Fluctuating sounds

[Nastytls]

I'm using TW8-6 cams, woods lifters, DT oil pump and stock 09' cam plate. Riding down the road steady throttle the engine will go from sounding like a sewing machine to having some clatter back to sewing machine. This is a continuous cycle I'm hearing and engine RPM does not change the cycling sound. Any ideas? Is this a potential problem or should I just ignore it?

[Nastytls]

Any ideas?

[Admiral Akbar]

What is the oil pressure doing?

Max

Add: What pushrods? 

Max

[Nastytls]

It's below my leg so I can't watch it continuously but it appears to operate in the 30-40 psi range at cruise. Fuel Moto PR which I think are Smith Bros.

[Admiral Akbar]

Well if you could look at it when the noise gets worse.. What is the period of the cycle?  Seconds? Minutes?   Smith Push-rods are pretty hard to bend.. Maybe not straight? As they rotate, they hit someplace then don't?  Could the tensioners be collapsing?  Running stock ones?   These are all wildassed guesses..

Max

[Nastytls]

I'll try to look at the gauge more consistantly tomorrow. The cycling lasts about 5 seconds or so ( I'll try to time that better tomorrow too ). Stock tensioners. I rolled the PR's on a flat surface when they were new no wobble was noted but that's hardly scientific...

[Nastytls]

So oil pressure seems pretty steady around 35ish psi and there is no noticeable drop or spike in psi at all. The fluctuations last 5-8 seconds per time. It spends much more time "quiet". Very weird.

[Rugby_fxdwg]

Detonation?

[Nastytls]

It's a distinct valve train clatter sound. Sounds like it did before I got the preload set right.

[BUBBIE]

Could it be the FI butterfly Rattlein the intake manifold?

signed....BUBBIE

[Nastytls]

i think that is an issue with TBW bikes, right? Bike has a HPI 55mm Tbody.

[Admiral Akbar]

I actually thought Bubbie might have found an issue.. Too bad...

So the cycle time is something like 30-50 seconds.. You hear the noise for 5-8. It goes away for 20-40 and the process repeats?

Strange one fer sure.. Could it be something like a loose plate in the exhaust system?   You might want to list the model and year and everything done to the bike.. Plus when it first started and what you tried since then.

Max

[kd]

Could it be related to a gear where it cycles through the effected component every x number of turns?  Because it has a "timed" cycle, it may be able to be related to road (wheel) speed, gear speed or engine RPM. 

[Nastytls]

The bike is a 2009 Dyna w/ 107'', 11-1 compression, heads by fuel moto, tw8-6 cams & pr, dt pump, HPI 55mm plugged/welded/timken crank w/ H beams.

I had an initial issue with the top end being what I thought to be excessively noisy. I adjusted the PR several times until they quieted down. If I remember correctly it ended up being around 5 full turns or aprox .150

The cycling has been there ever since I was able to quiet down the top end by further pre-loading the lifters. There are only about 120 mi on build since completed. I've done a bunch of shorter rides around town trying to figure out the initial top end noise and yesterday I did about 60 miles and it was fluctuating the whole time. The clatter isn't as loud ( like the motor is about to grenade ) as when I had the lifters set at .120, but it's definitely there. Gear and speed are not related as it happens at any speed and gear. I have not been in 5th or 6th gear yet though.

I'm starting to think it's not a big deal. If I have 120 miles on it wouldn't signs of trouble already have show themselves?

[BVHOG]

You do realize that the Wood 8 while being one of the best power producers comes at the cost of being a bit noisy.  I ran that cam and loved the power but hated the noise. tuned a few since and none were quiet. As for the fluctuation it is likely some sort of harmonics either in the valvetrain or how the sound is bouncing around you and the bike.

[BUBBIE]

 

Just to Please Max:

Max, The sounds are coming from the exhaust...

Odd burning of the fuel IN the Headers, choice of cam = noise and from that HIGH compression...

Once he turns on the fuel with his wrist, it is gone.

signed....BUBBIE

[Admiral Akbar]

You do realize that the Wood 8 while being one of the best power producers comes at the cost of being a bit noisy.  I ran that cam and loved the power but hated the noise. tuned a few since and none were quiet. As for the fluctuation it is likely some sort of harmonics either in the valvetrain or how the sound is bouncing around you and the bike.

Yeah.. One of the reasons I was thinking the stock tensioners might be freaking out.. They get lose and the noise will probably go to the valve train..  Could be something with the lifters.. I would either run the lifters til bottomed and back off 1/2 turn or add limiters and do the same.. Excellent cam for making power but as mayor would put it, "Sounds like a couple rattly skeletons dancing on a tin roof."   And that was with gears.. Running all the pushrods 1/2 off bottomed may make the sound more consistent..

Max

[Nastytls]

OK, thank you all for the insight. I did realize the 8 was noisy and I was able to mitigate some of that with adjustments. it was the on/off that had me wondering, but I don't really think I'm worried about it anymore.

I might cough up and buy one of those dual plunger tensioners to see if it changes anything.

Thank you again.

[jerry34208]

My tw8 is intermittently noisy too. (More accurately, it's intermittently quiet) Noise comes n goes with some predictability but not a lot.
I have 10k on this build. No worries.

http://www.woodcarbs.com/images/tc103tw8-1.jpg