1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

CB 750 coils

Discussion in 'XJ Technical Chat' started by Jetfixer, Apr 23, 2016.

  1. IHATERUST

    IHATERUST New Member

    Messages:
    7
    Likes Received:
    2
    Trophy Points:
    3
    Location:
    canada
    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...

    upload_2020-9-5_12-50-20.png
     
  2. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,634
    Likes Received:
    5,013
    Trophy Points:
    113
    Location:
    near utica, new york
    If the cb750 coils fit the 750 seca, they’ll fit the 750 maxim, the 650 maxim, the 650rj....... and probably others too
     
  3. IHATERUST

    IHATERUST New Member

    Messages:
    7
    Likes Received:
    2
    Trophy Points:
    3
    Location:
    canada
    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?
     
    StarGeneral likes this.
  4. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,634
    Likes Received:
    5,013
    Trophy Points:
    113
    Location:
    near utica, new york
    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
     
    k-moe likes this.
  5. IHATERUST

    IHATERUST New Member

    Messages:
    7
    Likes Received:
    2
    Trophy Points:
    3
    Location:
    canada
    Seems like a good call. I'll drop the extra money on coils specific for my bike.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
  7. Jetfixer

    Jetfixer Well-Known Member

    Messages:
    3,180
    Likes Received:
    1,491
    Trophy Points:
    113
    Location:
    Nothern Indiana
    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 .
     
    hogfiddles likes this.
  8. Dave in Ireland

    Dave in Ireland Well-Known Member

    Messages:
    517
    Likes Received:
    290
    Trophy Points:
    63
    Location:
    Ireland
    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.
     
    Jetfixer and Franz like this.
  9. Jetfixer

    Jetfixer Well-Known Member

    Messages:
    3,180
    Likes Received:
    1,491
    Trophy Points:
    113
    Location:
    Nothern Indiana
    I'm using Bosch VW wires ( because I already had wires ) have had no issues .
     
  10. Dave in Ireland

    Dave in Ireland Well-Known Member

    Messages:
    517
    Likes Received:
    290
    Trophy Points:
    63
    Location:
    Ireland
    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.
     
    Jetfixer likes this.
  11. SM85

    SM85 Member

    Messages:
    41
    Likes Received:
    3
    Trophy Points:
    8
    Location:
    Canada
    All the stuff arrived! Got them installed today! Flag Terminals would help, but you can get it done with straight spades...
     

    Attached Files:

    Franz, Dave in Ireland and Jetfixer like this.
  12. Yammaat

    Yammaat Active Member

    Messages:
    213
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Netherlands
    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.. :D
     
  13. Dave in Ireland

    Dave in Ireland Well-Known Member

    Messages:
    517
    Likes Received:
    290
    Trophy Points:
    63
    Location:
    Ireland
    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.
     
    k-moe likes this.
  14. Yammaat

    Yammaat Active Member

    Messages:
    213
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Netherlands
    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 :)
     
    Last edited: Oct 16, 2020
  15. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

    Messages:
    19,613
    Likes Received:
    6,707
    Trophy Points:
    113
    Location:
    The City of Seven Hills
    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).
     
  16. Yammaat

    Yammaat Active Member

    Messages:
    213
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Netherlands
    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
     
  17. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
    go with the specs of the manufacture of your new unit
     
  18. Yammaat

    Yammaat Active Member

    Messages:
    213
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Netherlands
  19. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
    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.
     
  20. Yammaat

    Yammaat Active Member

    Messages:
    213
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Netherlands
    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
     

Share This Page