Clownboy Posted April 12, 2015 Report Share Posted April 12, 2015 Ive been building a YFZSHEE for the past year now and im having some issues mainly due to lack of knowledge on engine mods and such. I am trying to make the bike suitable for MX and riding timber trails. When i built the Hybrid i fabricated the stock YFZ chassis to fit around my Vito's pipes. The main issue im having here is my motor is only bored over 1.5mm from stock making it 65.5mm Ive been told that is not enough bore for the Vito's Pipes. Second issue, IT WAS ALOT OF WORK days and weeks metal working to make the pipes and motor fit without a cobbled look, Basically re-engineered the entire front end of the frame. So long story short no other pipes except the Vito's will fit the contour of the custom frame so im pretty much stuck with those pipes unless i make my own from scratch or figure out a way to tune/gear the motor so it has mid range power instead of all top end. I just switched domes out from 22cc down to 21cc. Im running dual keihin pwk35 What needles would best suit application? Is pwk35mm to big? Should i be running higher octane fuel? What mix ratio? best quess at jetting pilot & main? Currently running +4 timing advanced on stator plate. Just installed OEM coil from china cheapy. Any suggestions on timing? Intake is a chariot billet dual setup. Carbs are to big for intake boots but the rubber will slip onto larger carbs just streched a bit and then hose clamped. Running a 2-1 airbox custom made boot from stainless tubing to a OFM alum YFZ 450 airbox no lid no outer wear. GOOD? yes? no? Last ride out i discovered the rear sprocket was -2 teeth gear ratio vs stock banshee ratio so i upped the rear sprocket from 38T to 42T Any comments? Advice? it did seem to help improve low end torgue a bit but i need a steady pull instead of power band snapping on violetly as i does on drag style rides in wide open fields. Im so damn close but so far away. he bike is kinda choppy all through the powerband so something is off yet? It acts like it wants to snap and then just kinda revs high and peters out a bit. Im trying everything i can before commiting to chopping a set of pipes up and making a dif set fit the modded chassis. ALSO would not having the drain or aire hoses on carbs for waste run off hooked up effect how it runs? And last problem on the list. My oversized 40mm alum radiator is spitting hot coolant out of the drain/gorund line after only running for a matter of 5 minutes. Any idea why? Im open for suggestions. I just wanna rip a huge wheelie and i cant get enough torque to pop one up. Power band wants to come on to late so it be nice to get that in a respectable range. I have a full service tool shop / metal fab ready so if alterations need be done its all gravy. Hopefully somebody has the magic answer and i can rip today otherwise looking like getting all bagged up wrenching again lol. Thanks in avance for your help & advice. Peace Clownboy ooot! PS click link in my sig to view pics Quote Link to comment Share on other sites More sharing options...
superfastyfz450driver Posted April 12, 2015 Report Share Posted April 12, 2015 Post pictures of your intake set up Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted April 14, 2015 Report Share Posted April 14, 2015 Whoever told you you need more bore for the Vito's Fat Bastards is a friggin moron and you should consider a thinning of your friends/acquaintances. A good ported stock cyl 4mil motor with a little compression and timing should motivate very well with those pipes. Maybe try some 35's What exactly is the full set up as of now? Gearing 14-38/39, or 15/40ish might make you happy Radiator spitting right away..... This could be the culprit of your issues. You may be eating coolant and pressurizing the system. Quote Link to comment Share on other sites More sharing options...
Clownboy Posted April 15, 2015 Author Report Share Posted April 15, 2015 Whoever told you you need more bore for the Vito's Fat Bastards is a friggin moron and you should consider a thinning of your friends/acquaintances. A good ported stock cyl 4mil motor with a little compression and timing should motivate very well with those pipes. Maybe try some 35's What exactly is the full set up as of now? Gearing 14-38/39, or 15/40ish might make you happy Radiator spitting right away..... This could be the culprit of your issues. You may be eating coolant and pressurizing the system. Thanks for the reply Tricked. Im glad to hear that those pipes will work out. Ive tried fitting up a few dif sets of various brands and they all swing way forward into the space that my radiator is now occupying. Also the vitos pipes just barely clear the A-arms where all the others did not. Ironically the people who i got the bad advice from was none other than Vito's Racing. He told me that i would need to either lengthen the pipes out from the head or after the fattest part of the pipe before the stingers. he said that my motor was not setup right for them and that id be needing to up the compression and possibly larger bore. He was kind of a dick on the phone too. Like i was annoying him or some shit. Current set up: 65.5mm bore Timing advanced +4 Chariot billet intake manifold V-force 4 reeds Keihin pwk 35mm duals 52 pilot 195 mains clip on middle position. Not 100% sure about the needles ( letters worn ) they need to be replaced dont know which ones i need? Vito's FB pipes and silencers. Gearing: Front sprocket is the stock banshee i believe its a 14 T Rear Sprocket is now 42T up from stock YFZ 38T And yes its spitting coolant right away. Ive had the coolhead off 4 times now for dif reasons. I think i may have torqued it wrong my first go round. Ive since replaced all the o-rings and used a smear of black rtv on the outer edge. Torqued to 20 ft/lbs in the proper sequence. One thing ive noticed about the Vito's pipes is they are smack on the head on both sides and they either are rubbing or melting the alum slightly. I can get some pics tomorrow. Starting to think i may aswell order a new coolhead and make some room next time for them damn pipes to breath. I checked the impeller for free spin and it seems tight. Radiator may be some of the issue. I had to use a brass 90 degree elbow with a smaller diameter flow hole than it had been. Im going to weld on a alum 90 and see if that helps. Ive also got a YFZ radiator fan that i thought about trying to wire in some how if all else fails. I take it if im sucking coolant it must be coming from the coolhead right? It does seem to be coming out quite violently when it starts spitting. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted April 15, 2015 Report Share Posted April 15, 2015 Pm BansheeHP for particulars on those pipes. Quote Link to comment Share on other sites More sharing options...
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