Author Topic: again different coils  (Read 3884 times)

Offline duzatun

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again different coils
« on: May 14, 2009, 10:43:20 AM »
ok so it has been said that we can put later model coils into say my 78 cb 550 will the coils out of a 1986vf 500 interceptor work in my 550

Offline matthewmosse

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Re: again different coils
« Reply #1 on: May 14, 2009, 01:40:41 PM »
depends as far as I know most coils for points are pretty much the same and are interchangable. cdi coils will work but not last if fitted to points system and visa versa. not always true as there are other variations - bmw's seem to have different again etc etc.
Specifically has the donor bike (vf500 interceptor) got points or cdi ignition I'd geuss at cdi. Although I haven't needed to buy any I think m&p and their ilk sell pattern coils in 2 resistances, one for points, one for cdi at about
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline Bryanj

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Re: again different coils
« Reply #2 on: May 14, 2009, 04:17:16 PM »
As has been said most modern coils with replacable wires are for CDI or "electronic" (NOT the same ignition and frequently have a 3 Ohm primary resistance.

This is lower than original spec of, I think, 5 Ohm which increase the current draw, in turn shortening the contact breaker life and reducing the battery charge. All of these can have an annoying and deleterious effect.

Offline duzatun

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Re: again different coils
« Reply #3 on: May 16, 2009, 02:27:57 PM »
thanks for the info guy,s
as i am having problems with breaking down at 2/3 to 3/4 throttle and have been through
valve clearance
timing
points 
advance
and all these have been set
carby,s have been done
i have new condensors and points on the way once i have installed these if the problem persists i will appreciate any advice on what to look at next.
due to the fact that my mate had installed pod filters and a jump from the 550 pistons to 610 kit i may also be looking at bigger main jets have no idea on the size to use hear
they are 78 model carby,s and the needle and seat jet only has 2.0 written on  it wich i would presume is 2mm is this correct

Offline matthewmosse

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Re: again different coils
« Reply #4 on: May 16, 2009, 02:47:21 PM »
I think jetting is the issue here, tried conical filters on my cb550k3 '78, was a right swine to start (k3 was never as good to start compared to the 500's in my expirience) but this was worse than usual. I would geuss that richer than standard jets would be needed, cann't say what that would be though. plug chops are the order of the day to see if the bike is running lean, or ideally a dyno run. Are the carbs off a k3 or f series bike? I think the k3's were jetted leaner to give better economy ???
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline Bryanj

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Re: again different coils
« Reply #5 on: May 16, 2009, 06:12:45 PM »
At least on the K3 type carb you have the screw in mains which are easier to get and cheaper than the push fit on the earlier carbs

Offline matthewmosse

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Re: again different coils
« Reply #6 on: May 16, 2009, 06:50:47 PM »
The k3's are in many ways a better set of carbs, economy being the biggest point in their favour but they do seem to clog easyer especially when stood, based on the set's I've played with. They also have a cable operated choke so more conventional / modern. I prefer the 500 carbs but the fuel economy of the k3's carbs means that what I have fitted at the moment.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline duzatun

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Re: again different coils
« Reply #7 on: May 17, 2009, 11:27:11 AM »
well i think the carbs are the off the k3  the needle and seat main jets  are the pressed in type and have 2.0 written on them
the slow jet is 42
the secondary main is 90
and has cable choke
ive put a pic in here to make it easier for me to explain
if i am to put lgr jets in do i replace the < pressed in jets > no 2 in picture
                   or do i replace the < secondary main jets >   no 1 in picture
as the pressed in jets have the size 2.0 written on them and all these type ive seen for sale have sizes example 95 up to say 125 written on them either that or im on the wrong track here
im just glad theres blokes like youse out there with some knowledge on all these variations
thanks edd.
« Last Edit: May 17, 2009, 12:44:14 PM by duzatun »

Offline Bryanj

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Re: again different coils
« Reply #8 on: May 17, 2009, 06:17:02 PM »
No2 is the fuel inlet needle seat and cant be changed, No 1 is the main jet

Offline duzatun

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Re: again different coils
« Reply #9 on: May 18, 2009, 11:07:48 AM »
excellent much appreciated
Bryanj

 

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