -5
Engine Setup Used For Testing [/size][/color] 1E40QMB Air Cooled Chinese Horizontal Minarelli Clone Naraku Crankshaft w/Big And Small End Bearing Oiling Improvements Naraku Wrist Pin Bearing Previously Used Stock 40mm Cylinder, Ported New Stock Replacement Piston From ScrappyDogScooters, Modified Stock Cylinder Head, Milled To Achieve 7:1 CCR Ignition Timing At 20° BTDC Stock Airbox, Carburetor, Intake Manifold, Reed Assembly Leo Vince GP 50-70cc Exhaust NGK BR8HS Spark Plug, 0.028" Gap Unfortunately, I just couldn't afford a brand new top end. Ideally, I would have liked to use a new spark plug, cylinder, piston, piston rings, wrist pin, and wrist pin bearing for each test. That's a lot of money, that I don't have. The only parts I replaced after every test were the spark plug and of course any gaskets needed. Otherwise, everything was cleaned up before/after each new mix ratio or oil tested. I did have to replace the piston before any testing, because the old one with the cylinder was damaged from a past circlip failure at high RPM. The piston came from ScrappyDogScooters with a coating on it. I wanted to have a finish that I could re-create each time, so I buffed it. I also had to file and smooth the piston's crown in order to get the transfer durations that I had used in the past with this setup with good results, so I smoothed out the rough crown in the process. Here are pictures of the piston before and after my changes. All pics of engine parts in this thread are 1920 x 1080 resolution so any damage can be viewed in greater detail. Click the appropriate thumbnail to go to a larger image. Click that image to view full size.    Cleanup includes honing the cylinder. I used a ball hone for 5-10 seconds, just enough to knock out the minor scuffs and put a crosshatch in the cylinder again. The exhaust port of the cylinder was cleaned with a wire wheel Dremel bit to remove any deposits or coloration. The cylinder head was cleaned with a wire wheel Dremel bit as well to remove carbon. The piston was sanded lightly with 400 grit to remove scuffs and carbon. Anything beyond a minor scuff, I made no attempt to sand out. The ring lands in the piston were cleaned with a wire wheel Dremel bit as well to remove coloring and deposits. The underside of the piston crown was cleaned with the Dremel wire wheel. The piston was buffed to a uniform finish. I also used a bench buffer to clean the wrist pin after each test. Here are pics of the cylinder, cleaned up before any of the tests were done.           Here's a look inside a cleaned exhaust port.  Here's the cylinder head after a cleaning.  I will provide pictures of any leftover scarring or points of interest after each cleanup, so hopefully you can get a good idea of what's happening during each test. Jetting DetailsThis setup was initially tuned before all oil tests at 50:1 using an 85 main jet. Changing the amount of oil in the fuel can affect jetting, so here's how I compensated. Unfortunately, I can only get jets in whole sizes. Mix Ratio | % Oil In Fuel | Correction vs 50:1 | Jet Used | 40:1 | 2.5% | +0.5% (+0.425) | 85 | 50:1 | 2% | 0% (0) | 85 | 80:1 | 1.25% | -0.75% (-0.6375) | 84 | 100:1 | 1% | -1% (-0.85) | 84 |
Each test was roughly 100 miles. It's hard to ride exactly 100 miles each time, but the lowest mileage was 98.X and the highest was 100.25. I rode in areas that would allow wide open throttle most of the time, but I did take a brief trip through a town with some part throttle riding on each trip. I attempted to be consistent in my riding method each time. The CVT was setup to work with the combo and generally kept RPM from the mid 8,000 range up to, and sometimes beyond, 9,000RPM. More details will be provided later. [/center] |
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Post by 90GTVert on Sept 19, 2012 16:30:15 GMT -5
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Post by 90GTVert on Sept 19, 2012 16:37:41 GMT -5
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Post by 90GTVert on Sept 19, 2012 16:44:59 GMT -5
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Post by 190mech on Sept 19, 2012 19:48:01 GMT -5
Very interesting transfer flow pattern on top of the piston!Note the blackening where the exhaust gas actually travels down the transfer before the fuel mixture gets a chance to get in the cylinder..Thus the first transfer to open is the last to flow..
The leaner oil mixture appears to have more deposits.Maybe the surfaces are 'dryer' and the stuff sticks better? :stumped:
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Post by stepthrutuner on Sept 19, 2012 21:50:37 GMT -5
This is kind of a side note but somewhat applicable to this thread.
I just came back from visiting my oldest sister who lives about an hour's drive out of St. Louis in Missouri. Her husband is a "wood cutting fool" for lack of a more appropriate term. Seems he is tireless and unstoppable when he has a chainsaw in his hands despite being over 68 years old . He uses Stihl saws. I was asking about his mix ratio which turned out to be 50:1. He uses Stihl brand two stroke oil and had both the standard oil and a 100% synthetic there on hand. They both mixed at 50:1 but Stihl doubles the warranty on a new saw when the synthetic oil is used exclusively. Just thought I'd add this little snippet to the conversation.
Your dedication to this time-consuming and costly comparo is commendable. :thumb:
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