350X engine build questions

[camoweasel]

Since I decided to tare the engine out to weld in some gussets, I have decided to "freshen up" the engine a bit with a few performance parts. Basically I am asking, what are the best parts to get the most bang for the buck while keeping it fairly reliable? So far my ideas were a cam and 10.25 piston at the correct bore size needed to clean the walls up. As far as big bore kits and strokers, I'm afraid those items will compromise the reliabilty and longevity of the engine. So what is everyone's opinions about pistons and cams? I'm leaning more for a mild/mid power upgrade cam; not a race cam. Webcam, Powroll, or megacycles??

[Dirtcrasher]

Mid range and 10.25:1 will still be very reliable, make sure to have the rockers hardfaced though..........

I believe WEBCAM makes the cams for Megacycles; Thats what I've heard. IDK if Powroll makes there own, the lift and duration compared to the others will let you know. Make sure to clean up the valves, lap the valves (some will argue they are coated, which I'd say "the coatings gone now" )and put new valve seals in.

Yep, just clean up the bore, keep the sleeve as thick as possible rather than go 2MM over like some guys do which doesn't really add anymore power. I agree with you about stroking the engine, it might be a blast for awhile but it won't last 25yrs.

The only downside is your looking at 600$ worth of mods but well worth it IMO........

If your gonna gusset it like I do to any 350X frame I get, now I make sure to use the right lower gusset to accept a 450R master cylinder since the 350X one can't be rebuilt. Easy to do.....

[camoweasel]

Mid range and 10.25:1 will still be very reliable, make sure to have the rockers hardfaced though..........

I believe WEBCAM makes the cams for Megacycles; Thats what I've heard. IDK if Powroll makes there own, the lift and duration compared to the others will let you know. Make sure to clean up the valves, lap the valves (some will argue they are coated, which I'd say "the coatings gone now" )and put new valve seals in.

Yep, just clean up the bore, keep the sleeve as thick as possible rather than go 2MM over like some guys do which doesn't really add anymore power. I agree with you about stroking the engine, it might be a blast for awhile but it won't last 25yrs.

The only downside is your looking at 600$ worth of mods but well worth it IMO........

If your gonna gusset it like I do to any 350X frame I get, now I make sure to use the right lower gusset to accept a 450R master cylinder since the 350X one can't be rebuilt. Easy to do.....

DC, Thanks again for the advise. I'll definitely look into that lower gusset. I have the engine torn out and now the frame is just a roller. I should have plenty of room to do all the gussets now. I've been doing some reseach on the 3 big cam makers for our bikes, (Webcam, Powroll, and megacycles), and they all have different lift and duration numbers as if they are all different cams. The two that sort of have my attention is the Webcam grind #213 and megacycles 162-30. They seem to be the biggest cams availible before you start getting into the race grinds. Any opinions on your favorites? About the valves, and rockers, it seems to me that buying new valves and rockers would be cheaper then having the rockers hard welded or the valves redone?
I know for a fact, my engine has low hours from factory, so I'm betting that there isn't much wear on the top end components. Heck I even bet the factory piston isn't even worn that bad. I just figured it would be nice to have mildly built 350X for braggin rights you know.
I talked to my local ATV shop and he said, he was going to tare into the engine and inspect all components for ware so I knew what to order. I told him I would burn him a copy of the service manual onto a CD so he knew what the tolerances were. Just yesterday there was a brand new webcam and kibbleworth valve spring set on Ebay for 175 bucks with no core. I knew I should have jumped on that earlier but what can you do...

[Dirtcrasher]

Because they build up the cam, the rockers have to have a harder material applied. The crate motor I'm using with 0 miles still has to be hardfaced.

Yeah, 175$ is a good price, esp. with the springs/retainers, then 120 for a piston/rings, 75$ to bore it, IDK what hardfacing is now but it isn't cheap, a gasket set etc; I know my SX cost about 500$ for all the mods motor wise...

From what I've read and others experience, even brand new rockers will not stand up to a hard faced cam.

I'm sure some will say "I never did that and it's just fine". I'd simply go with the cam manufacturers suggestions.............

[SWIGIN]

Web does NOT make megacycle cams and Powroll cams are megacycle. Megacycle is the brand most builder use it seems and the only 1 I use.

It's not the material the cam is made from that determines if you need hardened rockers. It is the high pressure from HD springs that call for hardened rockers.

As I have said before my all time favorit 350x motor was a 10.25 - 1, full race megacycle cam with springs and hardened rockers, full ported head and pipe. That motor ran over 10 years (till I lost track of it) and was raced for most of those years. That is a very dependable motor.

[Cuztom Racing]

We have cuztom cams ground for our drag bikes from megacycle so NO, web does not make cams for megacycle. But I've ran them both and web and megacycle both make great cams.

[needa250r]

i have a 200x needs to be timed. have a timing new chain and guide. lined up the timing marks it gets gas and spark. dont have a book to try an figure it out. need help. any suggestions?

[Dirtcrasher]

Web does NOT make megacycle cams and Powroll cams are megacycle. Megacycle is the brand most builder use it seems and the only 1 I use.

I knew it was one way or the other, :lol:

Just curious, what don't you like about Web camshafts? They are the ones that told me the welding they do hardens the cam and I had to use hardened rockers.

Then I've heard guys say "they told me a 200X doesn't need hardfaced rockers". Is that because they are only running 2 valves?

You said you ran a full race cam and a 10.25:1, when I look up full race cam they tell you a high compression piston. I always felt they meant 12:1 for a full race cam. Did you have to shorten your valve guides?

"It is necessary to use new or reconditioned cam followers or rocker arms with each new or reconditioned
cam shaft. Using worn rocker arms or followers will cause damage to the cam. We offer regrinding of
certain tappets and reconditioning of rocker arms for many models."

I figured I'd read through Megacycles PDF. That sounds like a new rocker arm is just fine on their cams? I understood they HAD to be hardfaced?

[SWIGIN]

I knew it was one way or the other, :lol:

Just curious, what don't you like about Web camshafts? They are the ones that told me the welding they do hardens the cam and I had to use hardened rockers.

Then I've heard guys say "they told me a 200X doesn't need hardfaced rockers". Is that because they are only running 2 valves?

You said you ran a full race cam and a 10.25:1, when I look up full race cam they tell you a high compression piston. I always felt they meant 12:1 for a full race cam. Did you have to shorten your valve guides?

"It is necessary to use new or reconditioned cam followers or rocker arms with each new or reconditioned
cam shaft. Using worn rocker arms or followers will cause damage to the cam. We offer regrinding of
certain tappets and reconditioning of rocker arms for many models."

I figured I'd read through Megacycles PDF. That sounds like a new rocker arm is just fine on their cams? I understood they HAD to be hardfaced?

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.

[WilliamJ]

I was taught that it is a long-standing rule that one should always renew the cam followers when a new camshaft is fitted. This presumably is the same for the Honda rockers. The two surfaces need to wear in together. No doubt the hardened followers will wear better.

With a new cam and followers it is mandatory to run the new cam at about 2000 rpm for 20 minutes to break it in - you should always use a special cam lube for the build to help the process and it should be supplied with the cam. If you have to shut down for any reason during the 20 mins you should cut the power totally and go back up to 2000 rpm when you re-start.

The reason that a higher CR is recommended is because the race cam has more valve overlap. This means it has a lower dynamic CR as some of the intake charge gets pushed out at lower revs. Increasing the CR helps to offset this at low rpm. And at high rpm, where there is less time for the gas to be pushed out, and where it is being sucked though by the high speed exhaust gas, the cylinder is really well filled and you make a lot more power.

Does anyone have the timing and lift figures for these after market cams?

[Dirtcrasher]

Thanks for the info. Good to know Megacycle cam is the way to go, I'll be doing this soon to a crate motor....

The reason I mentioned a 2 valves engine (200X) is you said it was the HD springs that required the hardfacing.
The 350X having one assembly operating 2 valves on both the intake and exhaust would require more force; I can see them wanting hardfacing as one lobe is opening 2 heavy springs. But in the case of a 200X one lobe runs one valve. Regardless, I'd go with their recommendations.

[SWIGIN]

I was taught that it is a long-standing rule that one should always renew the cam followers when a new camshaft is fitted. This presumably is the same for the Honda rockers. The two surfaces need to wear in together. No doubt the hardened followers will wear better.

With a new cam and followers it is mandatory to run the new cam at about 2000 rpm for 20 minutes to break it in - you should always use a special cam lube for the build to help the process and it should be supplied with the cam. If you have to shut down for any reason during the 20 mins you should cut the power totally and go back up to 2000 rpm when you re-start.

The reason that a higher CR is recommended is because the race cam has more valve overlap. This means it has a lower dynamic CR as some of the intake charge gets pushed out at lower revs. Increasing the CR helps to offset this at low rpm. And at high rpm, where there is less time for the gas to be pushed out, and where it is being sucked though by the high speed exhaust gas, the cylinder is really well filled and you make a lot more power.

Does anyone have the timing and lift figures for these after market cams?

You got it 100% right.

[camoweasel]

So I take it, the general consensus is use hard-faced rockers instead of new OEM rockers. I see now why HD springswould create more wear and tare on the rockers. I use 15W-40 diesel rated oils which are loaded with tons of zinc and phosphorous both great anti-wear additives. They most likely have just as much anti-wear additive as does the VR1 oils. So with the new cam, I should just worry about the springs, and use the new seals that come with the new gasket kit? Do I need to worry about retainers or guides? Also MC also sells needle bearing cams. Are they nessesary?

[SWIGIN]

Thanks for the info. Good to know Megacycle cam is the way to go, I'll be doing this soon to a crate motor....

The reason I mentioned a 2 valves engine (200X) is you said it was the HD springs that required the hardfacing.
The 350X having one assembly operating 2 valves on both the intake and exhaust would require more force; I can see them wanting hardfacing as one lobe is opening 2 heavy springs. But in the case of a 200X one lobe runs one valve. Regardless, I'd go with their recommendations.

That 1 large 200x valve should be heavier then 1 smaller 350x single valve meaning the 200x valve should need a much larger spring to control that valve then the 350x. I have no idea if that is the way it is since I do not build up 200x motors but they should take a bigger spring then 1 350x valve.

But you'r right that 1 spring is probally weaker then the dual setup but I'd still use hard rockers.

[SWIGIN]

So I take it, the general consensus is use hard-faced rockers instead of new OEM rockers. I see now why HD springswould create more wear and tare on the rockers. I use 15W-40 diesel rated oils which are loaded with tons of zinc and phosphorous both great anti-wear additives. They most likely have just as much anti-wear additive as does the VR1 oils. So with the new cam, I should just worry about the springs, and use the new seals that come with the new gasket kit? Do I need to worry about retainers or guides? Also MC also sells needle bearing cams. Are they nessesary?

Needle bearing cams are a great way to save a head you have hundreds of dollars into and the cam journals are wasted....so no you don't need one unless your journals are shot. You are using good oil for sure but since I dont know what you are building exactly I wont say what you need or dont need.

What I recomend as a great mild build is a 10.25 piston, full race cam or the next one down if you are really scared of the race cam...lol, nice head work,38mm PE carb, cobra header and whatever silencer you like.

Ask MC what springs they reconmend for whatever cam you pick out and buy them.

[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:

http://www.youtube.com/watch?v=gxJG-mJmsJc

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

http://www.youtube.com/watch?v=xFYO9_kO5j0

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 :lol:

[camoweasel]

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 :lol:

As of now, I haven't installed my chain, but I DO know that the countershaft does spin freely. Basically the best way to describe it, is about after 15 seconds of idling it starts to die on it's own. If you hold the throttle open a tad to keep it running, it will still bog and bog as if the engine is "seizing up" because once I let off the throttle, it dies immediatly. The more you hold the throttle open, the louder the knocking noises come from deep inside. By that I mean no more piston movement; dead in the water.
When I try to kick it again, for about the first 5 kicks its really stiff then it starts to loosen up again.

I mean the oil pump was working fine before i took the motor out, and never once did the right side case come off?? The only thing I did was take of the oil lines. But I'm pretty sure there were no blockages when they were reinstalled. If the timing was off, I doubt it would even fire up. If the it was starving oil, I would bet that it would stay locked up after it shut off.
I wonder if maybe there's a vac hose thats not hooked up right or a breather hose? After it runs for so long, it builds up to much pressure in the crankcase?? I'm lost and will probably just take the whole trike back to the engine builder and let him figure it out. I just hope there isn't any damage done.

[Dirtcrasher]

Sure sounds like damage was done.....

[camoweasel]

This afternoon, I popped of the return oil line coming from the cooler back to the filter and the line that goes into the head. Both had flow when I kicked the engine over with the switch off. So my pump must be working. It just seems like after about 20 seconds it starts to load up and shuts off. Right after it's very hard to kick, but within only a couple of kicks, it returns back to normal where it's easy once again. For some reason, maybe I cam chain is to tight, or maybe it's building up pressure in the crankcase??

[Dirtcrasher]

I wonder if the carb has an issue and is loading the cylinder with too much gas. That would make it tough to kick.

I hope you have a decompression cable hooked up to it and adjusted too.......

[camoweasel]

I wonder if the carb has an issue and is loading the cylinder with too much gas. That would make it tough to kick.

I hope you have a decompression cable hooked up to it and adjusted too.......

I do have the decompression cable hooked up and adjusted as per the manual. I did consider the decompression lever being the problem, so I disconnected the cable from the head. Well even with the cable disconnected it still loads up and is hard as hell to kick over! But I like said, if I give it 10 seconds after it shuts off, it will kick freely. But in those first 10 seconds, there is resistance in the kicker.

I never considered the carb? I took it off, and it sat in my outside basement for abot 3 weeks. I wonder what would cause it to load up with gas?

[Dirtcrasher]

^ Ya can't compress a bunch of gas. I didn't build the motor so it's just a thought.

Have you pulled the plug to see if it turns over freely right after it gets tough?

Lots of things can happen to a carb to flood the motor with gas but keep it in mind.