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alainttr250 · Veteran Member

1999 TTR250 engine refection

alainttr250 · Veteran Member

alainttr250 wrote:
hellos,

For some time the engine had been feeling some weakness of power.
A little click at low speed. A little slap a start. The clutch was sticking after a while.
A few weeks ago, she did not start any more, I stayed in the field.
Since then, I have found another 1996 TTR Raid engine, which function great ....... nothing to have.
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1999 TTR engine:
It is equipped with a piston 77mm? Normally 74mm.
A lot of scale on the piston and on the intake?
For the calibration of the distri compared to the doc was not top that? a doubt...

If someone with an eye seeing his photos can give me an opinion will be nice. thank you
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The project is to put it back into operation (Valve Embayage, and distri)

ttr steve · Super Guru

Your engine looks like it got seriously hot, you can see the colour change in the cooked parts cry

Is the blue gasket a sealer you have used or the actual gasket? the part by the oil filter (the flat one inside the engine) looks like it is covering the oil ways? I will have a look at some cases to see if the oil is meant to flows through the part that is covered by the blue gasket. Picture number 19

alainttr250 · Veteran Member

hello,

yes, this engine has suffered. He has twice taken the water in a river. The blue seal is a real real seal. No, I do not think the oil routes are clogged.

Photo after a good cleaning

Thank you

mossproof · Super Guru

Looks like it is burning oil, and I think the cause is the bore which looks too shiny to me - "glazed" which reduces compression and allows oil to pass the rings.

77mm piston sounds very big to me. The sleeve is only 78mm outside diameter normally, I think, but that piston is not standard anyway. Are there any numbers or markings that will tell you what it is? The valve cutouts in the piston crown do not match the ttr valve sizes so it must be from another engine I think.

I think you will need a rebore, but be sure what piston will fit before you start, and that the sleeve is thick enough. Check the valves move free in their guides (and not too loose), "lap them in" plus new stem seals.

By "distri" do you mean the timing chain? If the engine has had a hard life I would change it just to be kind to it! Difficult to see in your pictures if the lines on the sprockets are level in pic 20. They should be parallel with the metal surface - easier to see with the rubber gasket removed.

Bon chance!

alainttr250 · Veteran Member

hello,

Thank you for your replies.
Measures: