Moderator Cynic Posted April 11, 2014 Moderator Share Posted April 11, 2014 The only measurement that could scupper that plan is the deck to gudgeon pin (piston wrist pin) difference. The longer stroke will bring the piston down further which could mean the pin is lower in the piston body to give crank clearance or there is an extra 2or 3 mm of meat in the piston crown to cope with the bigger bang? Needs confirming early? Link to comment Share on other sites More sharing options...
rossonza Posted April 11, 2014 Author Share Posted April 11, 2014 Is this the sort of thing id be able to test without replacing the wrist pin? aka splitting the crank, Or would i be best just buying a 426 crank? Link to comment Share on other sites More sharing options...
dt502001 Posted April 11, 2014 Share Posted April 11, 2014 Cynic the stroke is the same on the 426 and 400 so if they moved the wrist pin location the differenc in clearence would have to be in the cylinder height, you cant move the pistion higher with the same stroke with out moving the head up,or shaving more off a piston that is allready so small in skirt that is almost unfeasable to think of doing. but it could have a larger wrist pin,hence the need for a 426 conecting rod but if they increased the crank pin size as well then you will need the crank as well. You need to finnish researching this and find all the measurements. A new cylinder is not that much more than recoating a old used one,it's the head that is expencive new,so the easy way to fix this is get a good head,rebuild you crank ( best way then the crank is new) and a new 400 barrel and pistion rings ect... or dig through the net on parts suppliers till you find the measurements of all the parts. A used crank is real only good for rebuilding as the bearing should be replaced anyway,these motors dont make for good used parts other than castings. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted April 11, 2014 Moderator Share Posted April 11, 2014 Just thinking that even though the stroke is the same, if the points at the limit of the stroke are in different places between the 400 and the 426 on the 2 cranks, if you know what I mean. They both travel the same distance but start at different points, relative to the crank centre line. Say (I don't know the proper numbers) the 400 decks at 100mm from the crank centre line and the 426 is 110. Did it make better sense this time? Link to comment Share on other sites More sharing options...
rossonza Posted April 11, 2014 Author Share Posted April 11, 2014 I think ive found a solution (im collecting a running wr400 engine tomorrow). Strip down and fix up will be on the cards. However I may keep an eye out for a 426 still. Link to comment Share on other sites More sharing options...
rossonza Posted April 12, 2014 Author Share Posted April 12, 2014 Well im now a step closer to a useable bike. Wr400 engine. Working. Think intakes been ported. Need to check it out fully Link to comment Share on other sites More sharing options...
Moderator Cynic Posted April 12, 2014 Moderator Share Posted April 12, 2014 yea, need to know why that head looks new? Link to comment Share on other sites More sharing options...
rossonza Posted April 12, 2014 Author Share Posted April 12, 2014 Dont worry it doesnt. Its just a good picture. Its in the same shape as the rest of the engine. Link to comment Share on other sites More sharing options...
welshwan Posted April 12, 2014 Share Posted April 12, 2014 now you're cooking on gas! Link to comment Share on other sites More sharing options...
rossonza Posted April 13, 2014 Author Share Posted April 13, 2014 Looks like wednesday ive got the day off so ill be hopefully getting the engine checked then put in and started. Reminds me I need a jerry can. Link to comment Share on other sites More sharing options...
dt502001 Posted April 13, 2014 Share Posted April 13, 2014 Never seen a gas station refuse to fill a gas tank on or off the bike. Like I said before the main reason these motors blow up is because the valves and springs dont get changed, So don't rush it pull the valves and check them bet they are streched and the springs are bent.The local yam dealer changes the springs valves and keepers every 10hrs on thier race bike,and after talking with Gord he told me he has seen as much as .010" strech after 1 weekend of racing on factory valves and spring that were bent .030" The full service interval on these bikes is every 1000kms (600 miles) and all the service is in the head or re plating the cylinder the rest of the motor is almost bulit proof.You dont have to change the springs evertime but if you test them for pressure you find they get weak fast and dont sit square.the other thing to check very carefully is the keeper area of the valve,the keepers will cut the shite out of the valve and eventualy break the top of the valve off and then the valve drops into the cylinder. Honestly its cheaper to throw them away and start with new,aftermarket stronger valves. The heads always look a bit better than the barrel on these motors,Yam must have used better ali when making them,that and they spend alot of time in a parts washer during service. Link to comment Share on other sites More sharing options...
rossonza Posted April 13, 2014 Author Share Posted April 13, 2014 Got a link to the better valves?? And springs? May aswell why shes in bits. Cheers Ross Link to comment Share on other sites More sharing options...
dt502001 Posted April 13, 2014 Share Posted April 13, 2014 Try these guys but I dont think they have a listing for your bike so you will have to contact them directly no doubt.http://www.delwestengineering.com/parts_titanium_valves.html If not at least replace them with new stock. Link to comment Share on other sites More sharing options...
rossonza Posted April 13, 2014 Author Share Posted April 13, 2014 Will do. Thank you for the recommendation. Didnt think about taking the tank to get fuel haha. Then again I havnt checked it holds liquid yet. Ive downloaded the engine manual so it should have valve lengths.and tolerances yes??? Looking maybe fitting the yzf450 cams that came with the original engine too. Any input on that? Thanks Ross Link to comment Share on other sites More sharing options...
rossonza Posted April 13, 2014 Author Share Posted April 13, 2014 Also lapping the valves. Any input? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted April 13, 2014 Moderator Share Posted April 13, 2014 Never seen a gas station refuse to fill a gas tank on or off the bike. Ah but your side of the water your not lumberd with namby pamby jobsworths that treat the public as idiots. Link to comment Share on other sites More sharing options...
welshwan Posted April 13, 2014 Share Posted April 13, 2014 Ah but your side of the water your not lumberd with namby pamby jobsworths that treat the public as idiots. Yeah!!! They wont even let you smoke at the petrol stations here Link to comment Share on other sites More sharing options...
dt502001 Posted April 13, 2014 Share Posted April 13, 2014 Ah but your side of the water your not lumberd with namby pamby jobsworths that treat the public as idiots. LOL as I just pointed out to lasso never get a scott or newfie to write anything down and expect anyone elst to understand what it means,,, lmao lumbard =labomobity + namby pamby= still on his mom tit? not even sure what jobsworth means but guessing not much good for anything LOL. I know you not a scott cynic but it get just aboiut as confusing at times LOL I defiy anyone to refuse to fill a gas tank that is certified for transfering fuel,,even when in the USA they guy at the fuel center for race fuel "not fo public sale or road use" laughed when we took the gas tanks off and had them filled,,had we pulled up on the bike he could have refused us be laughed when we showed up with just the tanks from the bike's,, AND said " well that one way around the law" Link to comment Share on other sites More sharing options...
Moderator Cynic Posted April 13, 2014 Moderator Share Posted April 13, 2014 Ha , not over here DT, only approved portable fuel containers. Some wont even accept military jerry cans. I have been refused with them in my Land rover before. What gave away that I wasn't a scot Link to comment Share on other sites More sharing options...
dt502001 Posted April 13, 2014 Share Posted April 13, 2014 Thats stupid,,so if it's attached to the bike you can fill it but if you take it off you cant what a BS rule.I would stand there and argue that point. Tell the dip shit that my bike ran out of gas and I need gas now stupid. Sorry we are jacking this thread lets get back to hearing how this 400 comes along Link to comment Share on other sites More sharing options...
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