A forum for owners of Yamaha TTR250 trail and enduro bikes!

Truxx · Veteran Member

rattly top end...

TTRfan · Super Guru

Piston slap? Is your TTR still on the original engine and, if so, how many miles has it done?

An air-cooled engine is always going to be a tad "whirry" and occasionally "tappetty".

It can be frustrating having checked the little end is perfect, fitted a new piston with rebore, adjusted the valve clearances perfectly and still to get the noise. My brother-in-law has this on his TTR. We fitted a new timing chain which quietened things down but the tap is still there although not sounding anything like terminal!

Brian

Truxx · Veteran Member

It doesn't sound like piston slap but then i haven't removed the head yet to check...Piston slap usually has a deeper tap to it if that makes sense :)
I don't know the history of the bike either and the clock reads 3000kms. but when i check the mileage history on the mot it only goes back to 2010 (had 856kms on clock in 2010)

It's annoying as hell lol i know what you mean about how far to go with it when it's not really harming anything but it's one of my pet hates :(

Does the play in the clutch basket sound normal ?

Thanks
Dave

Truxx · Veteran Member

I leaked oil on the floor aswell lol the wife won't be happy when she gets home haha

-- Edited by Truxx on Friday 29th of August 2014 04:37:34 PM

Truxx · Veteran Member

When i put it all back together i didn't grease the shims or tappets (completely forgot and just remembered now lol)
Would that cause the rattle noise ?

Thanks
Dave

dern · Veteran Member

Have you got the original decompression valve still installed? The spring broke on mine and that moved around quite a bit and made an annoying rattling noise until I tracked it down and fix it in place with some wire.

Mark

Truxx · Veteran Member

There's no decompression system on mine it doesn't look like it's ever had one either.
Put it all back together now exactly as the manual says so ill test it out in morning and report back, although I'm pretty sure it's gonna be the same :(

Truxx · Veteran Member

Took it to the local bike shop this morning and they reckon it'll be the timing chain tensioner ?

Is there any way of testing this part or does it have to be replaced?

Thanks

Dave

TTRfan · Super Guru

The tensioners have been known to fail - albeit rarely!

You can remove it and check that its spring is still working. You have fitted a new timing chain so that should be all good.

You will need to take the cam cover off, put the engine at TDC and make sure the cam gear marks line up before refitting the tensioner.

If the tensioner has failed then best to look out for a good s/h unit as new ones are a tad over £100 (part # 3GC-12210-10)

Brian

Truxx · Veteran Member

Thanks

The tensioner seemed fine and i've fiddled with it to make sure everything is moving smoothly and there's plenty tension on the chain with it installed. Clutching at straws really but i'll keep an eye out on ebay...

Went out and took a video today see if it helps but i'm not too sure how well the phone picked the sound up...

Any clues in there ?

Thanks

Dave

ttboof · Super Guru

I can't get the video to play on my phone (I'm actually out riding and having a break ) I've seen a few comments around cam chain guides needing replacing. Maybe your mechanic may have been referring to them as it's the tensioner that keeps the guides up against the chain and might be a general reference to chain tension .

Just something to think about

Back to my ride plenty of mud today

Truxx · Veteran Member

Sounds like your having fun :) where are you ?

I figured if the chain guides were worn the timing marks wouldn't line up ? Not too sure but I'll put them on the growing parts list lol

I may have found a temporary fix :) http://www.ebay.co.uk/itm/221530784980 almost new powercore 4 for 82 quid I'll never hear the rattle over this thing lol

TTRfan · Super Guru

Does sound more like timing chain noise than valves but that could just be the video.

I am guessing you checked both slippers for damage when you fitted the new timing chain. Damage is usually confined to the area around the rear slipper where the tensioner pushes against it. Cracks can appear and its then time to start thinking about replacing it.

Wear is not so obvious but is unlikely, in my opinion, to cause your noise.

Brian

ttboof · Super Guru

Truxx wrote:
Sounds like your having fun :) where are you ?

I figured if the chain guides were worn the timing marks wouldn't line up ? Not too sure but I'll put them on the growing parts list lol

I may have found a temporary fix :) http://www.ebay.co.uk/itm/221530784980 almost new powercore 4 for 82 quid I'll never hear the rattle over this thing lol

I'm in the manning valley NSW Australia been dry for a while enjoying a bit of mud

-- Edited by ttboof on Sunday 31st of August 2014 03:16:35 AM

Truxx · Veteran Member

TTRfan wrote:
Does sound more like timing chain noise than valves but that could just be the video.
I am guessing you checked both slippers for damage when you fitted the new timing chain. Damage is usually confined to the area around the rear slipper where the tensioner pushes against it. Cracks can appear and its then time to start thinking about replacing it.
Wear is not so obvious but is unlikely, in my opinion, to cause your noise.
Brian

I don't think the phone is picking up the noise properly.

there was no obvious wear to the guide So I doubt its that but at this point I'll just have to check/replace everything :(

I'm going to give up on this now and just run it for a bit see what happens but it's not over lol I'll collect a load of parts over the next few weeks then I'm going to strip full engine down split case etc.

so damm annoying

thanks

DaveDave

Truxx · Veteran Member

ttboof wrote:
Truxx wrote:
Sounds like your having fun :) where are you ?

I figured if the chain guides were worn the timing marks wouldn't line up ? Not too sure but I'll put them on the growing parts list lol

I may have found a temporary fix :) http://www.ebay.co.uk/itm/221530784980 almost new powercore 4 for 82 quid I'll never hear the rattle over this thing lol

I'm in the manning valley NSW Australia been dry for a while enjoying a bit of mud

-- Edited by ttboof on Sunday 31st of August 2014 03:16:35 AM

Must be nice :) I'd love to go ride about in oz Although I'd be a bit worried about poisonous spiders/snakes etc. good thing about uk is there's nothing poisonous. how do you guys avoid them when your ploughing through thick terrain ?

anyway, mud is something I see a lot of 'cos it never stops raining here lol think yourself lucky you decent dry times lol

ttboof · Super Guru

only dangerous things would be kangeroos a couple of near misses today .ive had a few snakes bite my boots but you would have to realy try hard to get bitten by anything nasty .pretty safe out in the bush .

-- Edited by ttboof on Sunday 31st of August 2014 09:31:55 AM

Truxx · Veteran Member

Since this has been driving me nuts confuse i decided to pull the top end yesterday...

Piston diameter 1.0mm from skirt is 72.84mm.. Minimum should be 72.92mm so it's out of spec...

Not sure if that'll be enough to allow the piston to rattle but for now will assume so. (looks like you were right brian biggrin )

I then measured the ring side clearance and get :

Top ring : 0.12 (limit is 0.12)

2nd ring : 0.4 (Limit is 0.12)

Oil ring : 0.2 (should be 0.2 - 0.4) {limit not specified in manual}

Measuring the top ring end gap manual says it should be 0.20 to 0.35. I managed to get a 0.60 feeler gauge into mine

The cylinder bore is also in a bit of a state aswell :

So it's looking like full rebore and piston job.

Looking at the piston its covered in lots of carbon as are the valves :

So i'll have to wip the valves out and clean them up ..lap them in ...

On the plus side... Having checked the timing chain guides and tensioner they are definately looking fine to use so hopefully a litttle bit of elbow grease and i should be back on the road, with a nice quiet engine biggrin

Thanks

Dave

Cubber · Super Guru

How unfortunate. bleh

There appears to have possibly been some water in that engine at some time to cause the "rust" marks on the bore.

Here's hoping there's sufficient meat to give a rebore.

Martyn

Truxx · Veteran Member

Yep it looks that way...

I threw my valve spring compressors last month aswell thinking i wont be needing them again lol

This whole thing won't be cheap biggrin

TTRfan · Super Guru

Glad you found the cause Dave!

Looks like the engine had been burning oil by the state of the head and piston crown so it's well due a rebore and head refurb wink

It's also worth considering fitting new valve stem oil seals whilst the valves are out. It's usually the exhaust VSOs that got hot and harden but it's not really possible to check if they are working by a visual inspection so I routinely fit new - just in case.

Brian

Truxx · Veteran Member

I'm actually putting a parts list together right now :)

Do you sell the stem oil seals ? If so i'll have 4 of them

I also want to replace my carb jets.

Planning to try the powercore 4 with a db killer in to see if it's bareable just wondering what size jets you'd advise to run it with the db killer ?

my stock jets are 48 pilot and 145 main but it seems to run a touch lean (with stock exhaust) Not sure if i should replace these like for like or go slightly bigger ?

list :

Valve stem oil seals

Carb jets suitable for powercore 4 with db killer

Carb jets suitable for stock exhaust

A powercore 4 db killer if you have one? biggrin

Float bowl screws
Float drain screw
Float bowl gasket
accelerator pump gasket

Think that's all for now

Truxx · Veteran Member

So I got my rebore and new wossner piston all fitted but theres a new rattle lol
Its sounding rattly in general but theres like a tapping noise as the revs drop. Hard to explain these things but kinda like the timing chain rattling or a valve rattle.

When I was putting it together I must have lost tension on the chain and it slippped of the teeth on tye crank but after a little bit of faffing about it slipped back on. Cant see this as a problem but thought id mention it incase it is?
Either way the chain is tensioned and timing marks line up...
I removed the valves replaced the valve stem seals theen clean and lapped the valves refitted and adjusted the clearances to suit..

Any advice ? Im out of ideas.

Thanks
Dave.
(Sorry for typos using sons tablet,have fat fingers )

Truxx · Veteran Member

small video clip. Couldn't run it for long as i was in my pals living room biggrin

Fladdem · Senior Member

After my re-bore I had a noise like that, It turned out that it was something to do with the cam chain tensioner, It wasn't holding out tight enough, luckily it was the chain guides that were worn and the tensioner was at its outer limit, so new guides and chain. It had a funny whirring noise for the next few oil changes as well, but that went away as it bedded in.

Truxx · Veteran Member

Ive checked the tensioner and the chain guides amd they all look fine, plenty of tension on the chain and the marks line up perfect. I suppose the next step is probably gonna be replacing them anyway just to rule it out but its an expensive way to do things :(

Truxx · Veteran Member

Stripped it back down today...
Only thing I can find that wasnt right is a slightly sticky exhaust valve, as in if I try to open the valve by pushing on the bucket theres a very slight resistance to it as it initially opens. It also looks like its been blowing slightly.
I cant see that causing the rattle but but theres not a lot of options left ?

Only thing left to replace is the tensioner and guides which ill do if I have to but they appear to be in perfect working order.

( I know I should just replace this stuff anyway but ive spent a LO
T of cash on this bike now and I cant afford to just keep throwing money at it :( )

TTRfan · Super Guru

Truxx wrote:
Stripped it back down today...
Only thing I can find that wasn't right is a slightly sticky exhaust valve, as in if I try to open the valve by pushing on the bucket there's a very slight resistance to it as it initially opens. It also looks like its been blowing slightly.
I cant see that causing the rattle but but theres not a lot of options left ?

It could cause your rattle. If the valve isn't returning immediately it will leave a small momentary gap between the bucket and the cam lobe. When the cam lobe comes around again to open the valve it will hit the bucket a little harder than if the bucket was fully returned. That could cause your noise? Just a thought.....

I have heard of sticky valves but not experienced one. Possibly caused by a leaky valve stem oil seal in the past and the heat allowing the oil to burn on the valve stem impeding the sliding action?

If your cam chain etc is all within spec then don't go throwing money at it!

Brian

Truxx · Veteran Member

Thanks for the reply
Its a possibility so ill have to go with that. Itll take me 10 mins to lap the one valve in again so no big deal but getting the bike from barrel off to running again is a bit of a pain lol

Is there a cam tensioner from another bike that'll fit the ttr? Or would it be worth stripping the stock tensioner to see if I can shim the spring a little just to rule that out. Cant find any service specs for tensioner but in theory I could stick my finger in the tensioner hole and become the tensioner lol so its a prettybasic item.

TTRfan · Super Guru

You have checked the cam timing, chain tensioner, slippers and chain pretty thoroughly looking back over the thread. It therefore seems unlikely to be a problem in that area.

Why not wait and see what the valves etc are like?

Brian

Truxx · Veteran Member

Still rattling...

first bike shop (one that did rebore) thinks it's the spring on the back of the clutch basket?

next one thinks it's the little end so probably new conrod.

next bike shop thinks it's the Piston rattling in the bore a little?

They ALL said it's not a problem "they all do it" just ride it it'll be fine. I'm not so sure lol

heres another video taken today hopefully the sound will come through a little better on this one...

If anyone has any other ideas I'd love to hear them 😄

thanks

dave

Truxx · Veteran Member

Oh I forgot ... Another bike shop also said it could be valve guides?
I noticed a really small amount of play on the valve when it was sat in the guide,not so much you could see it but could feel it. Not sure how tight a fit they should be?
If the guide was worn would it cause this type of noise?

Truxx · Veteran Member

ttboof · Super Guru

Just a suggestion if everything looks ok could it be a warn clutch basket .eg if the bike was running with the clutch in and in gear the noise may decrease

Another tool that's handy is a stethoscope (auto shops sell em fairly cheap ) or just use a screw driver with your thumb on the handle against your ear pressed on the motor it's suprising what you can hear . And locate the area the noise is comming from

Just a couple of ideas

TTRfan · Super Guru

Looks like the "rivets" fixing the alloy basket to the steel gear are loose. Not come across that before confuse

Not sure that would produce your noise but will only get worse if not tightened up.

Don't know how much play the oil pump gear should have so can't comment but I just checked the fiche and it's correct not to have a washer behind the circlip.

The suggestion of worn valve guides is interesting but, again, that's a new one on me. The only guides we have sold have been to owners where the originals have been damaged in a valve bending incident.

The sound seems more piston orientated to me......

Brian

Truxx · Veteran Member

ttboof wrote:
Just a suggestion if everything looks ok could it be a warn clutch basket .eg if the bike was running with the clutch in and in gear the noise may decrease
Another tool that's handy is a stethoscope (auto shops sell em fairly cheap ) or just use a screw driver with your thumb on the handle against your ear pressed on the motor it's suprising what you can hear . And locate the area the noise is comming from
Just a couple of ideas

Thanks for the reply...

There's no change in sound between clutch in or out, in gear or not the noise is always there hmm

I tried the screwdriver to ear thing but still couldn't pin point it. It does sound like it's coming from the cylinder head.

Truxx · Veteran Member

TTRfan wrote:
Looks like the "rivets" fixing the alloy basket to the steel gear are loose. Not come across that before
Not sure that would produce your noise but will only get worse if not tightened up.
Don't know how much play the oil pump gear should have so can't comment but I just checked the fiche and it's correct not to have a washer behind the circlip.
The suggestion of worn valve guides is interesting but, again, that's a new one on me. The only guides we have sold have been to owners where the originals have been damaged in a valve bending incident.
The sound seems more piston orientated to me......
Brian

Had another look at the clutch basket today. The gear on the basket is pretty much a floating gear so if the springs weren't there it could be turned seperate to the basket. The movement in the video above is just the free play in the springs.

Question is how much free play is acceptable ? Don't suppose you have a clutch basket lying around that you could do the same test on do you ? or anyone ? biggrin

At this point i really think it's valve related so tomorrow i'll take the head to the bike shop and get there opinion on the valve to guide clearance. I'l be very happy if it turns out to be just a valve guide smile

Thanks for all the help so far i do appreciate it smile

Dave

Truxx · Veteran Member

Few extra pics:

Some slight scoring to the new barrel :( not sure how that happened as i though i had everything really clean before assemble. Obviously not.

Little end does have some slight marks to it where the gudgeon pin would sit :

And this is how the top of the piston looked when i took the head off :

Is this confirmation that the valves aren't fully seated ?

TTRfan · Super Guru

Doesn't look good cry

It looks to me like some swarf has either got past the filter or has occurred after the filter. What do the camshaft and cam journals look like - are they scored as well?

Is the piston OK?

What does the oil filter and lower gauze filter look like - any metallic bits trapped in them? Was there any sediment in the oil or in the bottom of the crankcase?

If I am right, any idea as to where the swarf came from?

I have seen another engine where the barrel and piston were damaged by swarf from a disintegrating start pinion and starter gears. Couldn't see how it got past the filter but it did

The carbon spots on the piston look odd. Any marks on the piston to indicate it was getting close to or touching a valve?

Brian

Truxx · Veteran Member

It looks to me like some swarf has either got past the filter or has occurred after the filter. What do the camshaft and cam journals look like - are they scored as well?

Cams and journals look fine i showed them to the engineer that did the rebore.

Is the piston OK?

There is some light scratches but but nowhere near as bad as the bore. I'll grab a pic of all these bits tomorrow...

What does the oil filter and lower gauze filter look like - any metallic bits trapped in them? Was there any sediment in the oil or in the bottom of the crankcase?If I am right, any idea as to where the swarf came from?

I didn't actually inspect the filter and gauze when i stripped it but i did put them aside to inspect later, so i'll get some pics of that tomorrow aswell...

I'm pretty sure i seen something metalic looking on the gauze...

I have seen another engine where the barrel and piston were damaged by swarf from a disintegrating start pinion and starter gears. Couldn't see how it got past the filter but it did

I do have the clunk when i turn the engine off so definately need to do the sprag. I'll take that cover off tomorrow and see whats happening. This is starting to sound expensive lol

The carbon spots on the piston look odd. Any marks on the piston to indicate it was getting close to or touching a valve?

No marks on the piston or the valves so nothings hitting.

If the valve guides are no good i'm assuming the valve could close slightly off centre which would allow it to leak(and possibly the tapping noise?). Then if the valve is rattling it could damage the oil seal which could explain the carbon spots? biggrin

First job tomorrow is to check those starter gears...

Thanks for taking the time brian, i'll report back with the findings tomorrow.

Dave

TTRfan · Super Guru

To help explain the swarf thing, have a look at the pics below sent to me this morning by a customer.

The metal from the chips on the large starter gear teeth and the starter pinion will have found their way down into the sump and possibly any chips that were finely ground in the process might have found their way past the oil filter.

A magnetic sump plug can help gather in a lot of the metal swarf and will show tell tale signs when removing the plug to change the oil.

The problem is that a clonking sprag might look perfectly OK to a mechanic cry

I had an owner recently who had to replace the large starter gear and starter twice because the first mechanic said the sprag didn't look worn so put all the new parts in and left the worn sprag to do the same damage all over again. Sadly, the second time it also cracked the generator cover as well - a very expensive lesson. Needless to say the owner took his TTR to a different mechanic second time around who, after a chat with me, agreed to replace the sprag thank goodness!

Bad sprag 1.JPG

Bad sprag 2.JPG

Bad sprag 3.JPG

-- Edited by TTRfan on Sunday 5th of October 2014 10:41:38 PM

Truxx · Veteran Member

The splines on my starter are in good shape aswell as the gear it engages with but i'm sure there'll be some nasties waiting when i get the cover off :(

Thanks
Dave

Truxx · Veteran Member

Few more pics from today... got a couple more little vids uploading now aswell

Valve guides were fine aswell :( so there not causing the noise...

Some very light marks on the journals but there not deep...

I know it's a mess but it's organised mess biggrin

Since giving up the garage i've been struggling with parking. Luckily my pal doesn't mind biggrin Still got to fit the drz in there too haha

TTRfan · Super Guru

That all looks like very good news in terms of all the parts looking in very good condition but, in a way, bad news as you still haven't identified the source of the noise cry

Brian

Truxx · Veteran Member

Truxx · Veteran Member

TTRfan wrote:
That all looks like very good news in terms of all the parts looking in very good condition but, in a way, bad news as you still haven't identified the source of the noise
Brian

Yup cry I don't really care what the problem is because i'll fix it regardless of what it needs but until i know cant do much... cry

Those little allen bolts holding the starter cover on are really bad biggrin had to hit them with a chisel to get them moving lol

The flywheel puller just didn't work it ripped itself to bits instantly but the rear axle bolt got it out straightaway...

Truxx · Veteran Member

Not sure if the end float is normal on the cams, i couldn't find any specs in the manual for them.
The bearing journals do have the slightest bit of movement but pretty sure they are within spec (i have no means to measure it)

So what's next then...

Heres a silly idea : when i stripped it down i noticed the front pipe is touching a part of the clutch cover.
Listening to one of the above vids again i'm not so sure lol I know i'm clutching at straws here ha ha but possible: Yes? No? I'd feel very silly if it was something like that biggrin

Truxx · Veteran Member

Another quick question... If i was to give up and sell the bike in bits would it make much money ?

TTRfan · Super Guru

There is normally quite a bit of end float on the cams. The timing chain centres it all up. Can't really see from the video but there shouldn't be any perceptible up and down movement on the cam shafts. The problem is usually a bit of galling on the journals that locks the camshaft tight so that it doesn't turn at all.

The first time you have to get the starter gear cover off is a bitch. Replace the original bolts with something a bit more sensible!

You won't know if the header pipe was the culprit unless you put the engine back together and try it.

If you were really sure about selling then you would get a much better price for a running bike (even with The Noise) than a basket case. But I am sure you want to put it back together to test your header theory wink

Brian

Truxx · Veteran Member

It means i'll have to buy another head and base gasket just to find out lol Then i'll also have to replace the sprag clutch and the cover gasket aswell :( More money... and i might be back at square 1 at the end of it...

Hmmm decisions :( i'll try one more time put it all back together then if it still doesn't work it's going on the evilbay :)

I'll be in touch real soon for the parts Brian. Alternator cover gasket, sprag clutch (and anything else in this area you reccomend ?), and head and base gaskets...

Thanks
Dave