Yamaha RD125 tapping sound new

[Fatfreddy1973]

I bought a RD125 lc 86 plate last year and have done about 500 miles on it, just pootling around local. I use top 2 stroke oil and the best fuel. Today after starting her and letting it idle for a while, a tapping sound from engine area started, completely new sound. Here's the embarrassing bit but I do have to ask, apart from the Motul 710 oil, do I need to be topping up transmission oil? I can't believe I'm this stupid, I've gone through my Haynes manual, but can't really find the answer and instead of doing any damage I'd rather ask. The window on engine is low, about a 5th full and won't go any further.
I really do appreciate any help thank you.
James

[mangocrazy]

Two strokes do have an entirely separate compartment for the clutch/transmission and that oil does need to be changed at intervals and monitored for oil level. My 1980 350LC has a dipstick to check the gearbox oil level, but later bikes tend to have the sight glass. If you haven't changed the gearbox oil already, I'd do it as a matter of some urgency.

'Back in the day' we'd just bung 10w30 engine oil in, but these days there are specific lubricants for bike gearboxes. I used Silkolene light gear oil for mine but if you prefer Motul products then Motul Transoil Expert 10W-40 Gear Oil is readily available. Not sure of the capacity, but t'Internet will know...

And welcome!

[Fatfreddy1973]

You sir are a legend, thank you. Was about to go for a little ride but put bike away as was worried and ime ordering that oil as soon as I finish here. It's strange, 30 years ago, the last time I had 2 strokes, I rode it seemed without a care in the world, bikes just seemed to go forever. Now I'm 50 I'm ashamed at how useless I am with the maintenance, how could I not know about the oils needed?!
Really appreciate you messaging back so quick, thanks man.
James

[mangocrazy]

No worries, glad to be of help! Got to keep these stinkwheels on the road!

[Fatfreddy1973]

Hi mate, so the time has come for me to finally tackle this, I've SORN her for the winter, bought the recommended transmission oil. I just wanted to ask, when I empty old oil and open case up, is there anything I should be looking out for? I'm talking things which an inexperienced person wouldn't know, I have a Haynes Manual to assist.
Reason for doing now is the previous owner messaged me asking to consider selling back to him, tempted but I'd like to enjoy it myself, so I have to man up and do this.
Hope you're well, appreciate your help and advice.
James

[mangocrazy]

Emptying old oil is a matter of finding a suitable container that will hold at least 3 or more litres of oil, positioning it under the gearbox drain plug and undoing the drain plug. You may find it easier to release the tension on the drain plug (i.e. undo it a quarter/half turn) before positioning the container under the drain plug. Try not to lose the drain plug in the oil...

Once all the old oil has drained out (give it half an hour or so), refit the drain plug, tighten it up to the recommended torque and refill the gearbox using the screw filler cap on the RH crankcase cover. A suitably sized funnel can help here. Absolutely no need to 'open the case up'. Refill with the recommended type and amount of oil that the Haynes manual states. Re-fit the screw filler cap and you should be good to go. Once you've been for a run, check the dip stick to ensure the oil is at the correct level.