Full Choke>low idle + Discoverd CDI probslems. Need mad help from the wise!!!!

[Islandsteve]

K I'll break this down into two sections for both my problems.

#1, choke/carb issue - after getting my ignition sequence figured I hooked up the o'l 2L gasoline IV tank and cranked 'er full choked. It fired up right away on full choke but instead of idling really high like normal when full choked, it idles very low like when my engine would be warm and no choke. As soon as I turn the choke off the bike dies. Full choke the bike idles barely, and no choke it dies...is my choke circuit even doing it's job? I mean. Giving an engine air shouldn't kill it. And before on full choke my engine would be idling high until I un-choked it after a minute or so, that was normal I thought.

I have thought of the possibility of a vacuum leak, I have a newer good condition air box to replace my current bad condition one. It will go on when I get my carbs in the mail (any *business* day now). The mechanic i had goin on my carbs apparently found a vacuum leak at the intake boots and replaced the o-rings/seals there thus apparently fixing the leak. I was inspecting some of the carb boots and it looks at if the mechanic put in some spots around the carb boots some sort of sealing agent that dries/cures red with bubbles in it, dunno what that is, i assume its a commonly used sealing agent or whatever..correct me if im wrong.

So I read somewhere that I can spray some wd-40 around the area where the rubber carb intake boots meet the cylinder head and see what? see if it sucks the wd40 in on compression strokes????

My carb issues ***MAY*** be solved with the arrival of new carbs but in the meantime i want to troubleshoot troubleshoot troubleshoot


#2, Tach problems figured...I think - Today while trying to figure out why my NEW tach and gas gauge still weren't working, me and a friend spent about an hour pouring over an electrical diagram for the (what the manual said to be) 89-93 GSX600f's. After figuring out what wires did what, we determined that the igniter (CDI/ECU) controlled the tachometers functioning so we measured resistance of the B/R (black/red) wire which gives the tach the RPM signal which comes from the signal generator then goes to the CDI then is applied appropriately (I assume at least I may be wrong still). So there was no resistance, wire had no breaks splits shorts etc etc.

I should add I dont know much about electronics but my buddy knows a bit. Enough to read the diagrams atleast.

So Then I looked to the CDI for the problem it was taped a little bit. I have no idea why I never looked at this is the past I just overlooked it. I am amazed at the fact that I did not think electrical tape all ovr the CDI/ECU maybe spelt T.R.O.U.B.L.E. After taking the electrical tape off the cdi cover i realized the cover was in two pieces, so I figure someone either tried ripping it open to fix a melt down or they dumped the bike hard, noodled* the CDI box, and taped it back together and were happy to see that the bike still ran, but the tack didnt work but that was no big prob...I dunno maybe ive watched too much CSI but i think thats what happened...OH and then they got new plastics hence the new paintjob on my bike..."midnight blue" oh ya!! OR NOT.

So dont ya know the CDI is fu**ed on closer inspection. The lower portion of the main chip on the board (as if you were looking at the cpu from the left side of the bike without the plastic cover over the circuit board). Anyways, the portion of the board that is fried is the bottom portion of the main chip that the first 2 or 3 pins go into. This portion of the chip coincidentally I traced the Tach circuit to. This telling me that probably why my tach doesnt work is because the part of the chip that controlled that is either corroded or fired/shorted whatever. Something bad happened to it whatever it was because the part of the board that controls everything else that works is undamaged such as ignition and signals or whatever else it controls. Anyways im looking to buy a new igniter or ebay so we'll see where that goes. Does anyone have anything to counter this, am I on the wrong track?

Thanks everybody!!!

[kevin2502000]

Sounds like you are on the right track to figuring it out. Maybe replacing the cdi will solve the other problem, one step at a time.

[Islandsteve]

Thanks kevin. Now I need a magical carb fairy to drop in this thread and save my brain from thinking itself to death.

[Kfreak]

Well.... you bought another set of carb's, so wait till they arrive then replace the airbox. Don't forget that the replacement carb's may not even be bench sync'ed, so you will have to do that before installing them. There is 2 ways to do that. And after bench synching, install the airbox onto the carb's before installing the carb's to the motor. I have found that to be the easiest way.

[Islandsteve]

Well.... you bought another set of carb's, so wait till they arrive then replace the airbox. Don't forget that the replacement carb's may not even be bench sync'ed, so you will have to do that before installing them. There is 2 ways to do that. And after bench synching, install the airbox onto the carb's before installing the carb's to the motor. I have found that to be the easiest way.

I am told they are synced and ready to ride...I will soon find out tho. I will take them in to get synced I think just to be sure. Out of curiosity what are the two ways of syncing carbs? I understand it has to do with all the carbs sucking the same amount of mixture or however that is put to words.

Haha, yes, I found it next to impossible to get the box on the carbs after the carbs where on the bike. not easy at all. haha.

I am going to check for a vacuum leak today on the intake boots and take them off and inspect them thoroughly. Do you think the intake boots could leak where the carbs meet the boot like where the clamp is? or just where the intake boots meet the cylinder head?

Thank

[Kfreak]

The bench sync is a matter of setting all 4 butterflies as close to opening at the same time. You can adjust them so all 4 butterflies are just inside of the small opening at the bottom of the throat or you can stick 4 drill bits of the same size at the bottom of the butterflies holding them open ( like using a feeler gauge), adjust till there is slight drag on each drill bit. Make sure your idle screw is turned all the way out so it makes no contact with it's perch. Adjust that when you are ready to start the bike. I went with the first method then hooked up my carb sync. I was done in a few minutes. Hopefully your's will be bench synced' and all you will need to do is use a carb sync tool. I had to change all of my boot clamps because they were all not sealing correctly. Once you bend a clamp, it's done. That's my opinion. A bad clamp will cause a leak. that's another reason to put the airbox onto the carb's first.

[Islandsteve]

The bench sync is a matter of setting all 4 butterflies as close to opening at the same time. You can adjust them so all 4 butterflies are just inside of the small opening at the bottom of the throat or you can stick 4 drill bits of the same size at the bottom of the butterflies holding them open ( like using a feeler gauge), adjust till there is slight drag on each drill bit. Make sure your idle screw is turned all the way out so it makes no contact with it's perch. Adjust that when you are ready to start the bike. I went with the first method then hooked up my carb sync. I was done in a few minutes. Hopefully your's will be bench synced' and all you will need to do is use a carb sync tool. I had to change all of my boot clamps because they were all not sealing correctly. Once you bend a clamp, it's done. That's my opinion. A bad clamp will cause a leak. that's another reason to put the airbox onto the carb's first.

Crap i've got a bent clamp on the intake boot on one... not too bent...just the bit of metal that completes the circle and tucks under the rest of the clamp when you tighten the screw. It looks like someone got it stuck and just forced it and its bent now...Im not at my bike atm but will be soon aargh. Can't believe i overlooked that..glad I asked.

What is a Carb Sync tool and why would I need one if my carbs were Bench synced.? Im missing something here :P

[Kfreak]

A sync tool allows you to balance all 4 carb's at the same time. A bench sync will get you close. Using 4 drill bits of the same size will get you closer in the ball park than eyeing up the butterfly to the top of the hole. The clamps are fairly cheap. I got mine from the local dealer. As long as the boots are in fairly good shape, use them. Mine were crap because the PO tightened them down wat too tight and ruined them. You don't crank the crap out of the screws. As soon as one end of the clamp touches the other, you are done. If you noticed the shape of the carb throat, it is kind of oval and the clamp is round. The clamp will conform to the shape of the throat opening. Everyone makes the mistake of overtightening the clamp.

Go here: http://www.carbtune.com/

[Islandsteve]

A sync tool allows you to balance all 4 carb's at the same time. A bench sync will get you close. Using 4 drill bits of the same size will get you closer in the ball park than eyeing up the butterfly to the top of the hole. The clamps are fairly cheap. I got mine from the local dealer. As long as the boots are in fairly good shape, use them. Mine were crap because the PO tightened them down wat too tight and ruined them. You don't crank the crap out of the screws. As soon as one end of the clamp touches the other, you are done. If you noticed the shape of the carb throat, it is kind of oval and the clamp is round. The clamp will conform to the shape of the throat opening. Everyone makes the mistake of overtightening the clamp.

Go here: http://www.carbtune.com/

Very good help! Thanks, ill check out that site...lots of handy tools there

[Kfreak]

If you don't want to spend the clams on the sync tool, there has to be someone close to you that has one. Just ask around. I prefer to purchase any tool that I need for a job. To me, that is an investment and I have done many.

[Islandsteve]

If you don't want to spend the clams on the sync tool, there has to be someone close to you that has one. Just ask around. I prefer to purchase any tool that I need for a job. To me, that is an investment and I have done many.

I agree. A man can never have enough tools

wait. I've got feeler gauges so can i just use that instead of the drill bits? wouldnt it be better? heheh.

[Kfreak]

I am one who refuses to pay anyone for something that I am able to do myself. From mechanic's to carpentry and everything in between. But I choose to play stupid when someone wants something done.

[Islandsteve]

So would a set of feeler gauges work better than the drillbit method? ive got some feelers... Lol btw ^^^

[Kfreak]

No.

[kevin2502000]

When you synch them on the bike, it synchs to each individual cylinder. It's impossible to synch from one bike then put on another and have then still synched. Each bike has different wear and compression, vacuum, etc. That's why you need to synch after you get it running.