Author Topic: Carbs,pods,&misc. (Read 5492 times)

mrbreeze · « **on:** May 29, 2005, 12:58:08 PM »

I spent a good deal of time yesterday looking through the tech discussions and archives and am a bit confused.I am preparing to rebuild my carbs and I don't want to make a big project out of it.I have never had them apart but after reading some of the stories here,I decided that I should do them.I have them off and have #4 tore down.As I suspected the pilot has crap in it.I can see a little light through it but it obviuosly isn't delivering the full shipment!I still haven't got into the others yet because I want to get kits first.I was trying to follow the advice of some of the members to get the Yamaha carb dip but the dealership here didn't have it so I went to auto parts store and bought Berrymans dip for $14. I have used this stuff many times with auto carbs and had great results. I know better than to soak gaskets,rubber,or plastic in it.It will be just the carb bodies followed up with compressed air to clear passages.Now for the confusion....I noticed a lot of posts about what jets to use and I can't believe some of stuff I read like #130-140 main jets.That seems way too extreme to me.My bike came from Wyoming last year (5000 ft.) and is now in Central California(sea level). Ihave installed 4to1 Kerker and want to go with K&N pods so what I was thinking was go from 105 to115 mains and leave pilots stock at 40.From what I read yesterday, 115"s will probably still be on the lean side so how about 120's? Carpy says thats what he runs and I know he is down in LA so the elevation is about the same. But then there are posters saying to use jets as high as #140? I am thinking I should go with 120's.Also people were advising against the pods but I don't care for the look of stock box and think it is a hassle to work with.These pods are $160.00 at Dennis Kirk which is pricey to me but I am still planning on getting them.This will also give a good place to mount my Dyna ignition module... on the bracket that held the upper air box to frame.That brings up another ?... where the hell would you mount the module with stock air box in place? (750 K5 by the way) I had it strapped under the air box before and didn't like it there(was concerned with weather damage). Where does everybody mount theirs? the directions you get with this ignition don't say where to mount it.I know I am long postin' here but I need to find some answers and I know alot of the people here have the answers.Last of all,has anyone used these K&L carb kits from Dennis Kirk? Ihave read that Napco are definitly junk and Keyster are ifffy.Thanks for any info and I will hopefully be back out on the road in a couple of weeks...........mrbreeze

Tim. · « **Reply #1 on:** May 29, 2005, 01:53:05 PM »

I started trying to read your post, but had to give up. Edit it, breaking it up into some paragraphs if you wouldn't mind.

mrbreeze · « **Reply #2 on:** May 29, 2005, 02:37:15 PM »

Yeah,I know,sorry about the rambling post.I'll try to keep it down next time.At least I didn't write about taking my bike around the corner!! That would have really pissed some people off today.

Einyodeler · « **Reply #3 on:** May 29, 2005, 03:08:23 PM »

The way I have done it is like this:get a small mm drill bit set and drill them out to the 115 size and ride it to see how it runs and do your plug chops,if too lean drill them out to 120 and see if that gives you the right mixture and so on.When you get it right then buy those size jets,this way you`ll only have to buy 1 set instead of trying to guesstimate it and buying 4 or 5 different sets.Don`t forget, it`s better to be a tad on the rich side than too lean.

mrbreeze · « **Reply #4 on:** May 29, 2005, 03:45:40 PM »

I like this idea about drilling out my main jets.What about these K&L carb kits? Are they any good? Does anyone know? They come with new jets so even if I screw up my originals by drilling, I will still have another set. I assume these new ones will also be 105's. I read that i can get a new set of 120's for about $20 so I think this will work OK.

Dennis · « **Reply #5 on:** May 29, 2005, 07:44:12 PM »

All I can tell you is that I have a '75 CB750F, with the original equipment 4-1 Honda header.
OEM muffler, which was very restrictive is long since gone, replaced by a nondescript megaphone, much easier flowing.
OEM airbox with K & N filter. Original 105 MJ were lean, now running 115 MJ, original pilot, don't remember the size. Plugs were a little sooty, but never fouled out so I dropped the needles one position, to the 4th groove (from the bottom).
Don't have any knowledge of K&L kits.
Still running points type ignition.
Located central NJ, near sea level.
I hope this information will be helpful to you.

mrbreeze · « **Reply #6 on:** May 29, 2005, 10:22:10 PM »

Thanks for the info Dennis. You say that you are running stock air box with 115's at sea level...maybe I will have to go higher with pod filters because of more air intake but I don't think it should be as high as 130-140 as some others have posted. I think I will start with 120's as Good Ole' Carpy suggested and go from there.After all... I am in California and running a lot of air through this bad boy so I am really starting to think that 120's are the way to go with my set-up.Still wondering about these K&L kits though.Anyone have input good or bad about these kits? It's the only thing Dennis Kirk offers and they seem to be pretty well complete. I also am getting one of those Morgan Carb Tune units from England. It really sounds like the way to do it...... mrbreeze

seaweb11 · « **Reply #7 on:** June 10, 2005, 07:10:27 PM »

I have a 78K that I just finished a cafe/restoration on and also wanted pods. After reading all the same stuff you read, I decided to go with 120s to start. Not enough! Then put in 132s. Way better! but still a bit of missfire at the very top end. I have now put in 138s and will post tomorow of my results. The whole Re & Re of carbs is now getting to be a bit of a bit of a pain, although I am getting faster

seaweb11 · « **Reply #8 on:** June 10, 2005, 10:37:01 PM »

BINGO! 138s have done the trick

kghost · « **Reply #9 on:** June 10, 2005, 11:11:45 PM »

Pretty much guess for your particular application and ajust from there.

MikeDeB · « **Reply #10 on:** June 11, 2005, 06:49:54 AM »

On my K2 I'm running an old MAC 4-1 system and K&N pods. The slow jets are stock but the mains are 135's with needles in the middle clip position. It runs rather well for 34k. You will love the Morgan CarbTune. I've got one and synch all my runners with it.

I forgot to mention that when you use the Chemdip, wash all the parts in soap and water after soaking them. You want to get the residue off the carb bodies.

Uncle Ernie · « **Reply #11 on:** June 11, 2005, 07:52:45 AM »

Don't know if the comparison is valid, but I have a 400 w recently installed K&Ls and I'm ordering stock Hondaware.

NorthernYankee · « **Reply #12 on:** June 11, 2005, 08:21:05 AM »

Quote from: Einyodeler on May 29, 2005, 03:08:23 PM

The way I have done it is like this:get a small mm drill bit set and drill them out to the 115 size and ride it to see how it runs and do your plug chops,if too lean drill them out to 120 and see if that gives you the right mixture and so on.When you get it right then buy those size jets,this way you`ll only have to buy 1 set instead of trying to guesstimate it and buying 4 or 5 different sets.Don`t forget, it`s better to be a tad on the rich side than too lean.

What kind of drill bits would be needed to do this...I have a 80 CB650 with a MAC 4-1 and it runs leans, since the stock is a #92 I was told to start with at least #98 but I have no clue where to get those size bits.

Thanks

TwoTired · « **Reply #13 on:** June 11, 2005, 10:50:39 AM »

The jet numbers are referenced to millimeters, with #100 being 1.00 mm. So, a #98 would be 0.98mm or 0.0385827 inch.
Dremel sells a drill bit set #6412 that's 20 assorted drill bits No 61 to 80 (.0135 to .039). A machinists supply would have others and if they sell the the PC board maker industry, they will have any size you can think up.

Be aware that the jet orifice is not a just a drilled hole. It is a shaped, ramped, orifice that allows fluids to flow without adding turbulence, (with its inherent restriction and the possible addition of air) for a wide range of fluid speeds.

Drilling may be good enough for testing purposes, but if the hole isn't pretty under the microscope, it can do unpredictable things at different flow rates. Fluid dynamics is a study unto itself...

Cheers,

kghost · « **Reply #14 on:** June 11, 2005, 11:34:57 AM »

Roger that TooTired,
I made it about half way through that class. Can you say Drop/Pass boys and girls?

Funny tho, I really liked Statics and Dynamics. Go figure.

nopivnick · « **Reply #15 on:** June 11, 2005, 12:06:59 PM »

For what it's worth, someone pointed out somewhere (either this board or the HAWKLIST, can't recall) that individual pods on each of four carbs can accumulate different amounts of dirt (in other words, and I can attest to this, the outside pods - carbs 1&4 - get clogged faster than inside pods - carbs 2&3). That makes for one more variable you just don't want to worry about.

The solution was to use the OEM air filter arrangement but with an appropriate K&N reusable filter, but I agree, it's already a #$%* to break everything down and get at the carbs and the additional space in the air box is quite handy for extra tools and the like.

My thinking has been to rig some kind of consolidated filter element that feeds all 4 carbs without having to duct into the OEM air box. Maybe the chamber that splits the air from the air box into four carbs, but with the back hacked off and fitted with a piece of uni-foam or some such?

Has anyone tried something like this?

Does anyone have one of those air chambers they'd be willing to part with?

TwoTired · « **Reply #16 on:** June 11, 2005, 01:21:24 PM »

Quote from: nopivnick on June 11, 2005, 12:06:59 PM

My thinking has been to rig some kind of consolidated filter element that feeds all 4 carbs without having to duct into the OEM air box. Maybe the chamber that splits the air from the air box into four carbs, but with the back hacked off and fitted with a piece of uni-foam or some such?

Has anyone tried something like this?

Does anyone have one of those air chambers they'd be willing to part with?

Is this what you had in mind? Its a K&N I took off a CB550 a few years back.

nopivnick · « **Reply #17 on:** June 11, 2005, 05:17:35 PM »

hmmm. I assume that contraption came from the inside of the air box?

I was thinking more like cutting the backside off the intermediary chamber (the one between the air box and the carbs) to get lots of surface area for foam. Then you loose at least two bottleneck/choke points in the stock setup... one on top of, and one on the front side of the air box.

sorry if this isn't clear. l could try and draw a sketch, I guess.

TwoTired · « **Reply #18 on:** June 11, 2005, 05:44:51 PM »

Quote from: nopivnick on June 11, 2005, 05:17:35 PM

hmmm. I assume that contraption came from the inside of the air box?

No, the air box itself gets discarded. This lives in it's place. It bolts to the plenum collector that is located just before the carbs. The small tube accepts the engine breather. And, that keeps it from dumping the engine fumes into everyone's lungs. It's supposed to be freer breathing than the stock set up. But, I just don't have any data to support that assertion.

cben750f0 · « **Reply #19 on:** June 11, 2005, 06:04:22 PM »

MikeDeB.. you say you are running 135's... thats good to knoiw, i am running aftermarket pods now, a free exhaust and 836cc kit, and when i put the pods on it ran leeeaaaan, went straight to 130's, but i thought it was running still lean, how are you plug colours?, i find that when i am winding throttle on i get to the point where the bike hits a wall, but if i back off a bit it starts to accellerate again... my mech reckons that it should be ok with that jetting, but it feels like it should go more.... what do you reckon... i am just worried about drilling them too far cos i dont have i only have the one set.. thanks for the time...peace

seaweb11 · « **Reply #20 on:** June 11, 2005, 06:39:14 PM »

cben750f1

Read my post above. I had a loss of power at the top end with pods. After a few tries with 120s & 132s just yesterday I went up to 138s and now all was fine. Still pulling great at 6000-8000 RPM now with no hesitation. Try jumping up to 138s and I can almost guaranty success. 78K with 4-2 MAC exhaust, c/w pods.
I know its a pain to pull it all out but my bike is running great now

cben750f0 · « **Reply #21 on:** June 11, 2005, 10:20:04 PM »

seawed11,

i am a gun at fitting jets while still in the bike, bought a little tool that screw driver tips fit into, only time i remove the carbs now is when i change the needle clips.... got it down to a fine art..

.. will try the 135's first, then work my way up... thanks for the info... BTW were do you have your clip position, i am in the second fromthe top.... my plugs fowl up round town.... just interested... peace

nteek754 · « **Reply #22 on:** June 12, 2005, 04:49:28 AM »

Hey all through the years (thirty now playing the 750 jetting I found that yes you can use a wide verity of jet ranges but the bigger the jet the higher your clip setting (for the needles) and vise versa for the saller jet witch I found to be the better match going with the smallest like 110s and put needles higher now I got one for you all just put another engine on my K3 and I decided to put my K N pods on and wow all these years I thought I would have to re jet but damn this thing runs great gonna do a plug check but I was thinking if it aint falling on its face dont seem like its too lean we will see good luck Craig

MikeDeB · « **Reply #23 on:** June 12, 2005, 11:41:14 AM »

Quote from: cben750f1 on June 11, 2005, 06:04:22 PM

MikeDeB.. you say you are running 135's... thats good to knoiw, i am running aftermarket pods now, a free exhaust and 836cc kit, and when i put the pods on it ran leeeaaaan, went straight to 130's, but i thought it was running still lean, how are you plug colours?, i find that when i am winding throttle on i get to the point where the bike hits a wall, but if i back off a bit it starts to accellerate again... my mech reckons that it should be ok with that jetting, but it feels like it should go more.... what do you reckon... i am just worried about drilling them too far cos i dont have i only have the one set.. thanks for the time...peace

My plug color is dark tan for now. It won't hurt to try larger jets and may help. You should look into getting some more jets so you have a selection to work with (since they are available). I've got 120's, 125's and 135's (still have to get a set of 130's). With the 550 I will be drilling jets since it seems that only the stock size is available (when I get to that project).

cben750f0 · « **Reply #24 on:** June 12, 2005, 06:23:18 PM »

yeah my plugs are just... and i mean juuust got some color.... really light tan... so am thinking that it si ok till you want it to go... then its just not quit getting the fuel it need.... i dropped my needle clip and i think it may be a bit lean round town, but its too rich in the original position... almost need a shim so i can put the needles in between clip positions... speaking of shims, can they be purchased?

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Author Topic: Carbs,pods,&misc. (Read 5492 times)

NorthernYankee