Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Oggers on March 27, 2020, 11:06:31 AM
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Folks
Strobe required to time 400/4. Any particular recommendations? Plenty on Fleabay for under 20 quid....are they much of a muchness?.
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Dont understand this fixation with strobes only used one once in 20 yrs in dealerships
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In my experience get a decent on from a a known company.
Make sure it is one that is powered from the battery and has an inductive pick up.
P.S. keep the leads away from the exhaust headers ;)
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Dont understand this fixation with strobes only used one once in 20 yrs in dealerships
Brian,
I used to do it with an old transistor radio set to AM turn the crank and wait for the click on the radio ;D ;D
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If you go modern with electronic you don't get a click.
But a bulb on a lead also works well
Sent from my SM-A750FN using Tapatalk
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Bulb holder with a couple of crocodile clips works fine. Still got the one I made years ago.
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Thats exactly the way Honda say to do it in the manual
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Workshop manual says use a strobe - so I use a strobe. I don't on my Brit bikes, using the points position and a rod in the plug hole. That is fine for those numb old things, but the 400/4 can rev to 10 000 so a little more finesse required I feel.
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Thats exactly the way Honda say to do it in the manual
Workshop manual says use a strobe - so I use a strobe. I don't on my Brit bikes, using the points position and a rod in the plug hole. That is fine for those numb old things, but the 400/4 can rev to 10 000 so a little more finesse required I feel.
I have the ubiquitous Honda 350/400 shop manual (see cover image); As Oggers says, in it the timing instructions only describe using a strobe - no mention of the simple test light.
However, my owner's manual only describes the simple test llght (see attached page)...
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So to get back to the original question “recommendations for a good strobe” not “do i need to use one” lol..... I am also in the market for a strobe... i was considering a gunsons as they were always popular..... any suggestions??
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To work on a bike they must be able to work on a seperate battery and few inductive picups work well, dont know why.
When at Mead and Tomkinson we had the Honda " box" that had meters for dwell, volts, capacitor plus a coil tester and a strobe all powered from a large car battery we charged weely. Only ever used the strobe once to prove a CB400N was advancing too far(holed piston) always did static timing with bulb as in 750 manual.
Problem is as you move points plate to adjust timing gap alters as well and it is way too much faf with strobe.
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https://www.zoro.co.uk/shop/automotive/timing-tools/advance-timing-light/p/ZT1120553X?utm_source=google&utm_campaign=pla%2B%7C%2BAutomotive&utm_medium=shopping-pla&mkwid=dAYVX9ix-dt&pcrid=240096058921&prodid=ZT1120553X&pgrid=51826823924&ptaid=aud-640926587692:pla-395235818101&productparam=zt1120553x&gclid=EAIaIQobChMIkZj0_ue66AIVwojVCh1OdgV7EAQYDSABEgJ3cfD_BwE
A friend of mine uses this one to good effect (I've got an old sun one so don't need new) it's also sold as Gunson for twice the price.
I've not had a problem using them powered by the vehicle battery, possibly that has something to do with design circuit? on some examples.
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I’d rate the strobe any day over alternatives as you can set the timing with the engine running. My strobe happily uses the on-board battery; sorry Oggers, it’s so old I’ve no idea what it is. (tho’ an in-line HT connection & not inductive)
Brian, how does the gap change given you simply rotate the back-plate about the spinning cam - are you simply referring to the ‘slop’ in the back plate mounting?
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Brian, how does the gap change given you simply rotate the back-plate about the spinning cam - are you simply referring to the ‘slop’ in the back plate mounting?
If you rotate the crank until the cam only just touches the heel of the points to start lifting them, then try changing the points gap, you'll see it can delay or advance the timing according to how far you moved the heel into or away from the cam.
If that makes sense :)
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Because the plate is never a perfect fit in the mounts and can move sideways a fraction, same for 2-3 plate on big plate
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Bought an accuspark (with adjustable advance) to time my MG. The Suzuki 350 was timed using a dti as the timing marks are notoriously innaccurate. 500 four , came all set up, but will check the timing with my strobe. Electronic ignition fitted to that though.
Recommend the strobe for what it is worth though
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Strobe is great tool for fine tuning, but you need to have one that works with your sohc..
I bouth this one https://www.ebay.co.uk/itm/111945334787
It works on idle and up to 1500rpm than light does not flash and it does not show rpms.. Even in separate battery... Not issue with unit, I get new one from seller as replacement. The same bahaviour.
But works fine on my old car even with higher rpms
My procedure:
1. Manual adjustment (with bulb or led)
2. Using dwell meter fine tune gaps to be the same for both points
3. Fine tune by strobe
4. Recheck dwell
5. Recheck timing with strobe
Repeate in loop 4-5 until is ok. Takes time but pays off but great idle and smooth run!
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That accuspark looks ok and I certainly dont want to be spending much more than forty quid...I was looking at this one
https://www.machinemart.co.uk/p/gunson-g4113-timestrobe-xenon-timing-light/
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Y'know, if like me you're really brave, (or bloody stupid!!), you could try the following:- remove plugs so engine is easy to turn over, insert cigarette paper in between points, pull on paper until it feels like it's about to tear, then VERY slowly turn engine over whilst watching timing marks until you feel a slight release of grip on the paper which signifies the moment the points are just starting to open, and that's the point at which to set the 'F' mark. Not very scientific I know, but I've got away with using this method from 1967 on Hondas ranging from 90cc to 750cc, and I've got away with it so far!
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Y'know, if like me you're really brave, (or bloody stupid!!), you could try the following:- remove plugs so engine is easy to turn over, insert cigarette paper in between points, pull on paper until it feels like it's about to tear, then VERY slowly turn engine over whilst watching timing marks until you feel a slight release of grip on the paper which signifies the moment the points are just starting to open, and that's the point at which to set the 'F' mark. Not very scientific I know, but I've got away with using this method from 1967 on Hondas ranging from 90cc to 750cc, and I've got away with it so far!
this is legacy method I used on all 2-stroke jawa's in 80's (those powered by generator only, thus no battery available). I had only one problem that time (woould have even now) - I'm not smoking, so I have no cigarette papper, even no lighter! ::)
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Same tissue paper method for Lucas mags on old Brit bikes
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That accuspark looks ok and I certainly dont want to be spending much more than forty quid...I was looking at this one
https://www.machinemart.co.uk/p/gunson-g4113-timestrobe-xenon-timing-light/
Be careful, as I wrote, that Accuspark does not work on RPMs higher than apprx 1500. So no way to check if you advancer behaves properly...
I would not buy it again...
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Thanks Erny...I think i may plum for the gunsons....if i do i will report on its suitability
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Great, if it will work in higher RPM I'll but it too (till full #@%$ will take place fully and we'll need to pay VAT+customs fee)
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Hi K2...understood (I think) what you’re saying, but still unsure how a (eg) 16 thou points gap (set at static peak cam) will subsequently deviate from base setting. Bryan answered as I figured... ie slop in rotating the back plate, but given this is how Honda expect you to alter the timing, is the resulting small variation in pre-set points gap (due the slop) not allowed for?
As an aside, and a nerdy question, I further like the strobe coz you can check the Advance / Retard working correctly. My question is... would it not be better to set the timing at 3000+ rpm, between the fully Advanced marks... ie where the engine spends its useful life?
The bottom line I guess, is it’s a 1970s very mechanical set up, and whether ya use cig paper, 12v lamps... whatever... it’ll basically work fine. Horses for courses?
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"The bottom line I guess, is it’s a 1970s very mechanical set up, and whether ya use cig paper, 12v lamps... whatever... it’ll basically work fine. Horses for courses?"
How true, and unless you've just had a total rebuild and blueprinted the engine, when you take into consideration the age and possible condition of all the components involved in the power train, the absolute accuracy of the ignition timing probably has at best a maginal effect on efficiency. The same could be said for the argument over tyre choice and tyre pressures when considering the accuracy and age of the various type of gauges available. :-\
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A good point Lobo and Bob...the points gap is something like 0.014” to 0.018” which is a fair old target and anywhere in that range was good enough..
I used to use tissue paper myself when i was a skint teenager, never seemed to cause any problems... my biggest niggle back then was the screw heads constantly chewing up due to the use of incorrect screwdrivers, back then i put it down to shitty japanese metal, how wrong i was as that shitty japanese metal is still in my garage giving me great service 40 odd years later 😄
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Gap should be 0.35mm or 14-16 thou, guess what-----unless you buy an expensive set you dont get a 15 thou!!
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Get one from the correct period lol, it works really well.