shimming sirio evo2 5 port engine
 

Need tips from you guys.....

I have been running the 5port evo2 for mths with a added .01mm copper shim during breakin till now but not teribbly impressed with the low end punch.

No match for a nova rs12s5 or ns12s5 in all rpm range.... sigh.

This guy seems to prefer temp round 120-125degC to stay competitive using nova short turbo #6 plug with stock centax clutch on a mtx2,3 on 16/20 vs 43/47 gears.

Should i remove that shim to gain more low end? Or remove the carb restrictor?

What other tuning variable can i play with to get more punch without putting a hole in my pocket?

Thks ......mav

try this
 

15/49 1st

Re: shimming sirio evo2 5 port engine
 

What % nitro are you using? Need to know to determine shim.
Ideal plug is Novarossi C7TGF or sirio S001720127
What pipe are you using???

AFM

Ok I think I will jump on that EVO2.Thanks for the advice.What about a head shim?I will be running 30%,and I think its a turbo plug.Do I need to do anything?

IGNITION TIMING FACTS

·You advance ignition with a hot plug, which will give you more torque or low speed
·You retard ignition with a cold plug, which will give you more rpm’s or top speed

The above is true in both cases if you have the same compression ratio (combustion chamber shimming), and use the same nitro % on fuel.

But if you change compression ratio (combustion chamber shimming, and or nitro %), you have to compromise.

·If you increment compression (smaller combustion chamber = less shims) you are advancing timing, thus incrementing torque, so you will need to put a colder plug to compensate for top end., and more generated heat, which could cause pre-ignition.
·If you reduce compression (bigger combustion chamber = more shims) you are retarding timing, thus incrementing top speed, so you will need to put a hotter plug to compensate for torque, and less generated heat.

The ideal combustion chamber for .12 engines at sea level is:

· For 16% nitro = .015 inch or 0.381 mm
· For 20% nitro = .016 inch or 0.410 mm
· For 25% nitro = .018 inch or 0.457 mm
· For 30% nitro = .021 inch or 0.533 mm

So you have to shim the engine accordingly to get those total combustion chamber sizes

AFM

evo 2 3p running temp
 

what is the best running temp for a evo2 3p for a long life?


cjones

hey guys, i need some help desperately with my new sirio kanai .21 buggy engine. it's still brand new, and its in my mbx5, and its near impossible to get it to turn over or even start. i've broken in lots of .12's and a few .21 onroads, but never a sirio or a .21buggy engine. it's getting fuel, and i'm using a heat gun on it, but my box'll turn it over like 2 times, then it'll seize up. then i have to take the engine out and turn the flywheel over with a wrench. then repeat. its sooo annoying. can someone help me get my engine started!?! its very frustrating. i'm runnin an the standard plug head, and an os a5 plug, with a os 2050 pipe if that makes a difference? thanks

I seen people write that when you tighten up the glow plug, lossen it by about half a turn. This is suppose to allow a little of the compression escape to make it easier to start. Once engine is started then tighten the glow plug. The heat gun helps too.

sirio crank
 

Hi,

Can some please post a picture or a link to a picture of a sirio 12 SG cranks shaft part no. S12 081200.

Here you go..

http://www.star-motor.com/accessorid...offset=8&Id=85


Mark

That's exactly what I thought. I ordered this crank from someone and the crank they sent me didn't have the scoup at the back of the crank as you can see in that picture.
Where can i get this crank from (besides trinity) that will post to australia?

Could somebody please point out for me the location of the different needles on the sirio carb. I just dont want to be mucking around with them and adjusting the wrong one! :) Also does anybody have any tips on adjusting the mid range needle? I've got the low and high ends down and want to start learning the mid range.

Cheers,

Doy

High speed needle (HSN) is located on top, where the fuel inlet is.
Low speed needle (LSN) is located in the end of the slide, where you attach your throttle linkage.
Idle speed needle (ISN) is located near the engine cylinder.

When tuning your Sirio carb DO NOT adjust the mid-range needle. This is set from the factory on a flow meter to help calibrate the other two needles and should not be touched unless you really really have a grasp on carburetor tuning. The mid-range needle can be found underneath the high-speed needle on the end of the carb opposite the low-speed needle.

Sirio .12 (General Base Carburetor Settings)
High Speed - 5.5 turns
Low Speed - 3-1/2 (Generally this should be flush with the end of the slide)
Mid Range - Flush then one turn out.

AFM

this weekend, i put around 12 tanks through my sirio at the track, runnin real rich, so i got around 17 tanks on the engine total, and this thing still grinds at TDC and it still seizes!! man, this thing is gonna take forever to break-in...i'm just surprised, i mean, ususally after 10 tanks through another engine, its broken in, but this sirio kanai is the tighest engine i've ever broken in, and it still isn't even!:weird: :lol:

sirio crank
 

Hi all,

Just to let everyone know the sirio crank part no. s12 081200 is for the non-turbo crank and part no. s12 081300 is the tubo crank.

On the sirio website it shows a picture of the turbo crank againt part no. s12 081200 (which has been pionted out to me).