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  1. #1
    abarrassr07's Avatar
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    01xpl 1020 bigbore fine tuning and questions

    running the following set up:
    91mm wiseco forged pistons
    proks with stock springs, 2.3 n&s, 95ls with 167.5 hs turned .5 out without accel pumps
    a stock prop repitched by impros for the set up which pulls the same exact rpms as a concord 15/20

    my compression is right at 165 with the stock head. it had some pinging gone on with the one shaved by group k so i put a stocker on it. its sluggish out the hole when it transitions from the ls to hs jet and doesnt snap like my rx does. it kinda falls on its face if you get on it all at once. i trimmed the rave valves myself i was wondering if its possible to cut them down too much to not allow them to work right? i tried these carbs on my stock rx and it rips from 0 to 7050rpms with no dead spots.

    Secondly, when i open it up itl climb to 6900-7000rpms but wont hold steady it fluctuates between 6700 and 7000. i thought that with this set up i am already running a little rich on top but maybe not? my plugs are light brown . any help appreciated thanks guys Btw all fuel lines were replaced, new fuel filter, dumped and cleaned tank and fuel selector valve, carb filters are clean with fresh rebuild kit as well


  2. #2
    SURFnTURF's Avatar
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    My thoughts are you are a little rich and over propped at the same time which doesn't help with peak revs.

    I assume its a stock piped engine set up so the power band has not changed

    Your needle and seats Good ? What are your pop offs ? I would run 2.0 with the black springs personally as this gives 21psi P/Off but each his own.

    What are your low speed screws at ? as this effects the overall jetting as well

    When you say its fluctuating at peak revs does it feel like its hunting for the revs or it does it feel like its sluggish and struggling to stay at peak rpms ?

    To tall a prop wont help at all if its rich so you may have to change over temporarily to get it into the rev range you want then re prop .

  3. #3
    abarrassr07's Avatar
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    kind of feel more like its struggling to stay up there as it climbs strait to 6500 and climbs to 7k then down and up again. my lows are turned 1.5 turns out at the moment, ive been turning them in and out an 1/8th at a time to try to get it to jump out the hole without hesitating but no luck. im going to throw the stock prop off my other xp and see what it does. i have some black springs and 2.0 needles layin around i may swap them out as well. thanks. i do have a coffmans exhaust with mpem but i dont think im going to run it until i bore it to a 1050 bc my clearence is only as what wiseco recommends which i think is too tight for a coffman

  4. #4
    abarrassr07's Avatar
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    found the problem i think. i ran some octane booster i thought would help boost the points a little a couple weeks ago. pulled the carbs that i just cleaned not even a month ago and found a bunch of gunk by the jets and needles with a little trash in the filters. cleaned em put em back on and ran fine for about 30 seconds then started again. im guessing that booster broke down trash on the inside of the tank? guess ill be pulling the tank out to clean.

  5. #5
    165psi is too high for pump gas!

  6. #6
    Wrench's Avatar
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    +1^^. But i dont know how you get that kind of compression from a stock head. Mine is milled and im only at 145. -1 on the wisecos. bad choice for this motor.

  7. #7
    TEAM BRONX TECH FAT BOY's Avatar
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    Klotz high trate will gun up if left mixed with gasoline in colder temperatures. It will leave a skin looking red flame in the fuel. This is a result of ethanol mixtures. I've spun 7850 on Klotz, although I wouldn't recommend it. You should have no issue with the fuel additive at those rpm's. Check you grounds. I run 1 ground from from the negative to the stock position by the starter, and another from the battery to one of the bulge at the rave valve.

  8. #8
    abarrassr07's Avatar
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    Quote Originally Posted by FAT BOY View Post
    Klotz high trate will gun up if left mixed with gasoline in colder temperatures. It will leave a skin looking red flame in the fuel. This is a result of ethanol mixtures. I've spun 7850 on Klotz, although I wouldn't recommend it. You should have no issue with the fuel additive at those rpm's. Check you grounds. I run 1 ground from from the negative to the stock position by the starter, and another from the battery to one of the bulge at the rave valve.
    i dumped my fuel filter and the fuel is orange as can be and it runs good until it warms up then it gets sluggish and the detonation is back after 6500rpms. havent checked my squish yet would that make that much difference in compression? going to mix a few gallons of av gas and see if it goes away

  9. #9
    Wrench's Avatar
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    what has been done to it to raise the compression?

  10. #10
    abarrassr07's Avatar
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    Quote Originally Posted by Wrench View Post
    what has been done to it to raise the compression?
    all ive done was bore it out to 1017cc with cometec base and head gasket. on my gauge it read 153psi on each cyl but my stock rx only read 135 as did every other 951 on that gauge. checked on a mechanics gauge he gets pressure tested every month and it shows 165-167

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