@forgotten just google dowel pins and see what comes up.

@perky there are two types be careful, one has a round splitter box and one is oblong that is the later one, the problem arises when the oil pump cable goes into the housing and you try to fit the retaining clip and it’s the wrong length.

@spookdog I have no idea how it would have got broke, my only idea was a previous owner thought they new what they was doing trying to adjust it lol All the pre servo powervalve covers seem to have the pin I had a nightmare finding one NOS as the part numbers changed multiple times but turned out they all superseded each other and were the same. Will post a pic of the broken one the weekend hope this all helped tho as it was driving me insane, I was convinced it was carb problems or that my air box was blocked or something as it randomly started after a very muddy day in the woods .

@calum perfect cheers didn’t think it would be that simple

@llldennis I think the engine is suitable reliably without needing ceramic bearings. The main thing to wear are the piston rings and and wall etc.

@ninja I always went with Tsubaki Chains (Jap ) https://www.bandcexpress.co.uk/pages/news/latest-news-and-offers/tsubaki-chain---in-all-sizes.htm

@spookdog said in fitting later engine cases to older engine: @dan28 I didn’t know that there was a plastic side case, but if it has the same pumps it should be ok. I’d keep my original oil pump if it’s good. Just cause it’s calibrated right. 89 cases are plastic the later cases are alloy The oil pumps have a different part number not sure about water pump.

Carry a plug spanner and the next time it happens shut off the fuel and remove the plug, then kick it over ten/ twenty times to clear it. If it starts ok let us know... Also try putting the old plug back in, could be a defect... I’d give the reeds an eyeball as well, just to check they’re closed...

@jonne123 You can put it in from the side. Just lever out a bush, or put a screwdriver in one side and tap out the other... You shouldn’t t need to split the cases. Just lift the engine up in the frame till you have access... Edited for feckups

As mentioned the diamond shape fits the pulley with the square / rectangular end as well The grooves in the power valve aren't for O-rings, instead these fit into the ends caps as you cant refit the valve into the cylinder with O-rings in the grooves

@jimmydc98 As @jimmydc98 says you would be far better off getting it TIG welded, as that would be a much stronger and more durable fix. I've used several JB weld epoxy's / adhesives and have never found them to be any good. They do not seem to stick or repair stuff as stated, so I would steer well clear of them. I have tried this stuff tho and can recommend it; https://www.ebay.co.uk/itm/VersaChem-Steel-Weld-Epoxy-Black-2hr-Set-25ml-47709-VC-Automotive-Industrial/362460351914 The TIG welding would be your best bet tho IMO.

@jimmydc98 Cheap That's good to know at least. Connecting Rod for my RS is that price alone

Sorry for the mega late reply on this lads, sacrificed internet for the rebuild at the time and just wanted to say (now i remembered :P) Thanks so much for all your help. got it sorted with the loctite in the end and it all worked out! really grateful for the replies. will post some bike porn soon and start getting active!

@calum Yes found that out to my dismay once - think they are 1mm narrower than the nearest commonly available bearing. Why wont these casings go back together.....

@calum old thread mate but can you use a 4fu head on a 3mb barrel? ive got a 3bn head on atm and wondering what my best option is and how much more power will i gain from a 3mb/4fu head

@jonne123 im also trying to find something that matches the original silver, my stator cover needs painting

@challenger Typically it's Rotax Engines, TZ 250 Engines and Suzukis. I don't recall there being any examples of road going bikes, but I read it in 2013 so a long time ago now. I have since read the collection of other tuning books he wrote, they're very good.

If the bore is OK leave it alone you just need to find the right piston. Go through an authentic dealer, also get the bore measured by an engineer so you know exactly what size you’re looking for...

Is yours leaking? If yours has to be perfect then you will have to search all stockist for a New Old Stock, bound to be one somewhere. Unless yours is leaking I wouldn't bother personally. https://www.ebay.it/itm/Yamaha-DT-125-R-Wasserkuhler/254775187149?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20160323102634%26meid%3De28a135d13374a9191e1f0245e9bf5e5%26pid%3D100623%26rk%3D1%26rkt%3D5%26sd%3D254541640932%26itm%3D254775187149%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganic&_trksid=p2047675.c100623.m-1 That's in good nick. I run Yamaha DT 230 Lanza radiators on mine. https://www.ebay.co.uk/itm/Aluminum-Alloy-Radiator-Fit-YAMAHA-DT230-Lanza-DT-230-Braced-Cooling/283565759760?epid=24005913216&_trkparms=ispr%3D1&hash=item4205d61d10:g:nnIAAOSw8OJZxaQG&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%252Fn%252BzU5L90Z278x5ickk7PdDazAlGltMLJlUhrWsD%252BjagP3n2Wi2PP9H9bbty9tutqQhgUmp1bIIgObaPKvnRq4qjzkap19sQdRTMu9RsbKpgOEVg6judcuJ%252BAHjAPfwndPt2UyhP9oq%252BbS3hhJb1rHgOsNIry65rbCclIYXgf6WWcSTo7cJsTU5YRYaFdcFXLgqqsuXpLYsUYIm%252FC6dlsKTMXMUTRV%252BnSQmj10OesINYxpgS6H7NTYxgsYLF2EyKOE37yFlUqtWX%252BRHlmgywLwPqviCVEl2dlG5RlLst%252F9DwPge91S%252FQY2BgV1oqtgxadVjsCb5e9hw4Z0CfqZfRU1eHFZ3XsG%252FEDlFyZyHNDFR0G4zeUAuorzqL75lG7iMwdH2d7PigRQ6mtznOa4Vx40U%252BqXUPlpONHAazOLIsrypvLdnu%252Bf%252FNP08T7kujfukpU6OrOKhJoMrx%252FKbcyi4sVPHsM83%252F4W%252FFnUjGb%252F9juoi%252BwTcRJoyDKRlw7yhgAgFgLK0grurIiH9mbJTxBdCAwTKtuAICp27kxK2dGFQ2LIp6lNXP0F8caZmV1d5oohMWHxw3S7mo3g2OKUOGpwArBn9K6BYa5EiDTpg%252FHsSXeymS5N6AkMX%252BjrCjgjbjMQgZlMfFvt0xhilCkX26VkHJKgQ8ZJThio6W%252FGnRAX0it1NwnJty%252BuyoLGAe0Me%252FalaqhqqkjNvdw6AecMels%252F1zCH9NRDeffBkr9Wrd8sn4vTPsVUTO6EWwd6omaNnkIo8lygPJ4h37NUwigXDDncXr8nrLBAg1CBXDglm2Ggnjn4svzJ%252FWz7OEneJE6BC%252FMU%253D|cksum%3A2835657597609950dcfdfe2046e3839a1ef6d5214f1b|ampid%3APL_CLK|clp%3A2334524 You can get new radiators for those, just need the brackets.

okay thanks!