Author Topic: new issue on my 82 650 (Read 3415 times)

rab1dwolf · « **on:** July 18, 2006, 10:28:54 PM »

ok a new issue has come up recently on my bike that has me stumped for now.

When I'm riding along the bike will suddenly loose power. It stays at about 6krpm regardless of gear and will ever so slowly raise.

The engine sound also sounds deeper similar to when the choke is on.

It will suddenly get power again and run fine. It is intermitant and I cant seem to pinpoint whats causing it. It also doesnt last for very long either.

If i come to a stop while this is happening the bike will die.

I thought it may be an issue with something blocking my carbs so i took them apart and cleaned them on sunday and its still doing it.

I cleaned the petcock filter out and my inline filter as well.

I *think* I am not running on all 4 when this is happening but dont have a clue as to what may be causing it or how to troubleshoot since it is so intermitant.

strangely enough it happens at the same intersection all the time...any idea?

razor02097 · « **Reply #1 on:** July 18, 2006, 10:48:47 PM »

how is the float level set? It sounds like the engine is flooding out.

rab1dwolf · « **Reply #2 on:** July 18, 2006, 11:54:40 PM »

no idea i never changed the float levels and didnt double check them this last time i had em apart

this is a recent development which is why im perplexed but it doesnt act as if its flooding it reminds me of a blockage...

I'll check the floats just to be sure tho

bill440cars · « **Reply #3 on:** July 19, 2006, 06:43:10 AM »

I don't know how the tank is vented on the 650 but, that could could be the source of your
problem. If the vent is plugged, the tank builds a vacuum and fuel flow slows up. Might be worth
a shot. If your carbs and filters are clean and it's not flooding, then that's all I can come up with at
this time. Hope that helps. Later on, Bill

dusterdude · « **Reply #4 on:** July 19, 2006, 07:55:11 AM »

to check the fuel tank vent status,ride around a while with the cap open on the tank and see if it runs better.

byidesign · « **Reply #5 on:** July 19, 2006, 08:09:44 AM »

Mine had a CDI ignitor go south.....
it would run fine then {intermittently} it
would be at 1/2 power, and would die if i tried to
idle it..{after bike got warm.....}
got it home and started checking componants, brought out
some electronics {instant freeze in a can} for cooling
electronics, and sprayed the pickups, and then the cdi's under the seat
{engine running with throttle trying to die}
as soon as I sprayed them,{cdi ignitors} it fired back up on all
four cyl's.and idled fine.....
I replaced the bad one...
Hope it helps
Bruce

eldar · « **Reply #6 on:** July 19, 2006, 08:16:06 AM »

one thing no one addressed, you said it happens at the same spot? Does it happen anywhere else? AT ALL?

Try timing how long your bike goes before the problem occurs, that might be a clue. try going a different way if you can and see if it happens. Cause if it is only in one particular spot, there could be something affecting your cdi.

Ibsen · « **Reply #7 on:** July 19, 2006, 08:37:28 AM »

Could be a bad ignitor as already mentioned. Take a look at the ignitors, I think they are located under the seat on the Nighthawk as well, and check if the black stuff on the back of them has started to melt. That could be a sign of trouble.
Also a bad coil can act like that. Or it could be as simple as a bad connection or a bad plug wire/cap on one of the coils.

rab1dwolf · « **Reply #8 on:** July 19, 2006, 11:26:01 AM »

i've tried timing it but its hit or miss. I'm thiking of putting it up on the center stand this weekend and running it to see if i can test it under more controlled situations.

I just tested the electrocins system 2 weekends ago as I had to replace my rotor as it went bad. the coils and regulator/rectifier tested ok after the rotor replacment. this started happening shortly before I replaced my rotor. I havent looked at the cdis yet but will definately do that What Bruce posted sounds JUST like what is happening to my bike.

besides looking to see if they are melty is there any other tests i can do to them?

cb650 · « **Reply #9 on:** July 19, 2006, 04:26:18 PM »

Both them thar ideas sound good. FYI the floats are fn plastic so no adjustment.

Terry

rab1dwolf · « **Reply #10 on:** July 19, 2006, 08:55:58 PM »

just pulled them offa the bike when i got home.

The backs dont look melty but one of them has white corrosion all over it...looks like battery accid to me.

Would battery acid damage cause it to malfunction?

going to go hunt around for price quotes on ebay just in case

razor02097 · « **Reply #11 on:** July 20, 2006, 11:47:58 AM »

just so you know igniters from 79-83 cb750 (F,C,K) CB900 (F,C) 1000C and 1100F DOHC bikes will fit the CB650. I replaced my 1980 melty ones with 83 1100F ones and have has no problems.

Ibsen · « **Reply #12 on:** July 20, 2006, 03:02:03 PM »

razor02097 is right. The ignitors are the OKI 200 btw.

And they can be measured for faults:

LINK

But if you don't know what you are doing, beware of the danger of destroying them if the test is done wrongly.

Pinhead · « **Reply #13 on:** July 20, 2006, 04:21:33 PM »

Hmm... That link describes the ignitors simply as transistors... I wonder if there are some "normal" transistors that can be made to work as ignitors, with better heatsinking to make them last longer or spark hotter.... ?

rab1dwolf · « **Reply #14 on:** July 20, 2006, 09:14:01 PM »

I cleaned up the one cdi that had some corrosion on it. It doesnt look like it actually did much to the body of it but I'm thinking that since it was pretty much coated that it wasnt disappating the heat right.

rab1dwolf · « **Reply #15 on:** July 22, 2006, 12:29:37 AM »

ok cleaned everything up and put it back together. the contacts were a little dirty so ill see if that helped. Also the right hand cdi looks like it have have been touching the frame occasionally would that cause a short?

rab1dwolf · « **Reply #16 on:** July 22, 2006, 05:24:32 PM »

ok second update:

went and topped off my tank and it did it again right around 4 miles, issue cleared up a mile or two later.

Then the bike ran perfectly the rest of the day all day.

I'm beginning to wonder if its an issue when i stop to top off before leaving...

Ibsen · « **Reply #17 on:** July 22, 2006, 11:42:30 PM »

You have the carbs with the vacum controlled fuel shut off valve on top of the carbs, don't you?
Could that valve be causing some touble with the fuel dlivery? Or dirt in one of the float valves, or T connections between the carbs, or even a partially clogged petcock filter? Also a partially clogged vent hole in the filler cap can cause this to happen.
Normally when you shut off the petcock and continiue to run a bike, or run out of fuel, all carbs won't run out of fuel at the same time. It will quit on one or two cylinders first, then on the others. If the fuel flow to the carbs isn't sufficient, I think the same thing can happen. You will have a fuel flow that can make it run on 2 or 3 cylinders, while one will cut out. With the 650 carbs that isn't unlikely, since the fuel hose from the fuel tank runs down between carb #1 and 2, and carb #3 and 4 are fed via carb 2.

I remember I had a issue with this once when the inline fuel filter I had put on started to clogg up with dirt. And it acted a bit like your bike. When the tank was full the gravity of the fuel in the tank would feed the carbs with out any problem, but when the tank level dropped to under 1/2 full, the partially clogged filter restricted the fuel flow enough to make it sputter on one cylinder.

It's just a thougt.

DammitDan · « **Reply #18 on:** July 23, 2006, 06:58:15 AM »

I used to have this problem on my '82 CB650, too. It would get up to about 75mph, run fine for 20 or 30 seconds then start to buck and lose power/surge intermittently, and if I pulled over the bike would immediately die. But if I waited 2 or 3 minutes the bike would turn right over again and run fine. If I didn't stop, I found that the bike would run like crap for a while until it got its "breath" back.

It turns out the PO had installed 105 mains (should have been 120 mains) to compensate for the air filter cover problem on this bike (which obviously he didn't know about). If you leave the air filter cover in place, it doesn't allow enough flow at high RPMs and the mix becomes extremely rich. Found that out this past weekend.

I'm thinking it was an overheating issue since the bike had such small mains installed. It had to have been running lean at high speeds. And if you leave the air cover in place without rejetting, it will foul the plugs and flood mixture.

Have you tried removing the plastic airbox filter cover?

rab1dwolf · « **Reply #19 on:** July 23, 2006, 02:23:12 PM »

what filter cover? all i have is the side panel.

I rode the bike somre more today it seems like if i ride it a distance about 4-6 miles at above 6k rpm it will loose power but after another 1-2 miles it clears back up and runs strong all day long.

just new today aparently i have a small fuel leak from somewhere on carb 1 which is the same one that suddenly has gotten blow by on the header pipes....

I'm thinking im just going to have to tear into it at some point and hope for the best...

DammitDan · « **Reply #20 on:** July 23, 2006, 07:05:25 PM »

There should be something to hold the air filter in place inside the airbox. You DO have an air filter, right?

rab1dwolf · « **Reply #21 on:** July 23, 2006, 09:03:57 PM »

yeah i got an air filter but it just sits inside and theres three screws securing it in place....i think its time i looked and the micro fiche for that

edit1: ok just looked yeah im missing the stupid plactic cover never knew i was supposed to have one *sigh* geuss ill start looking for one of those now too....

edit 2: luckily just found one on ebay. put down a bid on it already, as for my jets i actually rebuilt the carbs a couple months ago with new jets and such so they are the right size.

Pinhead · « **Reply #22 on:** July 23, 2006, 09:59:54 PM »

Quote from: rab1dwolf on July 23, 2006, 09:03:57 PM

yeah i got an air filter but it just sits inside and theres three screws securing it in place....i think its time i looked and the micro fiche for that

edit1: ok just looked yeah im missing the stupid plactic cover never knew i was supposed to have one *sigh* geuss ill start looking for one of those now too....

edit 2: luckily just found one on ebay. put down a bid on it already, as for my jets i actually rebuilt the carbs a couple months ago with new jets and such so they are the right size.

Most of the time you'll want to leave that air cover off...

rab1dwolf · « **Reply #23 on:** July 24, 2006, 11:30:11 AM »

ok well ill buy the thing just in case anyways, looks like i can hopefully score it for cheap. since i dont have the cover on it obviously not that:)

would oil level have to do with anything? i checked my oil last night and its a little low so I figure ill add a touch more in.

its just odd that this happens when i start out but then clears up and runs fine. I thought maybe my fuel flow was being cut off but the engine will keep running as long as keep the rpms up when i pull in the clutch so that killed that idea.

I figured if one of my cdis were bad then it should do it more frequently and repeatedily during my day, but it doesnt.

I have checked my cam chain tensioner and my timing but havent gotten around to doing my vavles which are probably out of whack knowing my bike. could vavle clearance be causing any issues?

my plugs look good and seem to work fine so i dont think they are malfunctioning. I tried testing the blue wires for a resistance check coming from my pulse generator(?) like the book said but cant seem to get my leads into the plugs to get a good reading.

any more ideas would be greatly appreciated as I'm in the dark on this one as it doesn't seem to preform logically. I'm still leaning towards one of the cdis being flaky though...

Ibsen · « **Reply #24 on:** July 24, 2006, 02:20:45 PM »

Have you tried to replace the spark plugs?

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Author Topic: new issue on my 82 650 (Read 3415 times)

eldar

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