xjamesd93 Posted June 3, 2009 Report Posted June 3, 2009 Ok so running alcohol in a 4mm stroker 68mm cub...not ported 750ft above sea level What do i need as far as other engine mods, domes, carbs, lines, timing, bowls, etc. Also what should i know about running alcohol other than it goes by 2x as quick, How do i purge...just throw in how much of what octane and what mix gas...and just jack the rear end off ground and run it till gas is out?? Sorry for being a post whore and asking sooo many questions, but if im going to do this im going to do it right Also i have searced about running alky and found some things but not all =] Thanks Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 As far as domes, setup, timing, compression, etc., that is gonna depend on a lot of things. 300 foot bike, dune bike, pavement bike, etc. Also depends on the who set it up. More squish clearance = more timing, less fuel, etc. Way too many variables. As for purging, just get 87 octane pump gas and mix it a little richer than your methanol. 20:1 to 28:1 is fine. MAKE SURE you use the same premix oil that you use in methanol. Please, do NOT put the back end off the ground, it can and should be purged in Nuetral. When the motor starts bogging down, the tone of the motor changes a little...and you have to give it about 1/2 throttle, that's when you know it's getting into the purge gas. I usually wrap the throttle/hold it 1/2 open for another 30 to 60 seconds after that and let the bike kill itself. Warmed up, a bike with carbs setup for alky will die at idle with gas going through the fuel system. It's literally flooding the motor out with gas/oil once it's warmed up. Methanol bikes in warm weather usually start no problem. Cold weather, good luck. Instead of starting it with ether if it's tough to start, hold the throttle wide open and trickle a little purge gas/oil in the front part of the air filter to try and get it to start. Ether has NO oil in it...so you're almost starting the motor dry....I try to avoid ether unless I have to. Quote
xjamesd93 Posted June 4, 2009 Author Report Posted June 4, 2009 (edited) its a 300ft bike and its not being ported yet just assembled by my mechanic...and he said he hasnt a clue about drag racing, but it doesnt matter because all he is doing is putting in my over ride, and installing my cub. and thanks for the info about purging also aomeone told me that if i run a high octane gas or alky that i cant let it warm up..just start it at the line and go, then shut off at the end.or i will burn holes through the pistons...but how can a cold motor run at its full potential?? Edited June 4, 2009 by xjamesd93 Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 its a 300ft bike and its not being ported yet just assembled by my mechanic...and he said he hasnt a clue about drag racing, but it doesnt matter because all he is doing is putting in my over ride, and installing my cub. and thanks for the info about purging also aomeone told me that if i run a high octane gas or alky that i cant let it warm up..just start it at the line and go, then shut off at the end.or i will burn holes through the pistons...but how can a cold motor run at its full potential?? Two things, without trying to sound like too big of an ass. 1. Find a new mechanic, one that knows how to not only assemble one, but to leak down check it, check for squish, compression test it, etc. 2. Do not listen to whomever said that. That is the WORST possible thing you can do to the motor short of throwing the bike off a dock into a lake. It is absolutely important the motor is properly warmed up before going out and making a full throttle pass. Short of the lines I've heard firehead use to pickup pirate hookers, that is possibly the worst advice I've ever read on any forum. Briefly, a engine needs to warm up to expand and move. Doing what this guy said will more than likely leave you with a "cold" seize...where the piston doesn't reach operating temps and seizes in the bore as a result. I would make sure your mechanic assembles the bottom end and bench tests the shifting as well...make sure it goes through the gears. He'll more than likely have to spin the countershaft sprocket over while assembled to get it to shift. Overrides are like that. Or...spin it in the bottom half of the cases to make sure it'll spin/shift. Quote
Rodneya Posted June 4, 2009 Report Posted June 4, 2009 Short of the lines I've heard firehead use to pickup pirate hookers, that is possibly the worst advice I've ever read on any forum. ?? You need to use pickup lines on them down there Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 Have you seen Firehead? He needs a pickup line just to get his order at Burger King... :biggrin: Quote
xjamesd93 Posted June 4, 2009 Author Report Posted June 4, 2009 lol...i didnt think what that guy said was correct, but thought i would make sure..haha and my mech. can do all those things listed but i was asking him about which pipes bb or sb to use and he said that he doesnt truly know about that and to ask someone who had more experience in dragging....so all i have to figure out is which pipes to use and im good to go..haha Quote
shanYE west Posted June 4, 2009 Report Posted June 4, 2009 Small bore pipes would work best on that setup. Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 My apologies to your mechanic. I didn't realize he was only talking about the pipe choice, I thought you meant motor in general...my bad. Quote
xjamesd93 Posted June 4, 2009 Author Report Posted June 4, 2009 (edited) no problem....i agree if someone had a mech. who didnt know how to do those things, i would tell them to get a new mech. too..haha but i think imma go with some smallbores and what size flange i need to fit cubs?? so heres the setup: 4mm crank 4mm stroker 68mm cub weiscos small bore pipes (unsure of brand) override tranny v-force 3s lockup clutch k&n pods cool head unsure of dome size carbs with billet bowl...unsure of carb size running on methanol 800ft above sea level any idea what size domes i need, and what size carbs?? also will all domes be ok to use with alky?? thanks! Edited June 4, 2009 by xjamesd93 Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 20cc domes cut for alky. Yes, there is a difference in gas and alky domes. Both fuel have different combustion characteristics. Will it work with a gas dome? Sure....but you bought a cub, you plan on running alky, get domes cut for alky. Get 39PWK carbs. Cheap and easy and they work. Quote
xjamesd93 Posted June 4, 2009 Author Report Posted June 4, 2009 20cc domes cut for alky. Yes, there is a difference in gas and alky domes. Both fuel have different combustion characteristics. Will it work with a gas dome? Sure....but you bought a cub, you plan on running alky, get domes cut for alky. Get 39PWK carbs. Cheap and easy and they work. ok 20cc it is and 39PWK's too lol...i dont know what i would do without the HQ.... thanks dajogejr!!! Quote
dajogejr Posted June 4, 2009 Report Posted June 4, 2009 Call up Dave Noss, or PM dlnoss. He is NOSS Machine. He will work with you on whatever spec dome you want and cut a set. I know he offers a slight discount on his cool head and domes to HQ members. I do not know if he offers a discount on domes only. He may have other advice as well. In my motors, I like to keep alky cranking compression around 160 to 180 PSI...just my personal preference. Quote
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