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Discussion Starter #1 (Edited)
I´ve got this rattle from the drivetrain somewhere on the bike and i can´t for the life of my localize it.

I´ve had the "outers" of the engine and box apart to check the obvious things. Clutch,stator,the lid over the end of the crank etc etc.

What i CAN tell you is that it is the sound of like a chain that bottoms out/grinds/slaps vs metal. Kind of,and it´s only there at light load.

Coasting along,at any sane speeds,the bike sounds as it should. When i apply a little throttle tho...it rattles alright.
Bike puts the power it is supposed to to the ground as far as i´m concerned. It runs well. That´s not the issue.

Have checked the timingchain and guides as well as tensioner and can´t really find anything at fault there either. No broken pieces of guide plastic. The upper chainguide is there and in working order et al.
The timing chain per se looks fine to me and with the tensioner at work i can´t really say that it seems lose in any way either. The timing chain being of silent link type...yeah well.

No...it is not a bearing slap or piston pin slap. It is a rattle as per above. IOW,no thumping sound. Just a rattle-like a chain vs metal.

Drive chain and sprockets are fresh as of yesterday.

Sound is there regardless of gear. You can however NOT provoke when it neutral just blipping the throttle. Nor at steady state throttle.
It doesn´t transmit through the bike but is a sound only really. No imbalance or anything of the sorts.

As such my thinking goes towards the timingchain after all....and the tensioner indeed is more or less at full travel from what i can judge but i have a hard time understanding where said chain could bottom out?
Could it be that the timingchain transmits that sound through the tensioner?

Valve clearances and what have you not are all in order. Sound is metallic. Just had the valve cover off the other day and while at it checked camshaft phasing too-which was on par. Dead par even,which makes me wonder...cause as such that would render the chain being in order in my book?(Ie-not stretched to death)

Any ideas?
 

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I´ve got this rattle from the drivetrain somewhere on the bike and i can´t for the life of my localize it.

I´ve had the "outers" of the engine and box apart to check the obvious things. Clutch,stator,the lid over the end of the crank etc etc.

What i CAN tell you is that it is the sound of like a chain that bottoms out/grinds/slaps vs metal. Kind of,and it´s only there at light load.

Coasting along,at any sane speeds,the bike sounds as it should. When i apply a little throttle tho...it rattles alright.
Bike puts the power it is supposed to to the ground as far as i´m concerned. It runs well. That´s not the issue.

Have checked the timingchain and guides as well as tensioner and can´t really find anything at fault there either. No broken pieces of guide plastic. The upper chainguide is there and in working order et al.
The timing chain per se looks fine to me and with the tensioner at work i can´t really say that it seems lose in any way either. The timing chain being of silent link type...yeah well.

No...it is not a bearing slap or piston pin slap. It is a rattle as per above. IOW,no thumping sound. Just a rattle-like a chain vs metal.

Drive chain and sprockets are fresh as of yesterday.

Sound is there regardless of gear. You can however NOT provoke when it neutral just blipping the throttle. Nor at steady state throttle.
It doesn´t transmit through the bike but is a sound only really. No imbalance or anything of the sorts.

As such my thinking goes towards the timingchain after all....and the tensioner indeed is more or less at full travel from what i can judge but i have a hard time understanding where said chain could bottom out?
Could it be that the timingchain transmits that sound through the tensioner?

Valve clearances and what have you not are all in order. Sound is metallic. Just had the valve cover off the other day and while at it checked camshaft phasing too-which was on par. Dead par even,which makes me wonder...cause as such that would render the chain being in order in my book?(Ie-not stretched to death)

Any ideas?

Does it stop when you pull the clutch lever in?
 

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Discussion Starter #3
Yes,but the point to have in mind is the circumstances.
Ie;yes. The sounds stops but then on the other hand i can´t very well put the engine under light acceleration/load with the clutch depressed/engaged.

It´s gotten to the point where i actualy feel frustrated. Just for the sake of argument...i AM an old wardog as far as this goes. No BS. In short,i should be able to get this without even breaking a sweat,and i presume that to a large extent is what bugs me.

I´ve had more bike engines apart over the yrs than i care to remember.
(Albeit being an old pro formula mech)Tuned tons of ém...ported them aso aso.
This tho.?

Lemme put it this way. It sure sounds like a timingchain bottoming out somewhere but how can a timingchain under that amount of tension get to do that? I´m just at a loss...:mad:

Again. If it was a bearing or pistonpin sound...the engine would have gone kaboom by now. I´ve ridden it like 500km or so since i got the bike just recently and those 500km hasn´t been the most mellow the bike´s seen. I can attest to that much.
Likewise..
In spare time i tend to take it into the shop of mine to alter or adjust basicaly anything servicable and for every tour within the shop the bike just runs nicer and more mellow as well as picks up grunt.
This sound tho...i don´t get it.

Pretty thin...but COULD it be a bearing sound from one of the ballbearings for the box?

It´s getting to the point where i´m giving thought to ripping the engine out of there and pickin it apart just to understand this,which OF COURSE shouldn´t be needed.
 

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Yes,but the point to have in mind is the circumstances.
Ie;yes. The sounds stops but then on the other hand i can´t very well put the engine under light acceleration/load with the clutch depressed/engaged.

It´s gotten to the point where i actualy feel frustrated. Just for the sake of argument...i AM an old wardog as far as this goes. No BS. In short,i should be able to get this without even breaking a sweat,and i presume that to a large extent is what bugs me.

I´ve had more bike engines apart over the yrs than i care to remember.
(Albeit being an old pro formula mech)Tuned tons of ém...ported them aso aso.
This tho.?

Lemme put it this way. It sure sounds like a timingchain bottoming out somewhere but how can a timingchain under that amount of tension get to do that? I´m just at a loss...:mad:

Again. If it was a bearing or pistonpin sound...the engine would have gone kaboom by now. I´ve ridden it like 500km or so since i got the bike just recently and those 500km hasn´t been the most mellow the bike´s seen. I can attest to that much.
Likewise..
In spare time i tend to take it into the shop of mine to alter or adjust basicaly anything servicable and for every tour within the shop the bike just runs nicer and more mellow as well as picks up grunt.
This sound tho...i don´t get it.

Pretty thin...but COULD it be a bearing sound from one of the ballbearings for the box?

It´s getting to the point where i´m giving thought to ripping the engine out of there and pickin it apart just to understand this,which OF COURSE shouldn´t be needed.

If it stops when you load up the clutch springs then it's probably the damper springs in the back of the primary gear and perfectly normal.
If you're convinced it's a chain then check the oil pump chain as they do run very loose even when new.
 

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Discussion Starter #5
To ad to the confusion,not that i believe it to have any bearing on the above...
When i took the valvecover off i also checked torq for the camshaft bearing caps. All in order,but somewhere down the line some Schwarzenegger had obviously overtightened the exhaust side cap bolt for the upper guide/cap.
Instead of doing it right,Ie;heli-coil,they´ve drilled the cap out as well as the windings in the head and have redone the entire thing to M8. Doesn´t seem to interfere with anything...just a massive overkill that i have in mind to correct as season comes to an end in late oct.
 

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Discussion Starter #6
DAYUM!!! Didn´t even give the oilpump chain the time of day!!
Thanx. Will look into that asap.
 

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Discussion Starter #7
Speaking of which. By damper spring you´re thinking of the seat ring and spring at the back of the clutchpack? Cause i´ve had all that apart and it all looks ok to me at least.
 

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Speaking of which. By damper spring you´re thinking of the seat ring and spring at the back of the clutchpack? Cause i´ve had all that apart and it all looks ok to me at least.

No.
When you remove the clutch basket to check the chain you will see the coil springs in the back of the primary drive gear.
 

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Discussion Starter #9
Ah. Awreight....then we´re on the same page.. Thanx. I´ll look into it come tomorrow with a little luck
 

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Coasting along,at any sane speeds,the bike sounds as it should. When i apply a little throttle tho...it rattles alright.


I just noticed this bit.
You are trying to accelerate from above at least 3000rpm?
If you're trying to accelerate below that point you'll likely hear detonation, especially in the higher gears.
 

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Discussion Starter #11
BR.
No offense,but like stated i am an old wardog around engines and know perfectly well what detonations sounds like.(I do build race engines for a living)
This isn´t it.

If push comes to shove i´ll simply rip the engine out of there TBH. I´m just completely stomped by this...which is why it´s frustrating. I should be able to get this...which i don´t so far.
Reasoning with rippin the engine out of there is simply cause its like a ton easier to work with it sitting on the bench and TBH it isn´t the end of the world.
 

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BR.
No offense,but like stated i am an old wardog around engines and know perfectly well what detonations sounds like.(I do build race engines for a living)
This isn´t it.

If push comes to shove i´ll simply rip the engine out of there TBH. I´m just completely stomped by this...which is why it´s frustrating. I should be able to get this...which i don´t so far.
Reasoning with rippin the engine out of there is simply cause its like a ton easier to work with it sitting on the bench and TBH it isn´t the end of the world.

Yes, I know you mentioned your background but you don't seem very familiar with bike engines. Bike engines put out a _lot_ of horsepower for their small engine capacity so the tuning is very different to car engines. Car engines have to be able to pull a lot of weight at low rpm so they have to be tuned to cope without detonation. Bike engines don't have to pull much weight at all so they're tuned very close to detonation and any extra load will cause detonation very easily.
I've built over 100 engines myself, mostly bike engines but I've done quite a few cars as well. The smallest I've built would have to be the PW80 and the biggest I can recall is the 4.9 Ford V8.
To clarify and answer my question, you are talking about higher rpm in the lower gears?
 

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Discussion Starter #13
I appreciate what you´re saying but i think you´re getting me wrong.
It´s been bike as well as cars,and when cars mainly single seaters.
Like...



Back ontopic.
No.
It rattles in all gears from approx 3grand up to like 6 or thereabouts.
This under light acceleration only.
If i go WOT or similar it isn´t there. If i just coast along it isn´t there.
 

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Discussion Starter #14
Brought my old engine stetoscope out. Listened in to the engine both at idle and while running.(It is an electronic "ear"). Without a doubt the large portion of the rattle comes from the right side/timing chain side of the engine...so i´ll hopefully install a fresh one come tomorrow night.
 

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Discussion Starter #15
Update.
Picked up a 919 localy that had been put into orbit. Flywheel had come lose and that in turned made the crank go awol on the left side pulling a conrod and piston with it in the process. Block is of course blown...and crank asf...
So that all went into the bin but before bolting it all apart i checked how the timingchain and guides are SUPPOSED to look and work on a 8000 US mile engine...and burst into laughter. :D
It is to the point where i´ll bring the bike of mine to the shop come tomorrow and pull a low n dirty...just swappin guides,sprockets,chain,tensioner asf for more "fresh" pts in an effort to find out if that is the culprit-which i suspect.
At a 70 USD total it can´t be wrong anyways...
(Cut a deal on another low mileage 919 eastbound of here that i´ll pickup come sunday. Totaly complete down to carbs,airbox,exhaust aso and includes extra clutch,cylinder,cylinderhead,pistons aso aso...this time to the tune of approx 300 USD)

Will report back..
 

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Discussion Starter #16
Well i replaced the entire timingchain setup today inc guides,tensioner,sprockets and what have you not.
Replaced the clutch basket. Inspected the springs...fiddled around with the clutch per se. Changed the chain and sprockets for the oilpump...

..and...that wasn´t it :(

So.
Gonna pick that 919 up come sunday...then haul the OEM engine out of my old warhorse and rip it apart to find out WTF is up. Enough is enough already.

I DID however notice something that almost sent me into orbit. Seems Mr Schwarzenegger has pulled jobs on this bike previously cause as i let go of the bolts for the cam carriers...most windings were shot. Exhaust cam especialy.
So...thought has struck me if what i´m hearing is a cam that simply is let to flex and move around.?
In that case...no worries as i´ve got a full in order surplus cylinder head just laying around since yesterday..
 

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Discussion Starter #17
Update again.
Come sunday i´m leaving for "Örebro" to pick that 919 up. A roundtrip of approx 700km :(
Well.
That done will entail me rippin that motor and trans apart come monday and throw pts i unbolt into the hottank of mine.
Basicaly what i wanna have done is check the engine out in every way i can at a minimum of work.
That done i´ll place that engine under the bench. Then i´m gonna rip the engine out of the bike and do the same thing. If my thoughts are correct what is amiss is that the caps for the cams simply aint stable under load.
Well,i´ve got a really good working spare cylinder head...so i´ll toss that on there if that is what it turns out to be.(Gonna spend tonite lappin valves of that head asf)
What´s more the complete gearbox axles coupled with shifter drum n forks from that grenaded engine are in more or less pristine condition so i´m giving thought to toss that into the existing block just cause the pts are there so to say.
Then check mains as well as conrod bearings and piston pins for any clearance that shouldn´t be there.
Check pistonring end gap...and...again..toss it all into the hot tank of mine to be cleaned out.

Will report back,but one thing is for certain and that is that shot windings coupled with busted bolts for the cam caps are NOT a good thing so that needs to be adressed.
 

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Discussion Starter #18
Spent the afternoon with what i at first thought to be a nice,quick,little spare time job and that was to mod a front sprocket to take on a fresh apperance.
Ie; i got a 16 point universal sprocket delivered by a friend of mine and had in mind to cut the OEM front sprocket down....and the press the universal one on to the cut down OEM centerpiece.

So.
I drilled and turned the universal piece out. Have done this numerous times before with front sprockets for other bikes with no issues what so ever. Normaly these sprockets are hardened...but normaly only like 20% or so in from the "top".
Not so with the Honda one tho. I bolted the OEM piece up into the lathe by the use of an OEM output axle. I just turned a shim to backup the sprocket making it sit firm on the axle end.
As these are normaly hardened i use a "coromant" cutter for the lathe. These are of "industrial diamond" quality and hence they can be used for even abnormaly hard materials.
Well.
I´m here to tell you that an OEM Honda piece is hard beyond belief!
I had the entire 2 ton lathe stompin on the floor as the cuts were made. Bit by bit.

With everything done i pressed the fresh piece onto the old now cut down centerpiece(i cut it down to 50mm) and then fired up the TIG welder i DC mode with some Inconel 600 weldrod in hand at approx 160amps.
That part worked surprisingly well and i had beforehand turned a shim to make the centerpiece line up with the fresh sprocket on my welding table. Basicaly i only had to ad very minor amounts of weldrod.
After it all was done i pulled out the torch and heated the entire sprocket to avoid what is known has hydrogen brittleness.(You basicaly heat the entire sprocket slowly til it turns dark cherry red and leave it to aircool. That "minor"(like 600deg or so) won´t affect the hardening process of the sprocket per se.

Lessoned learned is that this worked alright but it was NOT by a longshot worth the effort compared to what a factory fresh sprocket runs.
A job that i at first expected to be done in like 30min or so took me the better part of 3hrs due to the insanely tought OEM sprocket.

Goes to show you i guess.

A couple of things i noticed;
1. The OEM sprocket is hardened so tough it´s beyond what could be expected. Kudos to Honda!
2. When i had everything lined up in the lathe and fired the lathe up i was quite surprised to see the rather massive amount of runout-in both directions. Both static and dynamic.
Indeed with the new "higher precision" homemade front sprocket in place i have to say that the entire ride felt more....subtle. I´m not talking a couple of tenths of a mm here but more along the lines of millimeters-as in plural.
The new sprocket wasn´t a miracle of precision either TBH...but runout was at least along the lines of 1/10 of a mm-in contrast to the OEM piece.

Anyways.
Job done and as far as that goes i´m a happy camper. ;)
 

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Discussion Starter #19
As stated i now suspect the rattle to be especialy the exhaust cam moving around. Just cause the former "Mr Handyman" never heard of a torqwrench

Well.
I picked up a busted 919 as i´ve written previously and as i´m one a those boys that believe in "seing is believin" i ripped that cylinderhead apart.
All i can say is....it is basicaly factory fresh almost. No measurable wear what so ever.



..and after a quick trip into the hottank of mine it even looks fairly fresh :)
Gonna get another turn in there as i´m done-before install.



I almost just had to touch the valves with lapping compound for them to come out 100% :D

So...i´d say we´re step by step moving up to the point of rippin the heart out of the old warhorse and have it checked up..
Head will most def be replaced at least seing how busted the M6 holes for the bolts for the caps were.
 

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Discussion Starter #20
Productive day.
Picked up the second 919 yesterday as stated. A fair roundtrip around the country of approx 450 US miles..
What i picked up was one pile of spares n motor that was basicaly covered in sawdust..:nono:

Buuuuuuuuuut..got me a hot tank,so that wasn´t really the end of the world was it.
Cylinder head i played around with past weekend i got assembled today first of all and as i strongly suspect that being the issue as written previously it might very well be that replacing the head will suffice. None the less...better to many spare than to few.



So that there is one 919 that has been picked apart and sent through the hot tank and then been reassembled and ready to go if need be.



What´s more i got me yet a spare head coupled with rods,pistons and what have you not down to starters,a clutch and god knows what else.



In short i´ve got two of these filled to the brim with Fireblade spares...:eek:
 
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