Some time ago, I installed a Andrews 26H cam for a little extra pull on the hills with wife on board. The 26H is pretty mild but it has done what I wanted. The issue is; ever since the cam was installed, I get this clattering at certain rpm’s. At highway speeds it seems to disappear but I can still hear it a little. I have the solid original pushrods. Here is my question; would adjustable push rods make a difference? Before the cam was installed, I did not hear the clatter. Any thoughts on what may case this clatter.

 

Good timing on this thread. I just bought new lifters, used stock pushrods and almost new rocker arms for my bike which runs the 26 G ( gear drive,) installed 45,000 miles ago.( Everything's fine this is just a refresher for the valve train with 127,000 miles on it.)

I have adjustable pushrods and since I too have the '26' with their stock base circle I figured that I'd eliminate a potential failure in the new valve train. ( A pushrod came loose on me about 2 years ago, no serious damage but a days worth of pulling the cam chest apart to find a cracked pushrod nut.)

So on my bike now, the only "tick" I get is at idle from the gear drives. That tick goes completely away right off idle. I can hear the valve train faintly ( like a quiet sewing machine,) but no clicks, clacks or ticks indicating that something's looser than you'd like.

I would suspect your lifters are bleeding down more than you needing adjustable pushrods.

After your post I'll certainly be listening for it though!

Good Luck!

 

It's quite possible that the Andrews cam circle (the part that's not the lobe) is smaller than the stock cam you took out. If that's the case, you would get more valve noise. If you would have used adjustables, that would have made up the difference. BTW, why did you pull your heads just to replace cams?

 

Assuming you"re still using the stock lifters, then I would assume you would need adjutable push rods. The base circle could definatly be different enough to require longer push rods.

 

Did not pull the heads, We left the factory pushrods in place

 

Don't make it sound like a cam with a .490 lift is going to require adjustable pushrods. The base circle is the same as stock. (And your assumption becomes "fact" because somebody's gonna' read it here as such.)

Excerpts from an interview from Hot Bike Magazine with Andrews Cams:

"The term base circle means the lowest lift point on a cam lobe. Typically, this will be true circle for about 100-or-so degrees of cam rotation.
The term base circling means reducing the lowest lift point on the cam lobe to accommodate higher lift. If this modification is made, other components must be changed as well to compensate for the new shape of the cam, which can be expensive and time consuming. We think a cam should be manufactured the way you want it the first time, so no modifications are made to the cam.."

"A bolt-in cam is one that can be installed without modifying pistons, heads, or other engine components. In other words, it bolts in with nothing else to change or alter."

 

I am well aware of cam base circle and cam function for that matter. I was not aware of said cam only having .490 lift though.

That being said, the fact that the cam was the only thing changed, leads me too the assumption that the push rod length required might have changed. Tolerances can stack up and the op could be just on the short side for push rod length.

As far as someone on this forum taking my assumption as fact, that is there problem. no where did I say this is fact. As a matter of fact I believe using the word assumption clears me of trying to pass info as factual.

 

It may not be the pushrods at all. I could be the throttle slide in a carb engine or throttle plate in a FI engine....my 08' SG with Woods Tw777's has a chopping sound emitting from the air cleaner. So did my carbed FWDWG3 with .650 lift cams. Gently turn the throttle and all is happy.

 

Do not want to highjack any bodies thread,but since its on this subject,I have a 12 limited that the lifter noise is terrible,have tried diff oils and has not helped.Question is,do you think going to a better lifter and adj. push rods would help this problem

 

Again, thanks for the responses. Seems there is a lot of different opinions on this clatter issue with little consensus on how to fix it if it is fixable. My only comment is; the clatter did not exist prior to putting in the new cam. So, the new cam changed something that is causing the clatter. How much money is one willing to spend trying to eliminate the problem? Is it pushrods, throttle slider (whatever that is), head work, rollers, oil, etc....Frankly I am more confused now than before. Maybe I'll just live with the clatter as long as it isn't hurting the engine. Anyway, thanks for the opinions.