Topic: Changing out coils~Got a few questions.

[JAG]

I wanted to try the -drill the wires out the coils trick-, but I don't really trust myself with doing so.

I've called five different places, and they have No Idea what Wire Splicers are.

My local M/C salvage wants anywhere from 59-75 dollars for their used coils. Real A**Holes to deal with.

I have a 74 750K, that I thought about going to flea bay and ordering either 75-79 GL1000 coils as per this manual (http://www.motorcycleproject.com/motorcycle/text/sohcign.html) or going with early 80's CB900 coils. Both of which have the ability to change out the wires??....

From all the research I've done, I'm seeing that these certain coils run at 3 ohms (thereabouts), and our cb750's are at 5 ohms.

Now the drawbacks of course are the hotter running/more voltage, equalling to shorter points life.

I know (almost) for a fact that my spark plugs indicate ( has white all over them ) that I already run pretty warm. I've tried checking everything, timing, air screws, plug gap, to make it better, to no avail.

So with changing the coils, i'll undoubtedly run even warmer. So would it also be practical to run "NGK BP5ES, Bosch W8DC and Champion N10Y are hotter plugs." ( As stated in the FAQ.  http://forums.sohc4.net/index.php?topic=5752.0 )

I know the wires needs changing due to the crusty nature that they are in. I want to upgrade my coils, but not sure if it's the best thing to do to switch to 3ohms..

What do you guys think???

[6adan]

JAG you do not want to run hotter plugs if they are allready white,you would want to run a cooler plug.
Dannie

[Alan F.]

It was my understanding that a sorted 750 will run 3 ohm coils without a problem, or PM Hondaman and get one of his 'resistor packs' to raise your resistance/draw less current/extend point life.

[TwoTired]

Higher voltage spark does not mean higher operating temps.  The heat energy of the spark, at best, is 1/100 (mostly lower) of what combustion (oxygen mixing with hydrocarbons) brings to the party.

You don't need more voltage than stock, unless you have upped the compression ratio, or volumetric efficiency of the engine mechanicals.
Besides, the spark gap and the atmospheric conditions between the electrodes is what determines the spark voltage needed to create the arc.

If the open pipe and pods filters seen in your avatar are on the bike that you have tried "everything" on.  Then your list is seriously devoid of rejetting to correct the over lean conditions your "white plugs" are showing.  Do not expect a spark plug or spark change to fix this.  Carb slide needles and main jet will have to be addressed to cure "white spark plugs".

I was informed that the CB900 coils and the GL coils were even lower ohms than 3.  Definitely want to get a resistor in series with either of those coil types.

[JAG]

Thanks for the input guys..

Upon closer inspection of the spark plugs today I have discovered that numbers 1 and 2 were, what I think would be, well within the "Normal" range of what a spark plug should look like. Meaning they were dry, somewhat white/light brown..

Numbers 3 and 4 were wet with gasoline.

From another thread I posted these findings, and the conclusion thus far was that the floats were possibly set incorrectly allowing too much fuel in those corresponding cylinders (3-4). I will adjust those soon, and find out if they indeed match up with cylinders 1 and 2.

If they DO look the same across the board, I would like to upgrade/update my coils to the CB900 or GL coils.

I was informed that the CB900 coils and the GL coils were even lower ohms than 3.  Definitely want to get a resistor in series with either of those coil types.

I believe I've read that they put out somewhere in the 2.4 range. Not sure of the accuracy of the findings, but if that IS the case, a resistor would definitely be a must.

If the open pipe and pods filters seen in your avatar are on the bike that you have tried "everything" on.  Then your list is seriously devoid of rejetting to correct the over lean conditions your "white plugs" are showing.  Do not expect a spark plug or spark change to fix this.  Carb slide needles and main jet will have to be addressed to cure "white spark plugs".

I am running open pipes and pods. My needle is set (If I remember correctly- it's been so long) One notch up from the middle, in efforts to cure my past woes of running lean. My mains were 115's and I change them right now to 130's. I thought about coming down a bit from 130's. The only reason I went up was to help alleviate bogging down issue (from not getting enough fuel) at wide open throttle.

The engine still runs hot from what I can tell ( The oil in the oil tank is a bit smoky after just a 10-20 minutes run ), but this is the best I've gotten it in a long time.

If the spark plugs are looking good after the float adjustment, which kind of spark plugs should go with the set up of GL or CB900 coils with a resistor? Should one still run the Hotter spark plugs?

[TwoTired]

Upon closer inspection of the spark plugs today I have discovered that numbers 1 and 2 were, what I think would be, well within the "Normal" range of what a spark plug should look like. Meaning they were dry, somewhat white/light brown..

Numbers 3 and 4 were wet with gasoline.

what number on this chart for the dry plugs?
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html
Certainly you know that any tuning changes made should apply evenly to all carbs.
The fact that you have wet plugs, or any variance among spark plug deposits across the engine bank, means that some basic corrective action must be applied before fine tuning the mixture on the carbs.  Once they all show the same deposits, then you can move on mixture refinement.

From another thread I posted these findings, and the conclusion thus far was that the floats were possibly set incorrectly allowing too much fuel in those corresponding cylinders (3-4). I will adjust those soon, and find out if they indeed match up with cylinders 1 and 2.
If they DO look the same across the board, I would like to upgrade/update my coils to the CB900 or GL coils.

I think you've already made the coil decision.  Are you just looking for moral support?  Coils are not going to change an incorrect mixture.

I am running open pipes and pods. My needle is set (If I remember correctly- it's been so long) One notch up from the middle, in efforts to cure my past woes of running lean.

If you moved the clip "One notch up from the middle" you leaned the entire mid-range operation of the carbs.  And, might explain why you plugs are "white all over", since most of driving around is when using mid-range throttle positions.

My mains were 115's and I change them right now to 130's. I thought about coming down a bit from 130's. The only reason I went up was to help alleviate bogging down issue (from not getting enough fuel) at wide open throttle.

How did you determine you "weren't getting enough fuel?
Have you done a WOT plug chop on clean plugs to determine if the mains mix is correct?

The engine still runs hot from what I can tell ( The oil in the oil tank is a bit smoky after just a 10-20 minutes run ), but this is the best I've gotten it in a long time.

"Smoke" can mean many things, including normal water vapor being boiled off in the oil containment vessel.
How did you determine or quantify "hot"?

If the spark plugs are looking good after the float adjustment, which kind of spark plugs should go with the set up of GL or CB900 coils with a resistor? Should one still run the Hotter spark plugs?

No, you don't correct fuel mixture issues with plug heat range.  I get the feeling you do not know what plug heat ranges are all about.  Maybe this will help?
http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml

The engine manufacturer has told you what the cylinder heat should be for their engine by specifying a heat range for the plug.  Now your task is to make the carbs provide the mixtures to obtain that heat, compensating for the changes you've made to exhaust and inlet.

[bucky katt]

it's either Z1 enterprises or Dynoman that has the wire splicers.


it's Z1  http://www.z1enterprises.com/detail.aspx?ID=1890