Carbs for 1015cc or 1075cc Upgrade

I've learned more from this thread than from many others - thanks for asking, no offense taken, go for it.

DoubleDub wrote:

I've learned more from this thread than from many others - thanks for asking, no offense taken, go for it.

It's up to Larry, now? Larry I want to ask some basic questions, to help me understand, and to help others.
I know you sell, what you have learned, I won't be putten you out of business........

kzz1p wrote:

larrycavan wrote:

DoubleDub wrote:

Larry - I also see on your web site that you say the Webcam 118 needs a new cam chain - do you specifically mean that the cam chain needs to be a different length or just replaced with an OE cam chain?

Sorry for the dealy. I'be been busy and today is my birthday as well:)

Regarding the engine setup in your previous question. YES, it's a perfectly streetable. PM me and I'll put you in touch with a guy that has that exact setup. He just got it together and on the dyno. It went from 74HP - 55Ft/lbs Torque to 104HP - 77 Ft/lbs Torque. It's making like 92HP at 6500RPM.

Out of that 30HP increase, I'd dare say 20 of it came from the cylinderhead porting. That's 5HP per cylinder at 25$ per HP.

I personaly would go with the Web #45 Grind cams. They are not drop in. The 118 grind is a nice street cam, with or without head work.

The 110 & 45 Grind really shine with a flowed head. Or vice-versa...depends on how you look at things I guess.

Here's the story behind the cam chain.

You can take any drop in cam and bolt them in with stock sprockets on 110 lobe centers and they'll work fine. With an old cam chain, there's no way of knowing how muct later than 110 you'd be on the intake cam.

Once you get above that level of cam, they really should be degreed in. These motors are old. Cam chains stretch. A new cam chain is always advisable in a performance type application.

Here are 3 Web streetcams with more than the standard information. That 45 grind will put some ft/lbs where you want them

Master # Lift Dur@.020 Dur@.050 Dur@.100

45 .415 268° 244° 220°
110 .395 284° 256° 228°
118 .365 283° 246° 216°

Larry,
I guess you are an old goat, now! (you know, I love you)
Tell me in simple English. The #45 grind, is it in the 280*(+/-) range @ running clearance?

If so, that would be a dam good, upper mid range, torque cam.

What is your projected RPM range on that cam?

Do you think, it will work, in any size motor?.....John

PS - HAPPY B DAY!

I'm not sure what the dur. is at running lash.

It's relevant to the size of the motor it's going to be used in plus the size of the valve & the carbs chosen.

The thing with motorcycle cams specs is the manufacturers never give you enough information to begin with. Trying to compare two cams based on lift and a single lift point of duration won't tell you much about the cam.

Let's say for example you have a little 1015cc motor with 10.5:1 pistons. It's more cam for that motor than it would be for an 1075 with equal compression.

Let's say you have a typical 1075 street compression motor with 33mm Mikunis and something like a Web #109 grind and a stock or lightly cleaned up KZ head.

That sort of engine combo likes to see 4500+ RPM before it's in the "happy zone". Hit the carbs wide open down low and there's not enough signal on the carb to fuel the motor properly at low RPM because the cam duration is too great.

So you put some 34mm RS carbs on the motor and they help that situation because they have an accelerator pump.

But....if you swapped out the 109 for the 45 grind it would improve the midrange to a greater extent than the carb swap. It would be IMO a better street motor all around.

Now say you have the same 109 Grind in the 1015cc motor with the same 33 Mikunis. It would be a turd below 5000. Put the 34RS carbs on it and it will stil be a turd.... swap the cams for the 45 grind and it will really improve the street behavior...

In short, if you're going to put a carburetor sized for RPM more suited for the top of the tach and still want some respectable lower mid range pull.....pick a cam that will help do that. Compoents must work together. You can, at least to some extent, assist a poor carburetor choice by making a wise cam choice...

IMO and this is just me relating my experiences and preference based on them..... 34mm performance carburetors don't belong on anything less than a 1200cc motor for a streetbike. Guys want them. They buy some used dragbike junk cams off ebay that have way too much duration for a street ride.

They put the bike together and then spend the entire summer trying to make the bike accelerate hard in exactly the RPM range where they actually ride....

Then they're on the Internet trying to find the secret to making bottom end power with top end power components...

Guys want different things out of their old Z powered bikes. Some are willing to accept short comings in the power spread to achieve the thrill from 5500 on up. Some want that "wack it hard and go" at a lower RPM and will trade away the top end thrill for it.

Best advice I can give is this.

Be realistic in how your ride the bike. Pick components that compliment each other for that type of riding...and have a ball running around on your old KZ..

Larry whats your opinion on a vance and hines street meg? I've got my stock head pipes going two into one on each side. I just extended the head pipes and added some 2.5 inch chevy muffler pipes. It picked up power from the bottom to the top. I don't want to find out the 4 into one doesnt help anything over what I have on it now. I've never seen dyno results on any 4 into 1 pipes. If you seen what I did to my cylinder head you'd probly never stop laughing. As far as the ridability goes it's got it all. Ive got a 1015cc with norris .407 cams and 28mm carbs. I hate asking for free information but a 300 dollar myth is not on my list of improvements to make.

nads.com wrote:

Larry whats your opinion on a vance and hines street meg? I've got my stock head pipes going two into one on each side. I just extended the head pipes and added some 2.5 inch chevy muffler pipes. It picked up power from the bottom to the top. I don't want to find out the 4 into one doesnt help anything over what I have on it now. I've never seen dyno results on any 4 into 1 pipes. If you seen what I did to my cylinder head you'd probly never stop laughing. As far as the ridability goes it's got it all. Ive got a 1015cc with norris .407 cams and 28mm carbs. I hate asking for free information but a 300 dollar myth is not on my list of improvements to make.

Dual 2 into 1 can be a good setup. If it's working good and you're happy with the comsmetics. Run it. You might want to get yourself a Burns Stainless catalog. Some nice items in there if you're a DIY pipe guy.

How much you get out of a 4-1 pipe depends on the rest of the combination. One thing you do is loose some unwanted weight with a header.

What you gain in one respect you tend to loose somewhere else with a lot of pipes.

larrycavan wrote:

kzz1p wrote:

larrycavan wrote:

DoubleDub wrote:

Larry - I also see on your web site that you say the Webcam 118 needs a new cam chain - do you specifically mean that the cam chain needs to be a different length or just replaced with an OE cam chain?

Sorry for the dealy. I'be been busy and today is my birthday as well:)

Regarding the engine setup in your previous question. YES, it's a perfectly streetable. PM me and I'll put you in touch with a guy that has that exact setup. He just got it together and on the dyno. It went from 74HP - 55Ft/lbs Torque to 104HP - 77 Ft/lbs Torque. It's making like 92HP at 6500RPM.

Out of that 30HP increase, I'd dare say 20 of it came from the cylinderhead porting. That's 5HP per cylinder at 25$ per HP.

I personaly would go with the Web #45 Grind cams. They are not drop in. The 118 grind is a nice street cam, with or without head work.

The 110 & 45 Grind really shine with a flowed head. Or vice-versa...depends on how you look at things I guess.

Here's the story behind the cam chain.

You can take any drop in cam and bolt them in with stock sprockets on 110 lobe centers and they'll work fine. With an old cam chain, there's no way of knowing how muct later than 110 you'd be on the intake cam.

Once you get above that level of cam, they really should be degreed in. These motors are old. Cam chains stretch. A new cam chain is always advisable in a performance type application.

Here are 3 Web streetcams with more than the standard information. That 45 grind will put some ft/lbs where you want them

Master # Lift Dur@.020 Dur@.050 Dur@.100

45 .415 268° 244° 220°
110 .395 284° 256° 228°
118 .365 283° 246° 216°

Larry,
I guess you are an old goat, now! (you know, I love you)
Tell me in simple English. The #45 grind, is it in the 280*(+/-) range @ running clearance?

If so, that would be a dam good, upper mid range, torque cam.

What is your projected RPM range on that cam?

Do you think, it will work, in any size motor?.....John

PS - HAPPY B DAY!

I'm not sure what the dur. is at running lash.

It's relevant to the size of the motor it's going to be used in plus the size of the valve & the carbs chosen.

The thing with motorcycle cams specs is the manufacturers never give you enough information to begin with. Trying to compare two cams based on lift and a single lift point of duration won't tell you much about the cam.

Let's say for example you have a little 1015cc motor with 10.5:1 pistons. It's more cam for that motor than it would be for an 1075 with equal compression.

Let's say you have a typical 1075 street compression motor with 33mm Mikunis and something like a Web #109 grind and a stock or lightly cleaned up KZ head.

That sort of engine combo likes to see 4500+ RPM before it's in the "happy zone". Hit the carbs wide open down low and there's not enough signal on the carb to fuel the motor properly at low RPM because the cam duration is too great.

So you put some 34mm RS carbs on the motor and they help that situation because they have an accelerator pump.

But....if you swapped out the 109 for the 45 grind it would improve the midrange to a greater extent than the carb swap. It would be IMO a better street motor all around.

Now say you have the same 109 Grind in the 1015cc motor with the same 33 Mikunis. It would be a turd below 5000. Put the 34RS carbs on it and it will stil be a turd.... swap the cams for the 45 grind and it will really improve the street behavior...

In short, if you're going to put a carburetor sized for RPM more suited for the top of the tach and still want some respectable lower mid range pull.....pick a cam that will help do that. Compoents must work together. You can, at least to some extent, assist a poor carburetor choice by making a wise cam choice...

IMO and this is just me relating my experiences and preference based on them..... 34mm performance carburetors don't belong on anything less than a 1200cc motor for a streetbike. Guys want them. They buy some used dragbike junk cams off ebay that have way too much duration for a street ride.

They put the bike together and then spend the entire summer trying to make the bike accelerate hard in exactly the RPM range where they actually ride....

Then they're on the Internet trying to find the secret to making bottom end power with top end power components...

Guys want different things out of their old Z powered bikes. Some are willing to accept short comings in the power spread to achieve the thrill from 5500 on up. Some want that "wack it hard and go" at a lower RPM and will trade away the top end thrill for it.

Best advice I can give is this.

Be realistic in how your ride the bike. Pick components that compliment each other for that type of riding...and have a ball running around on your old KZ..

i love this guy! same thing the older guys told me when i was a kid and too smart to listen to them! :laugh:

larry is dead right about matching components i just thru a set of 33 smoothies on my little 1015 13-1 drag motor and below about 5000 if you whack the throttle hard it falls flat on it's face if you sneak up on it it will handle it by sneaking up on i mean rolling into the throttle gently. which will be fine for what i'm doing with the bike but unacceptable on the street theonly reason i put them on my little motor is that i want my 29's back for my street bike and i'm building a high compression 1197 motor for the little bike so i'll live with my pain for now. but definitly bigger is not always better the 33's will definitly work way better on my 1200 motor. the 33's made about 9 horse more on top than my 29's did but if any but me was riding it they would hate it the difference in throttle response between the two sets of carbs is incredable the 29's are way more responsive. which is why i like to run them on my street bike.

just for general info...i ran my bs34 s for about 50 miles today .....got a good feel for them...i m running 40 pilots and 140 mains......definitely have to back down mains to about 135...if i ease into it,pulls great...whack it at 4k and falls flat on its face.....avoid being a ham-fisted brute with the jets i have, and 100 is no problem....i m gonna re-jet this week sometime and post up results as there arent a lot of people running these....between my stock 26 and 28 s i have and these, the bs34 are by far the most responsive for the cash....just my results...yours may differ....

timebomb33 wrote:

larry is dead right about matching components i just thru a set of 33 smoothies on my little 1015 13-1 drag motor and below about 5000 if you whack the throttle hard it falls flat on it's face if you sneak up on it it will handle it by sneaking up on i mean rolling into the throttle gently. which will be fine for what i'm doing with the bike but unacceptable on the street theonly reason i put them on my little motor is that i want my 29's back for my street bike and i'm building a high compression 1197 motor for the little bike so i'll live with my pain for now. but definitly bigger is not always better the 33's will definitly work way better on my 1200 motor. the 33's made about 9 horse more on top than my 29's did but if any but me was riding it they would hate it the difference in throttle response between the two sets of carbs is incredable the 29's are way more responsive. which is why i like to run them on my street bike.

31mm Keihin CRS with the short velocity stacks would be sweet on that motor. I'll bet you'd ET better when them than 33 Mic SB's...

I should also clarify something in my other post regarding 34s on nothing less than a 1200cc street motor. I'm talking about 34mm throttle slide carbs like the RS Mikuni.

if i had a set i'd throw them on on the may 9th weekend i,m gonna go back and forth between my 33's and my 29's just to see how much differance their actually is if i had a third set of carbs that would be no problem to do them as well.

I had 33s on my 1105 and traded them even for a set of 29s. Im much happier with the way it runs now, Its a 10.25-1 1105 {sleeved 900 built in 77} Superbike Mike street head & drop in shim on top cam 395 260/260 and Kerker pipe. It may have been a hair stornger wide open but was a pain the butt with the 33s to ride around. Id like to try a set of flat slides but they are too expensive on Social Security. The 29s used are getting almost as expensive as new flat slides though

the prices that some of these guy's are paying for 20 plus yearold carbs is crazy i often thought about putting mine up for sale and buying a new set of cr's or a set of 34 flat slides and pocket the left over cash.