What do you take from this?

[DeadLastRacing]

this was an answer from a poweroll employee. I asked them what to expect from the setup I plan to run. that you any of you take from this?

"Hello Dean,

That cam was made specifically for our 430cc bore/stroke combo. Without the extra displacement pushing it, you’ll have a very peaky powerband. Not much low end torque, but a nice midrange and up pull.

In all our testing, we never found a better headpipe than the stock Yamaha header – best setup is that with a better flowing (and lighter weight!) muffler such as the White Bros E Series, or Supertrapp IDS2 - both are tuneable, very important for a two valve head design.

We did some preliminary testing with the Quicksilver carbs, but found the Keihin FCR carbs to be much easier to fine tune. The two valve engine you’ve got usually responds best to a round slide, butterfly or CV style carb. Not so well to a pumper carb.

Thanks,
Pam F.
Powroll Motor Performance"


My initial response is......****, did I eff up my engine rebuild?

 

[jasonp]

all good info.
I wondered why you went with such a huge cam. I think it still will be ok. The engine will have a ton of mid and top end power. I think that makes the four wheeler fun to ride. I know I love my .450 cam over the .390. But it really depends on how you ride...
This is also why I wanted you to try and get the deck height as low as possible (with gaskets) to get the compression up to make up for that huge cam. It will help the bottom end power.
Carb, any carb over the stock one in design is better.

 

[DeadLastRacing]

Another follow up.......

"Hi Dean,

Lumpy low idle, flat flat response at low rpm (think two stroke), picks up in the midrange with a bit of clutch work, and runs like a scalded cat on top end.

The danger from this setup is that this engine makes its best power in the torque range, and there is no rev limiter. Usually engines set up this way will eventually drop a valve from too much rpm – since there’s no power anywhere else, they get the guts revved out of ‘em!

Thanks,

Pam F.
Powroll Motor Performance"


I thinking now I need to swith up my cam purchase.....any suggestions? Should I stick with this set up for now?

 

[91warrior]

yea when i did my build, i got the alba kit with the .450 cam and i was to scared to run it, being all the power would mostly be at the mid and top end and i do not like to rev the crap out of things, so i got the webcam #88 grind cam and still have a brand new .450 megacycle cam in the box.

but again i think its all on what you want. i love my set up, great torque, expecially at a little under half throttle, and just a very smooth power deliver. what kind of power band are you looking for?

 

[dswwarrior350]

4 years of over revs here and no dropped valves yet!

Your set-up will be fine