???stock modified or replacement crank

[quad1rider]

Ok this is my question for you pro's!!!
In the 50 limited ....08 DRR LC

1. In keeping the cc's under 50 who has a crank that would replace the stock one without going over as the stroke cant seem to change or it goes over 50cc's..????

2. Would it be better to have the stock crank welded up to become a stuff and if so does it stay within the 50cc limits???

I was told that changing anything with the crank would put it over the 50cc limits as just the high comp head and clean up porting puts it at a 49.6 - 49.9

[dirttrack86]

Porting or cutting on the head or jug makes absolutely no change to displacement cc's. I have a real nice chevy small block crank I can sell you. The rules say under 50 cc's but it says nothing about cubic inches. LOL:) :) :D :)

[ecmini1]

Replace it dont fix it a good aftermarket crank is only about 100.00 bones and you wont have the fear of the repair comming apart on you.

[quad1rider]

This is correct about the porting work but a stuffer vs a replacment is the true question I suppose. what replacement keeps it in the 50cc limits...

[dirttrack86]

39.2.:)

[quad1rider]

ok 39.2 shaft but does it make any difference using the same size crank as the stock without going over 50cc


I'll tell you I did ever math problem i could think of and they all come out over 50cc with any mods... so what's the legal answer can anything be done that would allow this change ,,,I think NOT>> anyone disagree if so then what's the answer...

[dirttrack86]

LOL, sorry you lost me on that one. :) Just call any of the posters mentioned on this board. They will get you the right one. But I still have this chevy crank if you need it, Titanium, lightned, polished, balanced, nitro-methane inpregnated, ready to go. LOL.:) :p :)

[riding4fun]

Not sure if I am right but stuffer cranks dont increase CC's they increase compression. Thats the way I understand it.

Stroker cranks increase CC's.

[tireman43]

Don't waste the time or money with a stuffer crank. Been there done that and it seems to take away the bottom end. A stuffer does not increase CC's as stated, it basically takes up the space in your crank case so the fuel is forced to the top of the cylinder to be burned. If you need a crank for some reason, go with stock. They work as well as anything advertised. I can't tell you much more with the 50cc stuff as I have just decided to run a stock L/C motor and do cluthing and jetting.

[hotquads1]

quad1rider,
I think you must be referring to the 40mm cranks that are offered by some venders, these will be an increase in stroke therefore increasing cc's, but as dirtrack mentioned the stock crank is 39.2 mm and can be replaced by a stuffer that is 39.2mm and it will be the same cc as stock. Just make sure you purchase it from someone who knows the difference in the 2 cranks . don't expect too much gain from this mod are you might be disappointed.
marc

[quad1rider]

so your saying its like piz...n in an overflowing john....That's what I have been told so I should what til next year when it becomes the new 70cc and redo the think right...


Thanks all for the help here... I will keep the stock crank and as for modification forget that ...I have enough stuff falling apart from the why my son races ...

thanks marc and gary,