Whats the best?

[trx400exrider14]

What is the best octane rating to run while using a 12:1 piston with a stage 2 hotcam?

[finsteratv]

anything above 11:1 with 93 octane needs race gas or e85

[trx400exrider14]

would 93 with octane booster be alright with 12:1 and a stage 2?

[Honda#4]

Octane Booster is a waste of money, I would try some 110 instead.

[trx400exrider14]

Where would i get 110?

[400man]

Originally posted by trx400exrider14
Where would i get 110?

try asking around at nearby gas stations to find out where it might be sold at.

[CJM]

Small airports will sell it to you sometimes, race tracks, motorcycle dealers, some gas stations (sunoco usually).

One of the main reasons I wont run over 11:1 comp ratio-93 octane is expensive enough, race fuel 110 or similar is like 7-10 bucks/gal.

[trx400exrider14]

Can i use 93 with 12:1?

[NacsMXer]

Originally posted by trx400exrider14
Can i use 93 with 12:1?

You would be pushing it, not recommended. What happens if you get a batch of bad gas...it could detonate and cause engine damage. I wouldn't want to be riding the edge like that all the time. High octane fuel is what prevents stuff like that from happening, and is your safety factor when running high compression or advanced timing.

Find yourself some 110 octane leaded. I have two local gas stations that sell it. One is a BP that sells Sunoco 110 and the other is a Phillips 66 that sells Phillips brand 110 racing fuel. Check around locally, you might have a station that sells it.

[trx400exrider14]

is 11:1 alright? i mean,i want to be really safe and still run 93,race gas is way to expensive

[CJM]

Originally posted by trx400exrider14
is 11:1 alright? i mean,i want to be really safe and still run 93,race gas is way to expensive

Trust me, its got plenty of power. Its no 450R but mine is quite quick.

To make a 400ex quick all you need is the following:
-11:1 comp ratio. Compression is power-not insane bore size.
-Stage 2 hotcam or similar:wakes up the power
-Decent exhaust
-Open the airbox up
-Use a KN or Uni or anything better than the stock filter.
-Thinner gaskets. The stock gaskets on the 400EX detune the engine b/c they are super thick, using an XR400 head gasket or a cometic multi-layered viton coated steel gasket helps a ton.

That will give you great gains. Want even more-put an 04-05 450r carb on it or a FCR39 carb from a yfz or whatever.

But in reality compressions power, thats why so many run a higher compression ratio. 12:1 sadly pushes past what pump gas can do, 11:1 is the highest you can go on 93 pump gas.

[trx400exrider14]

Gotta have that airbox on,i race in the woods,what else could i do with that?

[CJM]

Originally posted by trx400exrider14
Gotta have that airbox on,i race in the woods,what else could i do with that?
I ride in sand and woods, outwears lid works wonders. I have the EHS outerwears lid, you cut a hole in your lid and sandwich a metal plate and the outerwears material they supply with it.

My filter doesnt get dirty to much, the outwears filter is pretty water resistant and Im happy.

[trx400exrider14]

Do i have to worry about overheating with 11:1,stage 2,and 93 pump gas?

[Honda#4]

Do i have to worry about overheating with 11:1,stage 2,and 93 pump gas?

Not really

[trx400exrider14]

Is an Cometic High Performance Type Head Gasket be alright? or too thick?

[CJM]

Originally posted by trx400exrider14
Is an Cometic High Performance Type Head Gasket be alright? or too thick?

Should be fine, they are .027 thick iirc which is less than the stocker. I think the stocker is like .043.