genosr, I don't know of the companies who make them, but I do believe they are out there. You might want to send Racer X a PM asking for his input. He's the guy that plays with all that stuff.... If you can't find anything through google, I know APE engineering www.aperaceparts.comhttp:// can make anything you want....
If you find some, please post up so we can add it to our ultra-list of 250 specific parts.
What genocr is going for, just like X did, is be able to change the characteristics of his engine. He probably wants to increase horsepower by replacing his stock cams with exacerbated cams (camshafts), meaning the lobe has a much more square shape, and keeps the valves open longer to get more air in/out.
If you do this, you usually also change out the valves and valve springs to be able to deal with opening/closing faster. Once you read the article, feel free to post questions....
Nothing yet from the aftermarket. Crowler made cames for the first gen but that is it. Keep an eye on Indonesia. If any body will do it they will. Springs can be had off the shelf but you have to know what you need .There aren't any that I know of for the new ninja . Or you can have Cu$tom $prings made.
The term interference engine usually means that if the tining belt broke the valves would hit the pistons.
Since this is a high compression four stroke with chain driven cams . If the chain where to brake . Or the tensioner where to collapse . and the chain where to slip .The valves would definitely be damaged by piston contact.
On that note . I would highly recommend a mechanical chain tensioner from APE to any modified engine project.
right. ztrack said cams wouldn't help because of clearance. I don't understand. I thought racier cams just kept the valves open longer, and I guess I was asking if it's interference motor, and that the interference is so great that making hotter cams is next to near impossible?
But then, why couldn't you grind them down and flatter, to keep the valve open longer but not push it down so far?
You cut notches into the piston tops to clear the valves if it is a problem.
What my engine builder will do is first port the head enlarge the valve by replacing the seats .And recessing the seat into the head. Then after flowing the head . It will determine how much air can go through the head. Then using slide rules I guess. He will measure bore and stroke along with RPM and figure out how much the engine will pump Then he can figure out how far to open the valves and how long it needs to stay open . If the piston comes to close .Notches are made to clear every thing gets balanced at the end of this process
Then the cams go to a grinder to be modified to his specs. After that springs will have to be made . That is the most critical part . If one brakes at 14000 rpm it is over.