Hi, I have recently acquired a relatively late (1960/70s) Optimus No.00. The stove came with a "normal" combined filler cap/air-release cap. but it will not screw onto the filler up-stand! It will start, but locks-up after a quarter turn: The thread is not damaged, it is simply a different pitch/thread form from the "normal" type used on Op.00 stoves. The cap supplied with the present stove fits other Op.00 stoves, so is the more usual type. In this third photo a "normal" filler up-stand, removed from an Op.00 donor stove, is shown alongside the fitted up-stand: Has anyone else seen this type of fitting on an Op.00? Any suggestions on how to resurrect this classic stove? Best Regards, Kerophile.
The threads are different all together! I just measured an old and a "new" 00 The old one measures 19.00mm and the new 19.73mm measured directly on the stove. The new cap is on the left:
Hi Henrik, as usual you are spot on! I checked the OD of the "unusual" filler riser this morning and as Henrik pointed out it is around 20mm compared with just over 19mm for earlier Op.00s. A stove friend from the US has found a replacement for me so hopefully I will soon have this late Op.00 working again. You always have something new to learn about stoves. I was never aware of the late Optimus filler cap change until this episode. Mr Ed, yes, I reckon the "standard" filler cap, shown on the right in CT's photo would fit your Burmos No.21. Best Regards, Kerophile.
Hi, yesterday I received a replacement filler cap/air release for this particular stove . It was a generous gift from a good stove-friend in the USA. Many thanks Matt. I wasted no time in fitting this correct cap to the stove, and after fitting new burner washers and cleaning the jet, I filled the tank and got the stove operating. The stove performs well and easily passed the "Kerophile Tea Test". I have now posted some photos in the Reference Gallery: https://classiccampstoves.com/posts/18899 Best Regards, Kerophile.
