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Cam sex change

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Did a little nip and tuck surgery on my 200X Sparks Racing cam ready for the new 277. Remachined for CRF cam bearings and the spark advancer appendage removed but still able to be re-attached in the future. Poor old Bruce cannot even do that. Some surgery to the head oil bath as well.

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I'm a terrible wrench and probably don't know $**t about what you wrote.... but, you get an award for great topic title!! :thumbsup:

Edited by scridercoach

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It's called "Gender Reassignment".  "Sex Change" is soooo last decade.

I can totally understand why this cam did not identify with being part of a 3-wheeler, especially after the scathing 60 minutes report way back when.  Who wants to be associated with being unstable and killin' folks.  I think this cam will be lots happier as a big-inch 230F bump stick not to mention totally deserving the honor.

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2 minutes ago, MetricMuscle said:

It's called "Gender Reassignment".  "Sex Change" is soooo last decade.

I can totally understand why this cam did not identify with being part of a 3-wheeler, especially after the scathing 60 minutes report way back when.  Who wants to be associated with being unstable and killin' folks.  I think this cam will be lots happier as a big-inch 230F bump stick not to mention totally deserving the honor.

I just watched the episode of Adam-12 where Malloy gets sucker punched by a 4'-8" midget in a bar long before politically correct terms were "cooked up" in academia.  They said midget in the episode.

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  Death to all political correctnessers (is that a real word?) Oh yeah, and death to all extremists too. Pretty nifty with the cam. I'm wanting to go the other way. CRF230 head and cam on an XR. I want the bigger valves and the roller cam (I know, megacycle, etc. for the XR). Are the rockers the same? I've made needle bearing shafts for mine.  Would need to mod the head to use the XR exhaust rocker for the comp release. And, of course, add a snout for the ignition.

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2 hours ago, Doogee57 said:

 I'm wanting to go the other way. CRF230 head and cam on an XR. I want the bigger valves and the roller cam (I know, megacycle, etc. for the XR). Are the rockers the same? I've made needle bearing shafts for mine.  Would need to mod the head to use the XR exhaust rocker for the comp release. And, of course, add a snout for the ignition.

Are you in some sort of contest to see who can spend the most time/cash/and effort to achieve the smallest actual gain??   If so, be forewarned, you are in over your head with some of the professionals in this forum... 

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Rockers are the same. The XR rocker cover will fit for the decomp. You will have to do a line bore in it for the CRF bearings.

The list of "people I just don't like" must be getting really long, Sheldon.

20160103_190021_zpsb2a1po3h.jpg

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Rockers are the same. The XR rocker cover will fit for the decomp. You will have to do a line bore in it for the CRF bearings.
The list of "people I just don't like" must be getting really long, Sheldon.
20160103_190021_zpsb2a1po3h.jpg.59c925188e383fb587669905ea325f56.jpg



Are they liberals or gun owners?

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You guys are aware that cam profiles are different , depending on what type of surface they are going to articulate with, right?

The geometry is distinctly different...

Another thing to consider beyond the geometry of the mating surfaces and how it affects all sorts of valvetrain action...

Is that the big advantage of roller rockers is they will allow for more radical acceleration lobe profiles without excessive friction and wear... A cam profile made to take advantage of roller contacts will have a more broad shouldered look to it.. able to vault to higher lift quicker and more duration spent at the higher lift portion of each event....

 

Next consideration is if you have a true roller cam profile... And roller followers, a rocker in this case... You could have a very nice performance oriented beginning of a valvetrain...

The fly in the ointment would be if you didn't have something to deal with all the stress on the valve end of the rocker assembly...

Rockers tend to "side load" a valve stem... As the rocker pushes down on the valve... And swings through it's arc...it also moves slightly across the tip... Putting a side load an the stem and guide assembly....  A more radical cam action would translate into more side load pressures and increased guide and stem wear...

A roller on the rocker end actuating the valve would moderate a lot of the side loading... But in this case also take away the ability to set valve to rocker clearance....

Now... If you pair a roller rocker assembly up with a cam profile not made for roller rockers... The difference in geometry will make that cam less performance profiled in terms of valve at lift ,than if it were mated with standard rockers... 

All stuff to be aware of when mixing valvetrain componentry...

A public service... Because I care

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Topic is mix and match, rambler...

Cams and Rockers....

Just helping with the greatest gift of all... The sharing of knowledge...

I don't really think the tech crowd is supposed to have an anti information bias.... No?!?

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 To mixxer: Nah, I'm not in a contest. I'm just trying to keep myself off the street messin with my old 2 valver. That's why I'm building a vintage sled. I've got a "sorta trick" 88 XR that runs good and a CRF250 when I feel the need for real speed. I've got the means and the time (and money) to do whatever I want so it's just a hobby thing for me. Kinda a what if Honda got serious back in the day. It'd be nice to have a chance against the old Cr's at the vintage races and not ring my poor little 88's neck. I went 1/1 against an 87 CR 125 last time I went vintage racing. Going older with a twin shocker seemed like it might be fun. I meant no offense to anyone. I really wanna thank Mixxer and Chuck and all the others for all their fantastic knowledge and input. I've been riding since 1972 (I'm 60, ugh) and always prefered 4 strokes, just wishing somebody would build a proper 4 stroke motocrosser. Relivin the past/what if. Now, I guess I'll just build my own.   :)

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. The topic is fitting an XR/ATC200X cam in a CRF head. No mention of roller rockers at all. I would not dare to mention anything I know would not work. Only things I have done that do work properly or things I am confident will be better when completed. All these negative waves are getting very tedious

 

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I'm trying to figure this out. 

So the rocker, is mounted securely in place in the rocker cover with a pin that does not move. The only movement is the "rocking" up and down with no other freeplay. 

The cam spins around and slides under one end of the rocker, pushing that end up, and forcing the other end down.

The other end pushes on the top of the valve stem, causing that valve to open. 

Ok so we might have a SLIGHT amount of sideload in Stock form, that still allows for hundreds, or thousands of hours of worry free running operation.

If the only thing that in this equation that changes is the cam, how is there more sideload applied to the valve stem?

Remember now, the rocker is fixed in place with no play, so regardless of cam, the rocker will ALWAYS follow the same arc. 

Only thing that will cause abnormal function, is abnormal wear on the top of the valve stem, or wear in the rocker pivot hole or pin or valve end of the rocker. Or worn valve guide or bent spring etc...

Roller rockers might be a different story, but I don't know jack doodly about them. But like others said, rollers were never mentioned 😯

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8 hours ago, adnohguy said:

 

 


Are they liberals or gun owners?

 

 

I don't know. Ask you downer mate. He is the one who said some people he just doesn't like. Especially ones with a different opinion.

Edited by greenhuman
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   Good grief guys, I was only joking about the extremist thing. Now, on to the subject at hand. It was the pivot shaft that I made with needle bearings. The guy that used to own the 3 wheeler (with the Curtis Sparks motor) cam to me and showed me the pivot pins. They were kinda blue and he was 'concerned'. He had a rocker shaft that had been ground down to fit needles inside the rocker. It was from an old cb750 single cammer drag bike (with a "big" cam). He asked me if I could make some for his 200x 3 wheeler. So I did. Now I've got that motor. I swapped the 3 wheeler chassis to the local junk yard to get all the parts that I needed to swap the kick start over to the 2 wheeler set-up.

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