4t Single running problems - battery, carb, fueling or engin

[Sun Wukong]

So, I have a 2004 Pulsar 150cc.

Obviously well looked after, runs and rides pretty well.

During my test ride it ran well enough, but had a bit of hesitance, and was missing. I didn't have much time for bike shopping, and it was miles above the last 3 bikes I'd seen, and coming from a mechanic close-friend of my friend. So I took a punt.

I asked for the carb to get cleaned out, but otherwise nothing extra.

They delivered it. Now it is more difficult to start, and takes a few goes to kick (there's only a kick start)

But it bogs down at the bottom of the revs, and wouldn't idle. I titted about with the idle (a screw under the carb throttle body, with a cable adjuster fitted) and it will now idle better.

But it still seems to be missing every now and then, or hesitating. Not really sure how to be sure which. If I blip the throttle when stationary, it sometimes doesn't react straight away.

Seems to run a bit better with headlights off, but that could be in my mind.

HT lead was a bit loose, so I wedged it back on.

Inline fuel filter was apparently replaced recently, but I don't know how much I trust that. Runs about the same on either reserve or on.

BUT, it did backfire quite well coming up to a junction earlier, which is low fuel (or bad spark).

I also checked its running with the fuel cap open, seemed about the same (albeit I wasn't moving).

Going on previous badly running bikes, could it be the battery? If not, what else should I jiggle?

It smelt/felt like it was running hot once I fiddled the idle, but then I was ragging her a bit
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Top cat
"Hard times lead to hard people. Hard people lead to good times. Good times lead to weak people. Weak people lead to hard times." Smegballs
"Oh and STE balloons would be one of the nicer things we would receive at the office, the amount of dog turd in jiffy bags is not funny." Jsmith86

[Taught2BCauti...]

Try a few things in this order:

1. Check the battery voltage with a meter, with the engine off, running at idle, again at about 4,000 rpm, and once more after the engine has been off for an hour or more. Post the 4 results.

2. Remove the spark plug and check the condition of the business end. If you aren't sure what to look for, post a pic. Measure the electrode gap with a 'feeler gauge', but if the electrodes are worn, buy a new plug and check the gap before you fit it - they are never correct out of the box!

3. Whilst the spark plug is out, do a compression test. This can tell a lot about the condition of the engine internals.

4. Check that the air filter is clean, and check the connection between the carb and the engine for air leaks.

5. Check the ignition timing (possible cause of backfiring).

6. If the oil and filter haven't been changed for a while, or the oil looks dirty, change them.

If all that checks out, maybe try some fuel system cleaner additive to the petrol, and take it for an 'Italian Tune-Up'.

If you are still having problems, you will need to strip the carb, and check things like float height adjustment, needle valve seating, correct jet sizes, blockages, etc.
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Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[Sun Wukong]

[Taught2BCauti...]

3. Not really - you need a proper compression gauge, unless your thumb can distinguish between 130psi and 165psi

5. You usually need a 'Timing Light' for this, but check your workshop manual.

If the oil level was low, is it using much oil?
This could be a sign of worn piston rings, but the compression test would also show this.
____________________
Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[Sun Wukong]

Just spannered it a bit.

All rubbers to and from carb were loose/crap. One backfire blew smoke between the engine and carb rubber.

Resetting carb/rubbers and fine tuning the idle speed seems to have helped a fair bit. Which is a relief.

The kickstart is kicking back quite often, which is concerning, but probably means the compression is ok.

Oil just seemed low, and I was worried they'd forgot to put any (enough) in. I only just picked her up, and last night was my first blat on her since buying it. I really hope it was simply that they put the carb back on wonky after cleaning it.

The battery is TINY, and has wires not contacts. Weird. Will get a socket set, multimeter and spark plug spanner (+plug) tomorrow.

That will help

Thanks for the list, really helpful
____________________
Top cat
"Hard times lead to hard people. Hard people lead to good times. Good times lead to weak people. Weak people lead to hard times." Smegballs
"Oh and STE balloons would be one of the nicer things we would receive at the office, the amount of dog turd in jiffy bags is not funny." Jsmith86

[Sun Wukong]

So, took her out for a 130km run up a mountain, blatted her around 30-40km that night around the mountain roads, and then came back via congested misery.

On the way I got her spark plug taken out and cleaned. It was black and sooty.

Still didn't run great, kept bogging down.

Eventually turned up the idle speed (with the screw under the throttle stop... not the normal idle speed adjustment I've grown to know and love).

But, with idle turned up, and a bit of altitude, she ran really well. Thumped 300km out of her. Started ok for the most part too, just ran a bit hot and smelly.

Oh, and by the end, most downchanges cracked a fairly decent backfire

Engine was racing at idle though, so thought to drop the screw. Same bogging issue.

Spark not good enough, fucked air filter, weak battery or not enough fuel?
____________________
Top cat
"Hard times lead to hard people. Hard people lead to good times. Good times lead to weak people. Weak people lead to hard times." Smegballs
"Oh and STE balloons would be one of the nicer things we would receive at the office, the amount of dog turd in jiffy bags is not funny." Jsmith86

[unitynotsocri...]

Check carb slide needle jet position and make sure its a 150 carb,.....the needle should be on the central notch. ,raising it weakens the mixture,lowering it raises the mixture.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS