Author Topic: Cb400f Points contact breaker brands (Read 3202 times)

Polio · « **on:** May 29, 2016, 08:18:08 AM »

I've been having problems with my cb400f in the past couple of days on and off,
the 1st and 4th cylinder would stop firing every now and then.

I think I managed to boil down the problem to a worn breaker point,
it's not as springy as the other one so I'm hoping that by replacing it the problem will be solved.

But I'm looking around and the price for these parts go from 10€ to 60€ for a pair of OEM Honda,
do you have any experience with some of the aftermarket brands?
also do I have to adjust the timing after replacing the breaker point?

kslrr · « **Reply #1 on:** May 29, 2016, 09:11:31 AM »

I have tried after market brands and have found that not only are the spings weeker, the frames are flimsy and the points alignment is not spot on.

Polio · « **Reply #2 on:** May 29, 2016, 11:17:14 AM »

Well the pair I had right now are not OEM and they lasted 20k km (since I had the bike), and only one of them seems faulty.

grcamna2 · « **Reply #3 on:** May 29, 2016, 11:45:37 AM »

Get stock oem Honda supplied points,even though they cost a few $'s they're worth it.

Polio · « **Reply #4 on:** May 30, 2016, 02:23:41 PM »

Can you tell me if these are legit?
It's a NOS but I've never seen honda parts with a packaging like that.

grcamna2 · « **Reply #5 on:** May 30, 2016, 03:47:15 PM »

Those are new old stock(NOS) oem stock Honda points;are they the correct part numbers for a pr. for 1-4 & 2-3 for your bike ? They are good quality

Polio · « **Reply #6 on:** May 31, 2016, 06:25:52 AM »

All right I figured the problem might not be in the contact breaker,
I tried to mount them back before ordering the replacement just to check and apparently
they seem to be working fine.

I'll have to use a multimeter to find if there's a grounding somewhere.

Deltarider · « **Reply #7 on:** June 01, 2016, 07:51:47 AM »

Quote

All right I figured the problem might not be in the contact breaker,
I tried to mount them back before ordering the replacement just to check and apparently
they seem to be working fine.

I'll have to use a multimeter to find if there's a grounding somewhere.

Make sure that not the connectors at the breakerpoints are too close to the plate and intermittently touch the plate and so ground. Can be very tricky.

Polio · « **Reply #8 on:** June 18, 2016, 06:19:36 AM »

All right,
turns out it wasn't the contact breaker or the ignition coils the problem but a faulty battery.

Now I replaced it and tried to start the bike a few times, at some point the starting motor started cranking by itself even without the keys inserted,
I tought it could have been the magnetic switch getting stuck for some reason, so I fiddled with it a little bit and it stopped.

But now I can't start the bike and it just backfires.
Is it possible that I screwed the timing by removing the contact breakers even without touching the plate? I regapped them properly.

Tim2005 · « **Reply #9 on:** June 18, 2016, 06:23:16 AM »

Yes, regapping the points will change the timing, if you open the gap wider it advances it and vice versa.

Polio · « **Reply #10 on:** June 18, 2016, 06:47:10 AM »

I see,
I tried gapping them as specified on the manual, but at 0.40 the spark don't even spark and at 0.30 it backfires.

Should I just manually set them and try until I find the right spot?
or is there a better way to do it?

grcamna2 · « **Reply #11 on:** June 18, 2016, 07:15:04 AM »

Quote from: Polio on June 18, 2016, 06:47:10 AM

I see,
I tried gapping them as specified on the manual, but at 0.40 the spark don't even spark and at 0.30 it backfires.

Should I just manually set them and try until I find the right spot?
or is there a better way to do it?

.40 & .30mm ? or .40 & .30 in. ? I set them from between .012-.016in. When the points arm fiber blocks get worn and you can't advance the points w/o opening up(or closing) the gap too much then it's time to replace them w/ good quality ones that'll last a good while when they're properly maintained.

Polio · « **Reply #12 on:** June 18, 2016, 08:16:29 AM »

Quote from: grcamna2 on June 18, 2016, 07:15:04 AM

.40 & .30mm ? or .40 & .30 in. ?

.40-.30mm, wich would be .012-.016 inch as the manual says.
The points don't look too worn, and they were eorking fine before I took them off.

Tim2005 · « **Reply #13 on:** June 18, 2016, 11:58:21 AM »

Just set them manually, connect a bulb up to them to time them accurately. Useful guide here http://classicmotorcycles.about.com/od/serviceandrepair/a/Ignition-Timing.htm

grcamna2 · « **Reply #14 on:** June 18, 2016, 12:54:47 PM »

Quote from: Tim2005 on June 18, 2016, 11:58:21 AM

Just set them manually, connect a bulb up to them to time them accurately. Useful guide here http://classicmotorcycles.about.com/od/serviceandrepair/a/Ignition-Timing.htm

A stroboscopic/dynamic timing light is a much better way to set the timing.

jamesv220820 · « **Reply #15 on:** June 19, 2016, 08:52:37 AM »

Daichi. Period , or just switch out for a electronic ignition

Polio · « **Reply #16 on:** June 20, 2016, 04:50:43 AM »

Quote from: Tim2005 on June 18, 2016, 11:58:21 AM

Useful guide here http://classicmotorcycles.about.com/od/serviceandrepair/a/Ignition-Timing.htm

Wasn't that useful, I tried following it using a multimeter but the points are always conducing when I measure them with the prods,
so I'm not really sure how am I supposed to use it.

I really cannot wrap my head around this, I haven't touched the plate so that should be fine, I tried to set them to .35mm and it gives me a slightly smaller keybang.
But I just can't find the right spot.

grcamna2 · « **Reply #17 on:** June 20, 2016, 06:08:25 AM »

Polio,
I liked your orig. idea when you first started this thread about replacing the points w/ good oem Honda points.

Polio · « **Reply #18 on:** June 20, 2016, 09:10:19 AM »

Quote from: grcamna2 on June 20, 2016, 06:08:25 AM

Polio,
I liked your orig. idea when you first started this thread about replacing the points w/ good oem Honda points.

Ahaha,
it's exactly what I'm about to do.
I should get them tomorrow in the mail.

Polio · « **Reply #19 on:** June 21, 2016, 09:23:17 AM »

All right, the new points are on.
Tried to set them to .30 .35 and then .40, the bike still backfires without turning on.

I've been trying to read on the forum how to use the multimeter as a ohmeter/voltmeter to set the gap,
but it's not really clear.
The value doesn't change until the gap is completely close,
and I'm not sure how to use the values as a meter to know how much should I open/close the gap

flybox1 · « **Reply #20 on:** June 21, 2016, 09:32:01 AM »

Rotate the crank until the point opens to its widest on the 1/4 point. Set the gap to .35mm.
Turn the crank just past this point so the point begins to close. insert the .35mm gauge
While holding and gently tugging on the gauge, rotate the crank around again, the feeler should slip out with the same resistance as when you First set the gap. If it comes out easier, stop here....re-set the gap to .35mm again, and repeat ^

once set, complete ^^^ for the 2/3 gap

Its easy to perfectly set the points gaps with a dwell meter... once the bike is running.

Polio · « **Reply #21 on:** June 23, 2016, 01:02:10 AM »

Done that, tried with .35 .30 .40 and even .45.
I just get some backfiring and no runnong motor.

The smaller the gap is the bigger the backfire is, above .35 they're pretty much similar.

tennesseebreeze · « **Reply #22 on:** June 23, 2016, 06:50:56 AM »

Quote from: Polio on June 23, 2016, 01:02:10 AM

Done that, tried with .35 .30 .40 and even .45.
I just get some backfiring and no runnong motor.

The smaller the gap is the bigger the backfire is, above .35 they're pretty much similar.

Just a thought- is your spark advancer assembled correctly? If it is 180° off it won't run, and it will backfire like crazy.

Deltarider · « **Reply #23 on:** June 23, 2016, 06:59:55 AM »

In case you want to check. After reassembly the marks are supposed to face eachother, like in the pic. Mark in the rim is tiny. Both marks are in the white at 5 o'clock.

Polio · « **Reply #24 on:** June 23, 2016, 11:47:58 AM »

Quote from: tennesseebreeze on June 23, 2016, 06:50:56 AM

Just a thought- is your spark advancer assembled correctly? If it is 180° off it won't run, and it will backfire like crazy.

Yeah, I just removed the condenser and the contact points from the plate to test them, I didn't disassemble the spark advancer.
I haven't even removed it from the bike, it was working perfectly before so I'm guessing something might have caused it to move,
but it's held pretty firmly in place as far as I can tell.

News:

Author Topic: Cb400f Points contact breaker brands (Read 3202 times)