Crankshaft: what should i do?

[Rollscanardly]

ok some of you may have seen my other post that started with carb problems, and ended in my cylinder destroyed somehow
http://www.exriders.com/vbb/showthread.php?s=&threadid=311700

when i did the rebuild i used a new hot rods crank, and honestly im not sure if that was my problem or if there was a problem with the bore, but i need to fix it, and my hotrods crank is in bad shape (ill post some pics later). I managed to pick up a stock bore, non-ported cylinder on ebay for 60$ but now i need a crank =( Im not a rich man but i dont wanna split these f'ing cases anymore after this for a while so where should i get a crank that will be good for sure?

Hunter

[Aceman]

Seems there's really only one answer to your question, an OEM from
www.servicehonda.com

[86 Quad R]

as mentioned, i'd get a new crank from service honda or other OEM parts retailer. of course the only crank that is avail now is the 87-89 long rod. so you'll need to run the 87-89 piston. go ahead and get the cylinder ported by neil or other reputable builder. you'll be glad ya did. good luck with the build. :cool:

[Rollscanardly]

The cylinder i bought i believe is from an 85-86 atc...so that means if i get the 89 crank ill need to run a spacer plate, and and the 89 piston? also how much would a cylinder port from Neil cost?

thx Hunter

[86 Quad R]

nahhhh. you can run the 85-86 cylinder with the 87-89 piston and crank with no problems and you wont need a spacer plate. the spacer plate is needed when ya run the 85-86 piston with the 87-89 crank.

as for the $$$ amount for porting.... you'll have to discuss that with him. :cool:

[racerx573]

I recommend going with the spacer plate set up. World of difference in the type of power delivery. Depending on your application..

[Aceman]

Neil was a month out when I spoke to him a week ago, unfortunately I can't wait that long so I'll have to send him mine at a later date.

[Rollscanardly]

what would be the power delivery difference between the engine with the spacer, and the one without...to use a spacer plate i have to have and 86 piston, correct? also....isnt an advantage of using an 86 piston the fact that you can get more, bigger sizes than the 87-89? Service honda told me my new crank would be here middle of next week =D

Thanks Hunter

[beerock]

the difference between the spacer plate and no spacer plate .

no spacer plate: 88 rod 87-89 piston
A real snappy power band that is very responsive, easy to get on the pipe(powerband) even if you are lugging a bit. this setup has more low to midrange and a good amount of top end the only way to add more volume to the crank case is to add a reed spacer and it will give you a little more top end

spacer plate:88 rod 86 piston
A very broad powerband with a little less snap then no spacer plate. A little harder to keep on the power band if lugging it.this setup has a fair low end equally powerful mid range as no spacer, more 3/4 throttle power and a top end that revs out higher then no spacer


now, you would think, damn may as well do a spacer plate setup. 2 draw backs

1. the 88rod 88 piston setup is better for xc

2. it will last 2-3 times as long as a spacer plate setup.


why is it better for xc? the snappiness


why will it last longer? honda redesigned the rod and wrist pin height because of piston skirts breaking on the 86 style.

Anyone that has owned a spacer plate setup has heard or has had the skirt break on there motor. so you need to keep an eye on the hours and piston replacement is more frequent, along with bore/hone jobs and you get closer to the sleeve life dying and needing to be replace sooner.


granted, if you buy a new piston then bore and hone the cylinder after 40-60 hours youll be fine for at least 250-350 hours of crank life. with an 88 setup no spacer, you can get 200+ hours without worrying about the piston skirt breaking(which wreaks havoc on the crank). Ive done it and the piston still looked new. of course the compression was low but it still ripped.

If you dont know how many hours are on the crank its always best to start fresh AND OEM

the hot rods are known for either blowing up right away or lasting for a long time. TO MUCH RISK fo me!!