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CBR600 F4i - Issue after checking clearances

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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 17:33 - 07 Jul 2020    Post subject: CBR600 F4i - Issue after checking clearances Reply with quote
Hello gents, hope lockdown is treating you well.

Over the weekend I tore the bike down to check the valve clearances. Looks like the exhaust valves are quite tight, so shims will be on order for them soon.

However, when I put the bike back together, I couldn't start initially, but with a bit of persistence she fired up. However, the idle was incredibly rough and the bike would not rev at all, in fact it would make a pretty bad rattle if I tried so I stopped quickly. My initial thought was that I'd buggered up the camshaft positions, so I tore the bike back down again last night to double check. With the T-mark on the index, both the IN and EX marks pointed out and were level with the top of the head, so for sure the camshaft positioning is correct.

It's back together now, and won't start at all (still cranks) because it looks like the battery is dying. It seems that when the ECU has gotten the camshaft and crank pulse (the point where usually the bike would fire up), the engine stops and the bike resets itself, like I've turned the key off and on. What's also weird is the bike doesn't do this if I disconnect the connectors to the coil-over-plugs, just keeps cranking over, so it seems like the ignition system has something to do with it.

It's still feeling like timing to me, like the engine is trying to run backwards or something, but I can't see how as I'd left both camshafts assembled (I.E. sprockets left on, pickup wasn't removed) so all the references are still the same.

I'm at my wits end a bit, doesn't help that I have a track day booked for the coming Monday! Serves me right for tearing into the bike a week before..

Any ideas?
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stinkwheel
Bovine Proctologist



Joined: 12 Jul 2004
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PostPosted: 17:48 - 07 Jul 2020    Post subject: Reply with quote
Firing on all four? Could you have a couple of plug caps back on the wrong way round?
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Nobby the Bastard
Harley Gaydar



Joined: 16 Aug 2013
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PostPosted: 17:49 - 07 Jul 2020    Post subject: Reply with quote
First off, you did put every bucket back on the same valve it came out of? Have you swapped the cams round?
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 17:54 - 07 Jul 2020    Post subject: Reply with quote
stinkwheel wrote:
Firing on all four? Could you have a couple of plug caps back on the wrong way round?


It sounded like it was firing on all four, but I didn't feel exhausts or anything to check. I've played around with connector order as well which caused some backfiring. Also checked the correct colour wire was going to the correct cylinder referencing the service manual and I had it right first time (the loom lengths are a dead giveaway really)

Nobby the Bastard wrote:
First off, you did put every bucket back on the same valve it came out of? Have you swapped the cams round?


Yep I made sure I only had one bucket off the bike at a time for this very reason. And the bike wouldn't fire at all if the cams were swapped, the pickup is only on the exhaust camshaft.
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 20:23 - 07 Jul 2020    Post subject: Reply with quote
I had the cover off once again to see if I still had the same valve clearance, which I did. I also checked the pickup was oriented how the manual states it should be.

Carrying on down the ignition route, I checked the spark plug gaps, which were fine, but the plugs were really quite loose in their threads. I wonder if maybe they'd relaxed somehow when I had the camshaft holder off? Either way I'll be fairly annoyed if I've gotten myself this crossed up over loose spark plugs...

The battery was too flat to start the bike. It still cranked over, but it didn't seem to stop instantly like it was doing before. I'll charge the battery at work tomorrow and give it a crank in the evening and see what happens
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Hong Kong Phooey
World Chat Champion



Joined: 30 Apr 2016
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PostPosted: 13:36 - 08 Jul 2020    Post subject: Re: CBR600 F4i - Issue after checking clearances Reply with quote
Campbell SOUP wrote:
...idle was incredibly rough and the bike would not rev at all, in fact it would make a pretty bad rattle...


Sounds like somebody forgot to reset their cam chain tensioner.

If the chain tension is loose it'll rattle, also the cam timing would be out.
I suspect it's possible you could get the marks to line up and it could be one or two teeth out of phase with the ignition pulse with a loose timing chain.
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 21:10 - 08 Jul 2020    Post subject: Re: CBR600 F4i - Issue after checking clearances Reply with quote
Hong Kong Phooey wrote:
Campbell SOUP wrote:
...idle was incredibly rough and the bike would not rev at all, in fact it would make a pretty bad rattle...


Sounds like somebody forgot to reset their cam chain tensioner.

If the chain tension is loose it'll rattle, also the cam timing would be out.
I suspect it's possible you could get the marks to line up and it could be one or two teeth out of phase with the ignition pulse with a loose timing chain.


I did check timing after resetting the chain tension, I spent far too long filing a sheet of metal into a chain relief tool to forget it was just poking out of the bike!

Anywho, turns out it was the timing after all! I decided I didn't quite believe the timing marks were giving me TDC, so I put a piece of wire into the cylinder through the spark plug hole to check where it really is. Turns out I had mis-understood the manual, and the 'T' mark means literally on top of the T, not between the two lines I thought it was denoting.

https://i.imgur.com/iXESVT3.jpg

Thanks all for your help anyway! Hopefully someone will find this post on google in 10 years time and have their problem solved too Razz
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Easy-X
Super Spammer



Joined: 08 Mar 2019
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PostPosted: 21:32 - 08 Jul 2020    Post subject: Reply with quote
RTFM Smile

Well done though Thumbs Up
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 21:44 - 08 Jul 2020    Post subject: Reply with quote
I did and it got me nowhere Laughing

https://i.imgur.com/Xmwfzlg.jpg

Be your own judge...
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Nobby the Bastard
Harley Gaydar



Joined: 16 Aug 2013
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PostPosted: 21:53 - 08 Jul 2020    Post subject: Reply with quote
Campbell SOUP wrote:
I did and it got me nowhere Laughing

https://i.imgur.com/Xmwfzlg.jpg

Be your own judge...


That seems quite clear to me. It says ' align the t mark'. Not 'align half way between the t mark and the next mark.'
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 21:57 - 08 Jul 2020    Post subject: Reply with quote
Nobby the Bastard wrote:
Campbell SOUP wrote:
I did and it got me nowhere Laughing

https://i.imgur.com/Xmwfzlg.jpg

Be your own judge...


That seems quite clear to me. It says ' align the t mark'. Not 'align half way between the t mark and the next mark.'


I do agree that particular statement is clear, but it's the picture that muddies the waters a little bit and I'd be surprised if I'm the only one to make the mistake!
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kramdra
World Chat Champion



Joined: 28 Oct 2010
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PostPosted: 23:59 - 08 Jul 2020    Post subject: Reply with quote
You still have it wrong, as I did originally. "T I : : I F", The timing mark is the line after the T, not the T itself. The poor quality manual photo does not help, but zoom in and you can see it. I have confirmed this elsewhere. The T and I are about 5 degrees, half a tooth difference.

I have no idea what the other ": : I F" marks are for.
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 06:27 - 09 Jul 2020    Post subject: Reply with quote
kramdra wrote:
You still have it wrong, as I did originally. "T I : : I F", The timing mark is the line after the T, not the T itself. The poor quality manual photo does not help, but zoom in and you can see it. I have confirmed this elsewhere. The T and I are about 5 degrees, half a tooth difference.

I have no idea what the other ": : I F" marks are for.


I didn't actually use the crank marks as my reference, just the wire method and built from there. The crank was aligned to the "T" when I did this, though it's not like I was using a DTI gauge or anything so probably not the most accurate method!

The bike does run properly and revs cleanly but I haven't tested by riding it. If it was still wrong as you say, how would the bike be running?
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steve the grease
Crazy Courier



Joined: 26 Jan 2018
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PostPosted: 15:20 - 09 Jul 2020    Post subject: Reply with quote
kramdra wrote:


I have no idea what the other ": : I F" marks are for.


F is the firing mark, the spark always occurs before top dead centre. The dots and line may give the advance range between retarded and advance positions. All the marks could be used with a timing gun.
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 16:22 - 10 Jul 2020    Post subject: Reply with quote
I think I might have really buggered something here lads.. bike's making a ticking noise that it wasn't before and it's definitely got a bit of a splutter at some rev ranges...

Does that sound like a bent valve(s) to anyone else?
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Hong Kong Phooey
World Chat Champion



Joined: 30 Apr 2016
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PostPosted: 21:34 - 10 Jul 2020    Post subject: Reply with quote
The tensioners are notoriously shit. How did you reset it?
Like this?

https://m.youtube.com/watch?v=TYnO_T5jQX0

How many revolutions did you manually spin the crank after resetting it, as the timing should be ok if the tension tightened and the marks stayed aligned.

Make sure the ticking is not exhaust leak, the header bolts loosen off over time.

If that's not it it could be chain tensioner guides loose or snapped internally, either way you're going in.
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 10:27 - 11 Jul 2020    Post subject: Reply with quote
Hong Kong Phooey wrote:
The tensioners are notoriously shit. How did you reset it?
Like this?

https://m.youtube.com/watch?v=TYnO_T5jQX0

How many revolutions did you manually spin the crank after resetting it, as the timing should be ok if the tension tightened and the marks stayed aligned.

Make sure the ticking is not exhaust leak, the header bolts loosen off over time.

If that's not it it could be chain tensioner guides loose or snapped internally, either way you're going in.


Hmm, I had reset it with everything bolted down, so I don't believe it to be overtightening onto the cam chain. I put 2 revolutions to get the IN/EX marks back to the same position in as I'd read elsewhere that turning anti-clockwise doesn't tighten the tensioner.

I've been riding around more on the bike today (I'd ridden to another house last night, my last post was from my phone) and I think I was a bit jumpy.. the bike does run as normal, there's a nasty flat spot between 7-9kRPM which was there before, but I think it's gotten worse somehow. There's definitely a rattle of some sort, but only present when the bike is warm, and doesn't sound like anything is broken. The bike is new to me so maybe I just wasn't listening for it before.

I think what I'll do is add a manual cam chain tensioner to my order of shims and change that as well for peace of mind and get it all done in one hit. After that, I can start addressing this flat spot.

I'll check the exhaust bolts now though as that's low hanging fruit.

Cheers
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 10:31 - 11 Jul 2020    Post subject: Reply with quote
The rattling doesn't sound anything like the video below though, so I don't think it's the CCT. Sounds more like a 'tapping' noise really

https://www.youtube.com/watch?v=jdTW5RzynEc
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Campbell SOUP
Two Stroke Sniffer



Joined: 27 Jun 2020
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PostPosted: 11:16 - 11 Jul 2020    Post subject: Reply with quote
I read through the service history and the CCT was replaced October last year, so I think I may just hang fire on the manual one for now
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Easy-X
Super Spammer



Joined: 08 Mar 2019
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PostPosted: 15:14 - 11 Jul 2020    Post subject: Reply with quote
Just flicking through the service schedule on my bike. Gratified to find hi-res photos for the timing and very clear explanations of the T, F and associated marks. Seems Honda have learnt something along the way Smile
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