BlownCorona Posted July 14, 2013 Share Posted July 14, 2013 Was sort of avoiding doing this, and was just gonna read/bump old threads, but it seems every experience with setting these up is different, so without further ado, here is my thread. ive put a set of GSXR1100 carbs on my 2.0l toyota 18r engine, i think the carbs are mikuni BST40s i drilled the jets out to 1.6 as instructed in the classic ford/bogg brothers article that most people will know about. this seemed to be still far too lean, it started, but was hard to do so, and didnt really want to rev, was generally rough, and it was spitting out the bellmouths of the carbs. randomly, and from all carbs, no particular order. CURRENT SETUP drilled 1.75mm jets air bleed screws at 1.5 turns out. (were set at 3.25?!) needle clip droped 1 down from factory (now at the lowest point) the engine fires very quickly and idles pretty smoothly, and fuck does it bark when you rev it up, sounds incredible and im really happy. BUT it still spits out the front of the carbs, it seems less so now, but its so random its hard to tell, someone it will idle for 5 mins perfectly, some times it will spit quite alot. it LOOKS like its spitting out of the air bleed jet in the front of the carb mouth, but again, hard to tell. heres a video of the first startup, running to lean, and generally horrible. http://www.youtube.com/watch?v=n0AtcaJ0dZk anyone got any idea whats causing this? timing looks to be fine. Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 14, 2013 Share Posted July 14, 2013 put an airbox on it and it'll suck that fuel its spitting back in lowl. recycling Quote Link to comment Share on other sites More sharing options...
shaneo Posted July 14, 2013 Share Posted July 14, 2013 Mine used to spit as well put air filters on and problem solved 1 Quote Link to comment Share on other sites More sharing options...
KIRK Posted July 14, 2013 Share Posted July 14, 2013 yeh should prob tune it with filters on anyway unless you plan on running no filters? edit: looks choice. I want those on my van Quote Link to comment Share on other sites More sharing options...
Rookie Posted July 14, 2013 Share Posted July 14, 2013 Yea, it sounds lean, are you confident with the seal on the manifold? and was that with it warm? Because my Lotus coughs when it is cold because the fuel doesn't atomise properly, and it runs a bit lean. The only way to tune them properly is with a wideband. Also doesn't lowering the needle make it leaner? Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted July 14, 2013 Share Posted July 14, 2013 He lowered the needle clip, which lifts the needle. Thats how I read what he did anyways hah Quote Link to comment Share on other sites More sharing options...
Rookie Posted July 14, 2013 Share Posted July 14, 2013 Ha, yea I'm a muppet, you are right Dayfe. 1 Quote Link to comment Share on other sites More sharing options...
Beaver Posted July 14, 2013 Share Posted July 14, 2013 Does it only spit at idle? maybe wind the idle screw out a bit more to richen it up (or what ever way is richer lol). And have you tried going bigger again on the jets? Ive heard the rule of thumb 1/1000th of engine size (ie 2mm for you) as a starting point. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 14, 2013 Author Share Posted July 14, 2013 2.0mm seems fucking huge, problem is that it doenst seem to spit above1/4 throttle, which leaves the pilot air circuit, which is where it spits out of, those little holes in the front. and yes a droped the circlip to raise the needle. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 14, 2013 Author Share Posted July 14, 2013 Yea, it sounds lean, are you confident with the seal on the manifold? and was that with it warm? Because my Lotus coughs when it is cold because the fuel doesn't atomise properly, and it runs a bit lean. The only way to tune them properly is with a wideband. Also doesn't lowering the needle make it leaner? im not 100% sure it vac leak free, probably never will be 100%, however it starts really easy, idles smooth, and revs cleanly, so im not sure if that makes a vac leak likly or not. the engine was run for around 5mins at a time, because i always got too concerned with what the issue might be that i shut it off. so it would have been warm ish, wideband is on the cards, im just still not sure if i want to spend the 300 required. i have the o2 sensor from an ae101 levin, anything that could be done with this? those o2 sensor kits they sell at jaycar? also might be worth metioning that i dont have the throttle hooked up yet, so have not actually applied load/driven it Quote Link to comment Share on other sites More sharing options...
Beaver Posted July 14, 2013 Share Posted July 14, 2013 another thought, have you stripped and cleaned them. might be worth the $100 to throw a rebuild kit through them all Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 14, 2013 Author Share Posted July 14, 2013 i have stipped and cleaned them, everything looked pretty tidy, came off a running bike, not a bad ideal to throw a rebuild kit at it, just at this stage it seems unnecessary as nothing leaks. and since i need filters anyway, it seems better to just buy those and see if it clears is up Quote Link to comment Share on other sites More sharing options...
Beaver Posted July 14, 2013 Share Posted July 14, 2013 Sweet as. I should probably throw some filters on mine as well....sucked up a few small children the other day Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 14, 2013 Author Share Posted July 14, 2013 i desperatly wanted to run chrome velocity stacks with a mesh cap to keep stones out, but i may not be able to now. where does one buy filters for these (58mm), that don't cost a fortune and are half decent? Quote Link to comment Share on other sites More sharing options...
NickTheFox Posted July 14, 2013 Share Posted July 14, 2013 bcdirect.co.nz sell the unifilter branded ones, I got a unifilter pod filter from them through work (Supercheap auto) but im pretty sure you can order direct. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 14, 2013 Author Share Posted July 14, 2013 i used to work there haha, in chch. I want to steer clear of foam filters, because ive seen bad things happen when carbs are spiting fuel out and then they catch a spark. Quote Link to comment Share on other sites More sharing options...
mjrstar Posted July 14, 2013 Share Posted July 14, 2013 as far as air filters go I had good service out of this dude... (seemed like a good price to me too) http://www.motozone.co.nz/products/?t=air+filter Quote Link to comment Share on other sites More sharing options...
Beaver Posted July 14, 2013 Share Posted July 14, 2013 you can get generic cheap pod filters for most sizes on trademe Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted July 15, 2013 Author Share Posted July 15, 2013 i got home from work, and i wanted to see how it would start, dead cold, in freezing conditions. started great, and idles smooth after a minute or so on choke. still spiting every now and again. but i did notice someone important that i wasn't seeing in the light. and that was on one of the spits, i saw a glow around the intake flange -> head join. so it looks like its probably vac leaks causing this. i might need to shim the intake and exhaust flanges since they fit together in some parts and may not be exactly the same thickness. does this sound likely? i know rookie mentioned vac leaks, just last experience i had with leaks has been much different. Quote Link to comment Share on other sites More sharing options...
Beaver Posted July 15, 2013 Share Posted July 15, 2013 diffinitly worth fixing regardless... Quote Link to comment Share on other sites More sharing options...
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