[SYCARMS]

Here are the long awaited results of the large camshaft now available for the 250cc. First I will tell you about the buggy used. It is a 250cc Challenger single seat which weighed in at the local scales at 639lbs. It has the MRP performance exhaust, UNI filter, DR Pulley hit set up with the heaviest clutch and lightest pillow springs, stock variator with 18gr rollers. Everything else is stock. I have run three complete runs with reference to 1/8 mile for top speed, 300’ for top speed and 300’ for E/T. The complete run consists of a 3 run average for each category of 1) stock, 2) with large cam, 3) large cam with ported head. The second run with cam installed we found the head would need some work. On the 3rd top speed run with cam installed I thought I lost my engine due to a horrendous noise, the buggy was severely cripples going back to the shop. When I removed the head I found both valves stuck open, so I knew something had hit. Turns out the retainers were hitting the guide seals than on the third run the seals let loose than it became retainer on guide. Not knowing how I was going to check clearances due to the setup requiring the cover to be installed to operate the complete valve system I consulted a good friend Mike with Fowler Racing. The conclusion was I would have to lower the guides, use of stronger springs to eliminate the spring bind and float, but also it was realized that the head flowed too well and that the intake port would have to be reduced to achieve top performance. So I lowered the guides installed better springs and also reduced the intake port along with porting and polishing the exhaust port. I made no changes to the valve grind. So here are the results.
The first run TOP SPEED = 42mph, TOP SPEED 300’ = 32.5mph with an E/T of 9 sec. Let me add that all runs were done on a coarse aggregate paved road.
The second run was with the large cam installed. The first thing to notice was how the engine woke up. Stock when mashed to the floor from dead stop engine would shutter due to the Hit setup, with the cam installed the rear tires spun causing the buggy to fish tail and I had not rejetted for the cam yet still running the 128 jet. After a rejet here are the results. TOP SPEED = 44.6 mph, TOP SPEED 300’ =35.3 mph with an E/T of 8 sec. As you can see top speed as well as e/t increased.
The third run was with the cam with head work done TOP SPEED=50.1mph. TOP SPEED 300’ = 39.9mph with an E/T of 5.9 sec. As you can see there is a huge increase over stock. The credit has to go to Harold from Hwy 9 Power Equipment up in Washington State who developed these cams. There are 2 cams available for the 250 small and large, so far the reports on the small cam have been positive, I will be installing this cam in my Blade and will also post results if no one else has, The cams can be purchased thru SYC Powersports for under $200.00 with exchange of old cam. If interested in the large grind I will be offering a package deal of cam with head mods with port and polish call (662)-301-1563 SYC Powersports for pricing. TOM