timing chain life

Good to know. This sleds got 20000 miles. The chain and rings should be done while I'm in there
 
You need to do a thread on the Hurricane head/cam upgrade. What other mods are done?
 
shadow44 said:
You need to do a thread on the Hurricane head/cam upgrade. What other mods are done?
Click to expand...
The plan is the stage 2 head and cam upgrade. With pcv and airbox mod, excell exhaust.

This is for a custumer / buddy. But I'll make a post when it hits the snow.
 
That's a lot of money for a 18hp gain. I'd like to see the dyno sheet to see what those cams do. I like the low end pull the Nytro motor has and installing a high lift cam will decrease that. There's always give and take when making cam changes and proper clutch tuning will definitely be needed to get the most out of the changes. I'd be leaning toward installing a turbo if I were spending that kind of money.
 
grizztracks said:
That's a lot of money for a 18hp gain. I'd like to see the dyno sheet to see what those cams do. I like the low end pull the Nytro motor has and installing a high lift cam will decrease that. There's always give and take when making cam changes and proper clutch tuning will definitely be needed to get the most out of the changes. I'd be leaning toward installing a turbo if I were spending that kind of money.
Click to expand...
He said everyone turbos!

Dave said around 175 hp after all said and done.
 
Joe ltx-le said:
He said everyone turbos!

Dave said around 175 hp after all said and done.
Click to expand...


That's a 40hp gain. Hurricane's website says at least 18hp gain with the stage II. I'd like to see those numbers when it's together. Keep us posted.
 
grizztracks said:
That's a 40hp gain. Hurricane's website says at least 18hp gain with the stage II. I'd like to see those numbers when it's together. Keep us posted.
Click to expand...

I believe the 18 hp gain is just the head and cam....he will also gain with the exhaust and air box mod....although I'd recommend the Hindle exhaust as its much larger than the excell and will flow more.

I'm pretty sure Dave had a guy making high 160s to low 170s with this set up
 
The excell pipe is already installed. It's a seat and pipe. Dave told me they have dynod both. And the difference is very minimal.
 
Did you ever see a dyno sheet with those numbers? I'd like to see were it's making max torque and HP compared to the stock cams. I've never experimented with cams in one of these 4 strokes but I do have experience with automotive and motorcycles. High lift cams (or increased duration) usually makes better HP at higher RPMs but by doing so there's always a loss on the bottom end. For trail riding I'd be concerned with the need to always keep it wound up to stay in the cams sweat spot.
 
grizztracks said:
Did you ever see a dyno sheet with those numbers? I'd like to see were it's making max torque and HP compared to the stock cams. I've never experimented with cams in one of these 4 strokes but I do have experience with automotive and motorcycles. High lift cams (or increased duration) usually makes better HP at higher RPMs but by doing so there's always a loss on the bottom end. For trail riding I'd be concerned with the need to always keep it wound up to stay in the cams sweat spot.
Click to expand...
I think with the compression bumped up you might not notice too much bottom end loss. But really on the trails we run there's no bottom end. Only when you leave the warming hut!!
 
grizztracks said:
Did you ever see a dyno sheet with those numbers? I'd like to see were it's making max torque and HP compared to the stock cams. I've never experimented with cams in one of these 4 strokes but I do have experience with automotive and motorcycles. High lift cams (or increased duration) usually makes better HP at higher RPMs but by doing so there's always a loss on the bottom end. For trail riding I'd be concerned with the need to always keep it wound up to stay in the cams sweat spot.
Click to expand...

I was certain there was a dyno sheet floating around here but can't find it. The only info I could find was a flow chart of the head porting and valve upsize. That sled made 162 hp with full bolt ons. Dave made 175 hp with the stroker version. I've asked Dave to get me a dyno sheet if he still has one.
 
With all the porting, bigger valves and cam lift along with air box and exhaust changes I'm wonder how much the throttle bodies and intakes are restricting the air flow.
 
i got the engine all together. im puttng the cams in now.
huricane did a good job with quick turn around and dave always helps with support.

my problem now is when i roll the engine by hand with the cams in and timed , the chain jumps when the engine rolls over .

dave and i are both in agreement the tensioner must be bad. problem is i cant see any issues with it by eye.

has anyone had a bad tensioner?
 
Even with a good tensioner it will jump due to the way the dual cams are timed. When the exhaust comes off of a lobe it want's to turn on it's own as it comes down the ramp. At the same time the intake cam is trying to open a valve so it resists rotation. The result is slack in the chain between cams and normally the chain jumps the intake gear. I use tie straps to hold the chain on both gears during rotation which requires several steps of cutting them loose and re-securing the chain again. The valve cover has a chain guide in it and when installed prevents the chain from jumping the gears.

http://ty4stroke.com/threads/cam-chain-tensioner-replacement-3-cylinder-engine-05-07.90826/
 
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