teddyurb Posted January 4, 2008 Report Posted January 4, 2008 Ive done some research on here ,oh im new to the 4 wheeler thing but not with engines.Any ways im a cnc machinist and have seen on here alota people are boring out there carbs to a bigger size.Ive seen people post on here that its a good top end mod,but yet have seen other people say that if you bore them out that you will run your bowls dry ,and need an inline fuel pump if this is done.I do all my engine work here at my shop in elkhart indiana.Ive got these carbs taken apart,and am deabating doing this,and am looking for a lil guidance whether i should do it ??Any comments or suggestions are greatly appreciated.The bike has wiseco bored over .020 pistons boost bottle ported and polished head shaved down .010 carbon kevlar clutch,lots of other odds and ins,but i want more power yet.But hey who doesnt.If any one else is wanting to have there carbs ported polised or ne other mods,let me know we have a full line of cnc machines lathes,and edms here,and have pics and refrences to prove.Thanks for any help teddy. Quote
dajogejr Posted January 4, 2008 Report Posted January 4, 2008 No way in hell you'd need a fuel pump, etc. for stockers, bored or otherwise...unless you converted them over to alky and drove a long time WOT. There is an interesting post here about boring them past 27.5mm (stock is 26mm) and it not idling correctly...however, I've seen plenty bored to 28mm without issues. In my opinion, dump the stock carbs, pickup some 28 or 30mm PWK Keihin carbs, just a much better design... OH yeah, and Welcome to the HQ. Quote
teddyurb Posted January 4, 2008 Author Report Posted January 4, 2008 No way in hell you'd need a fuel pump, etc. for stockers, bored or otherwise...unless you converted them over to alky and drove a long time WOT. There is an interesting post here about boring them past 27.5mm (stock is 26mm) and it not idling correctly...however, I've seen plenty bored to 28mm without issues. In my opinion, dump the stock carbs, pickup some 28 or 30mm PWK Keihin carbs, just a much better design... OH yeah, and Welcome to the HQ. \ Ok you say the stock diameter is 26 mm??I just checked the size on these mikunis,im getting 28 mm and they dont look like theyve been bored out yet either,Im puzzled now.So does this mean i can bore them over to 30 mm??I know that you have to leave a lil bit of material for the slides to shut off when its idling.Thanks again man,and ill probaly stick with these mikunis for now tho,moneys tight christmas shopping killed me. Quote
dajogejr Posted January 4, 2008 Report Posted January 4, 2008 Stocks are 26mm. Perhaps they're bored already...can you post a pic? Quote
teddyurb Posted January 4, 2008 Author Report Posted January 4, 2008 will post one when i get home,i know manufactuers only sell carbs in even mm sizes but like i said im a machinsist don this stuff for daily its my job lol,and well if they r bored over they ,did a damn good job on the finish.Theres is a miss match owever in the 28 mm part that meets up with the slides that imma clean up and polish the hell outta.Thanks man Quote
dajogejr Posted January 4, 2008 Report Posted January 4, 2008 Don't polish it too much, you want a bit of a rough texture for the fuel and air to atomize better...that's why you don't see shiny smooth intakes or ports on motors... Quote
White06Shee Posted January 5, 2008 Report Posted January 5, 2008 ^^ What He Said, I Also Have My 34mm Pj's Line Bored To 35.5mm And I Dont Have A Problem, Now When You Bore Them DO NOT BORE All The Way The You Slide, If You Do You Will Have Air Leakage Around the Slide, So Stop Boering As Close As You Can To The Slide :biggrin: Quote
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