beebone

What kind of shim? And where should I put? T___T

rmdhawaii

iTrader: (4)

It's also called a head shim gasket. It goes on top of the piston sleeve between the top of the piston sleeve and the button head. It comes in different thickness. For Sirio engines, you can buy a "Sirio Head Shim Gasket Kit", which comes with several gaskets.

You adjust the amount of shims based on % nitro you are running to give a total "head clearance" between the piston and button head when piston is at the top of the compression stroke (refered to as "top dead center" or TDC).

This is a general guide based on head clearance:

16% Nitro .36mm - .40mm
20% Nitro .40mm - .50mm
25% Nitro .50mm - .60mm
30% Nitro .60mm - .65mm

Ballistik Mods

iTrader: (1)

hi mate im sydney australia dont no if this will help.alot of guys using sirio or sirio based engines have a similar prob of unstable idle after run in. after alot of testing i found nova carbs to work much better they r a straight fit.the settings are 4 turns out on bot 6 out on top.hope it helps if shims dont it worked 4 us

nikoskar

There is now problem with the idle after the run in guys.
Just use the same fuel every time and if you don't know how to tune it ask for your local distributor to fix it.Also you must check that your clutch settings are correct.

silverM3

iTrader: (1)

how you guys like the sirio xxxvk? how is it compared with novarossi 353 09 or .12 flash? thanks

Ballistik Mods

iTrader: (1)

There are issues with these engines eg ;runtime and base idle ive seen many drivers having these problems .simply telling someone to to run the same fuel everytime or take it to the distributor is not fixing his problem.but i agree you should run your engine in on the fuel you intend to use.my guess is the engine is not run in yet and the process should be restarted using a higher nitro content

Pattojnr

iTrader: (19)

the carb issue i had with the capricorn series of engine. what it is that you run it rich on run in, and compensate with the idle screw to keep it idling under rich conditions, but once you lean out the engine, the idle screw goes back out and then clearance on the slide is now achieved. it is the gap that creates the sticky slide. not had issues with the capricorn engine, so i now will rebuild it for future events.
most guys had runtime issues at moorebank at the nats. wasnt one particular engine that was better or worse. just who got time to sort it out.

Pattojnr

iTrader: (19)

i have just picked up a XXXV and upon dissasembly, i found that the piston to sleeve has no pinch left. now a conventional motor, the piston still has a way to go before coming out of the sleeve, and i take note of when a motor is worn that it reaches the top of the sleeve. so how do you know how much life is left in these motors where the piston on tdc is flush with the sleeve ? Cheers.

barg

iTrader: (6)

I check mine by having it fully assembled with Clutch or at least flywheel on.

Hold the engine by the flywheel at near to TDC and see if the compression can hold the weight of the engine. If it drops fairly quickly then she is probably gone. If it can hold the weight for over a minute then she should still be a fast engine if you can get it to idle.