Its got a miss

nukes · Post by **nukes** » Thu Nov 30, 2006 9:05 pm

The story so far. Just finished putting the top end back together and all was well. After 24 hours their is an intermitent miss in the number 2 cylinder[ or so it seems].Took it back to where the work was done and tried to find the solution. Plug in number 2 is black as arsholes so stripped the carby and put back together. No difference. New plug in number 2 and its all good again. Couple of days later and the miss is back but now both plugs are black no2 is blaaaaack number 1 is just black.[not wet but dry powdery sh#t] The other thing i noticed is the temperature guage went up a lot higher than ive seen before, whether due to the new rings and more compression i dunno. Played around with the mixtures yesterday and it seemed to do some good but the problem is still there, only slightly but its noticeable. Theres no exhaust smoke and im buggered where to start next so looking for ideas. Thanks in advance all

[/b]

nukes · Post by **nukes** » Fri Dec 01, 2006 11:35 pm

Just a couple more questions from someone whos not a mechanics arsehole, are people setting their pilot screw settings as per the book[ie2 1/2 turns out] as they are now at 3 but they were at 5 1/4 for number 2 and 1 1/2 for number 1.Problem isnt as bad but its still just there. Is this a tuning problem or something deeper[valves clearances etc].any one out there? anyone???

Post by **phuk72** » Sat Dec 02, 2006 12:25 am

Black (and dry) sparkplugs are an indication that the motor is running rich - a build up of soot.

What jets are you using (and have they been changed recently?)

nukes · Post by **nukes** » Sat Dec 02, 2006 2:38 am

i havent changed any of the jets since ive had it but one thing we did do the other day is we moved the needle one position in to the jet. Is this heading in the rigfht direction? i'll endeavour to get in there and see what size they are, the only other mod is a k & n filter.

Post by **Max** » Sat Dec 02, 2006 2:45 am

Are you sure the valve clearances were set within range? It's usually better to have too much than too little.

nukes · Post by **nukes** » Sat Dec 02, 2006 5:01 am

yeh max, the lad doing the valves left a bit of slack for that reason. Ive just been in the carbys and they were 142.5 jets in there. when i bought the bike the fella gave me a "factory" tuning kit from the usa. I had a look in there and there is a set of 144 and 137.5 jets in there as well as a set of needles with a loooooong taper to them. im going to try going with the smaller jets as there is still the slight miss and you can smell fuel a bit[icant smell that well due to busted nose but a mate said you can defff smell it].......just tried that and the miss is still there. another thing is why is the number 2 plug always blacker than the number1? shouldnt they be the same if the settings on the carbys are the same.the lad that helped me do the work also said if there was a problem with a valve then the vacuum would be all over the joint, it was fine when we put the carbys back on the first time, is he talking sh#t or not? sorry for all the questions but trying my best with the brain cells available[few and far between!!!!]

nukes · Post by **nukes** » Sun Dec 03, 2006 12:44 am

hey max, just checked the valve clearances to be sure and they are spot on.

Post by **Max** » Sun Dec 03, 2006 1:10 am

Just to back up here a bit (you may have posted this info but I haven't seen it or more likely forgot...)...

What exactly did you do in the rebuild? Just new rings? Valves reground? How was it running before the rebuild?

I'm a bit stumped with the info so far. Sounds like carb trouble if the clearances are okay and it's not smoking. When you say cylinder number 2, which side is that when you are sitting on the bike, left or right (silly question, but some people number them differently...)?

nukes · Post by **nukes** » Sun Dec 03, 2006 9:29 am

gday max, the full history. Bought the bike with 114000 ks on the clock. developed bit of a problem with blowing a fair bit of smoke at all times. now on 134000 ks and decided to give the top end a bit of a going over as i was advised that new rings would rectify the problem. we did the valve stem seals, new rings, new camchain and thats about it. all the pistons and gudgeon pins didnt seem to have any wear so i reused the existing gear. the bores were given a hone before reassembly as well. i know its being a tightarse but i didnt want to spend any money if i didnt have to as thinking of selling it for a newer model with nowhere near the ks this one has. i have also just clicked to a few other things about the scooter as well. all the drain bolts have lockwire holes and there is wear on the sprocket cover [for race change gears] that leads me to believe it has been raced or a trackday tool for someone somewhere along the line. the thing that has me and my old man[fitter and turner/mechanic] buggered is why only one cylinder is going wrong? would wear in t the emulsion tubes cause this as ive read on the forum of other people having dramas. once again sorry for the questions but im tearing mybloody hair out here.

driving me to :drunk:

nukes · Post by **nukes** » Sun Dec 03, 2006 9:41 am

sorry max number 2 is on the right when sitting on the bike

Post by **Max** » Sun Dec 03, 2006 11:36 am

Right side (sitting on the bike), number 2 will normally run hotter than number 1 meaning you should have a lighter color plug. This is due to more metal around the cylinder (cam chain tunnel).

If your sure the valve clearance (and cam timing) is set correctly, and it's not producing oil smoke then I'd suggest a process of elimination. Easiest on down. This probably sounds silly, but it's what I do. I've had bad fuel before... Also, I haven't messed with the stock carbs on this bike much at all so some of this may not relate...

Assuming it ran fine before the rebuild...

1. Put in a fresh set of plugs.

2. Drain all fuel, dump what you have in your ute (they'll run on anything) and start with a fresh batch of something you're sure is good.

3. Make sure there is nothing obstructing intake or exhaust.

4. Check to make sure that your choke circuit is fully seated (when started), isn't binding and has some freeplay in the wire.

5. Give it a run. After warmup, if it runs through the rev range fine at first, but later starts crapping out on top, or idles well but doesn't pull up top it could be electrical, the CDI box could be going bad. Make sure all connections are good, the contacts clean. If you have a mate with the same CDI, borrow it for a test. (If not, skip on to the carbs and keep your fingers crossed...) Also make sure your plug cords are not leaking anywhere (best checked at night).

6. If the electrics check out, it must (well... more than likely must) be carbs. Drop the float chambers and look for crud that could be keeping the float valve from seating (flooding) and float height. Make sure all air circuits are free of blockage. While you have it apart make sure the choke is seating properly and that the CV diaphragms are in good condition. Check your emulsion tubes for wear, THOROUGHLY clean and reassemble everything.

7. Reset your standard adjustments to the manual (pilot air screw, needle clip-if it has one... can't remember). Mount the carbs and check balance (vacuum gauge). This is normally a bigger problem on 4 cylinder bikes as just pulling off the carb bank can throw them out of synch. Still, worth checking. Also, before remounting, check the condition of the rubber manifold insulators for leaks or cracks (that would normally make it run lean, not the problem you seem to be having).

8. I'm probably forgetting a bunch of stuff, but that's pretty much the routine I go through. Perhaps other less intoxicated individuals can pick up from here.

nukes · Post by **nukes** » Sun Dec 03, 2006 1:45 pm

cheers mate , first up tommorrow ill run through the list and see what turns up.

nukes · Post by **nukes** » Wed Dec 13, 2006 10:42 am

gday back again.
max #1 done
#2 done been through a tank but did it anyway
#3 done
# 4 done
#5 coils and leads being checked tommorrow at auto sparky but no loose connections anywhere[ dont know any other trx owners up here so cant check the cdi]
#6

when pulling the carbys apart i was thinking to myself lately theres been a few people talking about worn emulsion tubes, i didnt kbnow if id be able to tell. shit yeh, theleft one no probs, the right one is worn on one side. the other thing is one of the o rings on th float has a few dags on it so it needs replacing as well. the tubes that are in there are 'factory' ones from the tune kit with the bigger jets and different needles. is there any difference in using the factory ones against standard as i cant see any difference?

hoping this fixes the problem and itll be happy days again

[/u][/b]

Post by **Max** » Wed Dec 13, 2006 10:49 am

I never did anything with my standard carbs, which were low milage so the emulsion tubes had very little wear. Maybe someone else can chime in here. I didn't use any of the Factory Pro stuff either.

P.S. The emulsion tube thing has been a long discussed issue on the old forums as well.

dandywarhol · Post by **dandywarhol** » Wed Dec 13, 2006 2:20 pm

If one emulsion tube is "worn" or marked then something has caused that cos Factory Pro tubes are as hard as a hard thing!
Can you take a pic of it and post on here????????