dune rider

[jjfizzle51]

hey i mostly hill shoot at the dunes some bowl riding but would a noss machine cool head give me a noticable power gain and i am running 40:1 currently would 60:1 actually give me a power gain thanks

[lincster]

Any head that you can get change domes in will give you more power.

What you have to be careful with is how much compression you go to before you gotta do other stuff.

Like going from a stock head to a head with 17cc domes in it.... I would recommend running 100% race gas and getting your crank welded.

There are lots of things you have to think about if you want your bike to last very long when you start changing stuff.

 

I don't see how changing oil/gas ratios will give you more power, it will just give you less lubrication...... not good.

[racer]

I don't see how changing oil/gas ratios will give you more power, it will just give you less lubrication......  not good.

346370[/snapback]

i concur, unless you particular oil calls for the 60:1 ratio. that isnt too far fetched either since some guys run up to 100:1 with the proper synthetics.

[jjfizzle51]

what size dome can you run normal pump gas

[Hunt4BigGame]

what size dome can you run normal pump gas

346510[/snapback]

 

It all depends on the elevation you will be riding at. I run 19cc domes and 50/50 race/pump gas at 2500 feet with 5 degrees timing advance, and premium pump gas at the St. Anthony dunes (5000 feet). You may not need a 50/50 mix with stock timing and 19cc domes around the SLC area or higher....

 

You will notice a power gain with 19 or 20 cc domes...especially in the mid-range.

 

My stock compression was 105 pounds and with the 19 cc domes it jumped up to 155 pounds....just to give you an idea.

[XxMeltIcexX]

what size dome can you run normal pump gas

346510[/snapback]

 

20 cc is like the max for pump gas, then you should go race fuel for 19 cc down

 

Eric

[05bansh]

Dave Noss recommended running a 50/50 mix with 19cc domes here in slc. I was running a 50/50 mix with the 19cc domes even before I advanced my timing. I look at it like its better to be safe than sorry. You should be safe with 20cc domes and premuim pump gas, but why would you want the 20's why you can have the 19's! 50/50 mix isnt that much more $$.

[Ducman]

Smaller domes are not really going to give you a lot more noticeable top end power, but it will give you a lot more low/mid torque which will often keep you from boging in a certain gear, basically let you pull a gear in a lower RPM which is very useful in hillclibs like if your spinning the tires and suddenly catch traction and loose a bunch or rpm's. Keeps you from feathering the clutch as often to get RPMs back up. Also gives more lugging power for cruising around in sand and not having to use as much throttle or as high of RPM's.

 

Changing the oil ratio doesn't add any power if you are mixing at the oil manufacturers recommended ratio. If you are mixing it way to oil rich then you'll foul plugs, way to lean and you'll burn rings or seaze a bearing. If you change from say 20:1 to 40:1 the percent difference in fuel is only 2.5%, thats only about 2/3 of a main size if you were going from say 280 to 290's (which would be a difference of 3.5%).

[sand rocket]

Sent you a PM. Utah dune rider here too.