Misfiring / clanking, possible cam timing problems...

[snakebitey]

Decided to make a topic rather than hijack someone else's

So I got some shiny new manual CCTs today (thank you Rider on a Storm ), and fit them following the guide on here... This would have been a victory post, but...........

On the rear cylinder, set to RT on the alternator window thing as per the guide, the cams pointed upwards and towards each other. Such as...


That's good, matches all the comments and pictures.. Ok, set the tension to 7mm, reassembled, on to front cylinder.

JESUS TITTY-F*CKING CHRIST that front rocker cover is a b**ch to get off!

Much more time, and much less skin left on my hands later, cover's off, and alternator window thing is a turn-and-a-quarter anticlockwise and showing FT. All good so far.

But I notice, the cams are facing AWAY from each other. Like... directly away from each other. Like ...


I thought they were meant to be facing away, but also slightly up or down (can't remember), but I checked the markings on the cam wheels and they lined up with the casing so presumed all was good and I'd just wheeled the alternator bolt around a little too far or something silly... (THIS PROBABLY WAS MY MISTAKE).

Reassembled everything (GODDAMNED FRONT ROCKER COVER!), turned it over a few times with the alternator bolt and all seemed smooth.

New plugs in, started it up, all seemed great. F*CK YEA I'M A MASTER MECHANIC.

NO.

I took it for a gentle ride around the block and same problem - just cruising at 30mph doing about 3000 revs in 2nd or 3rd, it makes a metallic 'CLACK' and lurches as it loses power on that stroke. Carries on normally a few seconds, then another lurch and CLACK. Definitely from the front cylinder.

The front end is still fairly noisy, not more than my old CBR 400 though, but still louder than the rear end.

I didn't clean the carbs out, but I'm fairly sure that's not the cause here. Just doesn't seem carb-y, if you get me.

All I can guess at this stage is that my front cylinder has gone out of time by slipping a tooth, and if so I'm lucky it got home after this trip without it falling to bits.
If that's the case though, I'm puzzled how the cam wheel markings lined up with the casing still. Unless there's more than one marking - it was getting dark at this point!

Any help would be greatly appreciated!
Adam

[VTRDark]

That's not right mate, don't ride the bike until it's sorted. On your second pic the cam lobes should be pointing away and outwards which is the exact opposite to the rear. Did you hear any noises while loosing off the original cct. It may have slipped a tooth if not undone slowly alternating between the two bolts to loosen off. Or when setting the timing from the rear did you turn the flywheel round enough. The FT should have passed the mark once and then as you come back round, stop on the line when you see the FT for the second time. You may have the timing out 180 degrees.

Your going to have to remove that front rocker cover again set the timing so your on the compression stroke. Flywheel mark being the FT and verify your on compression from the the cam lobe position. I only have pics for the rear cam sprockets but if you look at the following pics, you will notice a scribed line with RI (rear inlet) and RE (rear exhaust) on the front it will be the same except it will be FI and FE. Make sure these line up parralel with the top of the cylinder head.

If not then your going to have to re-position the cams.






(:-})

[snakebitey]

That's not right mate, don't ride the bike until it's sorted. On your second pic the cam lobes should be pointing away and outwards which is the exact opposite to the rear. Did you hear any noises while loosing off the original cct. It may have slipped a tooth if not undone slowly alternating between the two bolts to loosen off. Or when setting the timing from the rear did you turn the flywheel round enough. The FT should have passed the mark once and then as you come back round, stop on the line when you see the FT for the second time. You may have the timing out 180 degrees.

Your going to have to remove that front rocker cover again set the timing so your on the compression stroke. Flywheel mark being the FT and verify your on compression from the the cam lobe position. I only have pics for the rear cam sprockets but if you look at the following pics, you will notice a scribed line with RI (rear inlet) and RE (rear exhaust) on the front it will be the same except it will be FI and FE. Make sure these line up parralel with the top of the cylinder head.

If not then your going to have to re-position the cams.
(:-})

Thanks for the quick reply!

So the front ones should be pointing upwards too? Like...

...?

There were no noises as far as I could tell - I didn't hear anything slip while I loosened the original CCT, I did that slowly and alternating just to make sure, but it maybe could have happened without me hearing.

I'm pretty certain I had it on the right stroke - I turned it 1 & 1/4 turns anti-CW from where it was set for the rear cylinder. The FT mark passed by once, then came back around.

Are the FI and FE marks the only marks on the cam sprockets? It was getting dark and I couldn't read them properly, but there were definitely marks lined up with the case like...

(Forgive my awesome MS Paint skills!)

If I need to reposition the cams, is it a matter of setting the flywheel to FT on compression, then slacking off the cam chain tensioner til it's loose enough to hop the cam sprockets round a notch or two?

Cheers!

[VTRDark]

Superb diagrams.

So the front ones should be pointing upwards too? Like...

Correct

Are the FI and FE marks the only marks on the cam sprockets? It was getting dark and I couldn't read them properly, but there were definitely marks lined up with the case like...

There are other marks on sprockets but they are of no concern. It's just the FI and FE that shold line up as on your diagram. On that diagram your little cam lobes should pointing up and out.

If I need to reposition the cams, is it a matter of setting the flywheel to FT on compression, then slacking off the cam chain tensioner til it's loose enough to hop the cam sprockets round a notch or two?

Flywheel should be on compression (FT) you will have to slacken off the cct to loosen off the chain, and then you could lift the chain and slip them round and reposition. I'm not sure of this but you may have to slacken off the bolts that hold the cam in place. I wouldn't undo them totally, just slacken them off as it may give you a bit more play to slide the cam round without catching the chain. Be very careful with the chain, you do not want to drop/loose it inside the engine casing. It would probably be a good idea to attach some wire around it as a safety precaution. You could also use this to hold the chain up out the way as you re position the cams.



Get the timing set and the rocker cover off, have a look and get back to us with the results.

(:-})

[snakebitey]

Ok thanks!

So it seems likely at this stage then, that the chain's slipped a couple of teeth while on the original CCTs (the bike was behaving the same before I put the manuals in), and the position that it's slipped into coincidentally lines up with some other markings on the front cam sprockets, just not the FI and FE ones it should line up with.

I'll get onto that after work tomorrow and report back

Bed time for now though! Thanks again!

[VTRDark]

When I first done my cct's I had a similar problem. This may be of some help http://www.vtr1000.org/phpBB3/viewtopic ... +tensioner

(:-})

[tony.mon]

Given the circumstances, the only way to be sure is to pull the cam covers off, rotate the engine gently to the correct rear cylinder position and start again.
I can only think that you have set the front cams to a different marking than the correct one, but you seem from what you've said to have got it right, at least, following the how-to by Sirch.
Getting the front cam cover off can be tricky; I find it's easiest to get the oil cooler out of the way, but to get it low enough to clear everything you'll need to undo and rotate the lower rad brackets; they bolt onto the front head and dowel into the underside of each rad.
That lets you lower the oil cooler onto the back of the mudguard- use a rag to prevent paintwork damage.

And yes, Carl, you need to remove the cam cap bearings in order to rotate the cam under a slack chain. The cam needs to be tilted in its housing to get enough clearance.
But only one needs to be undone, once that's out the chain's slack enough to get the other one rotated.

By the way, when you're lining up the marks, make sure you pull the chain in the correct direction, so that the non-tensioned run has no slack in it.

[VTRDark]

And yes, Carl, you need to remove the cam cap bearings in order to rotate the cam under a slack chain. The cam needs to be tilted in its housing to get enough clearance.

That's what I thought, it seemed logical. Thanks for confirming that.

(:-})

[snakebitey]

Ok, update:

Took the rocker covers off again, actually all the timing marks line up perfectly where they should - it was just me being a tit and working after dark and not being able to see well enough

Double, triple checking everything was where it should be, I reassembled and took it round the block again. Same problem, but knowing it wasn't the timing I left it running a bit longer this time.

It does actually seem, after all that, it's some kind of fueling problem - it runs fine for a little while, then the lurching starts and it eventually makes that different exhaust noise you get when you're about to run out of fuel ( I know that noise all-too-well from my CBR! ).

Then it loses all power after 10 sec or so of lurching about. If I feed the clutch back in, or use the starter to turn the engine over it'll eventually fire up again, and I'll get another 30 seconds of so of normal riding before it repeats.


POSSIBLE CAUSES

• The bike had been in a garage for a few months when I bought it, maybe some crap that settled in the tank got pulled through. Carbs are clogged with something from that or something else.
  I've hooked up some breathers / vacuum lines wrong - I didn't note down where each hose on the tank came from, but I'm 99% certain they're all back in the right place. Doesn't explain why this started happening before I took it apart however.
  The Redex I put through it a month or so ago killed it.

On hooking up the hoses, the fuel tap has a little fixing on the bottom of it that was attached to the Scottoiler (previous owner's work). I'm guessing it's a vacuum tube.
I noticed an extra hose that I couldn't remember unhooking from anything coming from the rear inlet manifold, just below where the carb attaches, was the right length and diameter to fit to this fixing on the fuel tap. So I thought that can't be coincidence and hooked it up on there. Here's a pic...


I'm heavily suspicious that's what's causing the problems, apart from one thing - why did this problem start before I ever touched the hoses?

Any ideas anyone?

And if this mystery hose doesn't belong on the fuel tap, where does it go to? I can't see anything else!

And thanks so much for all the help regarding CCTs and timings

Adam

[dave09]

Ok, update:

Took the rocker covers off again, actually all the timing marks line up perfectly where they should - it was just me being a tit and working after dark and not being able to see well enough

Double, triple checking everything was where it should be, I reassembled and took it round the block again. Same problem, but knowing it wasn't the timing I left it running a bit longer this time.

It does actually seem, after all that, it's some kind of fueling problem - it runs fine for a little while, then the lurching starts and it eventually makes that different exhaust noise you get when you're about to run out of fuel ( I know that noise all-too-well from my CBR! ).

Then it loses all power after 10 sec or so of lurching about. If I feed the clutch back in, or use the starter to turn the engine over it'll eventually fire up again, and I'll get another 30 seconds of so of normal riding before it repeats.


POSSIBLE CAUSES

• The bike had been in a garage for a few months when I bought it, maybe some crap that settled in the tank got pulled through. Carbs are clogged with something from that or something else.
  I've hooked up some breathers / vacuum lines wrong - I didn't note down where each hose on the tank came from, but I'm 99% certain they're all back in the right place. Doesn't explain why this started happening before I took it apart however.
  The Redex I put through it a month or so ago killed it.

On hooking up the hoses, the fuel tap has a little fixing on the bottom of it that was attached to the Scottoiler (previous owner's work). I'm guessing it's a vacuum tube.
I noticed an extra hose that I couldn't remember unhooking from anything coming from the rear inlet manifold, just below where the carb attaches, was the right length and diameter to fit to this fixing on the fuel tap. So I thought that can't be coincidence and hooked it up on there. Here's a pic...


I'm heavily suspicious that's what's causing the problems, apart from one thing - why did this problem start before I ever touched the hoses?

Any ideas anyone?

And if this mystery hose doesn't belong on the fuel tap, where does it go to? I can't see anything else!

And thanks so much for all the help regarding CCTs and timings

Adam

i had this problem couple days ago after taking my tank off the bottom nubbin on the fuel tap is to drain the tank the one on the back is the vacum i got it wrong way before and the bike was riding fine for around 10mins then kept trying to die on me

[VTRDark]

Nothing should be attached to the outlet on the bottom of the tap, this is an overflow in case of tap failure. The hose coming from the rear carb is a vacuum hose and should be attached on the fuel tap to the the outlet just behind the fuel hose on the left hand side of bike. It's not easy to see, but you can feel it directly behind it.

This would be causing you problems, a very common mistake when connecting the tank back up.

[/quote]

So after all that, taking the front rocker off again it possibly just the vacuum hose that's causing your problems.

By the way the feed for the Scotoiler should be taken off that vacuum hose as well.

(:-})

[tony.mon]

So after all that, taking the front rocker off again it possibly just the vacuum hose that's causing your problems.

By the way the feed for the Scotoiler should be taken off that vacuum hose as well.

(:-})

Yes, that will be the whole problem.

Just for clarification, the sideways facing pipe coming off the back of the fuel tap should go to a tee piece, one of the tee's is connected to the vac take-off point on the front face of the rear cylinder head, just below and to the left of the carb connection rubber, and the other tee should go to your scot oiler.

[snakebitey]

Nothing should be attached to the outlet on the bottom of the tap, this is an overflow in case of tap failure. The hose coming from the rear carb is a vacuum hose and should be attached on the fuel tap to the the outlet just behind the fuel hose on the left hand side of bike. It's not easy to see, but you can feel it directly behind it.

This would be causing you problems, a very common mistake when connecting the tank back up.

So after all that, taking the front rocker off again it possibly just the vacuum hose that's causing your problems.

By the way the feed for the Scotoiler should be taken off that vacuum hose as well.

(:-})

You sir are a genius I didn't spot that little outlet back there, but now I think about it I do remember removing a hose from there....
It was the previous owner that put in the Scottoiler, I don't even use it. I'll remove it next time I tinker!

And thank you too Tony, if I do refit the oiler I'll do that

Running sweet as now, thanks everyone so much for all the advice!

[dave09]

Nothing should be attached to the outlet on the bottom of the tap, this is an overflow in case of tap failure. The hose coming from the rear carb is a vacuum hose and should be attached on the fuel tap to the the outlet just behind the fuel hose on the left hand side of bike. It's not easy to see, but you can feel it directly behind it.

This would be causing you problems, a very common mistake when connecting the tank back up.

So after all that, taking the front rocker off again it possibly just the vacuum hose that's causing your problems.

By the way the feed for the Scotoiler should be taken off that vacuum hose as well.

(:-})

You sir are a genius I didn't spot that little outlet back there, but now I think about it I do remember removing a hose from there....
It was the previous owner that put in the Scottoiler, I don't even use it. I'll remove it next time I tinker!

Running sweet as now, thanks so much for all the advice!

Happy day

[VTRDark]

I've been called many things but never a genius. Glad your all back up and running.

Next.

(:-})