my 900f on the dyno!

Posted: Sun Sep 30, 2007 4:18 pm

Eddie,

Great thread you have going here. This is just the type of informative (learning for me) discussion that I love about this site.

What is your opinion on EFI for these bike? A buddy of mine in Alaska is interesed in setting up EFI on his old KZ and also on my 900F. I have not made up my mind on that option. Right now I have decided to get the CV's off this winter one-way or another. I do have 9-10 months to get it ready for next summer.

Dave

Posted: Sun Sep 30, 2007 5:03 pm

EFI is my savior! Laughing

after 25 years of dealing with jetting and my hands smelling like gas im very glad im doing less and less jetting and efi mapping taking over.

are guys talking a megasquirt?using a set fo throttle bodies from a different bike?

or does someone make a set up for these?

this a very good thread!

i like good discussions with out personal attacks and random blanket statement with no proof.

seems like a very good group of people.pretty tight knit community. Cool

Posted: Sun Sep 30, 2007 5:33 pm

Hey there Burned, check out the "GSXR throttlebody conversion" thread for details on how to set up some TB's.

73HP at the wheel is pretty good for a 900F. There is a CB900F PDF on DynoJet's website that shows stock vs pods and jet kit. I don't remember the exact figures but I think stock was 66 and pods were 72 so you are doing better than they did.

My 900f got 86HP/55lbs torque on the dyno with EFI, 38mm TB's and a Supertrapp w/18 disks @ 38 degrees advance, I also use the 54mm larger oval pods from a GS1100. It was still running a bit rich when we finished at the dyno, I'm thinking its getting around 90hp currently because I have cleaned up tuning a lot since then and I'm running 40 degrees advance.

The new Megatune/logviewer software IS cheating...Hook-up the laptop, go for a ride, datalog 15-30minutes. After, just feed the datalog into the VE analyzer...10 seconds later your VE table has been tweaked! I did pretty darn well tuning manually and later by studying my datalogs, but this is amazing. The throttle is like a volume control on a Telefunken Cool

Posted: Sun Sep 30, 2007 6:18 pm

very cool!i will check out that thread!

theres a couple hp left in mine if i were to lean the main jet more.

once i actually have it road worthy i will do some more tuning.

are you controlling the ignition as well with the megasquirt?if not whos ignition?

mine has stock igniton.pods and vh chrome megaphone only.the baffle is pretty small on the vh so im sure there power to be had with a differet pipe.im sure it will be way louder though.

Posted: Sun Sep 30, 2007 10:41 pm

I'm running a "fuel only" MS1 with a Dyna2000 ignition. Ignition control is available on the newer MS stuff.

Exhaust makes a difference, the ST with 18 disks is on the verge of PITA loud! Taking the endcap right off is hardly louder. But playing with the disks on the ST you can quickly see how you can seriously limit hp. I have three different exhausts for this bike. The most recent is the Jardine set I got this summer right before I upgraded to the new software with the analyzer.(see "Jardine install, tuning, and review") I got the bike really screaming with the Jardines, so now I'm in the process of using the VE analyzer to retune for my stock/V&H duals, and then the Supertrapp. Today I tuned up for the stock header/V&H mufflers combo. It came out almost the same as the Jardines with a tad more fuel required at the beginining of the torque peak at 6500rpm..top end is almost identical. You can quickly pin the tach in the first 4 gears, but will only struggle up to about 9100-9200 in 5th...but I'm geared a little higher than stock too. Wink

CB1100F Joined: Mar 03, 2004 Posts: 3278 Location: Seattle

Quote:

no jet kit. stock needles.never had the air box.

please point me to the proof that the stock air box makes 8hp more.

this isnt my first day.

Oh, dont let them bother you.. This is just the "I cant figure out how to tune my Pods with CV carbs" whiners..... They are quite the vocal bunch.... Cool

Posted: Mon Oct 01, 2007 3:07 pm

The 64 $ question is: Should anyone bother to tune CV's? I haven't seen any reason to learn to tune them wheras I know I'd have to learn to tune something else, like Keihin CR-S, FCR or EFI. I don't think Burned is swayed by Ray's feedback and quite willing to have this conversation about all of the options.

Should someone go down the path of working with the CV's at all? Matt at PSB didn't think so and I have not fealt from my reading that I should do anything more with them myself when factoring in $$/performance/reliability.

Does anyone believe that the CV's are worth investing the time and $$$ to tune? Again, I am asking this for my own selfish benefit because I am trying to make a decison for this winter's build and I want that PITA airbox off my bike for good. Right now, I am waffling around between FCR's and EFI.

Dave

Twinstar Joined: Jul 16, 2007 Posts: 226 Location: NorCal

burned! A big welcome to the board! I've only been a member of this site for a couple of months myself but, found out early on that this whole CV carbs w/o stock airbox topic is a fairly touchy subject around here. I'm really glad to see someone on board that can voice some positive input for the "modified" CV crowd. I don't run them myself but, I had some great results with my first "F" back in 79'.
I posted a thread here that was titled: "The new guy is going to ruffle some feathers", which basically questioned why the "F" riders who ran modded CV set-ups were "dissed" by other members here. It garnered some pretty weird (real high performance knowledge type) comments along the lines of "CV's with pods look gay", etc.
I'm giving you a big high-five right now for showing up with your dyno backed experience.

Posted: Mon Oct 01, 2007 3:56 pm

Dave, if all it is a set of main jets and the pods themselves, I say it isnt near the same money as a carb swap. I have a feeling there are plenty of guys who just want to get rid of that huge airbox. It makes our bikes look oh so much lighter with that thing gone. That alone would be good enough for me.

Now if you want big power gains THAT costs money. Depends on what you really want. I will say this about your particular bike, what made that bike change in looks so dramaticly was going to the lattice pegs. Look at the two pics before and after. Even those make the bikes look light and airy. Pods would do it too. Wink

Feel free to post those pics again too. I never get sick of your looking at your bike.

Posted: Mon Oct 01, 2007 4:00 pm

As a relatively old guy here, its great having fresh guys like Norcal and burned on here.
A huge welcome from the old guard. beerchug

Posted: Mon Oct 01, 2007 4:05 pm

Yes, I'm paying attention. Wink

Posted: Mon Oct 01, 2007 4:28 pm

if there is one thing ive learned helping people on the internet is some people should just leave their motorcycles alone.

ive read some really scary stuff,here included.

my 900 didnt have a air box when i got it.the 750 parts bike i just got has it but the boots are hard as a rock.

as to whether or not the stock carbs are worth pods or jetting,i guess that depends on the owner.

i personally plan to go to fcr's,but even at that i still would not have hesitated to go with pods even if i had a stock air box set.

its left to be seen what the ACTUAL difference on pods vs box deal in on F but i can clearly state on other models with CV carbs there are good gain by removing the air box and using proper jetting.its worth nearly 20hp on a zrx 1100!

the pods gain the bad rap becuase people struggle with the jetting.thats most likely the same crowd that should have just left them alone.

here at 5500 stock F's are rich on the main jet so they really need to be jetted regardless.perfect op to ditch the glove box i mean air box.

ive never not been able to make them work at least as good if not better than the air box.

ive never gone from pods to a air box becuase they were deemed "unjettable".i HAVE removed worn out or just poorly R&D ed jet kits.

like i said before,im a dynojet dealer/center.however,not every kit the make works correctly.im not afraid to tell them that or to remove or just not use there kit.

they tend t o get way over zealous with the taper.that is the case with the F kits as well.

seems liek every case of "couldnt make it" work here involved installing the dj kit at the same time.

Posted: Mon Oct 01, 2007 4:31 pm

also,on added note im very happy to help any one with their jetting.

i have a method of questions and procedures that are very effective in helping sorting out jetting issues.

this basically my main job at thumpertalk.com.i have my own forum.

CB1100F Joined: Mar 03, 2004 Posts: 3278 Location: Seattle

Quote:

The 64 $ question is: Should anyone bother to tune CV's?

I think the question should be, is it worth it vs spending $600+ on a new set of carbs? Some folks dont have that kind of cash lying around. I ran PODS/CVs for several years with NOTICEABLE results. Until I found a set of VM33s for the right price, I had no reason to change the setup... especially when I listened to the guys @ K&N w/regards to jetting.

Flat out LOGIC dictates that the increase in air/gas flow would be better then any factory setup with a severely restrictive air box....

But thats just me... Twisted Evil

Posted: Mon Oct 01, 2007 5:53 pm

burned wrote:

ive never not been able to make them work at least as good if not better than the air box.

ive never gone from pods to a air box becuase they were deemed "unjettable".i HAVE removed worn out or just poorly R&D ed jet kits.

Wow, nothing like a new guy. Doesn't even start with gas or oil or torque. Jumps right into the holy grail, knocks it down and kicks it around in the dirt. Anybody ever see the movie Galdiator?

Laughing

Posted: Mon Oct 01, 2007 6:14 pm

I've worked in 3 new motorcycle dealerships. Between them, all of the 4 major Japanese brands and Harleys were included. I've seen dozens of CV equipped motorcycles successfully tuned with low restriction intakes and exhaust systems. At the Harley/Honda dealership, they have been tuning stock Keihin CV's on stock displacement Harleys with aftermarket intakes and exhausts for years with excellent results. Hell, I can even do it, most recently on my wife's Mikuni CV equipped 2003 Suzuki 650 thumper. I got rid of poor idle quality and backfiring on decel (larger pilot jet and idle mixture adjustment), flat spots/lean surge in the mid range (shimmed the needle .05"), and better top end (larger main jet). When I was done, it had nearly identical jetting to the late '80's model, which wasn't tuned for emissions the way the newer versions are. As beautifully as it runs, I won't be spending money on a new "real" carb. If she wants more power we'll get her a bigger bike. It depends on what the individual wants, and as far as I'm concerned, to each his own.

This is interesting. These dealerships sold a lot of jet kits to customers, but I never saw them in the service areas that I recall, especially at the Harley shop. I've never used a jet kit either, although I'm sure if the kit had the optimal replacement needle for an application it would be better than shimming. I buy individual jets. The goal was to make the bike run beautifully, and that was accomplished. If we left 2-3 hp at WOT on the table so be it, everyone was happy. It's not uncommon to get a lean surge in the mid range of CV equipped bikes if low restriction intake and exhausts have been installed. Get a thinner needle or shim the OEM needle.

This is all shade tree stuff I realize. But it works. I bought an OEM air box for my 11F. If I like the way it runs with the OEM carbs I'll leave it alone. I have no interest in trying to make my F into an R-1, but that's OK, that's my choice. For those that want to spend up to $1000-1200 on better carbs, that's OK too, why would anyone care?

Posted: Mon Oct 01, 2007 6:48 pm

shimming needles works to cure a high rpm steady throttle lean conditions (surges).

shimming the needle doesnt cure low rpm steady throttle issues.that is dictated by the straight diameter of the needle.

this one of the areas jet kit needles help in most of the time.occasionally they make it worse.

the carbs on theses F's are unique that they have a primary main jet in addition to the normal (secondary) main jet.

the primary main jets have a very big effect on the overall jetting.esepcially when "asking" for power when opening the throttl from steady throttle.

Posted: Mon Oct 01, 2007 6:52 pm

My main motivation is what larryg points out. It is looks and getting rid of that PITA airbox.

Now since I'm planning to do that, where is my money best spent (I have the budget to get something better than the stock CV). Should I spend anymore time or money with the CV's or just go for the next level (good looks without the airbox and better performance). I am at the place that Matt at PSB refers to where most end up moving past the CV's anyway. Is that time and money wasted on the CV's. For me, the $250 I spent resurrecting my old girl's CV's carbs was the limit. I'll not put any more money into them to get rid of the airbox when I can put the money towards the next setup that I'd probably go to in the future anyway (just like many of those here who don't run the CV's themselves anymore came to that point).

Thanks for the opinions and the continuing conversation. This is really cool and each of us will have a point where we make the decison to put money/time into the CV's or move up to the next level.

Dave

Posted: Mon Oct 01, 2007 7:00 pm

clearly your next move is different carbs.put the money toward that.

i intend to ride mine as is for a length of time as im building my other motor/collecting parts.

if some one never intends to upgrade carbs and likes the ease/looks of pods and increased performance (lets say possible at this point Wink

) than pods would be a good project.

its the perfect DIY project imho.

an important point that i was thinking about at lunch..........

as i noted earlier,the accelerator pump is non functioning on alot of the F/K/C ive worked on.removing the air box makes them alomost 100% intolerant of that,where as many dont notice with the air box still on.

i spent alot time getting the pump passages clear on my carbs.

Posted: Mon Oct 01, 2007 7:19 pm

burned, I'd be very interested in learning more about these CV carbs and how to tune them for pods. When I bought my 900F last summer one of my first inclinations was to get pod filters for it because the filter was dirty and needed replacing anyway, but based on advice I got here I just bought a new paper filter for it (Honda OEM filter cost $32!).

I've been inside a few sets of carbs before, but only while following explicit directions for rebuilding them to replace o-rings and such using rebuild kits. I don't really understand what the parts do and what's really going on in there. I'm always yearning for knowledge and I'd love to understand carbs better. I just put a V&H street megaphone pipe on my bike and it is popping quite a bit on deceleration, even sounds like backfiring. I probably need to synchronize the carbs, could it be that it needs different jetting too? Can you really guide me through this kind of project even though I don't have access to any dyno or analytical equipment? I'd be greatly appreciative! Too bad its such a long drive from Milwaukee to Littleton!

Posted: Mon Oct 01, 2007 7:25 pm

sure,no problem.lets adress the decel pop first.

first thing it it absolutely imparitve that all the passages are clean in your carbs.

where do you have the fuel screws set now?are you 100% its idleing on all 4 cylinders?

the pressed in pilot jets can make getting the pilot passages clear an adventure.

have you looked at tha air cut off valves?they reduce the air to the pilot circuit under heavy vacuum (throttle closed,more than idle rpm) to help supress the decel pop.

if the valve rubber is bad shape they will not do the job they are intended for.

carb sync only effects the smoothness of the idle.

Posted: Mon Oct 01, 2007 7:42 pm

CB1100Fun wrote:

I got rid of poor idle quality and backfiring on decel (larger pilot jet and idle mixture adjustment), flat spots/lean surge in the mid range (shimmed the needle .05"), and better top end (larger main jet).

Sounds just like my 900. Rolling Eyes

To the T actually. Shocked

Do you want to come over and fix it?

Posted: Mon Oct 01, 2007 7:53 pm

burned wrote:

sure,no problem.lets adress the decel pop first.

first thing it it absolutely imparitve that all the passages are clean in your carbs.

where do you have the fuel screws set now?are you 100% its idleing on all 4 cylinders?

the pressed in pilot jets can make getting the pilot passages clear an adventure.

have you looked at tha air cut off valves?they reduce the air to the pilot circuit under heavy vacuum (throttle closed,more than idle rpm) to help supress the decel pop.

if the valve rubber is bad shape they will not do the job they are intended for.

carb sync only effects the smoothness of the idle.

My carbs are 100% set at wherever they were when I bought the bike. I've never taken them off or done anything to them. Given that the bike was 24 years old when I bought it there may have been something done to them at some point, but the bike was completely stock so I doubt that there was any jetting done.

When I first got the bike it was running pretty rough and one of the first things I did was run some fuel system cleaner through it. I think I used some Chevron and then a couple tanks later some Seafoam. There was some improvement but then when I found and fixed a bad ignition coil and plug wire it really started running better.

Once it warms up it idles pretty good. When its cold I think it may be missing a few cylinders. The other day when I rode it for the first time in months after putting it back together I'm pretty sure it started on only 1 or 2 cylinders, sounded really funny, then it picked up after a few seconds and sounded more normal again.

Where are the air cutoff valves? Do I have to take anything apart to check that? I think I need to study some diagrams of the carbs so I know what we're talking about.

Carb synchronization only effecting smoothness of the idle is news to me. I thought it had an effect on the overall running of the bike, both idle and under load. I guess that shows what I know. Embarassed

Posted: Mon Oct 01, 2007 9:15 pm

sounds like you have partially plugged pilot jets more than anything.

the air cut valves are under the round covers on the side of the carb.you can only get at one of them with the carb on the bike and assembled.

you want to make sure before you venture into the jetting that the carbs are functioning correctly to begin with.

other wise you are just throwing another variable into the mix.

removing the limiter caps from the fuel screws should be the first step.then you can properly set the idle mix.

the screws typically want to be 3.5 turns out from seated.

Posted: Mon Oct 01, 2007 11:50 pm

pontiacstogo wrote:

If CR31's weren't becoming so difficult to find,

I read this the other day and started to worry what I was going to do with my 1100 when I was ready to buy carbs... Can't you buy CR31S carbs new, any day of the week?

Hawk Joined: Sep 16, 2005 Posts: 410 Location: Sikeston,Mo

Were are the pods are (gay) and the you cant tune a f bike with pods gays (oops I meant guys)now LMFAO.
Been running them that way myself for a while now and love them . Just wasnt worth the hassel trying to argue whith the know it all's and the other dumbass.
Love this thread. Thanks burned still laughing LOL LOL LOL

Posted: Tue Oct 02, 2007 12:35 am

CB900SS wrote:

I read this the other day and started to worry what I was going to do with my 1100 when I was ready to buy carbs... Can't you buy CR31S carbs new, any day of the week?

You'd want CR33's for an 1100F.

My cousin's sister's brother-in-laws, father's, gardener's mechanic overheard something about Keihin focusing more on FCR production and not doing any more new castings for CR31's.

Posted: Tue Oct 02, 2007 1:13 am

The best thread I read in a long time, Thanks Burned

Posted: Tue Oct 02, 2007 1:25 am

pontiacstogo wrote:

CB900SS wrote:

I read this the other day and started to worry what I was going to do with my 1100 when I was ready to buy carbs... Can't you buy CR31S carbs new, any day of the week?

You'd want CR33's for an 1100F.

My cousin's sister's brother-in-laws, father's, gardener's mechanic overheard something about Keihin focusing more on FCR production and not doing any more new castings for CR31's.

I'm sorry... I meant CR carbs in general, I didn't think the sizing would have any effect on availability. Well that might make FCR carbs that much easier and cheaper to get, sounds good to me. Smile

Posted: Tue Oct 02, 2007 2:19 am

Ben,

It would be fun to help you out with the carbs, especially since it would prime me for my own bike. Ed just gave some good advice about checking the pilot circuits/jets for blockage. This could especially apply in your case if your bike ran fine at one point and then changed for the worse.

Scott