CB 750 coils

I had a set of CB 750 coils from an old project. I noticed one of my coils had cracks in housing. The cb coils have removable caps for plug wires, and since they are Hitachi flip them around and they mount just like stock. I'm so impressed runs so much smoother , and my tach responds better . Best thing since I had these laying around , used a set of VW Bosch plug wires so this was "CHEAP"LOL

 

did you ohm out the coils?
how do the CB 750 match up for stock set up ohm wise?

 

Update went for a 65 mile ride...i got TOTALLY lost lol ...bike ran great i hit 80 a couple of times....To answer the question yes I ohmed out coils they are the same as the stock Seca coils . The Honda CB 750 coils are Hitachi same as stock , if these had not ohmed the same I would not have tried it so far so good.

 

Here is a picture of the coil install .

 

Do you know the year for those CB coils? Obviously off a CDI bike, so late 70s-early 80s?

 

That's a great upgrade option with replaceable wires and stock mounting.

 

Yes these are off an 82 CB750 Custom , I replaced the originals chasing a cold cylinder got both for 25.00 $ it was not the coils I had a bad plug resistor. So I've had these for like 6 years almost pitched them, so glad I did not !!! So far bike seems to run stronger I had to adjust idle down a little after install. I like being able to change plug wires too , I desoldered the plug off old coils crimped on push on connectors so these "plug" in to harness as stock . My picture only shows the right coil ,but looked at my old coils both have numerous cracks bike ran ok though. I've seen some "new" coils on eBay for a cheap price, but I'm Leary of these (CHINA) . Yes if I had crazy money I could go to Dyna Coils , but if you can find a good used set try the CB 750 coils . I was shocked how well they mounted all I had to do was flip them around, and no interference with the tank either.

 

Hey Jetfixer, just wondering if you would suggest this as well as wondering if those coils would work with my 81 XJ with TCI Igniter.

I just got my bike and I'm having a lot of issues getting XJ coils for a decent price but I can get CB750 coils locally.

 

Looks like a nice fit and not a budget killer. Bet there is plenty of used ones around that can be had for cheap!

 

These are plug and play with the TCI , I have an 82 XJ750 Seca . These coils are Hitachi so they are the same manufacture as stock coils. I would recommend if you do this swap, de-solder the plug off old coils use some good quality crimp on connectors and use this to plug in to the bike wire harness. The wires on mine are orange positive (+) and gray negative (-) if in doubt hold old coil above CB coil there SHOULD be a small (+) and (-) mark on the coil (might not be marked ) . Looking on ebay there are many more CB coils for sale cheap.

 

Hi guys, just wondering if his mods will work with my 81 XJ 650 Special? i have a Honda CB750 coil available here, if its a good upgrade i would surely try its..

 

Yes it should work if you see my picture you will see how you mount it , flip coil pack over and it should bolt in just like stock.

 

A coil? You'll need two, unless you mean that you have an XS650.

 

Tnx. k-moe, yes i mean 1 have a pair 2pc this will be my project this coming saturday...

 

Would this be the CB750 coil you were using?

 

Yes they work great and fit in like stock ,you only have to flip them over , I desoldered the wires off stock coils and crimped on push on connectors.

 

Appreciate it, I have ordered a set and 25foot of 7mm wire.

 

How far away from the engine are you mounting the coils?

 

This is a great mod/upgrade!

I’ve also made it a “sticky”

dfox

 

Anyone know if these will work in a 1983 XJ650k? Tiny bit cheaper than xj4ever when factoring in canuck bucks. Coils left me on 2 cylinders and then very quickly stranded 4km from home today...

 

If the cb750 coils fit the 750 seca, they’ll fit the 750 maxim, the 650 maxim, the 650rj....... and probably others too

 

Just being cautious because it seems like a fleabay cafe racer one size fits none kinda listing. It says cb750 though so going by the logic in this thread its just plug and play right?

 

I wouldn’t do that..... personally, I find that “one size fits all” means “it won’t work for me”.

if I KNOW the coil came off a cb750, then I would assume it will fit on my xj

 

Seems like a good call. I'll drop the extra money on coils specific for my bike.

 

primary resistance would be good to know

just looked them up from US amazon 45$

this set at least lists yamaha part number same vendor different part number single coil
https://www.amazon.com/dp/B07KD7LLX...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

The factory CB 750 coils are made by Hitachi the same manufacture as the XJ . There is no modification to use these coils they slot in perfect only have to flip them around and they clear the tank perfect. Being able to remove plug wire a benefit and to be able to still buy these new at a reasonable price ...and believe me they can knock you on your keister if you get zapped .

 

First pair of these I got came off a CBR1000 (or maybe a CB1000R) about 20 years ago and they've been on a couple of bikes over the years, without a hint of trouble.
I always meant to get more, as the moulded-in nature of many bike coil leads just annoys me, and the Honda coils make it so easy to upgrade leads, or simply routinely replace them after a decade or two. Many mysterious running faults caused by duff leads that have been exposed to heat, oil and weather for too long.
Just in case the supply dried up, last year I scored another set off a GL1500, but that left an odd number so I'll have to get another set now.
The coil type is MT-08.

 

I'm using Bosch VW wires ( because I already had wires ) have had no issues .

 

The set currently in mine are blue silicone 8mm (which had to be shaved down to fit the coils). These leads were destined for a Hyster, but got mysteriously sidetracked along the way. Looking up the specs of them I could see they were definitely worth using - super-dooper core, super-dooper insulation, etc, etc. I couldn't bring myself to cut off the perfectly moulded caps, so I got some resistor plugs.
Looking at the price of them in the Hyster catalogue, I'm glad I don't own a fork truck and get thoroughly stitched-up for the cost of spares.

 

All the stuff arrived! Got them installed today! Flag Terminals would help, but you can get it done with straight spades...

 

had some major problems with the coils too and blew out the TCI. Bought a better TCI unit and coils from a renowned specialist overhere and blew them out too.
3 years of warranty so got a repaired TCI and a new rectifier instead of coils because the isolation of the leads melted against the cylinderhead so.. nope thanks.
Got me some tested yamaha coils but the problem still existed.. sometimes. She runs like a dream but sometimes only on 3 1/2 cylinders between 2500 and 4000 rpm. The RPMneedle flopping around.
Have torn the bike apart several times to measure etc.etc. but nothing to be found.
Untill I read something about zero ohm resistorcaps and started fiddling with the caps.
Turns out.. one cap had a infinite resistance... and another one sometimes..
Made them all into zero resistance caps en presto.. No more problem at all!
Already had some honda magna coils ready to replace it all but as it seems.. no use for them in the shortrun.

Sure wished I read this some time ago because it has caused me a lot of headaches and time since it started over a year back..

 

If you're using zero-ohm resistor caps, you'd best fit some resistor plugs instead.
Your system needs that resistance in the HT circuit.

 

Well.. as I was told here the resistor has only one major funktion and that would be avoiding distorsion in (old) radio or tv wave signals and a slightly slower buildup of the spark. That would be beneficial at high revs. My aftermarket ignition compensates for that.
But will look into that so thanks for the info

 

Which aftermarket ignition do you have?
Spark duration is a big part of what allows a TCI to function correctly so combustion happens at the right time (spark timing is not combustion timing, though they are closely related).

 

It's called a Carmo ignition.. named after the firm that makes 'm. Expensive though but comes with 3 years of warranty.
https://www.carmo.nl

 

go with the specs of the manufacture of your new unit

 

??

 

did you get you tci fixed or a new unit . ask new unit mfr what they recomend.
you can go with 0 ohm caps then use resistor plugs to keep in over all spec. with oem equipment.

 

Aha, got a aftermarket TCI and a second hand TCI. Everything measures like the oem specs now despite no resistors anywhere. Bike runs fantastic now the cap problems are solved.
Resistorplugs are not reliable I noticed when riding the Magna's. De resistor looses the resistance over time, but you never know when and how fast..., and start to create ignitionproblems (with the V65).
I've got them but only because they had only this type available back in Poland this summer. They brought me home though..lol

 

resistors are made to be changed on the oem plug cap.
aftermarket caps are built to be replaced when they go out of spec.
by going to zero ohm plug caps and using a resistor plug the resistor gets renewed every time you install new plugs.

if your tci is not getting any RFI issues by not using them you are set

the resistor lengthens the spark duration when firing

 

That isn't how resistors fail. They fail by increasing to infinite resistance ("burning out").

 

cars use resistor plugs, they're good for about 100,000 miles, so that's not a problem

 

I know it doen't sound logical but every plug below 3K delivered problems in the V65.. ranging from startingproblems to bangs in the exhaust. With new ones the bike performed perfect again.
Anyway.. no problem anymore since I sold the Magna's

 

So these coils should work with my XJ750RL?

 

Yes they will.

 

Nope.. got an aftermarket dig. ignition now.
The resistorcaps make the engine run 'softer', perhaps smoother imo
Now it seems to run 'crispier'.

 

I see a lot of the CB750 coils new for around 50+ a pair are these good for a xj700 maxim

 

Keep your eyes on ebay for a triple Glod Wing pack from the GL1500 - they often go for around 25 bucks.

 

Yes , I'm running these on both of my Secas .