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Showing content with the highest reputation since 09/15/2020 in Posts

  1. 1 point
    Your domes will determine the compression, but you need to have the right fuel for the compression. If you're running high compression domes, running the wrong fuel will damage the motor and obviously cause loss of power. He is right that fuel does not determine power, but running better fuel will make you able to run higher compression domes.
  2. 1 point
    More compression mean more power. Fuel have nothing to do with it. You chose fuel to match compression. Envoyé de mon SM-N975W en utilisant Tapatalk
  3. 1 point
    Race gas definitely means more power, but it is expensive to run. When I go out to the dunes, I run through roughly 10gallons a day, which comes out to $150 daily to run 110. If you don't ride much, or your wallet is fat, then go for it. You should be fine with the cylinders you have, if you want more power send them out to one of the sponsors of BHQ for a dune/trail port. You said you ordered new pistons, you should read the number on the top of the old pistons to see what size they were, that should have told you the bore size. If they were the 795s for a 4mil and it truly was standard bore, they should have read as 795M06400. The last 4 denote the bore size, 64.00mm is standard. If you are putting in new pistons, I'd recommend just getting a bore done when you send the cylinders out for porting. This way you can get the pistons matched for your setup. Go to like a 64.50. When I bought my trail bike it was already at 65.5. this means it had a bore done several times, which was expected from a 30+chest old bike. You should make sure of your bore size by checking the old pistons out, as people do this usually when they purchase the bike and most banshees are now old enough to buy alcohol.
  4. 1 point
    A 392 is a stock stroke with 68mm bore, to get the most out of it you would want to go for a 4mil and make it a 421. Going that far with the bike can be more expensive, so my recommendation would be to start with the basics. Get an adjustable timing plate, some aftermarket pipes, chariot reeds, and some 34mm carbs. These mods alone will add a ton of power and throttle response to your bike. You will need all of these things if you decide to go to a 392 or 421, so might as well start there. You can also get a lot more power out of your bike by getting port work on your cylinders. If you have these things and later on want even more, go for the full 421 setup. I say to do crank/cylinders at the same time because it's not that much more of a stretch to pull the crank once motor is out and cylinders are off. If you start with just the 68mm bore and later decide to do the 4mil as well, then you will need to change from 513 pistons to 795, get cut domes instead of standard, and also need to either change your head or get a spacer plate.
  5. 1 point
    Driveline Performance2978 Allen rdOrtonville,MI 48462Business hours are Monday-Friday 10:00am to 5:00pm248-793-3535
  6. 1 point
    You said it is a 4mil, which having a spacer plate makes sense. If it has stock cylinders that is fine, but if it has stock pistons then that is your problem. The stock replacement pistons are 513s. If it is a 4mil, then you need to be running 795s. Running the wrong piston is probably why one of them failed. Next, you say you are running 20cc domes, that means this bike is setup to run on either 105 or 110 octane gas. If you are trying to run pump gas, then that is a problem as well. You need to run 23cc/24cc domes if you want to run 93/91 octane out of a pump. If you are going to change domes, get some cut domes so you dont need the spacer plate. To answer your questions: 1: It could be what I mentioned above, wrong pistons or wrong domes for the fuel you are using. You didnt mention your fuel ratio, you did say you just bought it so you should know that you need to be running 2stroke mix in your gas. Personally I use Amsoil Dominator at a 40:1 ration, and thats what I would recommend as well. It could also be your jetting as I will talk about on 3rd question. 2: with your pipes I would run +3/+4 for timing. 3: Jetting varries motor to motor. You said big carbs but didnt mention their exact size or brand. I have a similiar trinity 4mil that is a 397 with its 66mm bore. It runs Mikuni 34s with main jet at 280 for 1800 elevation. I would start there as your build isnt to far off from what I have. Put in fresh spark plugs, ride it hard for a bit with WOT(wide open throttle), then pull the plugs. If they are black/wet then you need to go down a size and start over with fresh plugs. If they are white/ light brown then go up a size and try again. Ideally, you want them to be a chocolate brown. I will check back for any questions you might have or help you need.
  7. 1 point
    I just got back from an impromptu trip to Saint Anthony for labor day week. The dunes were amazing. Labor day we got a wind storm, and it cleaned out the dunes after the UTVs trashed them. Its funny because its 724miles and 12hrs for me, 761miles and 12hours for my brother, and 732miles and 12hours for my buddy. We always meet up and distance/time is about the same for all of us except my buddies in western montana who can take day trips there. Always a big crew, be great to get out with more than just my banshees!
  8. 1 point
    Sent from my iPhone using Tapatalk
  9. 1 point
    Piston done!! Envoyé de mon SM-N975W en utilisant Tapatalk
  10. 1 point
  11. 1 point
    Couple uh steaks n vegan kabobz Sent from my SM-A505U using Tapatalk
  12. 1 point
    What your wanting and what your buddy is telling you are two different things. Your ordering a LP 421, NOT a hp 421. So your already not getting a drag engine. Therefore your 34mm carbs are actually a perfect choice and I would not consider changing them. if you want to build a drag bike, you need to switch your cylinders and then you can consider bigger carbs, although still not needed. 19cc dimes and vp110 is costly and unless this is a real drag bike (cut, stretched, and lengthened) you absolutely don’t need it. if your building a general purpose fast dune bike, your current choice is perfect.
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