Valve tapping and backfiring

[Axewound]

My 98 MkII with 30,000 miles on it has, over the last 2 couple of weeks:

- started backfiring when I start her up, if I haven't used her for a day. Not all that borthered by noise (though does make me jump a wee bit), unless it will damage the exhaust or somefing, though started her up yesterday morning at about 07:00, and fook, what a bang, woke up a few of the neightbours dogs!

- much clearer valve ticking/taping noise now, most audible in second gear, coming off throttle at around 2-4000 rpm. Clearance was checked at 24,000 miles and was OK, but 1 valve was on limit, but dood said no need to do all the work for just 1 shim, might aswell wait for next time?

So, can backfiring damage stock exhaust, and is valve ticking a problem?

[alan]

<!--quoteo(post=22316:date=Mon 20th Nov 2006, 10:27 AM:name=Harry Axewound)-->QUOTE(Harry Axewound @ Mon 20th Nov 2006, 10:27 AM) <{POST_SNAPBACK}><!--quotec-->My 98 MkII with 30,000 miles on it has, over the last 2 couple of weeks:

- started backfiring when I start her up, if I haven't used her for a day. Not all that borthered by noise (though does make me jump a wee bit), unless it will damage the exhaust or somefing, though started her up yesterday morning at about 07:00, and fook, what a bang, woke up a few of the neightbours dogs!

- much clearer valve ticking/taping noise now, most audible in second gear, coming off throttle at around 2-4000 rpm. Clearance was checked at 24,000 miles and was OK, but 1 valve was on limit, but dood said no need to do all the work for just 1 shim, might aswell wait for next time?

So, can backfiring damage stock exhaust, and is valve ticking a problem?<!--QuoteEnd--><!--QuoteEEnd-->

I wouldnt like to comment on the valve ticking cause my valves are noisy, but mine do need shimming or checked but havent got the place/time or money if they need replacement so they have to wait .
As for the back fire well i had a YZF600thundercat from new and that use to back fire like yours but noticed it only done it if the choke was open to much,so didnt open it so much also the same thing happened with a new TTR600RE i had aswel!l It happened with my TDMMk2 the last time i used the choke. I hardly use the choke even in the mornings starting from cold in fact cant remember last time i did use the choke.
So try opening it enough say 1/4 choke just to get the bike started see what happens then

[tdm850rider]

<!--quoteo(post=22316:date=Mon 20th Nov 2006, 06:27 AM:name=Harry Axewound)-->QUOTE(Harry Axewound @ Mon 20th Nov 2006, 06:27 AM) <{POST_SNAPBACK}><!--quotec-->My 98 MkII with 30,000 miles on it has, over the last 2 couple of weeks:

- started backfiring when I start her up, if I haven't used her for a day. Not all that borthered by noise (though does make me jump a wee bit), unless it will damage the exhaust or somefing, though started her up yesterday morning at about 07:00, and fook, what a bang, woke up a few of the neightbours dogs!

- much clearer valve ticking/taping noise now, most audible in second gear, coming off throttle at around 2-4000 rpm. Clearance was checked at 24,000 miles and was OK, but 1 valve was on limit, but dood said no need to do all the work for just 1 shim, might aswell wait for next time?

So, can backfiring damage stock exhaust, and is valve ticking a problem?<!--QuoteEnd--><!--QuoteEEnd-->
<!--coloro:#FF0000--><!--/coloro-->"My 98 MkII with 30,000 miles on it"<!--colorc-->
<!--/colorc--> It sounds due for a valve adjustment.
<!--coloro:#FF0000--><!--/coloro-->"unless it will damage the exhaust or somefing"<!--colorc-->
<!--/colorc--> Any change in engine noise from 'normal' should be looked into.

This post was last modified: 20-11-2006, 11:35 AM by tdm850rider.

[bof69]

Could be some crud in the carbs???
Take em orf an give em a good clean, jets n'everythin.
A lot of motors have the choke adjusted wrong, cuasing all sorts of probs (rich/weak fuel mixture).
DON'T ride it untill its sorted, you could easily burn a valve out (can go VERY quickly) or at worst burn a hole in a piston.
Carbs will need reballancing once you put them back together as well.
The timing may need looking at, or 'black box' that governs it. If timings out you can get some horrible noises. Same problems with valves/pistons burning out tho.
Have you checked the sparkplugs and leads? Check the coils as well could be just a f**ked plug (you hope!!).
Backfires can blow out the baffels in silencers.
Have Fun !!!!!

[steveglover]

<!--quoteo(post=22316:date=Mon 20th Nov 2006, 10:27 AM:name=Harry Axewound)-->QUOTE(Harry Axewound @ Mon 20th Nov 2006, 10:27 AM) <{POST_SNAPBACK}><!--quotec-->So, can backfiring damage stock exhaust<!--QuoteEnd--><!--QuoteEEnd-->
It can damage the baffles in the silencer, and if you've got a weak spot anywhere due to corrosion, it can blow a hole at that point. As cyco says, there are lots of possible causes, but just to try to narrow them down a little, try or check the following:

(1) has the fuel tap been left in the RES position?
(2) try turning the fuel tap to PR (prime) for 30s before starting
(3) check that the throttle cable isn't too tight such that turning the bars to full lock opens the throttle a bit.

<!--quoteo(post=22316:date=Mon 20th Nov 2006, 10:27 AM:name=Harry Axewound)-->QUOTE(Harry Axewound @ Mon 20th Nov 2006, 10:27 AM) <{POST_SNAPBACK}><!--quotec-->is valve ticking a problem?<!--QuoteEnd--><!--QuoteEEnd-->
Yep, ticking valves means the clearance is too large, which can lead to accelerated wear on the camshaft or follower or both. If you were just a few thousand miles from the next valve service you could leave it till then, but you've got 18k to go, so you need to get it sorted. It also means the valve is opening a little later than it should, and closing a little earlier, which in severe cases leads to a loss of power. Take it to a Yam dealer with experience of TDM's just to pick his brains - it could just be the cam chain ticking?

[Axewound]

Thanks for the answers.

There is no loss of power and no backfires once she is started.

What noise difference is there between valve tapping or cam chain ticking?

I guess backfiring means petrol is going into cylinder while bike not running, and then on first ingnition the vapours blows in the zorst somewhere? What can allow fuel to drip through carbs?

Cheers

[robelst]

Sounds familiar:
Mine's ticking as well when braking on the engine (gets worse when warmed up, strangely), and also hesitant pick-up under wet conditions (had my 1st dry ride on it yesterday, it seemed a different bike). No back-fire though. I find it suspicious that my bike starts cold without using the choke, although the too high idling (set at 1500 rpm) may "help" here. Also if the bike is warmed up, applying the choke makes the engine stop runing so don't think it's sticky. On a dry day like yesterday the bike runs incredibly well, even pick-up in high gears from low revs and despite short gearing does 47 mpg so I don't think the fuelling is far of the optimum. Probably electrics, or carb-icing?

Valves / cam-chain: I also wonder how to distinguish them making noises. How many miles does the avarage cam-chain last on a TDM or is that difficult to predict? (my 2002 '850 has done 33k).

Over the years I have developed a great reluctance of having anyone else than myself working on my bikes, so I may have a go myself at measuring the valve clearance, don't think I am brave enough to do any adjustments (if needed) myself .
Does anyone know a proven reliably workshop in the Gloucester / Stroud / Bristol area that would just do the valves for me without having to undergo a full service? (no Fowlers pls)

[jandreas]

Hi Edman! My 850-MkII also backfired until I found out: Pull the starter (choke) full out! ( if it's below 10 degr. C.)
Don't touch the throttle! (wait 15 - 20 sec. before jou do!)
Give it some throttle and push the starter slowly inn.
Have no opinion about the valve-noise; been noisy al the time, but my mechanic says: no problem! And I trust her!! (yes, it's a voman!)
Jandreas.

[alan]

<!--quoteo(post=22569:date=Wed 22nd Nov 2006, 02:42 PM:name=robelst)-->QUOTE(robelst @ Wed 22nd Nov 2006, 02:42 PM) <{POST_SNAPBACK}><!--quotec-->Sounds familiar:
Mine's ticking as well when braking on the engine (gets worse when warmed up, strangely), and also hesitant pick-up under wet conditions (had my 1st dry ride on it yesterday, it seemed a different bike). No back-fire though. I find it suspicious that my bike starts cold without using the choke, although the too high idling (set at 1500 rpm) may "help" here. Also if the bike is warmed up, applying the choke makes the engine stop runing so don't think it's sticky. On a dry day like yesterday the bike runs incredibly well, even pick-up in high gears from low revs and despite short gearing does 47 mpg so I don't think the fuelling is far of the optimum. Probably electrics, or carb-icing?

Valves / cam-chain: I also wonder how to distinguish them making noises. How many miles does the avarage cam-chain last on a TDM or is that difficult to predict? (my 2002 '850 has done 33k).

Over the years I have developed a great reluctance of having anyone else than myself working on my bikes, so I may have a go myself at measuring the valve clearance, don't think I am brave enough to do any adjustments (if needed) myself .
Does anyone know a proven reliably workshop in the Gloucester / Stroud / Bristol area that would just do the valves for me without having to undergo a full service? (no Fowlers pls)<!--QuoteEnd--><!--QuoteEEnd-->
My Bike starts with out the choke on cold mornings and my idle speed is about 1100rpm seems strange but been doing it for a long while now.
Well im in Wiltshire and i asked 2 yamaha dealers about doing the valves for me,one said never done valves on a TDM before the other said he has done them and would charge £140 approx for doing it.
However when i went in about it again and asked, i got a diff reply saying they never done them so think ill do them myself when i got the time etc.Sooner the better i think!

[robelst]

<!--quoteo(post=22573:date=Wed 22nd Nov 2006, 03:07 PM:name=aytcat)-->QUOTE(aytcat @ Wed 22nd Nov 2006, 03:07 PM) <{POST_SNAPBACK}><!--quotec-->My Bike starts with out the choke on cold mornings and my idle speed is about 1100rpm seems strange but been doing it for a long while now.
Well im in Wiltshire and i asked 2 yamaha dealers about doing the valves for me,one said never done valves on a TDM before the other said he has done them and would charge £140 approx for doing it.
However when i went in about it again and asked, i got a diff reply saying they never done them so think ill do them myself when i got the time etc.Sooner the better i think!<!--QuoteEnd--><!--QuoteEEnd-->
£140 is a lot of money, but not too bad looking at "normal" tariffs. I've never done valves using shims, it's not (just) the challenge of having to remove the cams, but the need for buying shims that could make it cost even more than having a dealer have a go at it (who may be able to exchange them with used ones).

Most modern bikes are shimmed, is there anything different at the TDM that makes it more desirable to visit a TDM-experienced dealer?

[dapleb]

<!--quoteo(post=22575:date=Wed 22nd Nov 2006, 03:20 PM:name=robelst)-->QUOTE(robelst @ Wed 22nd Nov 2006, 03:20 PM) <{POST_SNAPBACK}><!--quotec-->but the need for buying shims that could make it cost even more than having a dealer have a go at it (who may be able to exchange them with used ones).<!--QuoteEnd--><!--QuoteEEnd-->

http://www.carpe-tdm.net/ipb/index.php?sho...l=shim+exchange

[alan]

The Shims are just over £3 at my local yammy dealer cause if i needed to do them all be about £36

[wicklamulla]

Hey Edman long time no hear.

[iand1947]

<!--quoteo(post=22570:date=Wed 22nd Nov 2006, 03:04 PM:name=Jandreas)-->QUOTE(Jandreas @ Wed 22nd Nov 2006, 03:04 PM) <{POST_SNAPBACK}><!--quotec-->Hi Edman! My 850-MkII also backfired until I found out: <!--coloro:#6666CC--><!--/coloro-->Pull the starter (choke) full out! <!--colorc-->
<!--/colorc-->( if it's below 10 degr. C.)
<!--coloro:#6666CC--><!--/coloro-->Don't touch the throttle!<!--colorc-->
<!--/colorc--> (wait 15 - 20 sec. before jou do!)
<!--coloro:#6666CC--><!--/coloro-->Give it some throttle and push the starter slowly inn.<!--colorc-->
<!--/colorc-->
Have no opinion about the valve-noise; <!--coloro:#6666CC--><!--/coloro-->been noisy al the time<!--colorc-->
<!--/colorc-->, but my mechanic says: no problem! And I trust her!! (yes, <!--coloro:#6666CC--><!--/coloro-->it's a voman!<!--colorc-->
<!--/colorc-->)
Jandreas.<!--QuoteEnd--><!--QuoteEEnd-->
Aye, thae cauld dark winter nichts are fair drawin' in!

[dandywarhol]

Hey Ed - how the devil are you??? Still wearing that ridiculous goatee and leching at anything in a skirt???????




Is yours the pre electric pump model? If it is, try turning the fuel tap off at the end of the day and see if it still backfires when starting up. mine used to do it after a few weeks lay off - nearly shat ma pants the first time it did it in an enclosed space

This post was last modified: 22-11-2006, 09:46 PM by dandywarhol.

[robelst]

Roit, I think on my TDM it's definitely the cam chain rattling and not so much the valves: The noise clearly comes from the right-hand side of the engine where the chain runs. It's also quieter when cold (oil still thick), while valves are usually are at their noisiest when cold (clearance is biggest).
I see there's a cam-chain spanner (bolts on the outside), does that need inspection or is it replacement only? Or does it simply need a new chain (seems a bit early at 33k)? Or is it just a matter of "they all do that sir"?
I am not overly worried, it's just that the rest of the bike runs so incredibly smooth; this engine is truly something special, being such a big twin.

This post was last modified: 22-11-2006, 09:49 PM by robelst.

[Axewound]

Well my 850 starts without the choke whatever the conditions, even after 2 months parking up during the snow and ice

And the ticking noise is definitely from the right hand side of engine (when seated on the bike).

Backfiring just makes me think petrol is dripping through, which is probably not good. Also I thumb the starter really gently to avoid the backfiring, but every time on a quarter turn of engine - bang!!!

Still getting 55 odd mpg, though she does smell a little petroly - might be running a wee bit rich, also a little more viby in the 3-4000 rpm range? - fooked if I know.

Yes Dandy, still oogle at a good bit of skirt - and yes, the daft goatee is still here.

Been a little busy lately, having decided to set up me own business down here - so far a lot of fooking work for meagre reward can be a little frustrating when you setup on your own.

Can't have it all: nice weather (20 degrees and blue sky today), cheaper booze and fags (thats the smoking variety Dandy), nice roads .......

[robelst]

<!--quoteo(post=22706:date=Thu 23rd Nov 2006, 11:13 AM:name=Edman)-->QUOTE(Edman @ Thu 23rd Nov 2006, 11:13 AM) <{POST_SNAPBACK}><!--quotec-->Well my 850 starts without the choke whatever the conditions, even after 2 months parking up during the snow and ice

And the ticking noise is definitely from the right hand side of engine (when seated on the bike).

Backfiring just makes me think petrol is dripping through, which is probably not good. Also I thumb the starter really gently to avoid the backfiring, but every time on a quarter turn of engine - bang!!!

Still getting 55 odd mpg, though she does smell a little petroly - might be running a wee bit rich, also a little more viby in the 3-4000 rpm range? - fooked if I know.<!--QuoteEnd--><!--QuoteEEnd-->
Did you check the sparkplugs? Any sooty deposits on them pointing to running rich? On my Africa Twin I needed religiously looking after the choke mechanism because it got sticky real soon, although 55 mpg would suggest otherwise (unless your TDM's got pedals fitted as an extra ); my Twin usually plummetted into the early 30's mpg-wise, would start without touching the choke (normally no chance for that) and got jerky in the (low) midrange when warmed up. So some of this sounds like what your bike's doing but I don't know if TDMs typically suffer from this at all (just got mine).

Ps: Confusingly back-firing can also be caused by a <i>lean</i> mixture (for example when carb-rubbers are leaking), causing excessive heat in the exhaust gasses. But if your bike only backfires at cold starts this is probably not the problem.

This post was last modified: 23-11-2006, 11:47 AM by robelst.

[oiler]

Get on an do them clearances, i can do em an i,m a twonk!

[Tarmac]

Mine ticks as well, started at about 7000 miles and has gotten prgressively worse, on 13000 miles now. I haven't had any back firing or trouble starting so I don't think it's the clearances and the noise does get worse when the engine is warm, but I am told <b>'they all do that'</b>.

I changed the cam chain tensioner (£45) easy to do, but still no better. (If ticking sounds are coming from the right side it's probably this.) I am starting to think that the cam chain itself is the source of the noise. Earplugs cure the problem completely!

It's driving me crackers though and I'm on the point of taking it to aYamaha Dealer for an opinion!