Chatter sound from HT-b cam - what is it?

sam2019

sam2019

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This is an email I received and as I do not have any such experience with the 2 HT-b I use for some time now I ask if anybody else has something similar or can shed some light on the phenomenon.
He also provided a picture which shows some "bands" which I also have seen on my cams so I assume its just normal wear showing.
I have requested a mp3 or video file so we can actually hear the sound - "chatter" can mean a lot of things really.

I had occasion to have the rocker cover off my BS4 Himmy recently as there seemed to be a high pitched ‘chatter’ (not like valve clearance sounds) and noticed these strange bands across and along the lobes of the HTb.

I replaced with the OEM camshaft and the chatter went away (as did the performance!) so replaced with a TEC cam from my BS6 - which resulted in a return to performance but not a return of the chatter so the sound would appear be camshaft related.

The bands shown on the pics are not present on the (7K mile) OEM camshaft or the (3K mile) TEC cam from my BS6. Any thoughts??
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The only thing I can think of that with a higher lift cam could the cam roller be hitting the cover? I would think there should be plenty of clearance for the roller but it looks as if the cam roller is sliding over the cam lobe instead of rolling.
 
Quite obviously being the same width as the Roller and right where the extra work is being done. Lift !
I have seen/got one with similar surface, you would not expect to see it anywhere but at the Pointy end.
Would be a problem if you could feel it.
 
A Roller going over this surface is a different situation than a Rocker.
Himalayan has Roller Rockers but maybe the lift/Load is a bit much.
Certainly they open more ;)
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2 different Cams
Why is it from an email? and not a Post!
 
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I had the same problem with the HT-b camshaft. She always rattled. I blamed it on the fact that the steep flanks of the cams caused the valves to close too quickly and hit the valve seat.
I now also drive with the TEC camshaft. It only rattles after starting when the engine is up to temperature. This calms down after about 15 seconds. Why that's so, I do not know.
 
The original questioner never showed up nor did he follow up with email so I guess the problem is solved on his side.
 
Truth be known, the problem was discovered and the C with the Decomp ( or without ) does not have the same intensity of noise, the Flank is quite likely the culprit.
Another sorry truth is that these things get made in batches and those batches need to sell before new batches are considered.
Ive done my part, I have bought many Cams :unsure: presumably to my Benefit :) but I say that if you havent bought 3 or more then your not helping the Cause:ROFLMAO:
 
just bought 4 - so big help here :cool:

also sold all of them already - should I wait now for another new one that needs testing?
 
how long can you wait?
I am not pushing because I want the Cam sprocket first.
 
Dool said:
how long can you wait?
I am not pushing because I want the Cam sprocket first.
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I can wait til the next order. also: cam sprocket - do you make it? is it a pre fabricated part? where do you get it from? will it fit without much modifying? is this worth its own thread??
 
I mentioned the sprocket before, it's not the difference between night and day but it enables the job of setting the Timing to be done correctly.
All the Pros say so :cool:
 
this one
 

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Hi Dool, my HT-b has about 10 000kms on it now on my 2018 carby but is still very noisy, which I don't like. I set the valve clearances to the tighter specs for both valves and they seem to go looser over time (5000km intervals) which speaks of wear to me. I have also gone back to 15W50 synthetic oil from the 10W40 synthetic which did not make a difference. Seen a case of rocker roller bearings fail on a standard bike, so I don't want that on mine. So I am contemplating pulling my cam out ( I have a TEC cam which I have not used) and maybe go 477 big bore too. Is there a HT-c with decomp in the pipeline. I like the increase in power of the HT-b but want longevity too which is where my concerns are.
 
Is there a HT-c with decomp in the pipeline. I like the increase in power of the HT-b but want longevity too which is where my concerns are.
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There was a HT-C with decomp but that was not delivering the power the HT-b does. I ran it on 2 bikes for a while, one carby and one BS6.
AFAIK no further cam is in the pipe. I also have the ht-b in my BS6 for near about 10.000km now and because we do open the engine for various reasons one of them checking on wear marks there is very little I could see on the surfaces that make contact. Some marks where there but they are similar to those on used OEM cams.
I do not recall if my mechanic had to adjust the clearances - will inquire as we are about to open the 477 again to change to 500cc. At that time I will take pictures of the cam and publish them here.
 
That would be great thanks. I like the cam and it has made such a positive difference to the whole experience with the bike
 
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