New pushrods
Posted: Sat Feb 08, 2020 11:15 pm
My bike has had a rattle recently that's become rather chronic so I spent today going over it to find the cause. As soon as the engine warmed up it would start tapping and the hotter it got the worse it got. Turns out that on the right cylinder 3 of the 4 pushrod ends were loose. The three ends had been clacking so much they had worn the end of the pushrod tube down slightly which caused the clearances to open up to twice what they should be.
I pulled the ends out with pliers but had to heat up the tube to pull the fourth. Then I took some quick measurements of the tube.
Simple enough to make so I got some 600 series ally and turned new tubes. Here is the end of my new tube compared to the old one. You can see where the end ball had sunk into the tube a bit
The ends stalks are 4.68mm so I figured I would drill and ream 4.5mm and press them in. Here's a quick test fit.
I made a quick jig to protect the ball, not that it needs it as it's hardened but you need to be sure. Pressed the ends in using my tailstock ram.
Two new rods next to the old one.
I checked the LH cylinder and those ones were still firmly fitted so I left them alone. I put the lot back together and set the clearances and it's now back to a satisfying rustle when running instead of a horrible rattle.
I pulled the ends out with pliers but had to heat up the tube to pull the fourth. Then I took some quick measurements of the tube.
- Pushrods01.jpg (136.3 KiB) Viewed 7581 times
Simple enough to make so I got some 600 series ally and turned new tubes. Here is the end of my new tube compared to the old one. You can see where the end ball had sunk into the tube a bit
- Pushrods02.jpg (123.47 KiB) Viewed 7581 times
The ends stalks are 4.68mm so I figured I would drill and ream 4.5mm and press them in. Here's a quick test fit.
- Pushrods03.jpg (133.58 KiB) Viewed 7581 times
I made a quick jig to protect the ball, not that it needs it as it's hardened but you need to be sure. Pressed the ends in using my tailstock ram.
- Pushrods04.jpg (170.23 KiB) Viewed 7581 times
- Pushrods05.jpg (166.19 KiB) Viewed 7581 times
Two new rods next to the old one.
- Pushrods06.jpg (216.97 KiB) Viewed 7581 times
I checked the LH cylinder and those ones were still firmly fitted so I left them alone. I put the lot back together and set the clearances and it's now back to a satisfying rustle when running instead of a horrible rattle.
