[Tom#91_crf250]

i surpose you guys are probably getting fed up with my questions but no one else seems to be able to help or end up giving me bulls**t advice.

I am now looking for some radiator braces, to cut a long story short some idiot (not me) tried to bend my radiator out with a crowbar and ended up going through that rad and blamng it on te soft metal. They have been sent of to be fixed by www.gmxradiators.co.uk but i know they probably will be weaker as they are going to have to bent back etc so i need something for more protection. ive been looking at some of the different type of guards you use and i realy like the moose radiator guards, but i think someone said in another post then dont offer protection from been pushed forwards or backwards. but i surpose i could make some braces to fit it like the works connections out of 3/4mm aluminum.

second
the stock louvers (the white plastic bits on the rads) are destroyed, dose anyone make these as honda oem are £30 ($60) and are there different styles or designs to improve airflow.


third
im thinking about putting in a new piston while there is no coolant, or radiators on the bike, but there is so many different makes to chose from,i dont need a new piston but it has done a whole year of racing and practice so im thinking it must be worth doing. wuold a 08 piston or a high compression piston work with a stock 07 motor or will i have to get a new cam and valves. another thing is i have only done piston changes on 2 strokes and i can do them in half an hour not bad for my age but is it possible for a 16 yr old to do a 250 fourstroke if i take my time and someone give me a decent walk through on the cam bits, like timing etc.

tom

[Asmith]

Tom,

The only good Rad guards left are the UNIbiker or the FlatLands (or maybe those Australian units that TattooArt has). They offer protection from roost, sticks, rocks, etc. as well as side impact and bendback resistance. None of those use the stock louvers. They run £ 40-£ 50.

So no need to buy OEM louvers, I just saved you £ 30.00. Net cost of rad guards...£ 10-40.00.

You can change the piston yourself. It's not difficult. You can go with OEM kits for as little as £ 50.00. Or go with the high compression models from JE or Wiseco available here on the site for £ 75.00. We can walk you through it no problem.

[Ray]

I am happy with the JE 13.5:1 piston.

As far as radiator braces, also look at the Devol braces. It requires shaving a little plastic off the inside of the shrouds, but they work well.

[Tom#91_crf250]

okay thanks for the advice agent.

i will look into those other guards, my main concern is that they might restrict airflow and with the stock louvers my bike still get quite hot after a race.


As for changing the piston my basic understanding in what i will have to do is

is to remove to remove the cam and valve cover

remove the cam avoiding dropping the chain down and mark the timing(like when you adjust the valves)

then i can remove the head and valves in one unit

then the barrel/cylinder

then to replace the piston i do the same as on a 2 stroke? remove the 2 clips, the pin, the bearing and refit the new ones.


then assembling it

i take it theres more than 1 ring, so do one a time right?

replace the barrel/cylinder

and pull up the cam chain

then put the head back on with the valves

then put the cam back in and make sure the 2 lines line up, then put camchain back on matching up a mark i should of made when i disasmble it.


as for run in. i take it run it on non synthetic oil as per the manual or do u have any better methods.

then after run in drain the oil and replace filter and check valves,

if im wrong on any of these stages please tell me what i need to and if u could elborate and any tips and trick would be helpfull, and i know i got to put all new gaskets in aswell.

also finaly would i need to adjust timming or anything else if i put in the je 78mm 13:5:1(or could i put a 08 piston in)piston into a stock 07 bike?? cause i was told i would have to do some other modifications.

should hopefully be able to order everything i want on thursday.