how many hp might i have

weldman

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Feb 24, 2017
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Ivee worked the transfer ports and intake put the boysen ports in and polished the exhuast port had the head decked and worked out and I'm 60 over on rings. How many horsepower should that have given me. The thing runs pretty good
 
So if I don't want to go big bore or stroker what can I do to get more out of the. Im not talking about gearing. Just motor. Iv got a bigger carb and fmf fatty pipe power core 2 silincer the pipe is already on it. But iv had to make intake from scratch to fit carb. All aluminum at work. Let me know
 
It's pointless fitting a larger carb if you are using a FMF Fatty, they perform best with the stock 26mm carb.

Raising the exhaust port 1mm will give you a good increase of power..

Just decking the head will not give as much power as a rechambered head will do.

Have you re jetted the carb for the FMF pipe?
 
We recut the slope on the head after decking it and I haven't re jetted carb it dosnt feel like it needs it. I havnt even had the carb apart to see what's in it yet. What's stock jet size. I appreciate the advise
 
We recut the slope on the head after decking it and I haven't re jetted carb it dosnt feel like it needs it. I havnt even had the carb apart to see what's in it yet. What's stock jet size. I appreciate the advise

Like Blaaster says, no need for a bigger carb until you make big rpm or displacement.
Likewise, the stock rubber intake tube is a very good design, well tuned. Just open the lid up a bit.
Here is how I fitted my 39mm KTM carb to the Blaster airbox, 2nd version:
577964_10150946178720803_1550763841_n.jpg

With this improved version, its length favours the midrange.
The angled entry to the airbox gives broader rpm range than the first straight entry I had.
Still, the stock Blaster carb and airbox intake work very well up to 35hp.
16473274_10154819055705803_7984596895213223637_n.jpg

Yes, that is snow and that is a Blaster inside a minivan. Try that with a Banshee/Raptor/450!

Even with the slope of the head cut to match the dome, the chamber is a poor shape.
423064_10150704345095803_1097655040_n.jpg

This drawing might give you some ideas of a good chamber design, and here is a photo comparison:
427174_10151168912820803_1690350583_n.jpg


You've got a pipe, good! Maybe good for 2-3hp more, 19-20hp, maybe.
The next step is a better cylinder head, it will allow everything else, compression and porting.
Raise the exhaust port 1mm and widen it 2mm, bring the piston to head squish to 1mm.
Leak test and then do some plug chops to get the jetting perfect, expect 25-32hp.

I've run lighter and heavier flywheels on my motorcycles and cars over the years.
There is a place for them, but I thing the average rider will do well with stock.
Lighter flywheels disrupt smooth idle and smooth take off. More of a drag racing mod.