hello all, first, i would like to thank all of you here. This is my first time posting on the forum but I have spent probably hundreds of hours over the past year scouring these pages for answers to all my commando questions with a lot of success.
I have a bit of a mystery I am hoping someone can help me with. Please bear with the long story-I think it is all relevant to my issue.
I recently put together my 1970 commando after it had been in boxes for many (16?) years. For the first few hundred miles after the rebuild, I could not get the right exhaust valve rocker to stay well gapped. I thought the lock nut was coming loose, so after the third retightening I even put a drop of non-permanent loctite on the threads as insurance. One other thing is that there was a good deal of noise from the timing side which I thought might be a loose cam chain.
At the 500 mile mark (which also coincided with a sunken float), I completed a thorough 500 mile service.
-I tightened the cam chain.
-I re-torqued the head nuts and double checked the base nuts.
-I checked the primary chain and oil bath which seemed fine,
-tightened the rear chain and checked rear wheel alignment.
-I rechecked the timing by strobe.
-And I rechecked the valve gaps.
When I first got on for the test ride, she felt better than ever. But then after about two miles, there was a little drop in power and loss of idle at stops and she seemed to be overheating. Then she started making a new noise which sounds like either a bearing or a rubbing chain. It was difficult to tell where it is coming from. Perhaps more of the primary side. It was intermittent and sounded like “swish, swish, swish” in rapid succession, then a pause, then repeated like this. Soon it was followed by yet another new noise which was more of a ting-ting but constant.
When I got home I again checked the valve gap and I realized that the gap was increasing even though the adjuster was not moving. Fearing a bent pushrod, I pulled the head to find the right two pushrods had rubbed against each other at the top ends. I then decided to pull the barrel to check the cam followers for any unusual wear. They were fine. I checked the cylinders and found a little wear front and back of both cylinders but seemingly nothing of real apparent concern. I replaced all four rods with brand new and built it up again with a brand new head gasket, well annealed and prepped. I also installed the newer mushroom type adjusters for posterity.
Last night I took her out again, but unfortunately the same ‘swish, swish, swish’ noise arose after a couple miles. It seemed to be worse at idle and it was definitely related to it getting up to temp because after it cooled down the noise went away and it ran fine. Everything feels great up until it gets hot.
I am at a loss at this point so any advice is greatly appreciated. I also admit I know a little about a lot so there is the possibility I did something wrong, such as over tighten the cam, etc.
Thank you,
Justin
1970 Commando named Sara
I have a bit of a mystery I am hoping someone can help me with. Please bear with the long story-I think it is all relevant to my issue.
I recently put together my 1970 commando after it had been in boxes for many (16?) years. For the first few hundred miles after the rebuild, I could not get the right exhaust valve rocker to stay well gapped. I thought the lock nut was coming loose, so after the third retightening I even put a drop of non-permanent loctite on the threads as insurance. One other thing is that there was a good deal of noise from the timing side which I thought might be a loose cam chain.
At the 500 mile mark (which also coincided with a sunken float), I completed a thorough 500 mile service.
-I tightened the cam chain.
-I re-torqued the head nuts and double checked the base nuts.
-I checked the primary chain and oil bath which seemed fine,
-tightened the rear chain and checked rear wheel alignment.
-I rechecked the timing by strobe.
-And I rechecked the valve gaps.
When I first got on for the test ride, she felt better than ever. But then after about two miles, there was a little drop in power and loss of idle at stops and she seemed to be overheating. Then she started making a new noise which sounds like either a bearing or a rubbing chain. It was difficult to tell where it is coming from. Perhaps more of the primary side. It was intermittent and sounded like “swish, swish, swish” in rapid succession, then a pause, then repeated like this. Soon it was followed by yet another new noise which was more of a ting-ting but constant.
When I got home I again checked the valve gap and I realized that the gap was increasing even though the adjuster was not moving. Fearing a bent pushrod, I pulled the head to find the right two pushrods had rubbed against each other at the top ends. I then decided to pull the barrel to check the cam followers for any unusual wear. They were fine. I checked the cylinders and found a little wear front and back of both cylinders but seemingly nothing of real apparent concern. I replaced all four rods with brand new and built it up again with a brand new head gasket, well annealed and prepped. I also installed the newer mushroom type adjusters for posterity.
Last night I took her out again, but unfortunately the same ‘swish, swish, swish’ noise arose after a couple miles. It seemed to be worse at idle and it was definitely related to it getting up to temp because after it cooled down the noise went away and it ran fine. Everything feels great up until it gets hot.
I am at a loss at this point so any advice is greatly appreciated. I also admit I know a little about a lot so there is the possibility I did something wrong, such as over tighten the cam, etc.
Thank you,
Justin
1970 Commando named Sara
