any help on cool eng mods for the 250x

[250x]

does a aftermarket cam help even a stock but healthy motor? what kind of aftermarket pipe is not so load? anyone know is the power much different between a 300ex and 250x?

[400exdad]

A cam will help a healthy engine. But you have to remember that you lose something to gain something. Therefore, if you go with too much cam, the motor will be very down on power in the lower end. The reason most want an aftermarket cam is for more power on top and maybe midrange. Because of this "loss" down low, most people install a higher compression piston. I now have a 400 and I think I will change out the cam to open up the mid and upper end a little. I still want the "grunt", so I'll up the compression to make up what I will lose on the lower end of the RPM scale. So, if you want to get more power with your stock piston, be conservative on the cam. Another idea for you would be to advance the timing using a degree key from Curtis Sparks. That will pick up the lower end as well.

As far as the difference between an X and a EX. 50 more (more like 30) cc's and better (bigger) carb.

As far as pipes go, I like mine quiet. Check out the T4. It was probably the best all around pipe in the last shootout I saw for 400's. (Again, sound is an issue with me.) I had a FMF Megamax on my 300EX. It was okay. More discs=more power=more noise.

Hope that helps.

[quadfamily]

The 250X and 300EX are pretty equal in power. The 250 is 26 lbs lighter due to the battery and starter on the 300. Gearing , suspension and tires are the same. There is only around a 30cc difference. The 250X has a little bit more compression which makes up for the difference in cc. The carbs are the same size and type. The idle speed adjuster is a little different. The head is the same and the airbox and intake tube are the same. I've heard that the cams are slightly different with the 250X having a slightly more agressive cam but I've also heard that the cams are the same so who knows on that one? Go with a 10.5:1 or an 11:1 piston and an all around "drop in" cam. You can just get a bigger head pipe like one from Powroll and use your stock muffler and it will give you a nice performance gain without being loud.

[400exdad]

Quadfamily, you sound like you know alot more about the X's and Ex's than me, but when I was researching the 300EX I bought, I thought I read about a carb improvement. I think it happened in the second year of the 300EX. Was that '93? I was thinking it was a little bigger, but I could be (and have been wrong before). I do remember the article talking about an improvement though.

[quadfamily]

According to my manual they're both QB series 29mm carbs. They both have accelerator pumps too. The carb model numbers are different for different year X's and for the 300EX's but it looks like all the EX's have the same carb for all the years that my book covers (up to 96).