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As far as I know, you have to have a cam profile meant to work with the geometry of the rollers...

You could simply swap to rollers if the roller was on the valve side of the rocker... As in automotive applications ... But in our case you couldn't set valve lash...

If I'm wrong, that would be great because I would love to fun rollers... But I dont think I am

Edited by mixxer
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They are meant to work with a zongshen head which is what I have. For $13 a set what can go wrong?

 

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1 hour ago, greenhuman said:

They are meant to work with a zongshen head which is what I have. For $13 a set what can go wrong?

 

If they are made for your application, then nothing to wonder about...

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Not being familiar with zongshen...

Are you saying your zongshen head comes with non roller rockers... But they offer these roller rockers as an upgrade?

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All the dimensions of the SZ std rockers are the same as the CRF so I can't see why these wouldn't work on a CRF.

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All I was thinking was that in my history of engine building I have only known of cams made with profiles specifically made for use with roller rockers...

Geometry of the lobe being affected by the contact patch of what is tracking on it....

If this works, it will be news to me...

Another thing to consider is what is to gain here... roller camshafts have Performance advantages because they can survive with their more radical pressure loading lobe profiles , simply because the roller followers will allow it...

Now... Take a rocker arms arrangement like the 230... And on a big stretch let's just say the roller rockers were in fact a bolt in arrangement that worked the same with the standard cam...

Your net gain would be so close to zero that it would fall below a dynos ability to measure it...

It would have to be mated to a cam that took advantage of more radical lobe profiles that rollers would allow , before any performance advantage would be seen...

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7 minutes ago, greenhuman said:

I just wanted to be popular at parties, that's all.

Well fer cryin out loud, man...!!

Why didn't you say so right out of the gate?!?

 

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Solid followers are limited in their ability to survive high lift rates and stiff springs. Rollers offer reductions in friction, ability to survive high lift rates, and stiff valve springs.  All positive, except the contact surface to the cam is curved rather than flat so a different cam profile is required to have the same valve timing. 

Great idea if the rockers will fit the cam box and I'm sure someone like Teamrude could find/provide an appropriate cam profile.

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They are meant to work with a zongshen head which is what I have. For $13 a set what can go wrong?
 


What could go wrong? Off the top of my head:

They could weigh more than stockers?
They could be made in China and not be as reliable as stockers?
The ratio could be different?
The valve height may need to be set differently?
They may not be compatible with aftermarket performance cams?
(I run performance cams that need the rockers and rocker boxes ground on for clearance.)
They could be no net gain in HP or Torque as well as reliability?

They may not be as exciting or rewarding as building the worlds first air cooled, electric start, 6 speed 500cc V Twin 230f.....

Or they may turn out to be the Cats Meow
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2 hours ago, adnohguy said:

 

(I run performance cams that need the rockers and rocker boxes ground on for clearance.)


 

 

Guy....

You know you have an addiction , I'm sure..

The next step on your list comes from the sand drag crowd...

"Trenched Cases"

Once you offset a stroker pin placement far enough out on the crank, you will run into clearance issues between the big end of the rod and the crankcase halves... 

Sometimes you can get away with shaving the rod a bit for clearance...And sometimes you need to machine a trench into the case to allow the huge stroker  to swing full circle...But when you go really BIG  you will need material welded to the outside of the cases to have enough meat to cut a big trench in... 

(Maybe shave a tranny gear or 2 also, but what the heck, as long as you're in there anyways :). )

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Yes familiar, built many Trx250r's with 4mm stroke (350cc) with no cylinder spacer for more of a (sleeper) look.

And quite a few 5mm with a spacer for larger smiles, 370cc

 

But 5mm strokers were at the end of my budget because to do 400 cc's in a 250, would of required Welding/trenching, etc.....wheelbarrow's of cash.

 

I have a zillion hours probably on my Honda 250r, Favorite Quad of all time... 4mm 350cc

 

I did the quad thing also from 1986 ~ 2005 and closed down my shop after 25 years. Now I work for the State of CA. and have been working for RETIREMENT. (And playing with mush less expensive toys, called beginner girls bikes.)

 

IMG_0558.thumb.JPG.cedd18332d06d80b4c9590d651870a55.JPG

 

How about this Long, long rod, wet sleeve 980cc Raptor engine my friend, Richard Simms is building? Complete Titanium custom Chassis.

His customer is going to have at least 50k invested IMO. Probably more actually?

 

Will have Nitrous also, not that he will need it but "way to fast is barley adequate"

 

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Greenhuman

Im not so convinced those rockers won't be a drop in upgrade but I understand all the concerns mentioned. A few quick measurements would answer the question but having the Zongshen head and rocker cover would be helpful as well in case there are any clearance issues.

I've been tempted to pick up a complete engine off ebay to autopsy and see what parts we can use for our 230's and 200's. I have heard that its possible to use a Zongshen top end and crank on our XR200's to boost stroke and displacement. I have heard that you can use the clutch and primary gears on the 200's to change the primary ratio and get an extra clutch plate. I've read that those engines are a great source of very inexpensive parts for our 230's and they actually have both electric and kickstart.

There are actually two different Zongshen 230 clones that use different bore and stroke combos but look the same. The one used in AJP motorcycles is the short stroke version.

On the flipside its likely that we have performance parts such as pistons and cams that will greatly boost the power of a Zongshen engine. These opportunities will be missed if no one ever investigates

Unfortunately there are no Zongshen distributors in the US that I could find. Can I get the source for those Zongshen parts? Would you be willing to obtain and forward links or copies of a Zongshen manual and parts list and maybe work with me to get my hands on parts for closer inspection? It would be great to know what parts interchange. 

We like to slam imported clones but in some cases clone engines are produced in greater quantities than Honda engines and run for many miles with good durability. I believe Zongshen is a primary producer of Honda power equipment engines too.

 

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Holy Mackerel Guy!!

That explains a LOT about why you know all that you know!...

Love the trx250r... Built and setup a zillion of them... Prefer the 86 cylinder style just because you have to have a favorite.... Never went above 300cc and actually couldn't come close to riding all the power a full on 250 made on a mx track... 

Built quite a few raptors... Not a fan of the 660... But have gotten 800cc versions into the low 90s for hp... Mid 60s for torque... epoxy filled intake floor and much  more downdraught port...Moreque than most singles have hp... Gotta cut the heads for cam clearance there too... But still not as crazy as your friend is going ... Not by a long shot...

If I won the lottery my tastes would change on esoteric builds...

I am a simple man with simple needs.... Slave to a budget.

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And on Chinese stuff....

My own experience with a lot them is that they may look like a Honda... And that's where the similarly abruptly ends...

Materials are different.... Quality is different... heat treating is different...Longevity is different...

Parts wear and break in ways you have never seen before...

Honda's are better off without Chinese parts... 

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8 minutes ago, mixxer said:

And on Chinese stuff....

My own experience with a lot them is that they may look like a Honda. .. And that's where the similarly abruptly ends...

Materials are different.... Quality is different... heat treating is different...Longevity is different...

Parts wear and break in ways you have never seen before...

Honda's are better off without Chinese parts... 

Yep. My first fear is the metallurgy.

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And on Chinese stuff....
My own experience with a lot them is that they may look like a Honda... And that's where the similarly abruptly ends...
Materials are different.... Quality is different... heat treating is different...Longevity is different...
Parts wear and break in ways you have never seen before...
Honda's are better off without Chinese parts... 



China junk crap, been there done that.... life is much too short and I'm more than busy with too many damn projects anyway.
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my riding buddy replaced his 200 motor with a zong 230 clone.  The 223 version same bore and stroke as the 230.  It has held up better than I thought it would.  I am not a fan of the 5 speed that it has.  He had to import that motor from down under.

He just bought the new PitsterPro lxr250. The Zong motor in it is a big step forward for the Chineese. Time will tell I supose.

I'm not ready to switch just yet.

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And by the way John, incase you were not aware, in a 6peed (230):

The rod has to be notched in two places on the big end in order to clear 3rd gear main shaft.

In fact it's so tight in there that the center case gasket has to be whittled on for clearance. (4mm or 6mm strokers)

 

It is possible to do more than 6mm stroke but it would require a smaller diameter crank pin using a shorter rod that has a smaller diameter big end from some (not as common) model of an air cooled 200 Honda single. (Or 185?)

 

Terry told me that it could be done but I don't remember what parts he said would allow it to work?

 

277cc is possible with a 6mm, so for me, I'm good.

 

If I'm going to dream, I want to dream big. Maybe get "greenhuman" to design and build a 500cc V twin 230f.

 

Have you seen his photos of "forward, lay down cylinder", 250cc (230f based) ATC 70's using xr200r six speed cases with and ATC forward kick starter?

He has video's of him blasting up steep sand dunes RAPIDLY.

 

Using Zongshen components, he states 300 cc will be easy....

 

 

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