sick zeal

[erik]

Riding to uni the other day the Zeal started going blaaarrgghh when trying to accelerate. It sounds normal idling and if I'm gentle with the throttle, but if I open it up a bit, it has no power and sounds like it's choking or something.

Of course this had to happen in the last few weeks of uni when I'm busy as hell trying to finish assignments!

Luckily my brother goes to auckland uni and they have a slightly different timetable, so I should be able to borrow his bike some of the time (and in exam week, in particular).

Anyway, anyone got any suggestions?

It started reasonably suddenly, one day it was ok, the next it started having problems. Is it worth trying some other petrol in case the stuff I've got in there is contaminated? (I filled up about 40km before the problems started - but wouldn't bad fuel affect the idle too?).
A guy at uni that races bikes suggested it might be something to do with the valves. I'm not sure what he said exactly, maybe a dropped valve? (what is a dropped valve by the way?). I hope it isn't. I can't hear any loud noises that weren't there before.

I'm thinking I should check the airbox and have a look at the slides in the carbs to make sure they're opening. And check the sparkplugs and compression.

[sAsLEX]

spark plugs mate easy enough to check

[Sniper]

Yep, check the sparkies

[Artifice]

yeah and folowing that clean the carbs.

[Posh Tourer :P]

check the airbox intakes for leaves and stuff..... If it is vacuum carbs, check the rubbers to see if they arent cracked/broken. Sounds like it is sucking either too much or too little air. Check all the air seals around the carb area.

[sAsLEX]

check the airbox intakes for leaves and stuff..... If it is vacuum carbs, check the rubbers to see if they arent cracked/broken. Sounds like it is sucking either too much or too little air. Check all the air seals around the carb area.

THATS WHAT ME NC30 WAS DIAGNOSED WITH but was found to be a plug that had worn out, electrode was rounded rather than sharp so gave similar symptoms to air leak bung carbs, of note is that the carb seals are notoriously difficult to get back on on a V4

[Posh Tourer :P]

heheh.. I agree with ya sAsLEX, but it is best to check the cheap things first. You dont have to take the rubbers off, you can just inspect. If it was a plug I would have expected it to be less sudden, and you'd have to buy new plugs to check it.

Do you know when the zeal last had new plugs Eric??

[erik]

the plugs in there at the moment are ones that were in there when I got it, I've got no idea how old they are (edit: except that they'll be over almost 2 years old).
I bought a new set of slightly hotter plugs to try ages ago. I don't think they made much difference, so if the plugs that are in there are stuffed, I can probably use the slightly hotter ones with no problems.

I think I'll take a look at it tomorrow and see what I can spot.

[Posh Tourer :P]

If ya got the plugs already, whack em in. Its easier than inspecting every seal.... See what the old plugs look like too. White/overly black/worn/cracked, and you might have hit on the problem....

[sAsLEX]

If ya got the plugs already, whack em in. Its easier than inspecting every seal.... See what the old plugs look like too. White/overly black/worn/cracked, and you might have hit on the problem....

easy way to check which plugs are working is take the bike for a quick ride and then touch the headers and see if you find one that is considerbly colder/not burning your hand then compare that plug to the others!

[erik]

well, i spent a few hours messing around with the bike this morning.

Checked the plugs, they didn't look too bad but were a bit greyish (lean mixture?). Put the newer plugs in and went to take it for a test ride. As soon as I turned out the drive and tried to accelerate up the road: "blllaaaaarrgh" went the bike...

So it's not the plugs.

I checked the compression, all the cylinders got up to 100psi plus or minus 2psi or so.
So I guess it's nothing to do with the valves.

I had a look at the airbox and airfilter, both were ok.

I didn't pull the carbs off, but from what I could see of the carb manifolds, a couple of them had small cracks in them but I couldn't tell if they cracked right through or if air was leaking in through them.

The fuel filter was replaced not long ago, when I took the tank off and disconnected the fuel pump,fuel seemed to flow through the filter easy enough, so I guess that's ok.

Does anyone know how to check if the fuel pump is ok?
I'm wondering if maybe it's not getting up to the right pressure. I disconnected the hose from the pump to the carbs and when I turned the bike on, the pump spurted fuel out, so it's pumping. But is it possible for them to still pump but not get up to a high enough pressure or flowrate?
I think that could conceivably cause the poor performance under load.

I ran the engine a bit with the airbox off to inspect the CV slides, they seemed to be working ok.

So I guess at the moment I'm thinking it's either the fuel pump or maybe air is getting through the small cracks in the carb manifolds.

I didn't try any other fuel, but I think since it idles fine, and since the problem didn't start till about 40km into a tank of gas, the fuel is probably ok.

But I'm going to have to leave it for a while because I've got a shaft design report due next friday and I've barely started it. And then there's the beam design report due the friday after that which will probably require about the same amount of work.

[Patrick]

Sounds a little like what I had on my bike recently...found that the fuel tap was dodgy and was allowing fuel to be sucked straight into the #1 cylinder...new tap and all is good... (only had to wait three weeks for it from Japan... :argh: ) The mechanic gave me the tap off his 400 Bandit he wasn't using much..awesome mechanic, could have ripped me off from my lack of mechanical expertise but diagnosed the problem straight away and at reasonable costs too...long live "Delatours" in New Plymouth. Massively recommended.

(Free plug for ya Alan, if you're on this site????).

[erik]

Sounds a little like what I had on my bike recently...found that the fuel tap was dodgy and was allowing fuel to be sucked straight into the #1 cylinder...new tap and all is good... (only had to wait three weeks for it from Japan... :argh: ) The mechanic gave me the tap off his 400 Bandit he wasn't using much..awesome mechanic, could have ripped me off from my lack of mechanical expertise but diagnosed the problem straight away and at reasonable costs too...long live "Delatours" in New Plymouth. Massively recommended.

(Free plug for ya Alan, if you're on this site????).
The zeal has a plain old fuel tap: reserve, on, off. It hasn't got any vacuum hoses or anything, so while the symptoms might be the same, it's not the tap in this case.

[Patrick]

The zeal has a plain old fuel tap: reserve, on, off. It hasn't got any vacuum hoses or anything, so while the symptoms might be the same, it's not the tap in this case.


Oops...sorry... See? Told you I know bugger all...good luck

[erik]

your comments were appreciated :) . If the zeal did have a vacuum fuel tap, then it would have been something worth checking.

[erik]

Well, finished an assignment I was rushing to get done by today, so I had a look at the bike again.

The same guy at uni as before suggested it might be the coils.
So I checked them with an ohm meter, one was about 30k Ohms which is what it was last time I checked them. The other was about 400k Ohms, way too high.
Turned out one of the plug caps had some corrosion in it which was increasing the resistance. So I cleaned it and put it back together.

Didn't make any difference though :(

Also took the camshaft cover off because I was wondering if the camchain might've jumped a tooth. It hasn't.

Anyone know how to tell if the camchain is too worn out?

If you take a look at the attached photo, you can see daylight between a couple of links on the chain and two of the cam gear teeth.
I'm wondering if that indicates the camchain is too worn out (stretched) or if it's normal.
Also I've noticed the timing marks on the cams seem to be slightly further back than where they should be (when the alternator flywheel is lined up with the TDC mark), also making me think maybe the camchain might be stretched. I dunno if it would cause the problem the bike is having though.

Well, if anyone else has other comments, they would be appreciated.

I've gotta leave the bike again for another week or so and concentrate on assignments again.

[Two Smoker]

if its struggling with power i would look toward carbs... it seems to be a fueling problem from what your saying... Have you checked and cleaned your carbs??

[erik]

nope, not yet. I guess that will be the next thing to check as soon as I get the time.

[justsomeguy]

Have you PM'ed either Frosty/Ixion/KK/Motu or rung Motohaus??

[Mr Skid]

Have you checked the tie rod in the tacho?

[forty two]

hi ya erik. I als ohave a zeal and have recently replaced the fuel pump and I am under the inpression they are prone to stuffing out and if that is the case a pump producing a weaker pressure would possibly account for your problem. Pumpng enuogh =for idle but not for higher flow at wider throttle.
Or, I am a bit drunk at the moment and may have miss read your post and have it totally wrong, in which case, sorry.
I'll go back to what I was doing.
As you were all. :spudwave:

[erik]

Have you checked the tie rod in the tacho?
yep, it's connected to the float in the fuel tank and seems to be working normally. :mellow:

[erik]

Have you PM'ed either Frosty/Ixion/KK/Motu or rung Motohaus??
not yet, I'll see what I can do with a bit of advice on my own first.


hi ya erik. I als ohave a zeal and have recently replaced the fuel pump and I am under the inpression they are prone to stuffing out and if that is the case a pump producing a weaker pressure would possibly account for your problem. Pumpng enuogh =for idle but not for higher flow at wider throttle.

*puts fuel pump on list of things to (re-) check*