Guypie Posted April 14, 2014 Share Posted April 14, 2014 Well anythingspoked seems to be well and truly defunct so I figured I would move this over to here. Hi allI have been keen to do one of these for a while so I got cracking during the holidays.Unfortunately i was too damn lazy to take photos through the build so im just going to show you the finished productMuffler is a home made slip on jobbie to avoid irritating the neighbours. stuffed it with newspaper cause i didnt have any fibreglass. Has worked fine so far, dont know how long til it disintergrates thoBuild came in at under $100!Its made from:2x 20" bmx bikes from the dump shop1x 2 or 3hp (unsure which) donkey engine. I think its 127cc .Has a centrifugal clutch.Bits of steel from the dump shopCouple of vee beltsPulleys came from work - fan belt tensioners etcTank came off a Honda ct125 apparently. and carb is from a nifty fifty. could do with a bigger one thoughCurrently have not tested top speed cause I only just put not-perished tyres on it but I have had it to 50km/h and its just getting started. i think it will do 70 with its current gear ratio (8.6:1) I have made another pulley to gear it up a bit for better take off.If anyone has any bright ideas on giving it a bit more grunt let me know!ChurGuy More early pics 3 Quote Link to comment Share on other sites More sharing options...
Guypie Posted April 14, 2014 Author Share Posted April 14, 2014 Ok so at dromeageddon 2 I got this thing to 74kmh, and have not broken that since. I really need to make progress as my local competition (mr boswell) is only a gear ratio change away from blowing me away, he has 50cc more and is topping out at the same speed, but with more accelleration.So I have devised a 3 step plan as follows:step 1:I paid a visit to a friend and had the head skimmed buy 1mm. its quite a bit, but the valves dont hit the head so its all good.step 2:remove the forced air cooling system, after all the bike is moving and the fan is taking precious horsepower!This is the new fan shroud, i have not gotten around to machining the flywheel yet so hopefully if i make sure this is relativley well sealed the fan on the flywheel will just "cavitate" and not pull and air in.there was a plate in the casting at the front of the motor that would stop all airflow from the front, so i removed that, here is a picture compared to an unmodified engine:Note the front air vent had been blanked out:Step 3 still to come...and heres some other pics of the bike:at the Kawhia:and in B&W: 1 Quote Link to comment Share on other sites More sharing options...
Guypie Posted April 14, 2014 Author Share Posted April 14, 2014 Ok so here is what I got done before last weekend.Step 3 Phase 1:Goodbye tiny carburettorHello Bigger carb and new manifold:And Step 3 Phase 2:This was going fine until my pullstart started seizing up, and ripped the pullcord after screeching like a banshee, hence no go at the drome also, the flywheel came loose at munched up its key, so i had to replace that too.anywho its currently running a bit lean at main on 66%meth 34%petrol on a 120 jet size. Im thinking 140 at 100% methanol will be about right, apparently the tuning window is quite large on methanol so rich is good.anywho as usual any advice on tuning or ideas let me know! 4 Quote Link to comment Share on other sites More sharing options...
Guypie Posted April 14, 2014 Author Share Posted April 14, 2014 So jetting is currently at 140 main and it sounds good at high rpm on methanol, but the idle circuit doesnt flow anywhere near rich enough so i need to try boring out the idle jet/ replacing with a larger item. Idles mint on petrol but wont revv as its way too rich for petrol on main. Awesome. a bike that wont run correctly on either! hahaha edit: added pics beacause pics. and one with a megaphone exhaust 5 Quote Link to comment Share on other sites More sharing options...
rot808 Posted April 14, 2014 Share Posted April 14, 2014 Sheeeeit this thing looks sweet 1 Quote Link to comment Share on other sites More sharing options...
governorsam Posted April 14, 2014 Share Posted April 14, 2014 remove the main jet for methanol. seen it work on bears bikes... more methanol means cooler running means higher compression means more power. Quote Link to comment Share on other sites More sharing options...
Flauski Posted April 16, 2014 Share Posted April 16, 2014 love it! Quote Link to comment Share on other sites More sharing options...
Spencer Posted April 16, 2014 Share Posted April 16, 2014 Cool bike man! I would say even on the main with that carb its still too lean. max power is like 4 or 5:1 haha Quote Link to comment Share on other sites More sharing options...
Guypie Posted April 16, 2014 Author Share Posted April 16, 2014 Cool bike man! I would say even on the main with that carb its still too lean. max power is like 4 or 5:1 haha I might try what governorsam said and take the jet out altogether, what could go wrong?! *queue burning valves and thrown rods* Quote Link to comment Share on other sites More sharing options...
Spencer Posted April 16, 2014 Share Posted April 16, 2014 Just drill it to the max. Quote Link to comment Share on other sites More sharing options...
Spencer Posted April 16, 2014 Share Posted April 16, 2014 It's hard work getting enough fuel in on small carbs. Quote Link to comment Share on other sites More sharing options...
KIRK Posted April 18, 2014 Share Posted April 18, 2014 chur bike cuz just put two carbs on. magic /get a big dirty old amal or an SU for lols edit: also i'm 2kmph faster than you so shame. kind of on topic but not realy....whats the smallest su crab I can get off a car at picklepart etc? Quote Link to comment Share on other sites More sharing options...
tortron Posted April 18, 2014 Share Posted April 18, 2014 1 inch wont find it at pickapart tho Quote Link to comment Share on other sites More sharing options...
KIRK Posted April 18, 2014 Share Posted April 18, 2014 cher what size motor is that for usualy? Quote Link to comment Share on other sites More sharing options...
tortron Posted April 18, 2014 Share Posted April 18, 2014 about 900cc. my 918 sidevalve came with 1 1/8. but the earlier morris 8's had the 1" im sure 1 Quote Link to comment Share on other sites More sharing options...
mikey205 Posted May 22, 2014 Share Posted May 22, 2014 Flip guy!! This thing is sweet!! Quote Link to comment Share on other sites More sharing options...
Mitch.W Posted May 22, 2014 Share Posted May 22, 2014 yo that is sweet, if its not idleing properly change the emulsion tube out? Quote Link to comment Share on other sites More sharing options...
Guypie Posted May 22, 2014 Author Share Posted May 22, 2014 yo that is sweet, if its not idleing properly change the emulsion tube out? Emulsion tube is the bit behind the main jet like a perforated tube right? I have never thought about the effect it has on the bike before, i didnt think it was used to correct fueling. What do you change about it? Number of holes and hole diameters i guess? And what effect does it have on the fueling? Flip guy!! This thing is sweet!! Thanks mikey, you will have to come over and take it for a ride next time you are in town Quote Link to comment Share on other sites More sharing options...
Rookie Posted May 22, 2014 Share Posted May 22, 2014 I'm pretty sure that carb doesn't have an emulsion tube, at least if it is the same as the ones I have it doesn't. Quote Link to comment Share on other sites More sharing options...
Mr. Boswell Posted May 23, 2014 Share Posted May 23, 2014 Get it sorted quick. Im on the verge of convincing Marnix to go out of town haha Quote Link to comment Share on other sites More sharing options...
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