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Discussion Starter · #1 ·
Hi,

I am going to take the ole raptor apart to check out some noises I have going on.
Whilst it apart I am thinking of some more upgrades. Sick of the 450's leaving me eating sand.
What's next for power, it is stock, except i have a rs3 full yoshi exhaust, k&n with adapter, no lid and a dynojet kit.
I use it in the dunes and trail riding, was thinking of the 11:1 with a stage 2 hotcam. What do you guys suggest and why ?
What are the differences between the bore size pistons 2 mm over 1 mm over .40 .60 over, what does this mean and why how much difference between these really?
If you just buy the standard bore piston are new sleeves and honing required for this and the ones that say over, I take it the ones that say over are requiring a rebore and sleeve
What else do I need to buy to complete the setup and installation ... cheers
 

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pewterpecker said:
A 102mm 11:1 piston, stage two hotcam, maybe some porting, and the mods you already have would be an excellent combination with great bang for the buck.
Agreed, except for the 102 part, bore the cylinder so it's straight and leave the material for boring it a later time. There's 100.5 and 101 pistons available.
There's a lot of options available, all depends on how deep your pockets are.
 

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Discussion Starter · #4 ·
The price differences are really nothing depending on the size, are the over size ones going to be better performance and if so will i need to change anything except for the boring itself ? thanks
 

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You will gain a small amount of power with the larger pistons. Most of the power comes from the increase in compression. Besides boring and honing the cylinder you will need to rejet. But while you have the motor apart you might as well do a cam, and have the head ported along with some stainless valves.
 

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Discussion Starter · #6 ·
Re: educated mods - piston configs - please assist

ok guys so who can suggest a build for me, what great mid range and want to beat the standard 450's..
I have a full exhaust/k&n/jetted...
From reading I am thinking of the 686 now, stage 1 cam kit will give me more mid range right ?
I want to get away with this without spending too much $$, only ride it for 6-8hours every two weeks...
any suggestions ?
 

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The stg1 is a cheaper upgrade but personaly I'd wait till I had the motor open to inspect the valves, they may be done. At which point if you need new valves would you opt for the stg2?
Also I'd build a 673 rather than the 686, you can bore it a second time with out replacing the sleeve or modding the case's for the 105 piston.
The stg1 is intended for low/mid range gains, that and an 11:1 would give you what your looking for.
When you open it up I'd look closly at the wristpin and rod end, if the pin has gauling it may be time for a rod.
 

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Discussion Starter · #8 ·
cool, 11:1 sounds like a good option then by the sounds of it...
If the valves need replacing what would be the best cam a stage 1 or stage 2 now that the mods I have made it goes hard, but with the dynojet needle it takes a bit to get it up to top speed, longer taper needle (instead of the stock which was a quick taper then light taper after 30% of the needle) would the stage 1 get it up to top faster..... and what power advantage would the stage 2 supply in comparision...
cheers thanks for any help, I owe my power to all you guys so far :grin_nod::thumbsup:
 
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