Top Speed, 80cc Chinese motor? what is the record?

Discussion in 'Motorized Bicycle General Discussion' started by scottcason69, Apr 26, 2013.

  1. LandSpeedRecord

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    Davezilla, thanks for trying that and sharing. It's fine if one person only wants to break in their motor on west bound, even numbered streets, on odd numbered days that end in the letter y. These pistons and jugs are quite inexpensive and fun to try things with so I for one want to hear different opinions and results, more data = more knowledge. It hit me on my drive home, I ultimately want to run at Bonneville. Even if I can go as fast as my hopes which is unlikely that will mean at least 2 plus minutes of full load wide open throttle at max RPM. That is a lot to ask of that poor little air cooled motor. I am really going to have to be conservative with porting, gearing, basically everything if I want to be sure it will hold together. I have not found the opti2 locally and was going to run the Stihl factory oil at it's recommended 50 to 1 for know. Any Tucson locals know where to buy the opti2 locally?
     
  2. Davezilla

    Davezilla New Member

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    The Stihl factory stuff or the ecko stuff they sell at home depot would work, I just order the opti2 from amazon.com in the quart size, they sell it in different sizes from the one gallon quick mix packs all the way up to a gallon of the oil. The quart size was appealing to me because it has the dz mix bottle that ya just squeeze the bottle to fill the little compartment and pour into the gallon gas can. A quart of this stuff lasts a long time too since the mix is 100:1.

    Another option is if you got a Northern Tool in your area they sell the Vp premix in 40:1 or 50:1 by the literal and by the gallon and you can get it in those ratios as 94 octane and 98 octane if I remember right. Considering the fuel mileage these engines have it's. Still priced really good for alcohol free high octane premixed in 40:1, 50:1, and I think also 32:1 and maybe even 20:1 but the 50:1 premix should be ok for normal riding and the 40:1 for all out full throttle runs likenyou want to do.

    I run mine full throttle for about a mile in each direction on my morning taco runs. The fuel I get over here is 93 octane and I mix it at 100:1, so far I hadn't seen ant reason to add more oil to the mix, but sometimes I like to add in about 1/4 ounce of castor oil to my fuel mix if I'm gonna run it hard for longer than my normal mile at full throttle. My gearing is quite low since I'm using the 44 tooth sprocket and hitting 41 to 42 mph, I still need to do the math but that's gotta be between 9500 and 10000 rpm.
     
  3. mapbike

    mapbike Active Member

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    My local Home Depot has the high quality NON ethanol premix in 32:1 40:1 and 50:1 it is pricey though, for me I can burn a 2L tank of gas in a day of riding easy when I ride into town which is normally a 30-40 mile round trip ride and I'll be running WOT most of the way there and back.
     
  4. mapbike

    mapbike Active Member

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    I wouldn't be afraid to run either of those oils, Stihl or Echo either one wouldn't recommend or make a junk oil for their products.

    I know we have members who run the Echo semi synthetic at 50:1 and have good results with it. Xseler is the first member that comes to mind.
     
  5. mapbike

    mapbike Active Member

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    Myself I mix my Opti2 as directed in my 5 gallon jug and then i put 4 cap fulls of Maxima 927 Castor in the mix just for a little extra prtection from the Castor oil.

    Since I been running Opti2 straight up @ 100:1 or with the tad bit of the Maxima 927, I have had no oil related failures.
     
  6. Davezilla

    Davezilla New Member

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    Yeah. The quart and gallon size premixes are a bit pricy if you ride long distances, but for racing or high speed runs, or if you need the extra octane either because of the heat, high compression, or too much timing advance etc its nice to have another alternative. Too bad we cant easily set the ignition timing or we could advance the timing and run racing fuel when needed then retard it back to run 92 or 93 octane premium for normal everyday use.
    There are formulas for boosting pump gas octane to a more respectable level cheaply in here tho if someone does want to run a higher compression ratio by adding toluene or xylene so racing fuel premix wouldn't really be needed either, but this stuff should only be done by people who know what they're doing and use proper safety gear while mixing, and the stuff needs to be used rather quickly after its mixed up, the shelf life is only about a week at best, kinda like methanol which has to be used the same day it's mixed and then the fuel system needs to be purged out afterwards because of its corrosive and destructive properties...
     
  7. LandSpeedRecord

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    I'm a bit nervous of pushing the limits of octane and timing on this motor at least until i understand it fully. I had my GSXR race bike set up for pump gas because I really only tried to competative in the endurance races and it would only make a couple more horsepower on race fuel and I didn't like the mapping and hassle of it. So far so good on the best pump gas with the high compression head with this motor. It has been really cold here when I have riden and it has gotten hot enough to burn the **** out of my knee ha ha but the motor seems quite happy now with the jetting change.
     
  8. Davezilla

    Davezilla New Member

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    I agree, if your not comfortable boosting the octane or don't have the safety gear and a safe place to do it its best not to. And like you said, the performance gain isn't that much. Its mainly only needed for racing where quarter mile or lap times are recorded down to a thousandth of a second and any and every little bit counts, no reason at all to do this on a daily rider unless the compression is super high, but again, there's no need to run the compression that high on a daily rider... compression can also rob power in some situations on 2 stroke engines. Its good for low end torque, but not so important for high rpm top end power...
     
  9. bairdco

    bairdco a guy who makes cool bikes

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    quick note on opti2. i love the stuff on my street bikes. i run them hard all day without worries. .

    but racing with it was a different story. i blew pistons apart on a regular basis. on the street, you hear noises and you stop. the bike gets a break at lights, traffic, or parked at the liquor store.

    on the track? a ten lap race at the grange gokart track is roughly 15 miles of full throttle, over revving torture, usually in hot weather. if my exhaust falls off i don't stop. if it makes grinding noises, i push it harder. the only thing that matters is crossing the finish line. if a brand new, fully modded engine makes it till the end of the day, it's a success, no matter what place i finish.

    one race i crossed the finish line, shut the bike off in the pits, and it was seized when i tried to start it again. just melted the piston to the jug.

    i run klotz oil at 20:1 now and the same engine's made it thru three races so far.
     
  10. Theon

    Theon New Member

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    I agree, run it a little rich to start and keep the first couple of runs short, keep an eye on the temp, retention the head.
    Job done!
    Then if it's not preforming as wanted, pull her down and try something else.
    But for me, they're just a toy.
    Not a 'daily' that I hope to get 10 000 Km from.
    I personally think, If you want it to do 10 000+ Km's, 10 000+ RPM is not advisable.
    Keep her fairly stock, break her in gently, (boring!)
     
  11. mapbike

    mapbike Active Member

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    Do you run your engines on the lean side?

    I use the Opti2 @ 100:1 and I've done many rides for up to 25 miles one way running wot most of the way at speeds of upper 30's to mid 40's depending on the bike and mine never show signs of serious overheating and I've had not oil related failures.

    Now i do understand that my engines arent turning 10,000 rpms either and if they were I'd probably have a melt down also.

    The fear on running my engines so hard for so long is why I started adding some Maxima 927 Castor to the mix, I thought a little extra protection cant hurt for sure.

    Ya know while typing this out i just realized that I have had one failure that could be due to overheating... so I guess this part of the post will be an edit of what I said about not having an oil related failure.

    The engine I built up to get me over that 50mph hump ended up trashing the tension in the rings and that engine lost almost all compression, piston looks fine and cylinder looked fine but compression very low, this engine wasn't running lean best I could tell either, good plug color.

    One of you math wiz'es can probably tell me what rpms I was running.

    24" rear wheel, 30T sprocket, maximum speed reading on GPS 52.0 Mph

    Tires were 24x1.75 not sure of the actual circ.

    So I guess now that I think about it I have had what could be said to be an oil related failure with opti2...shrug....

    None of my other bikes run the rpm's this one was turning at those speeds.

    maybe i'm learning something here about what I should consider as far as mix for any engine I get to turn the high rpms' from now on...????
     
  12. mapbike

    mapbike Active Member

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    something else that I've thought about before related to the Opti2 oil is this.

    Those of us who use it and know how well in performs @ 100:1 mix have a lot of faith in it because of its good track record in our engines so I'm wondering why we wouldn't also think that if the oil is so good at 100;1 why would it not be an excellent oil to use @ 20:1 - 25:1 - 32:1 for those applications that need more lube like the very high temp high rpm condition of racing and long full throttle runs?

    I've never run Opti 2 at say 32:1 but I know I've seen post here where people had done it and I think some of us have kinda scolded them for it and said they should run it at recommended mix which actually varies depending on how you by Opti2 the small packets are actually a 72:1 mix if I remember right and then the larger packet is 100:1, I never really understood this myself but never had any issue running it either way.

    Just thinking that if Opti2 is so good at protecting @100:1 why wouldn't we think it would be excellent protection @ 25:1 or 32:1 under extreme conditions?
     
  13. Davezilla

    Davezilla New Member

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    I would compare it to another well known good oil and see what the viscosity difference is... I have a hunch that the Opti2 is more like a concentrate and it's thicker than most oils so at 100:1 it would be about equal to let's say maybe Koltz running at 32:1 or 40:1.

    One could test this theory by making a simple viscosity cup, which is basically a funnel with a small hole on the end, the ones I've used for mixing automotive paints with are actually calibrated like a carb jet is... but anyway, with the viscosity cup made, we would need a sample of the fuel mixed at 100:1 with the Opti2 and the fuel mixed at let's start at 50:1 with the "other brands". The next step is to make sure we have equal amounts in a small container, then pour the mix thru the viscosity cup and see how long it takes for let's say 3 ounces of mix to go thru the cup (you can vary the sample size to get an accurate reading which may require more fuel in your sample). Once you get a time for the Opti2 at 100:1 then do the same with the other mixes at the different ratios.

    If I'm right on this, the Opti2 will have a very similar time to the other brands mixed at their recommended ratios, but if not, then the Opti2 mix will go thru the viscosity cup faster than the other mixes.

    To get these readings as accurate as possible I'd say we would need something to make the cup out of like a small metal funnel and then solder a carb jet to the end to slow down the flow enough to get a decent reading, but not make it so slow it would take more than about 30 seconds to run whatever amount thru it.
    Then a metal or glass measuring cup since we need to start each test with the same amount of fuel mix, and something to contain the mix as it's poured thru.
    Next a stopwatch is needed.

    Once someone gets a recording to what ratio the Opti2 equals out to, then we could say for normal everyday use, run 100:1 but for racing it needs to be 50 or 75:1 etc...
    Also knowing this, one can easily use a different oil and know what ratio to mix it at if they run out of their favorite brand and want to go for a ride.

    this is the only way I could think up on how to compare these 100:1 mix oils like Opti2 and Amsoil, and I think there may be a few others out there that mix at the higher ratios too. Too bad one of my friends down here don't still work in the oil test lab at E G&G /Southwest Research or I could just give him a few samples and get the results back in a few days, but they tested not only the viscosity, but the lubricity of the oil and how well it could protect your engine. Back when he was still working there we found out the best engine oil for the cars was Valvoline Racing for dino oil and Amsoil for synthetic, right under Amsoil was Mobile1... and Redline was like number 8 on the list.
     
  14. Davezilla

    Davezilla New Member

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    I'll find that link that has the rpm/speed calculator for these bikes, it's a cool little program that someone made just for these bikes so you just plug in your sprocket size, and your primary gear ratio along with your tire size, then engine rpm to tell speed. This can be played with if you know speed but need to know rpm as well... I'll come back in here and post the link once I find it.
     
  15. mapbike

    mapbike Active Member

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    I remember the calculator you speak of, but i dont remember where I saw it.
     
  16. SpecializedMountainMoto

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    I got 49.2 on my new build, 26" tire ,36 tooth, Fred head, Fred jug, Fred piston, 66cc gt5 bottom end, rt carb. Built that motor for only 215.00
     
  17. Davezilla

    Davezilla New Member

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  18. Davezilla

    Davezilla New Member

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    Just ran the calculation for mine... to go 41mph with the 44 tooth sprocket and 26" wheels it comes out to 9350 rpm...
     
  19. mapbike

    mapbike Active Member

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    Chemical composition and special additives have a lot to due with how well an oil lubricates also.

    Just judging from how it looks when pouring into fuel, the Opti2 doesnt look any thicker than any other 2 smoker oil to me and as a matter of fact I have a few quarts of Kawasaki 2 stroke oil that looks as thick as SAE 40w non-detergent and it's not recommended for 100:1 mix as far as I know and the Maxima 927 Castor is a lot thicker than the Opti2 also.

    Now after all of them are mixed with gasoline things may change, I've just always been under the impression that Opti2 amd the other oils that are recommended for the 100:1 mix are so because they have been formulated with special additives so that they have a strong film strength even at such a small oil to fuel ratio.

    The test you suggested would be cool to do Dave, just to see how different oil and fuel mixes act in a test like that.
     
  20. mapbike

    mapbike Active Member

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    Thats very good... ride safe...
     

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