175 cam in a Cb200

Gearing ratios are entirely independent of power numbers (unless you're measuring power at the back wheel and even then it only matters a little, but ignore that for now).

Manufacturer's power numbers are stated when the power is measured from the crankshaft, so gearing is completely irrelevant.

The amount of power an engine can generate is actually a mathematical calculation. It's derived from the torque produced at a given RPM.

Read through this when you have a couple of hours: http://www.dotheton.com/forum/index.php?topic=39814.0

As far as new cam and new carbs on the CB200, you're probably right. I admit I don't have a good deal of experience with these engines, but because the 200 has more displacement than the 175, it shouldn't take too much work to get it to the same power numbers. Cam and carbs should open it up at the top end, and that's where you'll find all those missing ponies.
 
Sonreir said:
Gearing ratios are entirely independent of power numbers (unless you're measuring power at the back wheel and even then it only matters a little, but ignore that for now).

Manufacturer's power numbers are stated when the power is measured from the crankshaft, so gearing is completely irrelevant.

The amount of power an engine can generate is actually a mathematical calculation. It's derived from the torque produced at a given RPM.

Read through this when you have a couple of hours: http://www.dotheton.com/forum/index.php?topic=39814.0

As far as new cam and new carbs on the CB200, you're probably right. I admit I don't have a good deal of experience with these engines, but because the 200 has more displacement than the 175, it shouldn't take too much work to get it to the same power numbers. Cam and carbs should open it up at the top end, and that's where you'll find all those missing ponies.
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Lol I have read it twice all the way through! That is why I am asking these questions. Common sense would tell me the 175 is a better motor. Back to my hypothesis. If you add a 200 jug to the 175 and put the same megacycle cam in the 200 wth the same carbs I would think the 175 would outperform the 200!
 
I think the 200's redline also has to do with rotating mass.

The 200 has a longer rod length and uses a 1mm bigger wrist pin (and a larger piston), than the 175. The stroke may be the same as the 175, but to compensate for the longer rods the Jugs were about 10mm taller on the 200.

I think the clutch basket on the 200 also weighs a considerable amount more with its ball and ramp type clutch, and a slightly wider basket drive gear. I didn't weigh both 175/200 clutch fully assembled, so its just an approximation.

All meaning that the rotating assembly is heavier to provide a smoother riding machine perhaps.
 
That's a tough comparison to make on paper.

While a stock 175 would put out better numbers than a stock 200, comparisons between two modded motors is very difficult without real world data.

Assuming you get 200cc out of the 175 motor, and them compare it to a cammed and carbed CB200, I think it would be a pretty close race.

I would expect to see more gains on the 200 by going with bigger carbs and a hotter cam than I would expect to see out of displacement alone on the 175.
 
acm177 said:
I think the 200's redline also has to do with rotating mass.
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I honestly admit that I don't know for certain, but I would feel confident in assuming this is not the case. Honda bottom ends are well known for their reliability and longevity. Furthermore, with only a 41mm stroke, the mean piston speed at 9,000 RPM on a CB200 is only 2421 feet per minute. Most engines reliably survive up to 4000. My 360 has seen 11,000 RPM more than once, and that's still only 3661 feet per minute.
 
acm177 said:
I think the 200's redline also has to do with rotating mass.

The 200 has a longer rod length and uses a 1mm bigger wrist pin (and a larger piston), than the 175. The stroke may be the same as the 175, but to compensate for the longer rods the Jugs were about 10mm taller on the 200.

I think the clutch basket on the 200 also weighs a considerable amount more with its ball and ramp type clutch, and a slightly wider basket drive gear. I didn't weigh both 175/200 clutch fully assembled, so its just an approximation.

All meaning that the rotating assembly is heavier to provide a smoother riding machine perhaps.
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That makes sense!
 
Sonreir said:
I honestly admit that I don't know for certain, but I would feel confident in assuming this is not the case. Honda bottom ends are well known for their reliability and longevity. Furthermore, with only a 41mm stroke, the mean piston speed at 9,000 RPM on a CB200 is only 2421 feet per minute. Most engines reliably survive up to 4000. My 360 has seen 11,000 RPM more than once, and that's still only 3661 feet per minute.
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earlier when you were talking about gearing ratios what did you mean? The cam to crank ratio?
 
Texasstar said:
earlier when you were talking about gearing ratios what did you mean? The cam to crank ratio?
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Cam to crank ratio is always 2:1. The cam needs to spin at half the rate of the crank and there's no way around that. The number of teeth the manufacturer chooses to use is based on materials and stress decisions. Higher stresses will usually require more teeth.
 
Sonreir said:
Cam to crank ratio is always 2:1. The cam needs to spin at half the rate of the crank and there's no way around that. The number of teeth the manufacturer chooses to use is based on materials and stress decisions. Higher stresses will usually require more teeth.
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forgive me for being stupid. I am just thinking it is possible to have vtec on a 70's bike :)
 
Everything is possible. How much time and money do you have? :D

The thing is, even with VTEC, you're still running at a 2:1 ratio. VTEC uses hydraulics and electronics to switch between multiple cam profiles. If you want to get the cam grind, machine the heads, install hydraulics and electronics, it may be a pretty fun project. :)
 
Cams always rotate at 0.5 times the speed of the crank. No more. No less. Not ever. Think about it. The cam has to open teh valves at teh same point in relation to piston position, It can't open at TDC on one revolution and BDC on another etc. Always 2:1

Taller pistons, taller block and longer rods require a longer cam chain and adding teeth to crank and cam help reduce wear on sprockets and chain.

CB200 is a less sporty motor by design. The market for small sporty bikes ceased to exist and the 200 became a starter/commuter bike. But the head flows way more than the motor can use. Who knew.

There no such things as 2 stroke cams. 2 strokes fire once per revolution versus a 4 stroke which fires once every two revolutions. Therefore two strokes tend to make more HP per liter than 4 strokes but burn more fuel and create more burned and unburned hydrocarbons.

CB200 has a higher final gearing Rear sprocket:drive sprocket at 2.33 compared to a 175 at 2.470 and 160 at 2.50, so it's won't rev as hard even if it could..

200 carbs are a little small for the size of the motor. Bigger motor breathing through smaller carbs = higher gas velocity and lower peak revs. CB160-175-200 make only about 10-12hp at the rear wheel stock and some modified race motors make less than that...

CB200 pistons are much heavier than 175 or 160 pistons and they have long skirts both of which inhibit free revving. Pistons can be lightened and shortened and modified to reduce that deficit.

Our motor does not use CB200 jugs. the "175" uses stock CB175 jugs bored 1mm o/s. Our 240cc motor uses custom pistons in modified CB175 barrels with modified CB77 liners. None of teh 160-175-200 motors likes to rev very high despite the abuse that they are handed. They are basically all done by 10 - 10.5. Want more out of a CB200, use a decent cam and better carbs. For a hot street 200 a mild cam, raised compression and 22mm crabs would probably be a decent combo. For a Mile motor, i'd be looking for more compression and more cam to go with 26 or larger carbs.

Full race CR26s would be nice.
 
Sonreir said:
Everything is possible. How much time and money do you have? :D

The thing is, even with VTEC, you're still running at a 2:1 ratio. VTEC uses hydraulics and electronics to switch between multiple cam profiles. If you want to get the cam grind, machine the heads, install hydraulics and electronics, it may be a pretty fun project. :)
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i have 8 years till my son is 18! We are buying a 175 to build for my daughter. Thanks for your patience! Sometimes we have a shoot first and see what flies out mentality in Texas. ;)
 
If you want to toy around with a motor, take a look at the CB125.

A single cylinder engine usually takes a lot less time and money to get "right".

Then you can apply what you've learned to bigger engines with less wastage.
 
teazer said:
Cams always rotate at 0.5 times the speed of the crank. No more. No less. Not ever. Think about it. The cam has to open teh valves at teh same point in relation to piston position, It can't open at TDC on one revolution and BDC on another etc. Always 2:1

Taller pistons, taller block and longer rods require a longer cam chain and adding teeth to crank and cam help reduce wear on sprockets and chain.

CB200 is a less sporty motor by design. The market for small sporty bikes ceased to exist and the 200 became a starter/commuter bike. But the head flows way more than the motor can use. Who knew.

There no such things as 2 stroke cams. 2 strokes fire once per revolution versus a 4 stroke which fires once every two revolutions. Therefore two strokes tend to make more HP per liter than 4 strokes but burn more fuel and create more burned and unburned hydrocarbons.

CB200 has a higher final gearing Rear sprocket:drive sprocket at 2.33 compared to a 175 at 2.470 and 160 at 2.50, so it's won't rev as hard even if it could..

200 carbs are a little small for the size of the motor. Bigger motor breathing through smaller carbs = higher gas velocity and lower peak revs. CB160-175-200 make only about 10-12hp at the rear wheel stock and some modified race motors make less than that...

CB200 pistons are much heavier than 175 or 160 pistons and they have long skirts both of which inhibit free revving. Pistons can be lightened and shortened and modified to reduce that deficit.

Our motor does not use CB200 jugs. the "175" uses stock CB175 jugs bored 1mm o/s. Our 240cc motor uses custom pistons in modified CB175 barrels with modified CB77 liners. None of teh 160-175-200 motors likes to rev very high despite the abuse that they are handed. They are basically all done by 10 - 10.5. Want more out of a CB200, use a decent cam and better carbs. For a hot street 200 a mild cam, raised compression and 22mm crabs would probably be a decent combo. For a Mile motor, i'd be looking for more compression and more cam to go with 26 or larger carbs.

Full race CR26s would be nice.
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Thanks Teazer my son just read it to me...it was good for both of us.
 
Sonreir said:
If you want to toy around with a motor, take a look at the CB125.

A single cylinder engine usually takes a lot less time and money to get "right".

Then you can apply what you've learned to bigger engines with less wastage.
Click to expand...

This is exactly what I'm trying to do now.. Looking for a CB100 or 125 motor to play with.. know anyone that has one for a friendly DTT price ? ;]
 
Sonreir said:
If you want to toy around with a motor, take a look at the CB125.

A single cylinder engine usually takes a lot less time and money to get "right".

Then you can apply what you've learned to bigger engines with less wastage.
Click to expand...
Thanks Sonreir we are finishing up our first motor. We have kept it basicslly stock. We lapped our first valves ever last week! We have made many mistakes none that haven't been redeemable. Yet. However we have learned more in the last 10 weeks from DTT than we could from the community college course we were gonna take. I want my son to have your wisdom even at my expense both pocket book and embarasssment. Things that may seem fundamental to you are just new to us. However we are not afraid to ask stupid questions I am too old not to. But if we ask a stupid question and learn from it it is better than not asking and not learning. The reason why we grow old is because we begin to be afraid to fail. Failure is an option and for most it is how we learn. Thank you for your patience. We have more engines and more mistakes in our future. Maybe one day my son will be like you and Teazer...willing to help and old bloke teach his son :)
 
Please don't talk to me about mistakes. Learning experiences are good and trying to get more power out of old engines provides many opportunities to learn :)

As for mistakes, that's what I just made on a brand new chain which is now 3 links short. That's a new one for me. I have fitted dozens of chains and this is a first for me. proving yet again that there are new mistakes to make whenever you look the wrong way for a second.
 
Texasstar said:
what I am wondering is why honda went to 2 more teeth on the cam sprocket for the 200. How many teeth are on the Primary drive at the crank of a 175 vs a 200? If they have the same number of teeth means the cam of 200 is turning slower than the 175. A slower cam rotation means less flow. They both have the same stroke. We know the 175 had bigger carbs. However Teazer said the cams have the same lift. The 200 duration is 220 ish and megacycle cam is 256 ish. 1500 rpm is a lot. So a 175 with a 200 jug would out perform a 200 with the same megacycle cam. Megacycles cam is the same lift duration for both bikes. Does that make sense?
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Dude, that would be impossible. crank always turns 50% in relation to cam. Thats just the way it is.
 
Texasstar said:
thank you! Do you know what the duration was on the stock 175 cam both intake and exhaust?

Why the did the 175 had a 1500 rpm higher redline?

Wouldn't a two stroke cam move faster than a four stroke cam?
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A two stroke cam? SERIOUS?

edit.. sorry had some beers, dont want to be a bitch. Just laughed real hard about it, thats all :)
 
Bert Jan said:
A two stroke cam? SERIOUS?

edit.. sorry had some beers, dont want to be a bitch. Just laughed real hard about it, thats all :)
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Hold my beer watch this :) that is what we say in Texas when we are about to do something real stupid...or as forest gump said. "Stupid is as stupid does" What are drinking Bert?
 
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