one cylinder ported two not?

  • Thread starter Thread starter zehrbrox
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zehrbrox

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bought my sled and was told it was rebuilt, it wasn't. so i had to buy pistons rings and two used jugs not realizing the one good one was ported. by the time i got my parts the trails were long open so i didn't bother porting the other two. the sled runs great but i'am hurting the engine or just losing some power? i was told it would be unbalenced put it doesn't hesitate or vibrate and runs good will i be fine or should i do something? thanks
 
Your forcing one cylinder to work harder than the other which can cause top end failure. Porting wouldnt cause the engine to feel out of balance though, so you most likely wont notice anything until the engine fails.
 
you can get away with it for a while but i would watch the plugs as the increased flow may result in it running lean.

I would highly recommend replacing that cylinder or porting the other two.
 
i have about 1000 kms on it so far and the plugs are all brown the middle might be a little lighter but not bad do you think i will be able to creap by for the rest of the season?
 
It will probably make it but unfurtunetly no one really knows i would just keep the RPM's down and not peg it all the time and it will probably make it. I had a similar problem with my sled when i couldn't get another jug i ran one 20 over and the other std, then right before the next season tore down the top end again and put them both 20 over for piece of mind and it ran great with two seperate sizes. However that doesn't mean it will last a long time.
 
hate to tell you but thats comin practice, to run different bores on rebuilds see it all the time, on twins,trips,fours,even one cyl over on V6 2strok/4strok factory says its ok dont know about porting though usually when you do porting it robs from one end and gains on other so that cylinder would be lacking on bottom and giving on top or vise versa (port timing) not clean up.
 
no1chevyboy said:
hate to tell you but thats comin practice, to run different bores on rebuilds see it all the time, on twins,trips,fours,even one cyl over on V6 2strok/4strok factory says its ok dont know about porting though usually when you do porting it robs from one end and gains on other so that cylinder would be lacking on bottom and giving on top or vise versa (port timing) not clean up.
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Different bores are very common, however different porting is not so common unless by design. I have seen them run a long time that way, but have also seen them have problems (usually weird ones like harmonic issues). If you want to take the gamble I think the risk is low for causing damage, it is there nonetheless.
 
well it got to me and i tore the motor apart tonight i'am going to port the other two and put it together i will rejet one size bigger this should be good? also what jug gets the richer jet the mag side or clutch?
 
jetting depends on the year you go with, everybody says go w/ the '01 jetting- PTO being richer, look in tech section under stock specs. running different bores is fine, but, you should always match the weight of the pistons being used.
 
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