Honda twins performance (cb350 cl350)

[foundation982]

Okay so I've been searching around and haven't found any solid testimonies on performance parts.


Pod filters? velocity stacks? straight pipes? constricted pipes? jet size? spark plugs? electrical upgrades? Battery/capacitor?
Weight reduction modifications also welcome


No big bore kits, crazy front end brake swaps, or LED lighting, because obviously these add performance I want this thread to be about questionable upgrades.

 

[session101]

performance....lol how much $$$$$$ are you willing to dump on a bike that will only get you about $3K when you're done?

from my research for this bike, performance is not a good idea, but reliability is the way to dump your money for a good price. such as Electronic ignition, better charging system, possibly fork/brake upgrade, possibly better tuning or upgrading your stock carbs to mikuni ones.

best case for anything like this is...if you want a faster bike, or better handling... just shave the weight, because thats about the cheapest and best way to go... the bike only has a small amount of HP but if you can get the weight below 300lbs then you go yourself a mover

fiberglass seat, cutting steel parts, lighter wheels, stuff like that

you'll spend over $1.5k on a motor with only like 2hp gain...its not worth it

 

[foundation982]

That was pretty much my thought is HP gain is not worth the money better off going out to buy a bigger bike than dumping money into this, I'm pretty much just wondering Exhaust and air filters my bike has straight pipes and some cheapo pod filters and it doesn't really like cruising around 30-35mph it was wants to be full throttle at all times

 

[Sonreir]

OK... here goes...

1.) Pod filters and velocity stacks - They both serve to increase air flow which has the potential to increase torque. More often than not, this will also require a rejet. Stacks are usually better for performance than pods, but also cost more.

2.) Straight pipes - When ever possible, keep exhaust pipes straight. If that's not possible, keeps the bends with a large a radius as possible. Tight bends causes pressure. The difference in pressure between the exhaust gases exiting your cylinders and the gases in the exhaust pipe are a large factor in determining how efficient your engine is running. Building for power is ALL about efficiencies. If you meant straight as in no muffler, than yeah. This will generally lead to an increase in power so long as you account for different fueling needs.

3.) Constricted pipes - Diameter of your pipes controls the exhaust gas velocity. There's a lot of math that goes into figuring out an ideal diameter, but one of the most important decisions has to do with the ideal range of RPM operations. The engine speed at which you desire maximum torque will help determine the diameter of your pipes. Generally speaking, smaller diameter means increased torque at low RPMs which sacrificing torque at higher RPMs. Go too big and you get no benefit at any RPM range.

4.) Jet sizes - Though not strictly true, it's best to ignore jetting and concentrate on air flow. At ideal fuel/air ratios for power (around 13:1 or a bit less) getting enough air into the engine is the difficult part. Adding fuel is easy. You choose jets depending on how much air is available and changing jets without changing air is only going to cause problems. If someone has an otherwise stock bike at sea level and they changed the jets thinking to increase power, they're not going to happy with the results.

5.) Spark plugs - Not much gains to be had here. Just make sure you're using decent plugs in the correct heat range. I've head that plugs with multiple side electrodes can gain a bit of power, but never tested it myself. The thought it that extra little bit of metal in the cylinder increases compression by a very small amount.

6.) Electrical mods - If your charging system it working well, there's no real gains to be made. A weak spark will often lead to a weak ignition, so focus on keeping the spark strong. Upgrades to 5 ohm coils can yield benefits but like anything else, do it for a reason, not on a hunch.

7.) Weight reduction - Almost all reductions in weight are going to be beneficial to straight-line acceleration. Reductions in weight usually help with cornering as well, but bear in mind that a change in weight is almost always a change in center of gravity as well and this will affect your corning (not always for the better). Weight reduction has no real effect on top speed.

 

[Sonreir]

Also... I dropped $1200 into my motor. It's not been on a dyno yet, but I'm expecting around a 30% increase in peak power. Most of this increase is coming at the expense power in the lower ranges of the RPM band though, so it's not an increase overall.

 

[foundation982]

^ pretty much what I'm looking for thanks sonreir I also would like to know of any electrical upgrades that make the bike more reliable as well I know some guys are making rectifiers out of cheap radio shack parts and such, I would love for people to post any valid upgrades and clarification on what works/what doesn't

 

[Rocan]

Weight reduction is the biggest difference in performance.

Focusing on the engine only:

Open stacks are not necessarily a direct way to get more power. Personally I'm designing an airbox when i get the time as it provides better power throughout the range (why do you think most ALL manufactured bikes and race bikes these days use an airbox?)

Pipes can be upgraded, but not by much. the biggest gain is the reduction in weight. Honda got the pipe dimensions right from the factory.

An early type 1 cam is a bit hotter then the later cams, but nowhere near that of a performance cams. loads to choose from; go mild on a street bike.

IMHO the best mod for your money is an electronic ignition. Yes, the classic points works perfectly fine for most everything you do, but the benefits of an electric are innumerable, including a rev limiter (keeping you from overrevving when you get false neutrals) as well as being maintenance free. Pricy, but worth it.


Truth is though, your best just making the motor run as good as possible stock (set to all specs perfectly) and then upgrade the things that have gotten better with time (mostly ignition parts). youll have a lot more RELIABLE of a bike, on top of the little bit of extra power.

its a 350. unless if your racing, don't waste your time (or money!). believe me, I speak from experience. the only thing big mods give you is bragging rights.

 

[foundation982]

Good stuff Rocan haha The "Stock performance" is all my dad who is one of the purist mechanics has preached to me my entire life that aftermarket crap is mostly to make money, he even frowns upon me for customizing this 350 he keeps telling me to make it all "original"
But screw that I have a mint stock CB360 already.
I don't plan on doing much to the engine Just mostly wondering about pod filters and exhaust and ignition as well as any other suggestions

 

[Wee Todd]

stick with the basics,,,,,,,,,wham it, slam it, blob it ,chop it????????????? ensure the carbs are right ,sound ignition and charging system,,,the rest of it,,,requires you stop and steer the thing down the road

 

[Rocan]

pod filters lose power everywhere except at WOT. I will stick to my guns on this one until i see dynos saying otherwise. they do look "cool" though.

I'm not about "stock".... i cant leave ANYTHING alone. but I'm about reasonable mods that aren't a waste of money. If cold air intakes really worked to make so much more power on cars wouldn't you think factories would do it in the first place? Airboxes not only make more reliable power across the board because of the way that it smooths airflow and makes it less turbulent, but also because of whats known as helmholtz resonance, which provides a pressure wave (which can be tuned for a different frequency) which increases power at a specific rpm range. very useful for getting a broad smooth power curve, which I will take anyday over peak HP.

 

[HondaCBGuy]

I know it's an old thread but I thought this might be relevant to anyone searching for mods. Kawasaki KZ400 pistons will fit but you do need to rebore. They are lighter than the Honda units so I guess this also comes under weight saving.

 

[Landon_cl350]

I've got a 1973 Scrambler that I just recently got the c ank case back together. Im looking for the best/easiest way to increase power and torque. Ive read that the 69 cb cam will have more lift than that of the stock cl350 cam. Whats the easiest and cheapest way to increase power? Im mainly lookin for a sort of Franken-twin . I would be very happy if I could just take other parts from other bikes to build this one basses bike. Thanks for any help.
P.S. im las looking for a simple wiring kit for a kick-only setup.

 

[crazypj]

Also... I dropped $1200 into my motor. It's not been on a dyno yet, but I'm expecting around a 30% increase in peak power. Most of this increase is coming at the expense power in the lower ranges of the RPM band though, so it's not an increase overall.

It's rumored Todd Henning's 350 is over $20,000, but, it is a 150mph bike 8)