'98 MSRX Big Bore

'98 MSRX Big Bore

'98 MSRX Big Bore

SETUP INFORMATION FOR MY
1998 YAMAHA MOUNTAIN SRX 800cc Big Bore

Please E-mail me your comments & experiences randolph@macr.com

My Conditions:

	Maxximum Performance / Mountain Performance 787cc Big Bore Kit
	7000 to 10,000 feet
	0F to 40F
	Camoplast 141" x 2" Track
	DEEP POWDER RIDING

Key Fix for Air Intake In Deep Powder - See 98 Mtn SRX Mods Page.

Primary Clutch (Drive)

	Roller Diameter 15.0mm (stock is 14.5)
	Weight P/N 8BU-10 45.41g (stock is 8DN-00 44.25g)
	Rivet Inner 2.4g (2.4g stock)
	Rivet Outer 0.8g (none stock)
	Spring Pnk/Grn/Pnk ( Pink/Silver/Pink stock) (139 Kg, 40Kg pre-load)
	Spring Shims None (stock)
	Engagement 3700 rpm (3500 stock)
	NOTES: The 8BU-10 weight is stock in a 97 VX800, I run a lot more secondary spring and smaller Helix to compensate for the additional weight. The larger roller also helps offset the additional weight. I'm not having any belt slip problems (possible with larger roller).

Secondary Clutch (Driven)

	Helix 46/38 multi-angle roller from Maxximum perf. (stock 47deg)
	Spring Silver (2 steps stiffer than Stock)
	Pre-Load 70deg (60deg on Hard Snow)
	Shift Speed 8400rmp SOLID!
	NOTES: I ran a 44/38 at 1st, but my RPMs fell off in the powder. I first ran a 42/36 non-roller which only increased hard pack RPM by about 50. The 44/38 would back shift to 8400, but then fall of to 8100. I LOVE the Maxximum roller clutch. See Mountain Performance at (888) 649-4609 or www.MounatinPerformance.com

Gearing

	Rolled Chain Case with 9 tooth drivers
	Top Gear 20 Tooth
	Bottom Gear 39 Tooth (stock)
	Chain 72 Link
	NOTES: I ran 22/39 with the 8 tooth drivers. The 20/39 with 9 tooth is the same ratio. If they made a 3" track, it would fit with this roller chain case. I have had no belt problems, etc.

Jetting

	Cyl #1 (PTO) 143.8 (stock 132.5)
	Cyl #2 (Center) 145 (stock 132.5)
	Cyl #3 (Mag) 146.3 (stock 135)
	Pilot Jets (all) 50.0 (stock 8K to 10K feet and 20/40F)
	Needle Clip (all) 2nd position
	NOTES: My jetting is a little fat. This stagger jetting gives me very even EGT temps on all 3 cylinders. I am not running the two vertical dividers in the air box. I am running the horizontal divider. Also have the bender cold air kit with three 2" holes drilled in the top of the air box. I run the foam. W/o the foam in EGT temps got up 50deg. -- See my MSRX Mods Page.