Innova 125 running like crap

[hebdenwill]

Hello!

I'm having a problem with my bike, a Honda Innova ANF125, and I thought I'd see if I could get some advice!

As the title says, it runs like crap - it won't rev high, if I fully open the throttle it sort of gasps and pulses, if I open the throttle quickly the engine dies, it doesn't like to start when it's warm. The best I've got out of it is 40mph flat out downhill, and it barely manages 20mph uphill. Obviously this sounds like a "give the carb a right good clean" issue, but that hasn't worked. Video link here to show what sort of noise it's making - https://www.youtube.com/watch?v=Gs-FUHivXTg&feature=youtu.be

I got the bike a couple of months ago and it had the same problem when I got it.

I've tried quite a lot of things so far and spent a fair while at it, with no results - here's a list of what I've tried

-I've had the carb off several times as you may expect and given it a really good clean, then another, even better clean with Wynne's, compressed air, copper wire down every hole etc etc. It's spick and span and as clean as I imagine it ever will be (although at the bottom of the air/fuel mixture hole there seems to be some sort of fuzzy muck on the threads. it won't budge)
-I've checked the airbox - it seals properly, all airlines and breathers into it and the carb are perfectly clear. The clamp onto the carb is nice and tight, but the rough running happens even when the airbox isn't fitted
-The fuel system has been checked - fuel cap vent works as it should, vacuum petcock works (tested by running a straight fuel line through to carb instead, problem persists the same) all lines clear and in good cond., tank nice and clean, no gunk or rust that I can see.
-Carb refurb kit from wemoto fitted, including all new jets, fuel screws, drain screw, springs, needle valve, float valve etc. Weirdly it runs every so slightly worse after using the carb refurb kit.
-New plug + oil change using good quality castrol oil of the correct spec (it won't be anything to do with these but worth doing anyway, eh?)

I'm really getting fed up with it not being right, I've tried everything I can think of and nothing has worked. any advice anyone can give would be massively appreciated!

thanks very much

[stinkwheel]

Have you checked the valve gear and clearances? Not unheard of for a tappet to have unscrewed itself.

Old saying goes 90% of carburettion problems are electrical.

Does it have a GOOD spark? Fat, blue and jumping from the centre of the electrode to the centre of the tang.

How does the electrode on that new sparkplug look now it's been running for a while?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[hebdenwill]

Hi Stink,

yep, forgot to mention, the valve clearances are bang on. the tappets are done up nice and tight (with the correct gap maintained ofc)

To be honest the plug doesn't have a great spark, and the electrode (that's the bit where the spark comes our yeah?) is very dark and sooty

[stinkwheel]

So it may be worth changing (or at least checking the connections of) the plug cap and HT lead. Also make sure the ignition coil has a good clean earth and that the terminals attaching to it are free from corrosion.

The symptoms you describe (can't view your video at work, youtube firewalled off) could also fit with a poor spark OR a retarded ignition timing.

So another thing to check is that the ignition pickup coil is still firmly attached and has the right clearance. May also be worth checking the flyweheel hasn't spun-up (this is the only way the timing could be properly retarded). It should be keyed onto the crank but I have heard of them letting go on small hondas. That would need checking with either a strobe or a visual check of the keyway, a bit more of a pest to do, you'd need a crank puller for one thing (although they aren't as expensive as most people seem to think).

Oddball suggestion, if some wag had shoved a humorous foreign object up your exhaust, it could cause similar symptoms.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[hebdenwill]

Hi Stink,

Thanks for taking the time to reply again.

A lot of these things are a bit over my head to be honest, I could fit a new HT lead but the one that's on looks fairly new.

The thing is, although it obviously isn't combusting perfectly, it's starved for fuel or air, you can just hear it. I reckon one might be related to the other - something wrong with the carb, somehow, and it's running rich.

It might be worth checking the exhaust, to be fair one of the bolts is missing and the little plate that bolts it to the exhaust port is sort of askew

[ART-ADS]

Check the timing. Probably not sparking at the right time
____________________
98' RZ50, 92' H100S2, 03' VT125, 59' Jubilee 250, 05' varadero chop,

[ART-ADS]

Also mate I’d take off the cylinder and have a look in the combustion chamber, might be some damage causing shitty combustion. Just an idea you got nothin to lose having a check. I’d leave the carb to be honest for the minute. They’re pretty reliable bits of kit after a good clean so I doubt that’s the issue. Maybe get a clear fuel bowl to see if the float height is fine if ur still concerned
____________________
98' RZ50, 92' H100S2, 03' VT125, 59' Jubilee 250, 05' varadero chop,

[sickpup]