greasygas said:

Well first off, If you have stock suspension and spring rates, then you'll need stiffer springs for your weight.
In regards to the sag, are you sure you are doing it correctly?
Here is a video by Transworld MX Magazine on setting your Sag: http://motocross.tra...om-setting-sag/

me three

how do u run to rich with a four stroke? to much motor oil? or transmission oil?

The basic of lean or rich mixture is about air fuel ratio

The perfect combustion need 14.7 part of air for one part of gasoline

Running it a little more rich (between 12 and 13.5) help reducing combustion chambers temp, so this can prevent knocking from predetonation.

Running richer than 12:1 make carbon deposit and some extra fuel (not burn) drop in the base. The fuel gonna wash the cylinder wall and give a bad lube of the piston rings. Also, the oil/fuel mix still in the engine (give the dark oil color) and the engine oil are now less performant.

Running leanner than 14.7 let the combustion chambers temp too high and the fuel explosion gonna happen before the spark (Predetonation). When this happen, the piston aren't in the top position, so the pressure on the piston can damage the surface and the piston skirt knock on the cylinder wall (Knocking)

how do u adjust air fuel mixture? I noticed a screw that i turned and it made bike idle higher and lower..thats not it, is it?

You have the throtle plate screw ...

the pilot screw it's the gold parts on this pictures



This is for low throtle and idle


For midthrotle you should adjust the needle position

For full throtle you adjust the mainjet


In the jetting section you gonna have a lot more information

Does anyone have a standard fork oil level for an 07 crf450. I would like to replace my seals and oil at the same time.

2007 CRF 450
Having recently checked the valves and discovered the inlets were in spec from new but he exhaust valves need a little adjustment I put the engine back together. When i first pulled the engine down the timing marks were not ligning up 100% so putting the engine back together i thought it would be a good idea to line the marks up. How wrong was I. With the marks lined up the compression was such that it was near impossable to kick over. It was obvious the decompressor was not engaging until too late in the storke. I took the engine down again and put the cam back one tooth and he presto now it is back the way it should be. Ps the marks are now back the way they were but are not lined up the way they should be. Take it form me the timing marks are wrong!

I'm having some trouble finding cosmetic kits for my 02 450R. Can anyone tell me if the cr250 plastic is the same as my 450r. I have found kits for the 250 so I'm just curious. Thanks for any advice...

I just bought a used 450R and when I started it for the first time I noticed the exhaust pipe turned red hot near the head with in one minute of it running. Is this normal.

yeah i had the same issue with an xr400. looks good in the dark! anyway apparently its setup too lean. on the xr i richened it up a bit with bigger jet and it stopped doing it.

wanted to add here that the 07 came with a 178 main jet and a 42 pilot jet stock, and the carb does not require an AP mod

"Its good practice to replace the cam chain and tensioner (especially 02-03 model)when replacing the piston."

What about a manual cam chain tensioner? Anyone have experience with these?
http://www.bigboreth...ltensioner.html

Yep, confusing to adjust the first time since we have a single cam & you can't see the slack between cam gears like on a DOHC and you have to rotate the engine untill you feel the cam chan tentioner add drag then back off a 1/4 turn or so. I think that's how you do it. Just adjust it every time you do your valves & you should be good.

Also about the Sealed chains, I have an RK sealed UW ring chain & it should not need the spacer to use it. It appears the same size as the cheapo no name(primary drive) chain I took off that the previous owner had installed. Time will tell though, I guess.