carb bogging after jet kit

[taylormade198002]

I have a 82 cb750, that I got for a steal....I did a dynojet kit with k&n filters...idle great about 1300 to 1500...the problem is when I rev it in idle it bogs down then picks up...almost like it wants to die...I changed the main jet to 126...and the idle jet to 74..did 3 1/2 turns..like the kit said...should I use a smaller idle jet...or is my mixture screw to much??? Also new user hello everyone. .

[TOOLS1]

I don't have much experience with the CV carbs, only enough to know that they are a PIA!!!! However what you are describing would be a rich hesitation on real carburetors.
TOOLS

[taylormade198002]

Yeah thought of putting the stock pilot jets back in..maybe that will fix it...ill let you know

[Lucky 1]

Jet "kits" are famous for not working.

You need to give us a lot more information before I could help you.
I would need to know what type exhaust system you have.
I would need to know what type intake system you have.

Are your K&N filters in the stock airbox?

To Quote:
"Your throttle response will always be sluggish with pods."
IF you do not deal with the slide needle.
You cannot just change main jets and think you are done.

[alehman]

The 126 is the secondary main jet, and the "idle" jet you're describing is the primary main, which handles the highest 1/4 of the throttle range. It doesn't affect your low end. It sounds like you might have clogged pilot jets. They're easy to miss in a carb cleaning. Also, I'm assuming you removed your carbs to install the kit, and there is a huge chance you didn't re-seat the carbs into the rubber insulators well enough or you have an air leak that only becomes apparent when you open up the throttle. I had that too when I rejetted my carbs until I got them fully seated in the insulators.

I have a Dynojet stage 1 kit with an airbox, paper filter, and stock exhaust, and it works great. It sounds like you're running pods because your jetting is for a stage III kit. I used to run pods with a stage III kit and thought I had them tuned well until I tried out my friend's cb750, which has an airbox. The throttle curve is smoother and the engine revs up way faster--- it convinced me to put the airbox back on and revert to a stage I kit. Your throttle response will always be sluggish with pods.

[taylormade198002]

Heres alittle more info, it has 4 into 4 stock exhaust, with k&n filter pods. I did put the stock #68 pilot jets back in today and turned the mixture screw to back down then instead of 3 1/2 like the kit suggests i did 2 1/2.  Much better results, still boggs alittle, but not to the point where it dies.  just bogs then picks put fast...the stock pilot jets where not clogged at all even on the first breakdown...maybe even going to a lower pilot jet might work even better.....heres a picture....

[taylormade198002]

http://www.dynojet.com/pdf/1127.pdf

these are the instructions i followed with the k&n filter pods rc-0984

[seestheday]

Did you just put those pods on?  That is why you're having trouble.  The CV carbs are notoriously hard to tune with pods.

If you want them to run right you're in for a lot of work.  Read this:

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Need to combine it with some more info/tips from here: http://home.everestkc.net/malsin/Motorcycle/carb/mc_carb_theory_101.htm

General consensus seems to be that once you're done tuning, you might be able to get it to run as well as you could with a stock airbox.

Your alternative is to buy a pair of real carbs for ~$800 that will allow you to run pods and will give you a very real performance increase.

[Lucky 1]

They give you 4 different sizes of main jets.

They also give you 8 "adjusting washers" for the needles.
If they give the right needles with clips why would you need "adjusting washers'?????

I would be wondering if the taper of those kit needles match the stock needles.

To me that means they do not actually know what will make it run right.
They are letting you do all the work to figure it out.

They need to be more specific, like instead of "STAGE I"  kit.
It should say Jet kit for use with pods and aftermarket exhaust CB750,then the model number.

I know that some of these dyno operators that take these jet kit coupons then charge you more money in addition to the "$100.00" coupon  must have learned just what is needed to make one of these bikes run correctly, and Dyno jet could put together a kit that has the perfect parts, but then the people that bought the dynos would not get any business would they?

WHAT IF a bike owner does figure it out? Then they could sell their $100 coupon back to Dyno Jet to NOT tell any of the other bike owners. Lol..lol

[taylormade198002]

Ill see what I can come up with...thanks for the info...just registered with this forum and already I can see I will be a long time member!!

[TOOLS1]

If you figure all the time, and money spent on making CV carbs run with pods, you would be way ahead paying the $700 -$800 for a set of Mikuni flat slide carbs.
TOOLS

[seestheday]

Yep

Sent from my BlackBerry device

From: TOOLS1 [via Honda CB750'S]

Sent: Monday, April 1, 2013 3:12 PM

To: seestheday

Subject: Re: carb bogging after jet kit

If you figure all the time, and money spent on making CV carbs run with pods, you would be way ahead paying the $700 -$800 for a set of Mikuni flat slide carbs.
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[thetimmyexperience]

ok, I'm the new guy, red the forum and still put on pods, jetted to 125/95 on the primary jet and main jet, left the pilot jet alone, and the air/fuel mixture screw is out  3 turns now and still running rich.. obviously the "bog after jet scenario" is where i'm at. I do despise the stock air-box but is was much more quick with it on. I am willing to go through the tuning process, and so I was curious if anyone has any advice since the last posts? Not sure yet if i over-jetted or not, planning on moving onto "shimming" the needle, or adding o-rings; i was told the needle can bounce a bit with washers, so a rubber o-ring for the needle height rise was recommended to me. Oh, I am still running stock exhaust, and really, stock everything. Any help will be appreciated. I had more time to tune/play previously, but now I am busy again and using the bike for transport as well. I KNOW it would of been smarter to leave it be with the stock jets and air-box, but I just couldn't help myself. I love to tweak on vehicles and learn!
Thanks,
Tim

[thetimmyexperience]

Right, it is an 81 Honda CB750C. CV carbs. And I think the pilot jets are stock #35, and thats what I'm still runnin with.