30years Posted December 26, 2012 Report Share Posted December 26, 2012 So I have never rebuilt a four stroke before, strictly two strokes. I have the motor out and cases split. What I don''t know is if the stock crank is rebuildable or not? I had connecting rod failure before I had the chance to have the oil mod done, by the way I have an early 04 model. I thought about buying a +4 stroke crank but don't know what is involved, what is needed? Run thicker base gasket? Stock piston? Any help and knowledge would be greatly appreciated. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Ctown208 Posted December 26, 2012 Report Share Posted December 26, 2012 Imo put a wr crank in it a 98mm athena cylinder.. With a good cp piston.. There's a YouTube video on splitting the cases.. Put it back together with the cam, i the mod position.. Buy yourself a fci intake and a good exhaust and it will rip. Now if your gonna drag that thing there's a few other odds and ends to do Quote Link to comment Share on other sites More sharing options...
Ctown208 Posted December 26, 2012 Report Share Posted December 26, 2012 Stock crank is heavy and you can replace it for cheap.. Quote Link to comment Share on other sites More sharing options...
Ryder25 Posted December 27, 2012 Report Share Posted December 27, 2012 do not rebuild a crank. it's pretty much just as cheap to go with a stock crank (try servicehonda.com, they are easily the most reputable parts dealer that sells oem cheap if you don't want to check other online sites). if you don't plan on building this motor for big power, then it is much much cheaper to go with 06+ crank (drops right in and is +1.4mm stroke), stock piston, decent full exhaust and "cam mod" (which you can look up on google and it will give you easy instructions to do). the WR crank is a nice crank but if you're going for big power then the piston selections are horrid. There are benefits to the crank (lighter, smaller wrist pin, "better" rod length/angle, slightly higher compression compared to 06+, ect), but you have to run a dirtbike piston and if you're custom building a motor it's hard to get good pistons other than shelf yz450f aftermarket pistons. Quote Link to comment Share on other sites More sharing options...
Ctown208 Posted December 27, 2012 Report Share Posted December 27, 2012 do not rebuild a crank. it's pretty much just as cheap to go with a stock crank (try servicehonda.com, they are easily the most reputable parts dealer that sells oem cheap if you don't want to check other online sites). if you don't plan on building this motor for big power, then it is much much cheaper to go with 06+ crank (drops right in and is +1.4mm stroke), stock piston, decent full exhaust and "cam mod" (which you can look up on google and it will give you easy instructions to do). the WR crank is a nice crank but if you're going for big power then the piston selections are horrid. There are benefits to the crank (lighter, smaller wrist pin, "better" rod length/angle, slightly higher compression compared to 06+, ect), but you have to run a dirtbike piston and if you're custom building a motor it's hard to get good pistons other than shelf yz450f aftermarket pistons. Tons of people making pistons for a wr crank now days, honestly there's only a few good ones though, but there available In lots of bore sizes.. Wr crank rapps out so much faster.. 18mil wrist pin gives you more strength in the piston skirt to.. Unless the op is hard core it probably doesn't mater what he chooses.. I guess we should ask what his intentions are with this quad Quote Link to comment Share on other sites More sharing options...
Ctown208 Posted December 27, 2012 Report Share Posted December 27, 2012 If you need yfz parts pm me i have a garage full. Also a complete 07 motor with a ported head.. Low hours. No oil mod needed for it. Quote Link to comment Share on other sites More sharing options...
30years Posted December 28, 2012 Author Report Share Posted December 28, 2012 What I wanted to do is keep it mostly stock, but everyone wants more power. Right? I have a 10 mil cub for drag. I would drag the yfz at the local track for fun, but I'm not trying to go all out, full drag setup with it, I also want a reliable, get on it and go type of trail/play quad. So, with that said. ? Quote Link to comment Share on other sites More sharing options...
BB3 Posted December 28, 2012 Report Share Posted December 28, 2012 The 06 crank is a good strong crank too, and as Ctown said if ya can swing a 98mm cylinder i would go that route and get ya a lil more power out of it. The 480cc setup 98mm cylinder and decent piston "Diamond or CP" piston would be my choice....Diamond first choice then get a 06 crank there cheap and still hold up very well. the +4 hotrod crank would need to be balanced to your setup to be 100% correct and true, so if ya can i would stray away from that setup unless u wanna put some $$ into the crank and if thats the case might as well get a Real crank for that money. This is just my option though.....it all depends on how much ya wanna dump in it.....but....either way if you just get a crank get the 06 crank and a new piston and call it a day if the cylinder is still in good shape. Quote Link to comment Share on other sites More sharing options...
Ryder25 Posted December 28, 2012 Report Share Posted December 28, 2012 Both cranks will be reliable and good for trail/play, and neither require spacer plates or thicker gaskets. Some guys will say you'll have trouble in tight trails with the WR crank because it's lighter (stalls easier), but that's not really as big a deal as they'll lead you to believe. CP is a great piston for YFZ's. I'd just get whatever crank you can get easier. The stock 06+ crank will be the cheaper route unless you can find someone selling a WR crank on another forum. I've never personally ran big bores, but if you do get a big bore, make sure you get a CP (or w/e you want) piston instead of the ones that come with the kits. Quote Link to comment Share on other sites More sharing options...
BB3 Posted December 28, 2012 Report Share Posted December 28, 2012 ya i agree the pistons are usually junk that comes with the BB kits, and ya some say the wr will stall...i havent had one stall on me yet but then again its pin it to win it....lol Quote Link to comment Share on other sites More sharing options...
30years Posted December 28, 2012 Author Report Share Posted December 28, 2012 So, does the 06 crank make it a true 450 without any other mods? I can just throw the 06 crank in? Is it crank works that makes the WR crank? Quote Link to comment Share on other sites More sharing options...
30years Posted December 28, 2012 Author Report Share Posted December 28, 2012 Oh, when ur talking about the WR crank, ur talking about the dirt bike crank. Right? Can that crank just be thrown right in? I would just need a certain piston right? Does CP or diamond offer a stock bore piston, or my options limited to the dirt bike piston. And, does the WR crank have the longer stroke to make it the true 450 like the 06 crank? I wanna keep it on pump gas, but I want as much power as I can get for my money. I decided I shouldn't spend money on a whole new cylinder and whatever else I would end up buying before I was done, so I kinda set a budget for myself. I'm looking to just do the new crank and piston. My cylinder is surprisingly good shape, still showing cross hatching, so a good hone through that and I should be good. I thought about porting the head, and maybe aftermarket cams, but haven't priced that stuff yet. Quote Link to comment Share on other sites More sharing options...
Ryder25 Posted December 29, 2012 Report Share Posted December 29, 2012 the WR crank is the OEM one. Hot Rods makes one but you lose some of the benefits (weight mostly), best off getting either oem 06 yfz450 crank or oem wr450 crank (can't remember the year but I think I used the 04 one, just look it up on google and you'll find the right year). Both cranks will make it a true 450. For the WR crank, it's just drop in (as well as 06+), same bearings you had originally (you should buy new ones), same gaskets (also should buy new ones obviously). With the WR crank, you have to run yz450f bike pistons. CP makes bike pistons so you can run them. The compression will be slightly higher using the WR crank, slightly lower than with your 05 with the OEM 06+ crank (this is taking into account you buy the same compression ratio piston). If I remember right, any OEM 06+ crank will have .3 points less compression (ie: 12.5:1 piston will be 12.2:1 piston with 06+ crank) and I can't remember how much more compression the WR crank has but that you can also easily find. Don't waste your money on cams. The oem yfz cams are absolute rockstars (not like the trx). Quote Link to comment Share on other sites More sharing options...
30years Posted December 29, 2012 Author Report Share Posted December 29, 2012 Thanks so much for everyone's input. I'll be doing some more researching and maybe I might receive some more input from here before I start spending money. Quote Link to comment Share on other sites More sharing options...
BB3 Posted December 29, 2012 Report Share Posted December 29, 2012 Ryder25 is correct there are only a few diff. between a wr and 06....weight and pin dia. the 06 crank has a 20mm pin which makes it more interchangeable with different piston variations and the wr is a 18mm pin which there limited options with them unless its a custom piston. Not to take away from BHQ, but Yfztech.com is a good place to look stuff up too. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.