xbig pitax Posted May 26, 2014 Report Share Posted May 26, 2014 I have a long rod rdz ported motor with shear pipes 35mm carbs, I'm runing 110 Sunoco with +9 timeing and my compression is 210. I've heard that it's not good to run such high compression with shearer pipes, but my real concern is that with the compression so high and running 110 is the motor pinging? Do I need to run q16? Please help Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted May 26, 2014 Report Share Posted May 26, 2014 Well u will get differences in opinion but anything 1/8,1/4 related I like to leave compression 170 ish . Rite now your running a shit ton of timing and compression that motor has to be fighting itself out the back and not overevving properly, as far as fuel goes if your plugs have signs of deto and loosen up not enough ,do you know your port durations and dome size because static compression isn't the end all on fuel type. I have ran q16 on a few bikes I learned the hard way one time I needed a power jet to get it tuned to the knats ass, unless you can really tune well stay away vp suggested a certain percent jet increase but it didn't work for me it sacrificed to much of the intermediate power needed for launch and 60 ft so I added power jet and all was well 1 Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted May 26, 2014 Report Share Posted May 26, 2014 Oh yeh and sorry I haven't got back to you,both my kids play travel baseball,softball I've been at away tournaments and preoccupied with practices ,I coach both teams but feel free to hit me up I'll be home all week this week 1 Quote Link to comment Share on other sites More sharing options...
xbig pitax Posted May 26, 2014 Author Report Share Posted May 26, 2014 Well u will get differences in opinion but anything 1/8,1/4 related I like to leave compression 170 ish . Rite now your running a shit ton of timing and compression that motor has to be fighting itself out the back and not overevving properly, as far as fuel goes if your plugs have signs of deto and loosen up not enough ,do you know your port durations and dome size because static compression isn't the end all on fuel type. I have ran q16 on a few bikes I learned the hard way one time I needed a power jet to get it tuned to the knats ass, unless you can really tune well stay away vp suggested a certain percent jet increase but it didn't work for me it sacrificed to much of the intermediate power needed for launch and 60 ft so I added power jet and all was well I have in there right now 17cc domes, I'm going to put in the 19cc domes I have which should have the compression down to 170-175. I'm not sure how to read the plugs for detonation but the top of the plug has a nice copper color to it so I know the bike isn't lean or to rich. I'll hit you up when my cylinders get here. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted May 26, 2014 Report Share Posted May 26, 2014 Your dome change will put you at about 190. They are usually about 10 psi per 1cc of dome. +9 degrees is ALOT of timing as well. I know of a lot of RDZ stuff that runs well with about 5-7 degrees. Also, that Sunoco could be stale. Especially if it's from winter. Mos of those places just don't sell it fast enough. I went from Torco to Sunoco and noticed some inconsistencies. I swapped to C12 and it ran great. The C14 might be an option for you if you are serious about wanting the higher compression and timing. There is also an oxygenated fuel called VP113. It's pretty much oxygenated C12. Good stuff! 1 Quote Link to comment Share on other sites More sharing options...
camatv Posted May 26, 2014 Report Share Posted May 26, 2014 17cc shelf domes or 17cc custom domes... makes a big difference. Quote Link to comment Share on other sites More sharing options...
registered user Posted May 26, 2014 Report Share Posted May 26, 2014 why does some poeple use so much advance. wont that take heat out of the pipe and not rev as well ? Quote Link to comment Share on other sites More sharing options...
xbig pitax Posted May 26, 2014 Author Report Share Posted May 26, 2014 Your dome change will put you at about 190. They are usually about 10 psi per 1cc of dome. +9 degrees is ALOT of timing as well. I know of a lot of RDZ stuff that runs well with about 5-7 degrees. Also, that Sunoco could be stale. Especially if it's from winter. Mos of those places just don't sell it fast enough. I went from Torco to Sunoco and noticed some inconsistencies. I swapped to C12 and it ran great. The C14 might be an option for you if you are serious about wanting the higher compression and timing. There is also an oxygenated fuel called VP113. It's pretty much oxygenated C12. Good stuff! I switched to the 19cc domes and I was at 180 ish compression. Bike felt horrible slow. Going back to the 17cc and dropping the timing to 6. The porting is really aggressive, compared to all the other ported cyl I've seen mine are way more ported, I'm going to try to post a pic of the transfers, intake, and exhaust. The domes are 17cc off the shelf I live in Miami fl where we are at sea level, and it's never cold lol. The Sunoco where I get my gas, I've talked to the manager and asked him how many times a month do they get 110 and they get it every month. Quote Link to comment Share on other sites More sharing options...
xbig pitax Posted May 26, 2014 Author Report Share Posted May 26, 2014 I don't have a picture of the exhaust but it's pretty damn wide Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted May 28, 2014 Report Share Posted May 28, 2014 Ive had those cylinders in my hand they came from ny rite Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted May 28, 2014 Report Share Posted May 28, 2014 I know because they had nitrous nozzles sticking in the side of them and I have the rest of the bike , and I degreed them Quote Link to comment Share on other sites More sharing options...
xbig pitax Posted May 28, 2014 Author Report Share Posted May 28, 2014 I know because they had nitrous nozzles sticking in the side of them and I have the rest of the bike , and I degreed them What would you recommend me to have them set up perfect. I have the compression at 210 and the timing at 6, but I feel that the motor has more in it. Basically what compression timing and other things would you change... What octane where they ran with? Quote Link to comment Share on other sites More sharing options...
xbig pitax Posted May 28, 2014 Author Report Share Posted May 28, 2014 I bored it out from 64.50 to 65 just to have a fresh bore and hone, I'm running it on a long rod stock crank Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted May 29, 2014 Report Share Posted May 29, 2014 why does some poeple use so much advance. wont that take heat out of the pipe and not rev as well ?Yes and no. As with every thing it depends on set up...... To an extent. On the banshee twins, I see more motors go in to detonation before they can just get away with an early burn and spit it out the exhaust. The bigger singles get away with more timing as they don't fight the another piston. Those big singles are definitely the motors you see where they can just burn early and "blow cold" with timing. I've only seen a handful of motors that do that.On the banshee twin, excessive timing definitely makes them go a little flat up top like when you have to much compression. In my opinion, if a motor needs that much timing to work, there is possibly a dome issue. The question really is, why does a particular motor need to be lit so damn early to get a complete burn? OP, 210psi and 9 degrees is a bit much. It'll feel like a freight train early on, but won't pull revs the way it should. I used to TRY to run my short track motors that way but they never lived or reved. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted May 30, 2014 Report Share Posted May 30, 2014 Not to mention the mega fucking heat soak! Quote Link to comment Share on other sites More sharing options...
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