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Hi im new to this forum but wonded if any one has got to the bottom of the pinking rattley engine as the more ive read the more im confused as some say no head gascket some say two are three blocked pipe or poor fuel and to add boost adatives what do i need to do as mine just chaters of idle and on low revs but have had the bike checked out and the guy carnt find anything worn that would coures this .cheers peter

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There have been a few previous threads on this before and the pinking issue seems quite common. I don't remember there being anything like the problems back in the day - although newish Yams would pink a little bit, most ran very well when new in the 1980s/early '90s - at one point half the entry was on a Yam and most only ran badly when worn. The earlier models struggled to breathe slightly and they were refined a bit as the years went on in terms of the airbox and carb.

Having said all that, and before forum members regale me with tales of woe, I'm sure there are some bikes which were a nightmare to sort!

My opinion is that with most Yams, the key is to get them back to near new. In my experience one of the first jobs is to clean out and repack the whole exhaust system, including the middle box. To do this properly takes quite a lot of time and needs a good welder. The holes in the core need to be fully unblocked and the mid-box chambers repacked and rebuilt. The bike will be transformed and will run far cleaner, smoother and will be easier to carburate.

Obviously use a decent clean air filter and check that the carb and air filter rubbers are sealing and the carb is clean. I use the higher octane unleaded at 50:1 with Silkolene pre-mix although I used Motul in the 1980s and it worked just as well.

The engines are usually bullet proof for years, but on a well worn bike the crank seals and main bearings can start going. These bikes will rattle like mad without blowing, and freshening up the top end is also often needed. I've always used original Yamaha pistons and rings in the standard engines with stock porting, standard gaskets and stock carb and jets. I've probably had half a dozen of these bikes over the last 20 something years and think they are a cracking machine. Good luck with yours - Alan

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