Father Son 75 CB200T Rise From the Ruins

simo said:
Thanks everyone, I've learnt a lot from this thread
How about this as a solution for melting cam journals
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ball bearings?mike riddel mod?


Sent from my iPad using Tapatalkwasn't mike riddel doing that mod?
 
berusuve.jpg

Crf70 top
Crf110 middle
Cb175/200 bottom


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Texasstar said:
berusuve.jpg

Crf70 top
Crf110 middle
Cb175/200 bottom


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Shorter will give you more leverage but not lift. The roller tip will change the profile of the cam. Roller cams have a different profile so the roller don't snap shut
 
teazer said:
First you have to make power above 11k and that's not a trivial task.

The thing about bearings is that stock cam towers need a fair amount of oil to provide a continuous wedge of oil to ride on. Any break in that film and it's game over. Needle rollers don't need as much oil to operate, but you still need enough oil coming out of the cam to oil the rocker arms.

To reduce oil churn at the bottom end, polish and chamfer the crank wheels so that they carry less oil "threads" and modify the oil slinger plates so they are closer to the crank wheels to "peel off" more oil. Then fit a crankcase breather to reduce oil pressure or even try a PCV valve to reduce case pressure.

Just as an FYI, a buddy of mine blocked off the breather hose on his GS1100 and it forced oil out of every seam. The cases have to breathe.

You could grab a pair of CRF roller rockers and see if they might fit. No one typically cares what goes on inside your motor as long as it's the appropriate size. But remember that changing the radius of the roller/pad changes the came profile - We used to do that on Triumph twins.
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Less friction for a roller bearing. The surface area the pin has is key to surface area friction per rotation . Hence the reason roller bearing require less oil. Two stroke rods are slotted because the two stroke oil you mix with gas is introduced to the bottom end (large end of rod). No crank slap ( when the crank dips to large end into a bath of oil to lay a cannon ball into) or crank wiper needed.crank slap is a power robbing. That's why we put dry (outside oil pumps) system on the 8 second Hondas
I have owned 8 rx7 turbo 2s and a couple of Yamaha sho s . The reason they rev to 11-12 k is because they fight friction.
 
acm177 said:
The length to the tappet adjuster is a bit shorter and wont reach the valve tip on a 175/200.
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Tapper adjustment appear close. The tips are too far apart. The great thing about crf valves is the ride on a cap that you can shim. They generally stay true
 
simo said:
Thanks everyone, I've learnt a lot from this thread
How about this as a solution for melting cam journals
Click to expand...

How is oil feed controlled in that ball bearing conversion? Or put another way, how is the bearing oild if the feed goes stright down to the rockers?
 
teazer said:
How is oil feed controlled in that ball bearing conversion? Or put another way, how is the bearing oild if the feed goes stright down to the rockers?
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I don't know , I'll ask. The cam has 20mm each side of bearing surface , the journals protrude 14.5 mm into the head ( with ball bearings in the head that 14.5 mm has to be removed but that still leaves 5.5 mm of original cam /journal where the oil flow is stock
If the bearings 14mm deep that would leave .5mm between the head and journal at the OD of the ball bearings. the bearings don't appear sealed. Or perhaps a small groove in the journals gasket face from the bottom of the plain bearing deep enough to reach the ball bearing cage? splashes from the rocker?
 
teazer said:
That's close and I may be splitting hairs here, but the big ends are fed oil under pressure - but that pressure is extremely low. They are not splash fed like a C100 single. Oil is fed to the main bearings and as it exits the mains, it is guided by a slinger plate on the bearing which sits inside a groove machined in the flywheels. Oil travels mainly by centrifugal force into the big ends.

But agree 100% that roller bearings need volume and not pressure to work. Typically the big ends are not slotted but the oil basically travels across the width of the rod and "leaks" out the inside edge of the rods.

Rollers do not need a high pressure oil feed and can survive with very little oil pressure or volume.
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I didn't want to get too technical with the details of it. ;D
 
crazypj said:
I didn't want to get too technical with the details of it. ;D
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crazypj and Teazer you didn't have cameras like we do today. So how did you gain your knowledge on how these bikes oiled? Every since we pulled the side cover off lucky to set the timing we have wanted to stick a camera in that oil journal at the bottom. ;)


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Texasstar said:
I am very interested to see that other mod fire up...if the cam journals are left stock for the first 5mm on both sides that is an fix
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Not really sure if that's how he did it it was just my postulating based on the pictures in his build thread.
http://www.hondatwins.net/forums/1-project-logs/15912-1975-honda-cb200t-restoration.html

I'm glad that my worry about the con rod is all for nothing, other than good learning for you and I

Thanks again Teazer, Crazypj, Kop
 
Texasstar said:
crazypj and Teazer you didn't have cameras like we do today. So how did you gain your knowledge on how these bikes oiled? Every since we pulled the side cover off lucky to set the timing we have wanted to stick a camera in that oil journal at the bottom. ;)


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Quite simple, buy cheap/broken stuff and take it to bits, then, see if you can improve things when you put it back together.
The 10,000 hrs thing is pretty reasonable assumption to become expert/maven
 
crazypj said:
Quite simple, buy cheap/broken stuff and take it to bits, then, see if you can improve things when you put it back together.
The 10,000 hrs thing is pretty reasonable assumption to become expert/maven
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"9500 more hours to go son" ;)


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teazer said:
Matt is correct that short fat megaphones make a stronger pulse over a narrow range and longer megs stretch it out. Honda typically work best with long megaphones and very short reverse cone.


Can't wait to see the next set of dyno charts.
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We ordered 2-1 1/2 inlet with 3 3/4 outlet 28" long with 4.6 degree taper megaphones and a 32.5 degree reverse cone that we will cut down to size. What we see on all the rc honda race bikes looks like there is maybe a 1" long reverse cone? Is this correct?


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Here is the tutorial on selecting a megaphone that we found online http://victorylibrary.com/brit/mega-c.htm


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Two and a half inch inlet is huge, if you meant two megaphones one and a half inch inlets it's still real big.
Primary pipe for a 175 twin will only be about three quarters to seven eighths inch inside diameter to pull all the way to 12,500rpm
I'll have to check but I'm pretty sure I''m only using 1.875" (inch and seven eighths) inside diameter on my 378cc motor and that's on a two into one system (it's been finished over 3 yrs now so I forgot ;D )
What bike are you putting it on?
 
crazypj said:
Two and a half inch inlet is huge
I'll hav eto check but I'm pretty sure I''m only using 1.875" (inch and seven eighths) inside diameter on my 378cc motor (it's been finished over 3 yrs now so I forgot ;D )
What bike are you putting it on?
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i am sorry that is 1 1/2" but we bought 2 of them


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