Heavy Duty Valve Springs 416?

[JD400exrider]

Just about got all the parts for the 416 mod. I have had different
opinions on getting heavier valve springs. I am going to run a HRC drop in cam. I know that "drop in" mean just that (ie no new rockers or springs needed) However this motor is a 2000 and I am going to have a valve job done along with new intake valves installed. Is heavier springs going to wear on the rockers more, rob HP or cause any problems. I see most of you runnning the stage 2 HC are not installing new oem or heavier springs.

Are the valve springs in a XR400 bike the same as the 400 ex They have a different part number at service honda. If so are the XR 400 springs stiffer?

Are kibble white or R&D springs that much stiffer? If so I think I will just replace the valve springs with stock ones when I have it apart. For the cost of the springs i feel is is cheep insurance. I did get a suggestion from one builder to double up on the retainer to give a little more seat pressure.

I guess what I don't want to do here is float a valve.

[YZROOSTINYA]

I have had no probs with mine, as long as you are not running a rev box you will be fine.

have about 65 hours on mine

[Guy400]

Take the springs to an engine builder and have him check them the springs. Most importantly check the seat pressure and installed height. I don't know what Honda's specs are for this, maybe a Clymer's manual tells you (I don't know for sure). We never here about guys replacing their valvesprings but we often here about something going wrong in the valvetrain after a cam install and they used their old springs without checking them.

[RAPTORAZ]

Originally posted by YZROOSTINYA
, as long as you are not running a rev box you will be fine.




What does a rev box have to do with valve springs?:confused:

[UglyMotha™]

Originally posted by RAPTORAZ
What does a rev box have to do with valve springs?:confused:


at higher revs if you do not have hd valve springs the valves will start to float and this can cause havoc on a motor:o


**edit: to be clearer revs higher than stock which a rev box allows you to reach

[YZROOSTINYA]

you got it.

the thing about springs is there not stiffer really. they just dont lose there spring if that makes sense. old springs lose there intial rate and fade over time. aftermarket kit may be slightly stiffer but are typically made of better material that does not fade as quicly

rev boxs will put stock springs past their limits

[JD400exrider]

So if i am understaning you right YZ installing a kibble white or R&D spring kit with new retainers will not cause other problems with my set up They won't loose there spring as quick as a oem spring?

I figure for the cost of the kibble white spring kit roughly 100.00 it it worth it to me to install them or new oem springs roughly 50.00 when i have it opened up. Which would you do? or be more reliable. I do have a rev box but i can take that off if need be.

[YZROOSTINYA]

rev boxes are a waste IMO

if your gonna do springs then get aftermarket ones. as they will retain there tension longer and probally are a little stiffer.

I have had no probs with mine so it is up to you

[Castor-426ex]

kibblewhite makes great springs and great valves...

do it

[RAPTORAZ]

Originally posted by UglyMotha
at higher revs if you do not have hd valve springs the valves will start to float and this can cause havoc on a motor:


The only way valve float will hurt the engine is if there is insufficient piston to valve clearance when the piston is at top dead center and the valves are at max lift. Otherwise valve float just limits the engines RPM. And most engines will have a dramatic loss in power long before the valves float. I've revved mine past the stock limiter hundreds of times and have never floated the valves.

[Quadfather]

I had heavy duty springs installed along with my 416 kit, and I haven't had any problems yet, but I've probably got only 10 hours ride time since they were put in. I also had heavy duty clutch springs installed. I had the HD springs installed more for peace of mind/insurance.

[Dune Surfer]

Colby at C&D told me that if you install aftermarket springs you need hardened rockers also. The heavy duty springs put more pressure on the rockers and wear them out.

[Colby@C&DRacing]

That is not completely true. If you are running a hard welded cam with stock rockers and heavy duty springs them yes you will need the hardened rockers because the cam will chew up the rockers. But if you are running a hot cam DO NOT USE HARDENED HARDS. Just wanted to stress that point:D . Hardened rockers on that cam will eat the cam in no time. You can run the heavy duty valve springs on the hot cams with no problems. If you are racing I would say you might want them for the insurance factor. I hope this answers some questions sorry for the confusion:)

[Dune Surfer]

Thanks for clearing that up Colby

[RED121572]

Do NOT use aftermarket springs with that cam.

Do NOT use aftermarket springs with that cam.

Not that I think he would need to but why do you think that?????


don't know what Honda's specs are for this, maybe a Clymer's manual tells you (I don't know for sure). THe honda service manual has a "free" height limit listed.


I've revved mine past the stock limiter hundreds of times and have never floated the valves. Just curious how you determined that you were hitting the limiter and not floating the valves or a little of both?


You can run the heavy duty valve springs on the hot cams with no problems. As I have said b4 the hot cam I had been running since the fall with the kibble white springs has no measureable wear.


To answer your question I think you would be ok either way and would need to determine if you were having any issues with the valves or clearences or the current valve springs b4 I would make any suggestions etc.

[JD400exrider]

The cam I installing is not a hot cam. It is a HONDA Cam The HRC cam for the xr / trx 400. In the hop up kit (which i did not buy) it comes with a piston, rings, HD clutch springs and a primary gear) No springs or roockers. It should be a drop in cam like the hot cam not hard welded. Same type of steel as stock rockers.
I am just thinking a better valve spring kit (kibble white) and some new OEM rockers should do the trick for better reliablity.

Why do you say "Do Not Use" Red :confused:

[RED121572]

Seeing that your not using a totally wild cam, your trusty ole thumper would not benefit from tighter valve springs. New OEM springs are quite fine and youll save some cash too.

You need to save all the cash you can, I believe a new set of rockers is about 300 clams. If I got the price wrong, let me know....my machine currently looks like this and I wouldnt mind getting a new set of rockers....

[JD400exrider]

Red The rockers are 21.97 each at service honda. That is just the rocker. Not the sub rocker. If you have a minute check the scamatic on servive hoda. Should the sub rockers be replaced too?
Part number for the rockers 14411-kcy-670

[RAPTORAZ]

Originally posted by 440EX4me


Just curious how you determined that you were hitting the limiter and not floating the valves or a little of both?




It's pretty easy to tell the difference between a mechanically limited RPM and an electronically limited RPM. The engine stutters when hitting an electronic limit. And the motor just flattens out when the valves float.

[RED121572]

Originally posted by JD400exrider
Red The rockers are 21.97 each at service honda. That is just the rocker. Not the sub rocker. If you have a minute check the scamatic on servive hoda. Should the sub rockers be replaced too?
Part number for the rockers 14411-kcy-670

Good question JD. Anyone else have any feed back??

[JD400exrider]

Anyone know if the sub rockers should be replaced also?

It's pretty easy to tell the difference between a mechanically limited RPM and an electronically limited RPM. The engine stutters when hitting an electronic limit. And the motor just flattens out when the valves float.

Thanks I did ask you that for 2 reasons 1. so I knew I wasnt as out of my mind as one of the popular builders was trying to convience me and 2. that we were all on the same page here and let some of the other members have something to think about.

So where I am going with this is that if your valves arent floating or you have some other mechanical concerns why pay for springs that you dont need?

Its the same thing for the rockers, and if you are not going to run a hard welded cam why the he!! would you want to spend the $$$ and trash the new cam with hardened rockers? And replacing good rockers with new ones (sure its only gonna be wasting a $100.00 by the time they ship to you etc) seems like wasting cash that could be spent elseware etc.

But I guess if you are wanting to waste good money replacing good rockers then you should throw some more into the hole for the sub rockers and hardware too. :rolleyes:

My advice is spend the cash where its needed and will do the most good not where everyone says to spend it.

[Dune Surfer]

In the installation instructions that come with the hotcams stage 2 they suggest new rockers. New metal against new metal. That way they wear together.

[YZROOSTINYA]

they most likely do that to cover there bum on high hour motors.