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Messages - exvalvesetdabbler
46
« on: September 24, 2010, 05:31:37 PM »
On the original 400/4 rear indicator stalks there was a male spade connector spot welded to the back of it. They will most likely have rusted away or broken off. Even if you find them ,with a decent coat of paint it is difficult to get a good earth on to the indicator base. Same for the front indicator bracket. I ran the green earth wires straight into the indicator bases and has been problem free. The Grommet might split with two wires so bung up the gap with silicone.
Best Regards
Dave
47
« on: September 17, 2010, 12:01:33 AM »
It the formation motorcycle display team attempt at parking
48
« on: September 16, 2010, 11:52:55 PM »
I have just removed one from one of my spare carbs which I am sure is original and not been messed with. The circlip in in the middle or third groove and is marked with the number 18234.
These carbs came from a ex courier hack with 72k on the clock that i bought for spares in the late 80's. You can see a slight narrowing of the needle where it would contact the top of the emulsion tube at idle. What killed this bike was a small washer embedded in the side of the piston and deep scores in the barrel. The top of the combustion chamber looked like someone had taken a chisel to it.
The Haynes manual also says the third groove.
The way that I noticed my problem was to insert the needle into the emulsion tube and try to wiggle it side to side, it was clear that one tube had much more clearance than the others. Closer examination revealed that the chamfer just inside the top of the tube had been eaten away and the inner diameter was enlarged.
From what I have read up on these bikes is that they always ran a little on the rich side at idle to workaround the drop in vacuum when you open up the throttle at low revs, and as I found out with my bike, wear in the needle/emulsion tubes can make it too rich when rolling on the throttle at low revs.
Problem is that the needles are a sod to get at so I'm leaving mine as it is for now and sort it out over winter, It's not too bad with a matched set of worn tubes and 10x better than it was with one completely duff tube. It does stumble a bit at 3000 if I'm very gently on the throttle in 6th, This could be carb balance because they have only been done statically, I put my vacuum guage adapters in a safe place a few years back and memory aint what it used to be!. I'll machine up a set when I get time.
Regards
Dave
49
« on: September 12, 2010, 09:30:37 PM »
same here
51
« on: September 06, 2010, 06:57:06 PM »
52
« on: September 06, 2010, 06:54:05 PM »
I guess from the reply above that the emulsion tubes aren't in the keyster kits. I emailed nrp carbs and got a reply saying that the needle is there, because I only need the needle and tube I might have to bite the bullet and order the OEM ones from Dave Silver.
The pilot circuit is separate to the main jetting but I assume that at low throttle settings where the vacuum is still high, it was sucking a bit from the main jet which was swamping and small changes you would expect to get from twiddling the pilot air screw.
Regrds
Dave.
53
« on: September 05, 2010, 10:43:21 PM »
No more black plugs.
I went for spin today and I have just pulled the plugs and they all look ok.
I have attached a picture of the emulsion tube that was causing cylinder #3 to run rich. I have changed nothing else except swapping the plot jets between #3 and #4.
Thanks to PatM for the suggestion that fuel may have been getting past the main jet o ring, this wasn't the problem here but lead me in the direction of why too much fuel was getting past the needle at lower throttle settings when it should have been pulling it through the pilot jet, no doubt why the pilot air screw had little effect.
All of this goes to show that modern fuel is quite corrosive when it goes bad. I also read somewhere that fuel suppliers are soon to be adding even more bio ethanol to pump fuel, this is the last thing that we need.
Thanks
Dave
54
« on: September 04, 2010, 08:26:34 PM »
Had a bit of a breakthrought today, I examined the emulsion tubes and noticed that one was corroded and larger than the other three right at the top where the fat part of the needle sits. In an impatient rush to try something I pulled an old set of carbs apart and salvaged a half decent one.
I can now hold 3000 rpm in top gear without it stumbling and snatching, even back on the throttle at 2000 in the lower gears is useable now.
The clutch basket sounds like a bag of spanners at tickover but that can easily be solved once I get a new set of tubes and needles in.
I'll give it a run around tomorrow and see what color the plugs are.
Regards
Dave
55
« on: September 03, 2010, 11:02:06 PM »
Looks good.
How did you rivet it up without chipping the paint?
56
« on: September 03, 2010, 11:00:46 PM »
I don't ever remember the sump, barrels and head being painted on 400/4's.
When I stripped my rocker cover many years ago the original paint was more like a modern day metallic having a silver base coat topped off with lacquer.
I have a NOS head and rocker cover, the head is bare ali' and the rocker cover is painted. I've never found an exact match for it in off the shelf spray cans it to date. The VHT SP127 engine enamel is the closest match that keeps its looks the longest.
Regards
Dave
57
« on: September 03, 2010, 10:47:01 PM »
Since my last post I have has 3/4 of a success.
After making sure that the tool tray cover was well clear of the air inlet last weekend it seemed to run a little better. This evening I put some new plugs in and went for about a 10 mile jolly around town (mix of urban and dual carriageway). I now have 3 very clean plugs and one completely black one . At least this gives me something to work with now. It certainly starts to pulls well in the higher gears once the tacho gets above 6500. At 8500 its willing to go more but I'm not at this point.
I'm going to whip the carbs off again and see where the differences lie. I'm convinced that a bit of crud has been missed somewhere or the float tang isn't hitting the needle square on. I'm not sure how critical that is other than if it's too far out the float drops too far and the needle drops too far and gets stuck.
So the plan for this weekend,
Change coil and plug cap on #3 pot (leads won't reach to swap 2+3 over)
bung in the best of the float valves from my junk box in #3 carb (just looking for a difference to what I have now)
check small passage ways on #3 carb
valve clearances on #3
leakdown test if I have time.
This leaves the question of whether the pilot jet in #3 is the wrong size so i'll swap it with one from another carb to see if the problem moves with it.
Since all of the float valves and jets were new genuine Honda a couple of years ago, I'm finding it hard to believe that they would be the wrong size or duff.
I'm using D8EA plugs at the moment however I remember dealers putting D8RESL at one time.
I know that the R means it's got a resistor in it but I'm not sure what the other differences are. These D8EA's must be a good 15 years old but new plugs shouldn't go off in storage should they?
What plugs are you guys using?
Regards
Dave.
58
« on: September 02, 2010, 11:11:53 PM »
I bought a brand new one with only kph on it years ago for about a tenner. Still waiting to be able to use it.
59
« on: September 02, 2010, 11:04:07 PM »
That oven looks a bit clean/new. Even I'm not brave enough to risk getting caught putting bike bits in a new oven.
60
« on: September 02, 2010, 10:59:44 PM »
Thanks guys.
There is only the needles and emulsion tubes left that hasn't been changed. The thing I can't figure out is that at idle and small throttle openings, the main jet and needle shouldn't be doing anything towards fuel delivery. What I am finding is that the plugs do start to clean up a bit with sustained higher throttle openings. If fuel was getting past the main jet o ring the problem should be worse at high throttle settings when the main jet comes into play.
So this leaves the idle circuit. From what I traced through, the small hole on the choke flap side is where the air goes in, the pilot air screw controls the air flow and it comes out of the small hole just in front of the needle on the engine side. This points to there being reduced air flow coming in and past the air screw.
I think I need to examine the small passages again and check for wear on the needles/emulsion tubes.
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