Is this a possiblitiy??? Missing Decomp spring!!!!

[stuntman_12]

As many of you know I have Done EVERYTHING to try to get my 416 to run. I have stock cam, but i'm missing my decompression spring that goes under the cam. Will this cause my quad NOT TO RUN???

I hope and pray that this is the problem..... if not then i am at a TOTAL loss... Will just any aftermarket cam solve the problem?

**How big is the difference between the stage 1 and 2 hotcam? I found a cheap stage 1 on ebay... just curious.


THANKS FOR ANY HELP!!!!!!!!!!!!!!!!!

[krt400ex]

i think that may be the prob, but i am not sure. the stage 2 is a bit more aggresive than the stage 1. it will give u more mid and top than the stage 1, but at a loss of bottom. the stage one will give u more mid and top, but u will still keep all ur bottom.

[stuntman_12]

Thanks man.... but i need to know FOR SURE!!!! Cause i need to know if i need to buy a cam or not...


WILL A 400 RUN W/ OUT THE DECOMP SPRING w/ a stock cam???

[ZSK]

You need the plunger and spring installed with the stock cam. It is possible to remove the decompression assembly from the stock cam however.

[stuntman_12]

HOW!!!???? would i remove the decompressor from the stock cam? Should this solve my problem? I hope and pray that it does... i'm tired of workin on it.



Gee i hope this is my prob... THANK YOU!!!

[rYan01400EX]

It has to be pressed off I believe? Someone correct me if I'm wrong.

[mic 902]

You dont need that. If you look at after market cams for a 400EX it does not have that part on the cam. The decompression spring and pin part are for the XR400 because thay are kickstart.
The top end of a stock 400EX is almost identicle to an XR400 so Honda just uses that cam.
Hope this helps. Probably not what you wanted to hear.

[ZSK]

I did it in a vice with a rubber mallet. You need to support the sprocket flange (Where the cam sprocket bolts onto) in the vice and drive the cam out of it. Pull everything for the decompression off and reinstall the flange. See attatched picture for reference.

[ZSK]

Originally posted by mic 902
You dont need that. If you look at after market cams for a 400EX it does not have that part on the cam. The decompression spring and pin part are for the XR400 because thay are kickstart.
The top end of a stock 400EX is almost identicle to an XR400 so Honda just uses that cam.
Hope this helps. Probably not what you wanted to hear.

Yes you do need to do that. The aftermarkets don't have the decompression, so you need to remove the plunger and spring. You need the spring and plunger installed with the the decompression assembly on the cam or remove spring, plunger, and decompression assembly from the cam.

Without the spring and plunger, the decompression assembly will hold an exhaust valve slightly open to decompress the cylinder pressures. The plunger actually holds the decompression assembly from spinning and allows the cylinder to build full pressure.

I did manage to get my motor to run without the spring and plunger with decompression assembly on the cam BUT I had to be towed to about 40 mph and engine speed was above 5000 RPM. It would stall at any slower speed and engine RPM.