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

ahunt · Member

Engine advice

Cubber · Super Guru

Alex, if you use the "Search" button above and put your query in there it will sort through all the previous messages and give you lots of clues.

But - white smoke on starting shouldn't be a big worry. It's when the thing shows smoke after running for some time, particularly on the over-run, that it's time to look at it the causes.

A slight rattle when you stop the motor isn't a sign of a sprag defect. When it REALLY makes you notice the noise is when you worry. It's really harsh and clunky as the sprag rattles and wears away.

Martyn

ahunt · Member

Thanks Martyn

Good to hear about the clunk!

It is smokey as you rev and not just after start up. After running for a while it is still smokey. I will try your search suggestion.

Alex

barra8 · Guru

Sounds like a top end rebuild is nessasary before any worse damage is done. If it continues smoking the rings will need replacement. The rattle is most likely the rings when cold until it warms & the rings expand & the rattle goes away. I would also be replacing cam chain,cam chain guides,valve stem seals & checking whether the valves are still seated correctly.

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Jarrah.

BaronGreenback · Veteran Member

Sounds like you need new valve seals, at the very least. I would also look into 'piston blow by' too. You will need some bore measuring guages and a service manual for this.
While you have the top end apart I'd check the timing chain, sprockets and valve clearances as well.
A top end rebuild, when needed, will save you a fortune in buying bottom end components after the top self destructs and destroys the lower end.

barra8 · Guru

ahunt wrote:
Hi. I have just picked up a 1997 TT250R Open Enduro. It runs but is not in the best state of repair. I have done the basics ie oil, air filter, oil and plug. It starts and runs fine but the engine is a is a bit rattly for a few minutes after starting.

I'm afraid valves stem seals won't be the only thing needing replacing by the sounds of the above & would be the least of my worries...

There won't be much point checking the rings as the rattle you will find to be the rings about to explode & piston about to shatter. (Don't ask how i know this blankstare ) Very expensive fix $$$$$$$$ cry

The fact that you mentioned it rattles when cold & not when warm suggests the rings will need replacement. Also to add to that the smoke described even when warm.

If it was a timing chain rattle this would not start until the engine was warm as by the time they need replacing they get stiff...When cold they remain stiff until the heat expands the metal & the old chain rattle kicks in.

I am not suggesting that your timing chain does'nt need replacing only it's not likely it would be making that noise when cold & also that if the noise goes away when warm it is highly unlikely to be timing chain....which points to ring rattle.

I would be doing all that is written on this page (but not the same thing twice as it reads :)

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Jarrah.

-- Edited by barra8 on Sunday 28th of October 2012 02:40:36 PM

barra8 · Guru

That is a pretty good starting price for a bike & if the bike itself is okay then it is definately worth re-building. It really is not that expensive to rebuilt the top end but when you start pulling the bottom end apart it can be costly. Also getting the bike up to scratch may not be worth the money you spent unless it is in a reasonable shape.

My suggestion is work out how much it will cost you to re-build,add $200.00-$600.00 more than you think & work out whether you think it's worth spending the hard earned cash on.

Whether or not the cam chain & guides are worn i would replace these anyway if doing a Top end re-build as this will need to be done regually anyway.

.........................

Jarrah.

-- Edited by barra8 on Tuesday 30th of October 2012 03:41:20 AM

ahunt · Member

Thanks for all the advice. I have checked and adjusted valve clearances (way out!) Timing chain and guides seem ok. Back together and running but still smokey and still quite rattly.

Bike cost me $1500 Aus (1997 Open Enduro). Is it worth rebuild or cut losses????? From the look of Ebay I could proabably get a bit back wrecking it.

At least if I get it rebuilt I will know it is OK. Thoughts???

barra8 · Guru

If your talking about the piston i bought a wizeco piston kit from the usa on ebay. see here for price http://www.ebay.com.au/itm/Wiseco-Piston-Kit-Yamaha-TTR250-99-06-73-5mm-/220616519738?pt=Motorcycles_Parts_Accessories&hash=item335dc4f03a

I would not get the barrel bored until you have the piston as this needs to be sized up perfect with the bore.

Also check out www.powersportsplus.com Great shipping rates,awesome prices but may take awhile if it's not in stock?? They also have aftermarket parts like Wizeco piston kits ect. & shipping will be less than on ebay. This is where i bought all my OEM genuine parts from & am most happy

So you know it costs nothing to import if the goods are under $1000.00 & are not tobacco,alcohol ect.. Motorbike parts will cost nothing to import if under $1000.00

............................

Enjoy,

Jarrah.

-- Edited by barra8 on Friday 2nd of November 2012 07:22:55 AM

ahunt · Member

Hi. Thanks again for all the advice.

I have started pulling it apart and cylinder is scored so rebore necessary. Made a couple of calls and it seems .5mm over pistion is the next size available. Any recommendations of where in Aus is a good place to purchase? What is a good price?

ahunt · Member

Thanks. On the Powersportsplus site what model do I have to look under?It list L, RL, RLC? I take it the 1999 fits the 1997 Enduro I have? Parts seem way cheaper but I suppose it will take a while to get them. Best price I have got in Aus so far is about $300 for piston, rings, gudgeon etc.

barra8 · Guru

The wizeco piston kit in the link comes complete with the gudgeon pin,clips,rings.

I'm not sure if the ones on powersportsplus come with the gudgeon pin & clips though.

It will take about two weeks-three max for the parts to arrive (depending how big your order is)

Just order TTR250LC parts as there is no difference from 1993-20012 unless it comes to the number of clutch plates (all clutches plates are interchangable) & clutch boss. Also the oil breather pipe is different on the 1999-2012 as it is on the head (not that this would matter). The clutch & rotor covers are different but all components are interchangable including the engine side covers. You will have no problems just buying the components and fitting them to your 1997 though other than mentioned above.

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Jarrah.

barra8 · Guru

See this thread for more info.... Usefull internet links & info for restorations and maintenence

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Jarrah.

TTRfan · Super Guru

barra8 wrote:
I'm not sure if the ones on powersportsplus come with the gudgeon pin & clips though.
It will take about two weeks-three max for the parts to arrive (depending how big your order is)

If buying genuine Yamaha parts, the piston, gudgeon pin, ring set and circlips have to be ordered seperately.

My last big order with Boats was made on 27 September and I got the parcel in the UK on 24 October. It took 6 days just to get through Heathrow customs to our local depot for collection

Brian

barra8 · Guru

TTRfan wrote:
barra8 wrote:
I'm not sure if the ones on powersportsplus come with the gudgeon pin & clips though.
It will take about two weeks-three max for the parts to arrive (depending how big your order is)
If buying genuine Yamaha parts, the piston, gudgeon pin, ring set and circlips have to be ordered seperately.
My last big order with Boats was made on 27 September and I got the parcel in the UK on 24 October. It took 6 days just to get through Heathrow customs to our local depot for collection
Brian

I was talking about the Wizeco piston kit....It says in powersportsplus that the Wizeco piston kit may or may not come with the clips & gudeon pin.

Last 3 orders from powersportsplus was huge & took just under three weeks. Some smaller orders gave been arriving in just under two weeks.

Customs over there must really be a pain in the %$##

........................

Jarrah.