Topic: update on carbs,pods,&misc.

[mrbreeze]

Hey seaweb11,cben750f1,MikeDeb,and any and all that are interested.... I got everything together and was pretty jazzed but after I rode for a bit and the day warmed up, I realized that it still wasn't good yet. A bit of popping and idle jacking up after warmup.If I turned idle down,it would run bad still. I started off with air screws out one turn and found that it runs a bit better with them turned all the way in! Definetly too lean so today I bought 137.5 mains. Will install them and report back with hopefully good results.I read that seaweb11 went to 138"s and bingo. I didn't catch your altitude or average temps though. I also bought new battery today. I noticed that when I was tuning that my electric start was dead after 15 minutes with key on although it was fine after half an hour on the battery tender. Damn!!!!.......I just wanna ride!!! will get back to you on results of fatter mains. By the way..... Needle clip is in middle groove.

[seaweb11]

I am at "SEA"  level. Let me know how you make out with the 138s
I gave you my run through, so I want to hear back on a HUGE success based on my years...months "maybe" experience on pods.

[cben750f0]

well my set up is still lean, am out to 142's... and its still a clean plug... no colour wot so ever... like new, but when i did th head swap the other day, the exhaust valves were  for love of a better desription... WHITE!!!!!.... that was with the 138's... so went straight to 142's... better but still not 100%... its alot of messing round but worth it in the end....i am running a wiseco 836 kit and bigbore headers... so thats why i am haveing a bit more trouble... will keep you lot of PODDERS up to date... cheers...

[cben750f0]

found out today why the ol girl is soooo lean.... i had put a see through fuel filter on it about 4 months ago, and while i was useing the air box, and standard pipes must have been flowing enough fuel, but after i changed to pods ,and beefed up the spark, and put the bigger exhaust on it... wasnt....P@#SED it off today and found that the bike was instantly better all over the rev range...am back at 138's, but havent done a plug chop... though am feeling that its heaps better.... one of those sillt situations where you go every were but the simple things.... will keep yas posted...peace

[MikeDeB]

A bit of popping and idle jacking up after warmup.If I turned idle down,it would run bad still. I started off with air screws out one turn and found that it runs a bit better with them turned all the way in!

If it's running better with the air screws all the way in that would suggest your idle circuit may have some crud in it or in the slow jets.  The slow jets should be #40's.  Make sure they are clean and all passages are clean and blown out.  If you increase the size of the mains to compensate for the lean idle condition then the bike will run rich at larger throttle openings.  Also, make sure all the holes on the emulsion tubes (needle jets) are free and clear of crud.  And finally, when you reinstall the carbs make sure all fuel lines are free of any kinks or sharp bends and and restrictive inline filters as suggested by cben750f1.

[eldar]

WHat year of bike do you have? We may be able to offer a bit more info then.
For example with my bike, if I turn the low speed screws in, the mix will lean out. My screws are on the engine side of the carbs.

[mrbreeze]

I just went through the carbs. Dipped in Berrymans....everything blown out with air and eyeballed real carefully. Tank is clean. Petcock is clean.I installed the 137.5 mains the other day plus installed new battery.It runs better than before but still a bit choppy goin' through the gears.I am pretty sure the fatter mains are what the doctor ordered(Thanks for the info seaweb11...you're the man on the pods!!!!)As for cben750f1,I think you are on the right track but I don't understand why you are having probs with the gas filter. I am also running clear tubing with see-through filter and don't see a problem there. I have no kinked lines and as near as I can tell,the fuel is flowing just fine. I still haven't done the main thing though.... Carb sync. I am ordering the Morgan carb tune this week and  I am hoping this will straighten things out. I am starting to get some $$$$ tied up into this but hey!!!!.....Its gonna be soooo sweet!!!! I'll keep ya informed.By the way....1975 K model...4to1 Kerker no baffle (sounds gooooood!) KN pods,Dyna 2000 ignition,the rest is stock.... later.

[cben750f0]

the filter i had only had a 4mm opening.... considering i am running 6mm lines... the filter couldnt keep up... went for a run today, heaps better, have fitted another filter today.. 6.5mm openings... flows abot 4 times more fuel... so i think that this was my main prob, was ok round town, but trying to make it go out on the freeway.. or higher speeds was leaning it out.... i want to hear that kerker without the baffle!!!.... make a wav file of it and post it so we can have a listen... ..peace

[mrbreeze]

I think I should wait till I get my carb tune and do the sync and if that doesn't smooth it out....raise the needles (I'm in the middle groove). Now I am wondering about what you are telling me about the fuel filter diameter Cben.Maybe this sucker is taking fuel quiker than it can be supplied.Man.....isn't all this detective work gettin to be fun? (Or did I really mean to say a pain in the ass?) Will keep yas informed.

[mrbreeze]

Well guess what cben? Took that inline filter out and it doesn't seem like I'm ridin around with the petcock closed anymore! I still want to find a filter that will work though cause I don't think the stock sock in the tank is enough. Although it is going better,I still have a slight stumble on takeoff but when I nail it,it gets er.I am hoping the carb sync and raising the needle will get me on the mark. Now I have discovered that I need swing arm bushings (IF it ain't one thing its 2 others!!) Thanks for the info on the cheap #$%* little in-line filter though.Hey.... do you know what you got with a blimp and 365 blow jobs? Answer....... Ones a Good year... The others a GREAT year!!!            Later....MrBreeze

[cben750f0]

i found with the stumble i had on take off was because i had the needle too high... it went away when i lowered the needle... just my experience... have just made some .02 inch(.5mm) needle spacers so i can lift or lower the needles half a clip, give me a bit more tuning scope...peace...(bloody filters)

[KB02]

Okay: 1976 CB750F. Stock (as far as I know) engine (CB750E...), stock 4 into one pipes, and pod filters. So far I have gone from the stock 115 main jets to 130 mains. The bike is still running lean.

Here's my question: Is it worth raising the needles? Or should I just try the next size up (or two) on the mains?

I know the mains are far easier the change, but is it better... or even worth the effort... to raise the needle at this point?

I have a set of "parts" carbs that took me the better part of half an hour just to try ang get to the needle. Is there an easy way to do this? Or is it matter a full on tear down of the Carb set to do this?

Right now the bike idles really well (once warmed up) and revs nicely, put as soon as you start moving ing, you can feel the lack of gas (just feels like somethin's missin'... you know?).

[kghost]

Needles control the part throttle operation.....Think about it.

[MikeDeB]

Okay: 1976 CB750F. Stock (as far as I know) engine (CB750E...), stock 4 into one pipes, and pod filters. So far I have gone from the stock 115 main jets to 130 mains. The bike is still running lean.

Here's my question: Is it worth raising the needles? Or should I just try the next size up (or two) on the mains?

I know the mains are far easier the change, but is it better... or even worth the effort... to raise the needle at this point?

I have a set of "parts" carbs that took me the better part of half an hour just to try ang get to the needle. Is there an easy way to do this? Or is it matter a full on tear down of the Carb set to do this?

Right now the bike idles really well (once warmed up) and revs nicely, put as soon as you start moving ing, you can feel the lack of gas (just feels like somethin's missin'... you know?).

Ok.  Have you pulled the plugs to see what their condition is?  You don't describe any popping or the like.  And, do you have inline filters installed?  These are things to look at.  Other things to consider are:  Are your valves adjusted properly, camchain tension adjusted, points gap set and timing set?

Until you make sure all the other engine settings and adjustments are correct it's hard to say whether or not you should change the needle settings.

[KB02]

The plugs are showing that it is running lean with the eletrode and the insulator.  Valves and points are set correctly. Ad yes, I do have an inlne fuel fiter (3/16 line with a filter designed to work with 3/16 line... I have no idea whatb the opening and outlet measurements are on the filter, though... I don't dare run with out it, though; the tank is on it's last legs and has already been coted with Krem once in it's life). The cam chain is as adjusted as it's going to be, and there is no popping sound. It just feels sluggish. And it seems to run hot. I really don't ride it for very long stretches yet. I'm still trying to get the tune right before I ride it too much.

And the pipes are getting fairly blued as I ride it. I was once told that blueing of the chrome pipes is a sign of a a lean running engine. Have you guys ever heard of that?

[TwoTired]

Yes raise the needles a notch and turn in your pilot screws an eight to a quarter turn.  You may also have to increase the size of your slow jets, too.  The main jet controls the max fuel flow at WOT. The needle dominate mixture from 1/8 to 3/4 throttle positions, as it restrict flow from the main jet.  Below 1/8 throttle the slow jet, pilot screws dominate the mixture.  See chart below:

[KB02]

Wow! Great chart. I have a couple days off coing up, so I think I'll try to asdjust the needles and see how that works.

Thanks for your responces to this guys!