head dome

[250R_SV]

Hi
I was reading this thread, and I dont understand much about domes, so it seemed interesting to me. I am running a 270cc with the stock head,dome and gasket height. 36mm carb, faty pipe and silencer. The engine feels with a lot of compression, kicks back sometimes, but its hard to start, it was fine before I changed the piston so most probably its something regarding the piston or head. What do you guys recommend me to do?
Im in the last bore so I was thinking on changing the cylinder and go for a smaller piston again.

[thedeatons]

I recommend buying or renting a compression tester and finding out where you really are. Otherwise you are just guessing.

After you find the number I would pull the head off and see what size dome is in there (should be numbered on it somewhere).

Report back after that, K?

James

[250R_SV]

Thanks for the tip, I'll see what I can do. Another thing I guess it has to be done is to open up or widen the exhaust and other ports, since bigger piston needs more airflow area to go out. Is that right?

[Honda 250r 001]

i think your jets are off. Thats causing it to hard start.

[250R_SV]

you mean the jets in the carb? there ok.
Its hard to start but when I get it to start everything is ok, with engine warm it starts right away. I dont know if the cylinder is getting to little gas or too many. I have a 36mm carb

[250R_SV]

ok guys, heres some feedback:
I still havent checked the compression
I checked my carb and I found a 150 main jet, the carb is 36mm, engine 270cc, guess that jet is to small, I found a 170main jet in my other stored carb and changed it.
I have a fatty pipe and a paul turner exhaust. According to fmf racing webpage I should use 158-160 main jet with their pipe, and 1.5 turns air screw,I suppose thats for a stock carb.
Im at 2160 ft over sea level.
I'll run engine tomorrow and see what happens.
What are your oppinion or comments?

thanks

[All250R]

Worn reed petals cause hard starting. Worth a check and simple to fix. Don't cause an airleak when installing the cage though.

[thedeatons]

What about the pilot jet? That is what is used for starting, not the main jet. The main is for 1/2 - wide open throttle.

Check compression too, so you know where you are. With all the Auto Zones around there is no excuse to not check it. If nothing else drive into town and pay someone to check it. You need a baseline, that way you will know if something is wrong later.

All250R - Is there a wrong way to install the reed cage? Should one use RTV? I think I just tightened mine down..... Just curious, I have never sprayed around mine to check for leaks....

James