motor upgrade combinations

[ralph2]

i am planning on doin alittle rebuild while i can... anyway i wanted to do a cam, piston, valve and clutch upgrade. im on a low budget so that narrows some things down, but my main concern is if i can use any combination of things. for example... i already have an hrc cam waiting for me to put in. now will this cam work with any high compression piston? or do i have to get a piston and cam combo? also is the hrc cam a good choose for mx?

on to the piston...
i wanted to upgrade to a slighly high compression without sacrificing reliability. i was thinking about going with a 12.0 :1 JE. from what i understand that is about the limit before switching to race gas. let me know what you think about that choose, and again will this piston work with any cam? hrc cam?

valves...
i have read that the titanium valves are more or less a waste of money since they are very expensive so i have put those out of the picture. what stainless valves are the best, and should i be going oversized on both exhaust and intake? or not at all?

clutch...
again i am looking to keep the cost down so i was thinking about going with a hinson clutch. plates, steels, and springs. i understand that the oem clutch is suppose to be the best but will the hinson be suitable?

any information on all this would be more then helpful

[DJJ450r]

What type of riding do you do, and for the clutch I would get a hinson clutch basket and keep everything else stock.

[ralph2]

mx

[MR.BIG]

The hrc cam is an excellent cam for motorcross or trailriding. I use the hrc cam and really like it. I would go with a JE piston and get a 12:5 after that you will need race gas or a 50/50mix.

[ralph2]

but my main concern is if i can run any cam with any piston?

[ghott]

Yes, you can run any cam with any piston.

If the cam you have is the early HRC Cam...as in the 04/05 HRC Cam....this is NOT A GOOD CHOICE FOR MX. The early HRC Cam is a mid-top end cam. This cam is most popular with drag racers and duners...Most Motocross guys want a healthy bottom to go along with a good mid-top.

If you have an 04/05 R. Look into the 02 CRF Cam, WEB 943/921 Cam, or the Hot Cams Stage 2.

If you have an 06/07 R. Look into the 06 CRF Cam, 06 HRC Cam (same as CRF), WEB 943/921 Cam, and the Hot Cams Stage 2.

Valves....titanium is expensive! IMO, I would go with Stainless Steel for longevity and cost. Ferrea Intake Valves are very nice. Also, the stock exhaust valves are very strong...much stronger than the stock intake valves. Take a look at the exhaust valves...you may not even need to replace them. If they do need replaced...check out Kibblewhite Exhaust Valves.

Piston choices:

If you have an 04/05 450R....the only stock bore (94mm) pistons that can still be used in conjuction with PUMP gas that I know of are: 11.5:1 Wiseco, 12:1 CP, and 12.25:1 Black Widow (Custom CP). Other than that...you can get high comp...13:1 and up JE's and even the 14:1 Baldwin.

If you have an 06/07 450R...I haven't done much research in this area....you're on your own!

Remember...12.5:1 and under is pump gas friendly. 12.6:1 and up is High Octane fuel territory.

Good Luck!

[ralph2]

thanks alot... very helpful information