(Stripping the Engine...) VVC Valve Clearance Adjustment

[Wudy]

Hey guys, in need of a little help...

First of all, my question(s):

1. How do you get the throttle cable out of the carbs?

2. How does the lead wire come off of the starter motor? Does it just pull straight off? (Didn't seem to want to move and don't want to break it)


Now, how I got to this point...

On my way home from work wayyy back on the 4th Jan, my bike suddenly make a horrible noise from the cam cover. After waiting over 3 hours in -6DegC I finally got it picked up and taking home. Later that week I got it delivered to my local mechanic (as I didn't have the time and just wanted it fixed) who took the cam cover off to reveal that my exhaust cam had jumped two teeth on the sprocket, and at one part of the cycle the cam chain suddenly goes slack between the two cams.
Presuming the cam chain tensioner has gone he said he could replace it and hope all is well but with the cam jumping two teeth like that he thinks the valves could've hit the pistons so it would be worth stripping the engine and checking if it has or not.
So I got it delivered back home and I've just started stripping her down today.
I've got the tank, air-box, rad, front sprocket and exhaust off. Just got the throttle cable, choke cable (which I've had off before), starter motor wires, and a few other little wires (neutral indicator etc) to take off then the engine's ready to come out.

Hopefully I can actually enjoy this summer with the bike working! Spent last summer in the the garage due to a relay that only exists on the VVC bikes so there was no mention of it anywhere! That was stressful...

Cheers  

[tomacGTi]

Why not try to retime the motor first and try to fire it or run a compression test?

Of course, put a chain tensioner on there first but these are cheaper and easier than assuming things are f'd and tearing a motor apart.

Throttle cable: loosen completely at the grip and you'll see how to manipulate the cam to slide the lead end out.

Lead wire: pretty sure its bolted into place under a cover.

[Chris H]

DONT throw away the cam cover gasket as they are VVC only!!!!
tomacGTi is correct in thinking its worth a compression test and a good inspection. Take the plugs out and shine a good torch down, see if you can see damage. Get a APE gsxr srad manual cam chain tensioner and it will never happen again.
Ive a VVC head in peices if you need some spares.

[Wudy]

Cheers for the reply.

Well I figured it would be best to check everything was ok first, as the mechanic (who knows his stuff, but isn't an expert on the B4) was pretty worried by how much it had moved and thought it highly likely it's hit.
I did contemplate just replacing the tensioner and seeing how it went but thought it could do more damage if something's taken a hit?
Just wanted to play it safe really.

Cheers, will give it a go when I'm next out there (Which won't be until next week, stupid Valentines weekend lol), couldn't really get my fingers on it but if it's as simple as that I'll try harder.
Cool, that should be easy enough then, ta!

So you think it's worth stopping where I am and replacing the tensioner (and chain?)? Only take few hours to half a day to get it run-able again.
Also, does the tensioner always keep it under tension or is it just when running?

Cheers.

EDIT: Just saw your post Chris.
I think I need a new cam cover gasket anyway, there's been a little be of dampness around the head but haven't looked into it properly yet. Will see what it's like, my normal parts place has been able to get things for me so fingers crossed for that.

Ok, so verdict is to just see if it runs as it is then (once timed correctly)? (He says worridly lol)

[Chris H]

I would only run it if you feel its 100%. If you take a really good look down the plugs and down the ports you may see any damage and when the tops off if you turn the motor over with the 17mm bolt at the end of the crank you can get a good look at how all the valves are working. Turn the Vcc from low to high and just take a real good look. I really would'nt throw the gasket away if all poss because it a special fit and only available from Japan. You could wait anywhere up to 6 months for a spare and they always work after a good wash in soapy water.

[Wudy]

So if there's any damage I should have a good enough view through the plug hole with the cam cover off? Yea the mechanic was turning it over by hand when he had the cam cover off and everything seemed to be working ok.
I wasn't going to chuck the gasket till I get a new one, but will see what it looks like when I get it off.
Well when I get a chance to get out there again I'll get the cam cover off and see what I can see from there, will post up with my findings. I'll also get the tensioner out and see what that's like (I just assume it's gone, but will check).

[tomacGTi]

All you will see is a possible witness mark on the piston tops midway through the stroke if you can see anything at all. Even with the cam cover off, it is very difficult to see anything down the spark plug hole.

My experience is with non VVC as I smoked a head in an ill-fated cam experiment a couple of years ago.

Honestly, the places to check for damage without going nuts would be the tips of the valves (check for mushrooming) and the rocker arms themselves (pad surface should be chrome, not worn through, look for stress cracks through the casting).

If those are fine, retime the motor, install a new tensioner and fire it. Aside from possible big end bearing wear from piston contact, you'll never know till you have the motor up and running or if you chose to completely disassemble the motor.

If it's phucked, you would be dropping in a new motor anyway right?

-Randy

[Wudy]

Nice one Randy, I'll see what I can see at those places. Will take some photos too (as I have as I've been taking this off for my reference) for confirmation of how they look.

Will post up on Wednesday eve with my findings

Cheers guys.

[Wudy]

Ok, so I've got the cam cover off and the cam chain adjuster out.
Couple of questions...

First of all, how the **** do I get the cam sprocket back to where it should be?

When the intake cam is like this:


The exhaust cam is like this:


And at one point in the cycle the chain suddenly drop to sit like this:


At the point when the chain is loose I tried just pushing it around the sprocket (hard to explain, but I'm sure you know what I'm on about) but there isn't enough slack between the two sprockets to go all the way. Any ideas?

Second question:

I took the tensioner out and I was able to turn the screw which was moving the tensioner arm in and out as I turned the screw, so it would appear this is a manual adjustment tensioner?
The automatic one is supposed to just 'lock' and 'unlock' rather than screwing all the way isn't it?

[tomx611]

First Answer:
I think the intake and exhaust cam should be like this (-    -). i tried to take aways the cam and then i can set the position freely, and it's not much difficult if u got a service manual.

PS, i only disassembe my 97 bandit, not much experience. hope it can help u.

Sec answer:
my 97 bandit tensioner will turn back automatically after i take away the screw driver. i think the use of it just stop turning after the arm contact the chain, and provide tension on the chain.

[Wudy]

i tried to take aways the cam and then i can set the position freely

I don't know what you mean by that mate?

my 97 bandit tensioner will turn back automatically after i take away the screw driver.

Yea that's what I think mine should be like as standard.

So, as it seems that I have a manual adjuster, how tight should it be? And how often will it need adjustment? I think I'd prefer to replace it with a standard fit automatic tensioner really...

[tomacGTi]

None of these bikes came with a manual adjuster. Only Jay or APE have or can get a manual tensioner for these bikes.

If it doesn't spring back and lock, that means the adjuster is worn out and allowing the chain to go completely slack.

You may be able to get away with sliding the chain over a tooth at a time with the tensioner removed but make sure your crank is on the zero mark as well. It may not be a bad idea to pull the cams just to make sure it's all timed right. I have no idea how complicated that may be on a VVC motor though.

[Wudy]

You may be able to get away with sliding the chain over a tooth at a time with the tensioner removed but make sure your crank is on the zero mark as well.

That's what I tried, and had thought would be possible. But it's not, although I will give it another go on Friday (got to spend a day on the road tomorrow, but might have a go in the evening).

It may not be a bad idea to pull the cams just to make sure it's all timed right. I have no idea how complicated that may be on a VVC motor though.

How hard is it on the non-VC motor? I don't think the VC mech will make much of a difference, think we need Chris H for confirmation on this.

If I can't manage to get the chain over the sprocket I guess that's going to be the only way?  

Cheers guys

EDIT: I have just though of another way, which would involve turning the motor backwards for about quarter of a turn, will this do any damage to anything? Or is it even possible? (My little nitro engines would only turn the correct way).

[tomx611]

Wudy

i post the part of manual which for remove the cam, how u can fix ur problem.

regards,
Hong

[Chris H]

Hi,
Have you got the VVC with VV on both exhaust and inlet or just Inlet?
To set the cam you must first remove the cam holders so the cam shafts are removable and the LH engine cover, then, line the T mark on the pick up trigger with the little arrow at the front of the case. Lift the inlet cam up and inwards so it can be turned and with the cam chain slack taken up you must fit it to the exhaust cam with its '1' arrow pointing to the front gasket surface and the '2' arrow facing up (do not move the crank T mark).from the '2' arrow you count 20 pins for the VVexhaust and i think 24 pins (will check) for the VV inlet only model and fit the inlet cam with its '3' arrow pointing to this pin, loosely bolt the cam holders in and turn the motor over and recheck. If good tighten the cam holders to 6-8.5lb-ft 8-12N.m.
Its now a good time to check the valve clearences but its a bIGGGGGGG job best done with a manual.