OZ ATV :: The Australian ATV Forum

[1sick6]

Hey Im just after some input on porting,
I bought a old 1982 YZ100 and it came with a spare parts engine, I noticed some 1 had drilled 2x 6mm holes on the intake side of the barrles and they lead straight down to the crankcase.

• By doing this what sort of power grains could be expected?
  
  
• Would it be top end power with a noticable loss of bottom end?
  

Cheetah cubs use simular intake port holes.

any info on this would be great thank you, Paul







Stock Banshee intake ports


421 cub intake ports

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He Who Dies With The Most Toys, Wins

[HaggLE]

They call them boost ports however those the smallest and probably the most useless ones I've seen, we did those on a cr85 for road racing and you need them at about little finger size at an ane where they barely turn a corner and a chamfered entrance

[1sick6]

It seems every 1 out there has different names and opinions on the with people giving different answers Some people also call them worm holes
Some people are saying they are for drag racing where top end power is needed, others are thinking the opposite saying they are for boosting bottom end power. 1 dude even said they smooth out the power curve claiming better all round power delivery.


So I don't know what to belive

Only 1 way to really find out what they do is to try it for myself.


Cheers, Paul
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He Who Dies With The Most Toys, Wins