Yamaha RD 350 LC Crankshaft Rebuild part 1

[@losttheplot1748]

That works great. Great idea with the insert

[@daviddanielstephenson2833]

Using the older ways with a proper pressing setup, IE, tube and the extra insert you acquire much better overall support when taking things apart, using the tube method there is also less inside distance between the outer edge of the crank web and the inside of the main tube, thus there is little to no flexing taking place, as the plate supports the whole of the crank once everything is placed together as shown in this video. This makes the pins much easier to remove, if one encounters any plate flexing during the pressing process and or pivotting this can be detrimental to the overall integrity of the crankshaft and hamper the re-pinning and or aligning process later on. The pins need to be pressed out and back in again as straight as possible, so they do not try to twist or pivot, "especially as they are being pressed back in", which can happen. KTM sell a superb setup like this one, but it comes at a cost for doing what is a relatively simple proceedure, you can see some of the parameters taking place that I have already aforementioned in this video, kzbin.info/www/bejne/aqi8p36KmthgkK8 Working with the tube types, supported on top of the press main beam you are working above it and not under it, which also makes things much faster and easier to handle, IE, there is no need to bend down and try catching things from underneath as crank pin/s etc break free. Many DIY presses are not wide enough to let the crank webs pass between them thus limitting the capabilities of the user, same goes for feeling what is happening, a manual press gives much better feedback when something is not quite right. The tube shown in this video is made from a large seamless hydraulic ram, it has a ten millimeter wall thickness which can handle up to 30 tons quite comfortably, I have several different bore sizes/tube to accomodate different crank web sizes, thus keeping the gap between them at a minimum.

[@borissciaroni53]

very very interesting. Many thanks. I just bought a 12t press

[@fabiobarbosa3704]

Tks for the vídeo! Great!

[@as3cs3]

I'm working on an older (similar) crank (1973 RD125) and the manual shows the left and right cranks being separated first with a simple tools which clamp on to the perimeter of each crank and are then pushed apart by turning bolts threaded in to one of the tools. They then press the conrod pins out of the individual cranks. Would this perhaps have been a method used if there was no tube like yours available?

[@BlackcatmotorcyclesCoUk]

interesting video, im looking to swap out the conrods on a 125 twin for ones off a 200 twin.. but having never done crank rebuilding i looked to see if a company can do it, but so far nobody local cant take the ends off ,like in your video on two cranks to swap the conrods over and rebuild n true .. i may look to do this myself

[@TouristExplorer-u4q]

Hi David, could you advise the thickness of the small plate which helps support the main plate ? I am guessing it is 5mm ? Also, what size vee block are you using, 4inch ?

[@3DCharacterArt]

Can you tell what is the OD of that 10mm wall press tube, I'm guessing 6.6" maybe, x 12" tall with 10" x 2" slot? And the size of the Magnetic V-block is it 4" long?

[@daviddanielstephenson2833]

The press tube is made from a seamless hydraulic ram, measuring 14 inches tall, the slot is 10 inches deep and the outer diameter is 6 inches, wall thickness 10.00mm. The magnetic block is 4 inches long.

[@3DCharacterArt]

@@daviddanielstephenson2833 ok thanks!

[@3DCharacterArt]

@@daviddanielstephenson2833 I have purchased a tube 6” OD 5.25” ID .375” Wall x 14” Long. It’s cut square but a little bit of sawtooth marking on the ends, debating to have the ends faced or not before cutting the slot… which brings to the next question, what is the width of the slot? Will be used for TZR250 or RZ350 parallel twin.

[@daviddanielstephenson2833]

@@3DCharacterArt The slot is 40.00mm wide, same for the pressing plate, which is large enough for most conrods, the slot in the pressing plate needs to clear whatever size the big end is across, so the plate can rest right up against the big end journal. If you can square the ends of the tube both ends so it sits perfectly square, then pressing out pins will be much easier.

[@3DCharacterArt]

@@daviddanielstephenson2833 Thank you!

[@daviddanielstephenson2833]

Here is an interesting view of how a crankshaft production line works, notice how the crankshaft operator uses a solid copper block instead of a hammer, also the large copper drift instead of a hammer, if you use a copper hammer the hammer eventually mushrooms and tiny fragments can flake off that can work there way into and contaminate and or damage the soft white metal big end bearing cage, which is what you want to avoid if you can, kzbin.info/www/bejne/hYDTdXptjM2Xra8 Also notice the dedicated stepped plate that is used while the main bearings are being fitted, this is essential to prevent flexing of the webs and should always be done before truing commences. I like to use a large lead block for the larger crankshafts to ease the re-aligning process, by placing the edge of one web on the lead platform, it takes most of the stresses away from holding it in your hand, and less force is needed to get things moving, I will do a video of the technique I use when I do another crank.

[@clutchitsystems100]

A steel hammer DENTS the crankshaft halves. Ugly. Use brass or copper hammer. Preferably copper.

[@daviddanielstephenson2833]

Another superb product in the making, kzbin.info/www/bejne/rZTSY5ZnnK16fpI

[@daviddanielstephenson2833]

It is good to see that production is coming back home again, Hotrods USA, kzbin.info/www/bejne/l5SYopyJeaZkjtE

[@daviddanielstephenson2833]

Tri-Jig crank tool India, this is a really good tool, simple but effective, kzbin.info/www/bejne/oZrOfpaojJZ9pJI

[@gvwa100506]

🤕👍👍👍👍🐧🐧🐧🐧