Jump to content
Sign in to follow this  

440 w/ stage 2 (3?) cam soooo stiff

Recommended Posts

Short version:

’98 440 w/ stage 2 or 3 cam = VERY stiff kick starter & seems to have 2 TDC resistance points, one about 1/2 stroke after the other. So stiff I can almost put full weight on it & I’m 200lbs. No idea what the piston compression ratio is. The bike is very strong & runs like a bat outa hell. Seems perfect otherwise.

’98 bone stock XR400 = kick starter is like going through butter it’s so easy & I never think to use the comp lever. Bike runs like a stock XR400.

Background: I’ve had the 440 for over a year & it came as described. Since I had no point of reference I never gave it any thought. Quite by accident I came across a virtually new ’98 (still had 50 percent tread left on original tires!). Got a smokin deal on it so I’ve been using that one all season & have since put a BD kit on it & had it plated. So I’m keeping the newer one. Now that I’m cleaning up the 440 for sale, it’s like night & day comparing the kick starting of the 2 bikes.

What gives? Did something give out on the crank to make it so dang stiff or am I just use to stock compression ratio now? Why would it feel like 2 TDC points? I don’t remember that from B4.

Any thoughts or help is greatly appreciated. PS – must sell ASAP!!

Thanks,

Bill

Share this post


Link to post
Share on other sites

i don't no anythig for sure, but the xr400 had the automatic decompression system that help when you kick it, and on most aftermarket cams the companies don't allow the use of the stock automatic decompression system.

I don't know if this is your problem but that my two cents

Share this post


Link to post
Share on other sites

you need to use the manual decompression lever. I bet there is something not set up correctly. even with the 440 kit and high compression, cams ,etc, it should not be that hard to start. kick it a few times, release the decompression lever and then try it again. I have heard upgrading to the pumper carb and being correctly jetted makes starting easier

Share this post


Link to post
Share on other sites

Heres how you use the decompression lever:

Kick the bike through until you feel the piston come up against TDC. Pull in the decompression lever, and push the piston a fraction past TDC, you should only move the kick starter about 1/2" at most. Let go of the decompression lever, and give it a very solid kick.

I've always used the decompression lever on my 400, even though it has a stock cam in it, as I can usually start it 1st or 2nd kick cold, even in flip-flops, using this procedure.

Share this post


Link to post
Share on other sites

It's probably just due to a high compression piston (stock is 9.3:1) that could be 10:1, 11:1 or 12:1. Also with a hotter cam you can feel the valve springs on the valve, on the rockers, on the cam, through the cam chain and on to the kick starter. Pull the plug and and you will still hit a stiff spot where you try to crack open the valves. Hotter cams require stiffer springs and then they travel longer to boot. If it ain't knocking and "runs like a bat" it's propably just the way it's suposed to be.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks all,

The stiff kicking is likely a product of the hi comp piston. FYI, a stage 1, 2, or 3 cam wont allow use of manual decompression lever so thats a no go. I sure dont even need it on my stock XR400. Anyway, it just seems too stiff. I sure like the link from Alex.

Still need to part w/ that bike. Starts on 3rd (stiff) kick!!

Bill

Share this post


Link to post
Share on other sites
It's probably just due to a high compression piston (stock is 9.3:1) that could be 10:1, 11:1 or 12:1. Also with a hotter cam you can feel the valve springs on the valve, on the rockers, on the cam, through the cam chain and on to the kick starter. Pull the plug and and you will still hit a stiff spot where you try to crack open the valves. Hotter cams require stiffer springs and then they travel longer to boot. If it ain't knocking and "runs like a bat" it's propably just the way it's suposed to be.

Thanks XR Rated. This explains the 2nd TDC I described. Seems you always have good insight. I got the technique back & it starts w/o a problem.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×