Help/ ideas please

[RGP750]

Hi All
KO 180 miles since rebuild, first 120 miles running great.
Last week went for a ride and stopped running on number 4, plug wet so thinking plug.
Tonight swapped number 4 plug with number 1, initially ran well but after 40 miles number 4 off again.
I got home and checked exhaust temperatures. Number 2 was 20deg the hottert but i seem to remember
this can be due to heat from the front disc???.
number 3 was next then 1, and 4 way behind, but still hot enough 300mm from head to make me think it is still firing
although not fully.
any ideas welcome please.
oh new coils and leads.

[K2-K6]

Check compression and then valve clearance on number 4 to make sure nothing obviously untoward.

[RGP750]

Thought i would try that next, just don't want to know compression down after all of the re build.
I'll let you know the outcome when i have done it.
cheers mate.

[K2-K6]

Yes you'd hope not after just putting it together, sounded as sweet as anything when you ran it at Ardingly.

Something else I do that is quick and no cost, run it in as dark lighting conditions as you can find and have a look at the HT lead to see if there are any tracking leaks on no 4. I've had things like that run me ragged before.

[MrDavo]

You've tried swapping the plug, next time unscrew and swap the plug cap from the lead with another cylinder and see if the problem moves with it.

Pre rebuild I kept fouling number 2 plug, a resistance test on all 4 plug caps with a multimeter showed a massive resistance on number 2 compared to the other three, a new cap solved the problem.

[RGP750]

I'll give that a go as well thanks.
The coils were new from US ,the brass terminal screws in the cap broke on 2 of the caps
when i screwed them on the Ht leads ,think i'll scrap the caps and get NGK
Checked valve clearance and all spot on.
Compression test when it gets here.
Cheers Rich

[JamesH]

I always insist on NGK caps and plugs from an official NGK distributor - and always check impedance of the caps before fitting. There's a lot of fake NGK parts in circulation...

[RGP750]

Cheers James , how do i check if the new ones are impotent??
Seriously how do i check?

[JamesH]

Get a multimeter, set it to the 20 kOhm setting and meter across the ht caps individually (removed from the HT lead). Should read 5 kOhms.

Then meter the ht leads for each pair of coils with the caps removed (stick the probe into the end of the ht leads ). So you'll be measuring 1&4 as a pair and 2&3 as a pair. Should read 15 kOhms.

Ring me if you get stuck or want to talk it through.

J

[RGP750]

Thanks James.
Mick is lending me some caps tonight until my new ones turn up.
Rich

[AshimotoK0]

Check my Coil refurb writeup Rich.

if you find anything amiss I will refurb them for you for free .. least i can do ...you do plenty for me and others on here.

http://info.sohc.co.uk/download/general/Ignition-coil-fix.pdf

https://www.youtube.com/watch?v=qxWtR_m80Fc&feature=youtu.be

[RGP750]

Thanks Ash
I'll give that a go as well.
I haven't forgotten your rim etc just over run at work and not stripped it yet .
Not forgotten the evening out with the other forum member yet  either.
Son getting married July 1st and hope to sort it after that.
R

[RGP750]

Results so far
150 psi on all 4,so happy with that.
Nicked the caps off of my 500 NGK all 5 ohms
checked the ones on the 750 the one i'm having trouble is 15 ohms number 1 is 7 ohms and 2 and 3 are 5.ohms
coils are 17 1 and 4 and 2 and3 is also17ohms.
3 plugs seem rich, there seems to be conflict ion on forums re weather the screw should screw in or out to richen/weaken
mixture your findings welcome please.
Hope for a ride after work tomorrow

[K2-K6]

Rich, looks like the mechanical stuff is ok. I always keep a close look at valve clearance on newly built engines just in case they have closed at all so that you can catch it with no harm done.

Honda give a routine for adjusting the slow speed circuit in their manuals, this is in their F2 book so for PD carbs.

Warm the engine on a 10 minute ride after setting idle screws one and a half out from closed, set tickover stop to give 1000 rpm +/- 100 then on no2 carb  adjust the idle screw in or out to give highest rpm then turn it in until you get a 100rpm drop. Reset the main tickover stop to bring overall rpm back to 1000rpm again and then do each of the other cylinders the same method. This should set the idle mixtures correctly if everything is functioning as it should.
Is yours four cables straight into the carbs? Not sure how you set overall tickover on that type if so.

[RGP750]

Morning K2-K6
Valve clearances were all as they should be .
Mick (Kettle) set the carbs up for me he is a bit of a wizzo with the guages.
Each carb is set individually to achieve tick over.
I'm seeing him tomorrow at a local jumble and have a word with him.
Cheers