350X engine build questions

[camoweasel]

So here is another question: What about billet cams; not hardwelded? For a few extra bucks, megacycles offers billet cams. Can you run factory rockers with a billet cam?

EDIT: My bad, it says hardfaced on billet.

[SWIGIN]

Like I said, cam material dont really matter as much as spring presure. If you pick a cam that needs huge HD springs then you NEED hardened rockers.

[Cuztom Racing]

Megacycle also says about getting rockers hard faced so that does not make Web speicial. I never liked Webs cam specs, they are just a ok cam for guys who want to say they have a cam IMO. I can name several top engine builder that only use Megacycle cams and that mean alot to me, I can name non that only use Web.

The number of valves have nothing to do with needing or not needing hardened rockers. It is all about the higher spring pressure rubbing a soft rocker on a moving metal object. This is where using a good oil like valvoline VR1 comes into play too. Think of it like this, you can lightly hold a piece of steel to a grinder and grind slow ( stock valve prings).... or you can push like mad and grind real fast ( HD springs).

I always use Megacycles full race cams in 350x motors. They are a great all around cam IMO and I use to trail ride the heck out of my old race quad with that motor. I did shorten the guides but you do not need to. I just blindly followed there suggestion to shorten them when I first built that motor and after I had the motor built I rechecked the guide to retainer clearance and it would of been fine. I'm sure they are just saying to that to keep guys from complaining when there full race cam with less then proper HD springs float and smashes into the guide.

Like you posted, megacycle recommends new or resurfaced hardened rockers for there cams. What that means to me is you at least need to run new rockers on a new cam (no crap) but it is best to run the hard ones. Right now my RX has RD HD springs just like the ones we use for the MC full race cam. But I am running a TC high rev cam ( made by megacycle) with new stock rockers. The only reason I did this is I could not see sending out new rockers to have them welded and hardened. They will not last to long but I don't ride like I used to and when they show wear I will ship them out.

Totally agree. Megacycle is the way to go. Its what all the top engine builders in the country use.

[boosted96cobra]

If you look on the specs of any aftermarket 350x camshaft it says needs hardface or new oem rockers. This has nothing to do with spring pressures or cam material or anything like that. What happened was the stock oem 350x rocker arm were just too soft. Almost every 350x rocker I have seen has been worn out. If you look at the honda oem parts online catalog you will see that they have 3 or 4 diffrent part numbers for those rocker arms. The older ones are all discontinued and the new # says replaces the old #. The new honda oem rockers are in essense hardfaced.

The older honda/acura car engine had this same trouble, so instead of junking all the rockers they had made for the next few years they machined out the pad and made the pad removable. Alot of junkyards in the know were paying top dollar just for the removed pads because of the steel they were made out of.

In my 350x I have a powroll small bore cam, new honda oem rockers, wiseco 10.25:1 comp piston (stock bore) and my own head porting. It rips and is very reliable. I had heard megacycle was the best cam but I was in a crunch for time and powroll had me the cam in 2 days. At 5000 feet elevation and running a supertrapp with 16 discks and a k&n with no lid, it jetted in with a 170 main jet and burns clean. It will run right with our 86 trx 250r racing sand mountain and other sand climbs. I love it because it is 91 octane gas and go. Great power, no race gas, no mixing gas, just kick and ride.

This vid my friend on his 85 250r is following me up the west side of sand mountain, decently steep and very long climb:


This one is right after running some bowls, my 350x out front followed by a trx 250r and the same 85 250r:


On the trails and road its a terror, in the sand it is decently tame, but will take you anywere you need to go.

Good luck on the build, I think your on the right track.

[SWIGIN]

Yes the factory rockers are hard faced but it is paper thin and will not last near as long as getting a set done through the after market companies. I have used both and stockers just aren't the same.

[boosted96cobra]

Sorry but your wrong, the new oem rockers I ordered from Ronnies were completely new hardened material. No coatings, no paper thin facing, 100% new hardend material. Id rather have new hardend rockers over old crappy ones known to fail with a new "facing" on the pad.
Plus you can have them in a week, they are cheaper, no sending off yours and waiting. Only down fall is they are heavier, because they are better quality material.

I'll trust oem Honda over anyone anyday, specially if they are still trying to make better parts for old 350x motors they stopped making a very long time ago.

[SWIGIN]

Do you even know that we are talking about getting factory rockers hard welded?

I have used new as honda rockers for years and unless they upgraded a now uncommon part within the last year, I know exactly what they look like. The pad on a untouched factory rocker is not heavier or thicker then one that megacycle does.

[camoweasel]

For some reason, I keep getting different ideas on how to proceed with this engine build. Now I am beginning to think, what about powrolls 393 big bore kit with the stock cam? Which setup would make more power and be fairly reliable? The big bore kit @ 10:1 comp with nothing else, or the 10.25 wiesco at stock bore with a aftermarket cam? I just read powrolls website. they say to either use a HW rockers or new ones?

Or for even more reliabilty, what about just a stock bore 10.25 piston with stock cam?

[boosted96cobra]

Do you even know that we are talking about getting factory rockers hard welded?

I have used new as honda rockers for years and unless they upgraded a now uncommon part within the last year, I know exactly what they look like. The pad on a untouched factory rocker is not heavier or thicker then one that megacycle does.

The pad on the new oem rocker is just the steel that is polished. No welded in pad, no coating, just steel. You said the hardfaced pad on the oem one is too thin, but there is no hardface on it.

Yes when they "hardface" the old oem ones, they cut out the pad and weld in it (the weld is much harder that the old oem rocker arm meterial), then they polish it.

I never said the pad was heavier, I said the rocker arm itself is heavier...because it is made from higher quality material.

If your even comparing the 2 rocker arms, old oem with the new oem honda ones I ordered from Ronnies.com, then you have not seen the new ones. The difference is night and day, you could put them in the hands of a blind man and he could tell you which one is better quality. But they are a heavier rocker arms. In the valve train world, lighter can always free up power, but usually doesn't last as long....thus titanium and aluminum retainers...

Yes camoweasel, all the people who make 350x cams, say use with hardface rockers or new oem rockers. They say this, as I explained above, because the old oem rockers were poor quality meterial, and the cam manufactures had to make a rocker arm that would last in a higher rev more lift engine. Then honda finally got their oem rocker arms up to par and the cam manufactures recommend them.

If your thinking of the powroll kit give them a call. They are more than helpful and know their stuff. They actually tried steering me away from their cam and back to a oem honda one with what I wanted in my build. They thought a stock profile may fit my riding better. My stock cam and rockers were junk so I got their cam anyway. I hear better reviews power wise with megacycle when it comes to cams, I am hoping to get a megacycle cam and higher comp piston for my sons 86 200x this winter.

If you want to argue old oem hardfaced vs new oem that is fine. My points are:
1. New oem is around $15 cheaper
2. Can be shipped to you with a click or a phone call, no shipping and waiting for your to be returned
3. They are completely better material, not just a new pad on an old rocker arm
4. Completely recomended by the person who is making the cam and or fixing your old rocker

I never said the hardfaced one won't work, but you gotta ask why you would buy them over the new oem ones.

[SWIGIN]

So your saying new Honda rocker pads are not hardened at all?

Look, I have bought new ones about a year ago, and I don't keep old junk ones on hand. But if you have a good set with worn pads why not get the resurfaced?

I'm not saying stock rockers wont work, heck, I'm running some right now but when the pads wear the best way to stop that is to send them out and get the hard welded. And after you get a set done youwill see that the stockers are in no way near as good.

[camoweasel]

In everyone's opinion, what is a better "bang for the buck" engine mod: 10.25 comp piston at standard bore OR a webcam bolt in grind grind 180??

Like I said earlier, the previous owner stated the oroginal motor had very few hours. Well he was right. There wasn't one ounce of carbon anywhere to be found inside the engine. The piston and cylinder wall and rockers looked and felt like new!! I'm almost sorry I decided to tear into it. Now Im having second thoughts about using performance parts. If my orginal parts are still in great condition, why get rid of them?? On the other hand, All I would have to buy now is a gasket kit, weisco piston kit, and just a cam if I decide to go ahead with everything.

[camoweasel]

ok so heres my update:

I got the engine back in the frame with a brand new weisco 10.25 piston. Put new oil back in the crankcase and fired it up. It runs great for about 15 seconds then all of a sudden it feels like the engine is struggling to stay alive as if there is way to much friction in the motor??!! When you let go of the throttle it comes to a dead stop!!! If you hold the throttle open a tiny bit, it will stay running longer, but then it seems like it starts clankin in the lower half of the motor?? The oil is brand new and the filter only had about 2 hours on it before I removed the motor so I left it in for the time being. What would cause something like this??

[SWIGIN]

Did you check your oil pump?

[camoweasel]

Did you check your oil pump?

I did not, only because I knew it worked before I took the engine out. I popped the rocker covers off to check the clearences and inspect for oil. The clearences were set right and it looked like theres was oil in the top end.

I'm not the one who disassembled the engine to put in a new piston. I only removed the engine from the frame.

[Dirtcrasher]

If you can't hear the restriction:

I'd take off the right cover, check the pump. Pull the primary gear and see if it's a crank/top end issue or a countershaft/mainshaft issue.

Isolate it, take that portion apart and you'll find it.

In neutral with the chain off, does the front sprocket spin freely?? Nice and smooth??

Or is it like pulling one of those 5' long lawnmower cables rigged up with the damn safety