I have had a simular bucking problem last summer.It was bucking so bad that it broke my motor mount. I took off the weber 28dcd and put a stock one on from my other car. I gave the carb back to the guy I bought the motor from last year. Then he said it might need new jets, Any ideas on how to select the correct jets If I buy new ones. They are different sizes correct? I picked the carb up yesterday and his dad said it if fine.
http://www.civic1200.com/discus/messages/1/4363.html?

By bruce (67.200.12.169) on Thursday, January 22, 2004 - 03:19 pm:

well here we go, the whole problem started when I put mid-grade gas in (?), it happened last time I did it too, I just though it was a bad tank of gas. I only have 1 vac. line, and I replaced that in Colorado last year cause it broke. (I did check it again) I burned up the mid grade gas, went back to the cheap stuff.....runs 80-90 mph...oops I mean 65-70 mph down the road, no problems, why I have no clue but it does not like expensive gas, maybe it is following owners lead...cheap a$$......lmao.

By Zippy (Zippy) (12.106.14.100) on Thursday, January 22, 2004 - 02:13 pm:

Here's my tentative guess. Clogged middle power jets. Idle jet is good and high-speed jet is good so it must be a middle jet. It can't be electrical as that always fails at high rpm/load. Check and see if your dwell bounces, that would indicate bad dizzy bearing, but you said that is new and that would show in other rpm/power ranges too. So, it's in your carb. But, I may be wrong.

Better idea: You have a vac leak. You have compensated for it at idle by adjusting your air/fuel mix and it dosen't show under load because of your generally rich mix then, but, it does show when you stress it in just the right way.

By bruce (67.200.12.202) on Thursday, January 22, 2004 - 05:52 am:

not sputtering any more, but still losing power in 5th, gonna screw fuel mixture in a little more and try again. These are the specs for the weber carb for the cvcc, stefan peters built mine, he said it was to these specs, they can be a lil finicky at times, lots of small adjustments to fuel air mixture till it is right, but anyway, here are the specs.
K724, K725 (Honda CVCC 1500-1800)
Main Jets = 130, 155
Emulsion Tubes = F5, F50
Air Correctors = 175, 200
Idle Jets = 0.50, 0.50
Accelerator Pump Jet = 50

By 79cvcc (69.19.0.1) on Wednesday, January 21, 2004 - 09:09 pm:

Hey Bruce
i have a question what jets are you using in your car. i pretty much have the same setup as you have but i just cant get mine to run right.
Jason

By bruce (67.200.12.85) on Wednesday, January 21, 2004 - 05:49 am:

ok, I have an early electronic dizzy, the one I took off was an electronic but with 2 vac lines hugh...could not throw it far enough to get it out of the yard. Advance in one I put in appears to work right, I sprayed a lil wd40 on it, let it sit while I worked on my 77. I also did a few adjustments on carb, re adjusted fuel mixture and turned my idle up a little (was idling at about 600, now about 800). took it out, worked ok, no sputters between 65 and 80 in 5th. I let it sit a couple of hours and took it out again, still no problems, I have to go to a town about 25 miles away today so we will see. Intermitent problems drive me

By bruce (68.156.75.28) on Tuesday, January 20, 2004 - 07:33 am:

it sure would be easier to fix if it was not intermittent. and I like my cvcc.

By Hugh Johnson (Oneson1) (144.138.198.168) on Tuesday, January 20, 2004 - 06:03 am:

Furthermore, it's CVCC so you get what you deserve!!!:D:D:D

hugh

By Hugh Johnson (Oneson1) (144.138.198.168) on Tuesday, January 20, 2004 - 06:01 am:

Is there a "two section" vac advance/retard unit on the dizzy, if so and one line is attached to the tranny that is a retard mechanisim and should be gently removed, hefted, and thrown as far as possible away from your car and replaced with an earlier model vac advance unit, run more advance anyway. Wind it up till it "pings" and back off a degree or so, or get your dizzy done over properly.
hugh

By Shea Laking (Sheaman71) (66.185.85.79) on Monday, January 19, 2004 - 10:41 pm:

Bruce,

You might very well be looking at some sort of ignition advance/retard problem, seeing as how it seems to be RPM related. How does the advance mechanism in the distributor look? Do the advance weights rotate freely ouwards, or are they sticky? Do the springs pull them back fully? You might want to pull off your distributor cap and take a quick peek. Let us know what you find.

Regards,
Shea

By bruce (67.200.12.55) on Monday, January 19, 2004 - 08:25 pm:

ok, I know my timing is right on.....actually amazed myself when I changed dizzy's, I just looked at the old one, pulled it out, the other one slid in right the first time. I will try the choke thing tomarrow, I have been playing with my mixture screw too thinking it may be that. My vacum advance might not be working quite right either.

By Darrell--Arizona-- (68.109.154.124) on Monday, January 19, 2004 - 06:01 pm:

I've noticed that two things effect perfomance at different RPMs...timmming and mixture. If you have a manual choke, try to pull it out a little when you'd normally have your problem just to see what happens. If it runs better with the choke out, you mixture is too lean.

Just a thought on that last one, but I feel more confident about this one... I think you'll need to retard/delay the timing a little.

Holy Cow! I forgot how addicting this site can be.

By bruce (67.200.12.151) on Monday, January 19, 2004 - 03:30 pm:

Ok, here is the deal, 78 cvcc, 5spd tranny, weber 32/36, been having problems at high speed-low rpm's....I can run at 80 mph in 4th gear, but when in 5th it is missing and bucking, I did have a ball bearing loose in my dizzy so I replaced it, did not help, changed plugs and wires. Today I took it for a short trip, I had no problems going, all gears were fine, cruised down the road in 5th gear doing 70+ mph. Worked on a guys car, on the way home, 4th gear -75 mph - 3500 rpm was fine, put in in 5th gear, rpm's drop to about 2500-2700 rpm's......started to sputter and buck again....any ideas???