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Messages - totty

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16
CB500/550 / Re: Electronic ignition
« on: July 07, 2017, 12:45:10 PM »
In that case you probably also want to replace the old coils.

The kit with coils fires all 4 cylinders at once, I wasn't keen on that when I fitted it but it performed fine and didn't cause any other issues, only practical minor downside was having to make brackets to fit the coils.

17
CB500/550 / Re: Electronic ignition
« on: July 07, 2017, 10:07:10 AM »
Comes down to what you're replacing and why.......

For example when I fitted a BB kit it was due to having a flat spot that I'd been troubleshooting for ages and had reached the point of wanting to rule out the entire ignition system. It was easier and cheaper to do this with a BB kit that included coils than with all original parts.
Where leaving it stock or using a hondaman kit makes sense is when the system is OK to start with.

18
CB750 / Re: re-jetting needed?
« on: July 05, 2017, 09:29:01 AM »
I'm not sure how to test a condensor, looks like the test in the manual is to charge it and look for a spark on discharge, I've just googled it and come up with two answers that I'll paste below, but a spark at the points makes me think a condensor has failed.

By the way I don't think condensors can give the symptoms you've described, but failed ones will wear out the points quickly so it's worth sorting out while you're on.
While you've got the meter out I'd check those plug caps are all still 5Kohm as rated as they can fail, and also the coil primary and secondary resistance - I don't know the correct values but someone on here will and they might be in the manual.
Once everything tests OK I'd then use the strobe, or carefully check that all exhaust headers heat up from cold to too hot to touch quickly and evenly to confirm that it's firing on all cylinders. Ignition should then be all sorted.


Capacitor test instructions from google:

Choose your tool. Even cheap digital multimeters often have a capacitance setting "– ...
Shut off the power. ...
Discharge the capacitor carefully. ...
Disconnect the capacitor. ...
Set the multimeter to measure capacitance. ...
Activate REL mode if present. ...
Connect the leads to the capacitor's terminals. ...
Wait for the result.

OR

To test the capacitor with a multimeter, set the meter to read in the high ohms range, somewhere above 10k and 1m ohms. Touch the meter leads to the corresponding leads on the capacitor, red to positive and black to negative. The meter should start at zero and then moving slowly toward infinity.

19
CB750 / Re: re-jetting needed?
« on: July 04, 2017, 07:21:34 PM »
I don't recognise the first 3 plugs, the NGK ones are resistor plugs, you can tell by the R in the name.
You shouldn't mix resistor and none resistor plugs on the same coil. I think but I'm not certain that you shouldn't have both resistor plugs and caps. Check your caps by part number or resistance.

20
CB750 / Re: re-jetting needed?
« on: July 04, 2017, 11:47:47 AM »
Are you confident that you've found all issues and you're ready to go back to jetting, or do you want to check for more issues?

For jetting you'll need to start with the mains and either keep increasing until you've gone too rich then go back a step, or do plug chops, or a rolling road.

A full checkup would be along the lines of

Ignition:
Advancer not seized, and confirmed working by strobe
points not pitted
points gap and timing correct
condensers tested, or a visual check for points not sparking
primary and secondary resistance check for both coils
plug cap resistance check (plug or cap should be resistor type but not both)
consider new plugs

Carbs:
chokes open as already covered
all passages clear
all jets showing no signs of wear
float heights set and float valves tested
all throttle open evenly, fully and are static balanced
no inlet manifold leaks
clean airfilter(s)

I'd also do a compression test

To be honest last time I had a flat spot to deal with I replaced the entire ignition system with a Boyer kit, it saves a lot of time and effort if you don't have to focus on both fueling and ignition at the same time. Although in your case I'd try to go back to standard airbox and filter so you can run stock jetting.


21
CB750 / Re: re-jetting needed?
« on: July 03, 2017, 04:06:17 PM »
You've got a whole mix of symptoms going on, not surprised you're going crazy.

There's probably more than one problem, might be time to find a local specialist or a dyno tuner who's good at diagnostics.


22
CB750 / Re: re-jetting needed?
« on: July 02, 2017, 06:47:49 PM »
"strobo light doesn't pick any pulse on cylinder 1
Plug one gets quite carbon fouled but the rest look ok."

I'd sort this first. Sounds like you've got a plug, cap, or lead problem.
After that get the main jets right for full throttle, leave the needles alone until the main is sorted. You will need a range of jets in order to find the correct one, you can't tell if you're got it near ideal or not in just one step, you have to see the effect of going a step or two either direction.


23
CB750 / Re: re-jetting needed?
« on: June 25, 2017, 01:13:30 PM »
Looks like you're going to have to do this by trial and error, so you probably need to order both +4 and +6. After finding best full throttle performance you'll them more than likely need to adjust needle height, then pilot adjuster and maybe even pilot jet. A lot of work on a four.
I don't know which jets this model uses, but I got my last jets from wemoto and I've also used allensperformance.

24
CB500/550 / Re: Charging issue! Help please
« on: June 24, 2017, 09:51:06 AM »
That type of reg/rec and that wiring of it is correct. (although I reverted to standard after having one of these regulate the voltage too low)

Have you tested the system as a whole? What voltage to you get at the battery with the engine at say 3k rpm?


25
Anorak's Corner / Re: Zinc content in oil
« on: June 21, 2017, 12:34:45 PM »
Isn't separate gearbox oil which is ran for high mileages normally single grade?
I'm sure I'd read somewhere that gearboxes break down some types of viscosity improves used in multygrade oils, causing the oil to get too thin at high temperatures.

There's another consideration but I'm not sure if it's just marketing hype, which is extreme pressure (EP) additives. Gearbox oil is typically marketed as EP oil, they used to market specialist EP oils for A Series engines due to them being one of the few cars with the gearbox sharing the engine oil, and it used to be one of the justifications for bike specific oils being required.

26
Recommended Sources for Parts and Services / Re: Timming Light
« on: June 21, 2017, 12:24:10 PM »
Avoid the cheap pass through ones that connect inline with the HT lead, you may get away with them at idle but when raising the revs to check advance you may get a few shocks, they also tend to be quite dim.
Any one that connects to the battery and has a pickup which clips to the HT lead should be fine, I think mine is a Draper.
You probably don't need a high end one where you can advance or retard the strobe, as you'll normally just be checking that the standard marks align.

27
CB350/400 / Re: Couple of hairy moments
« on: June 20, 2017, 09:28:30 AM »
On top of what has already been suggested check the pads have wear on the entire surface to see that they are bedded in. Some pads can take ages to bed in and it makes a significant difference.

28
Anorak's Corner / Re: Zinc content in oil
« on: June 19, 2017, 09:14:17 PM »
No, sadly he died a few years ago, but he would have been all over this, he loved a good oil thread.

The tickover rose on one car when I added Molly, definitely slippery stuff.


29
Anorak's Corner / Re: Zinc content in oil
« on: June 19, 2017, 07:51:11 PM »
I had mate who's brother was an oil blender, both were big fans of Molly. They talked me into ignoring the warnings and trying a Molly additive in an automatic gearbox and a couple of bikes with wet clutches. I really couldn't do their arguments for it justice, but I recall that it mostly related to how it bonded to materials (including that it wouldn't bond to itself unlike ptfe) and that it would help avoid getting to the extreme situations were zddp helps. Added over a few years every oil change it didn't cause any clutch slip.

30
CB750 / Re: Fork seals leaking
« on: June 14, 2017, 03:20:45 PM »
I'd file/sand down the high points and fill the gouges with JB Weld or similar, let it fully cure, then fit the seals without sealant.
Sealant is fine if you know a product well enough to be certain that it will be weak enough for easy seal removal next time, that it will be oil resistant for years, and that it wont corrode the slider.

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