View Full Version : Fatvo valvetrain noise

08-21-2004, 08:08 PM
I would appreciate any help/feedback on a problem I'm having with my custom Fatboy. It has a FATVO motor in it from Sputhe which is: EVO bottom end cases with 3 7/8" bore Twin cam cylinders. It has the stock HD 4 1/4" stroke crank assm. with Ross forged pistons. This gives it 100 cu. in. displacement. The valvetrain/etc. consists of .600 S&S cam, HD lifters, Crane pushrods and springs. It has less than 2000 miles on it. NOW, the problem is that it has developed a very noticeable knocking when I roll off the throttle at any speed; it does not do it at idle or under acceleration. It sounds almost like a small man inside the front cylinder area with a small hammer in there just tapping away! I have had to diffent shops look at it; One of them did some pushrod adjustments but it didn't change a thing! This particular shop says it's no big deal, BUT if I want it to go away I need to replace the lifters (these are brand new HD lifters) and install new EZ Adjust (ANDREWS) pushrods and travel limiters. The other guy says I should try going from a .600 to a .530 cam and change the spring in the oil pump?? Sputhe says "it's not a big event" and that I should just ride it... CAN ANYONE OFFER SOME GOOD ADVICE, other than the "just convert your experimental motor all over to an EVO" advice I got from the ClubChopper.com Forum guys??? Sorry for such a lengthy post but My new motor ain't acting new! Thanks

08-21-2004, 08:20 PM
Hi solfranbeth

Welcome to the forums.

I have to disagree with bringing the motor back to stock, that would be going backwards & I am not into history.

Lets try some very basic shit first before getting deep into this.

You say it happened after a while, you have big cams & your shop seems to think it's something in the lifters.

Pull your rocker boxes off & take a look at the top of them & see if you have a clearance problem, look at the top for signs of the rocker hitting the cover, while you have that off look for any signs of binding in the valve train (wear marks)

This should get you started

I'm sure others here will chime in we have some great wrenches here :)

08-21-2004, 10:55 PM
If you don't find anything that Wide suggested wrong, I would then check my cam end play and pinion gear shaft nut for torque. By the way, you have found the best site right here! Those cats on that other site are mostly "kit bikers" anyway :lol: If something doesn't work just by two more new ones. Keep us posted and let's see some pics of that Fatvo.

08-22-2004, 02:28 AM
i do tend to agree with wide on this one , other small thigs you can cheak are timeing, and did you put the heavy duty springs in on the valves we realy need to determen were the noise is coming from meaning area of the engine so we can determen the place and type of noise hard meatal or soft clicking right now it could be oil pump, cams, piston slap, valve train and so on....

08-22-2004, 04:06 AM
Gentlemen, thanks for the advice and the interest. You guys have already given me more help in the first few hours than those other guys did in a week! By the way, the shop that actually spent some time on it ( adjusting the pushrods, etc.) say that to them it sounds like a lifter that just doesn't have quite enough pressure on it to keep it where it's supposed to be, (did I say that right?). The guy that built it for me at Custom Works Daytona will send me any parts I want! He suggested a smaller cam (.530) and some travel limiters ( what would they do??), and he feels confident that this will eliminate the sound; he told me in hindsight ( he actually built this bike for himself, I bought it from him with 1510 miles on it) he should have done both these things originally. Please continue to send me advice. I'm adding some photos, and thanks again for being the anti-chopperclub guys.

08-22-2004, 04:20 AM
from the just of what i am reading it might be possible that the cam has to much lift and is maxing out the valve train also some cams have what they call rapid ramps i believe crane is one of the manufacturers these rapid ramps will pound the shit out of your rollers and lifters i am not nescessarily saying that this is your problem but given the noise you have and possibility of a weak lifter it might justify taking the nose cone off and investigating that area of the motor throughly you could sure eliminate a lot of possiblitys with a good visual inspection keep us informed and we'll keep thinking about the problem

08-22-2004, 05:08 AM
Gentlemen, thanks for the advice and the interest.

Your very welcome :D

and thanks again for being the anti-chopperclub guys.

Were not anti anything, sometimes the right people miss reading the post.

Let us know on your inspection results 1beer

Before I forget, Welcome to the forums & post us some good pictures of your ride, sure would like to see it :)

EDIT...I just saw your bike in the gallery , thats a really cool setup, I like bikes like this..

08-22-2004, 07:40 PM
welcome to the forums....

i'm thinking shovel might have something here. under acceleration, internal forces (torque) shoves components in one direction. under decel, the shift the other way.

if it were a reciprocating part, such as a lifter, rocker, etc. rpm and load would have little effect on change. items such as bearings usually complain loudest under load- not decel.

hard to say without being there- this is kind of an odd one. but i'd go with shov's suggestion on checking endplays, pinion nut for fastness..


08-23-2004, 05:24 PM
Welcome to HCG

Man, y'a gott'a hate those little guys with hammers :D .

Alot of good advise and idea's going on here.It is a little hard to figure out without actually hearing it. When working on weird noise problems especially the ones y'a can't duplicate on the bench I gott'a tool for that.

It's called a "ChassisEar" it consists of a set of headphones,a 6 channel breakout box and 6 cables with clamp on antenuators(mics). Its battery operated and can be strapped on the bike with the clamps attached to suspected noise areas. Then you can ride the bike around switching channels and moving clamps until you isolate the source.Originally designed for automotive use but works well on scooters.Even if y'a got dragpipes you can hear the engine sounds.

Steelman ChassisEar part #06600, phone 800/255-7011,fax 02/362/5084.
cost about 185.00.

Just a thought and a suggestion. B) Let us know what happens


08-23-2004, 08:27 PM

too cool! i'm gonna save that info and see about getting one....

i found it for $103 here ...http://www.sjdiscounttools.com/ste6600.html


btw> you might get a call from some portuguese lady in hawaii screaming at you about getting her husband to spend even more money on tools

08-23-2004, 08:50 PM
Junior never ever feel bad about buying tools. Just grin and bear the wifes beating :lol: .

I'll tell y'a once you use it, it will become a favorite tool. :wub:


08-24-2004, 05:42 AM
Once again, thanks to everyone! I have tons of ideas when I get it back to the shop. I will keep everybody updated and let you know what we find.

08-25-2004, 02:06 AM
Note to Wreckerman; you were right on about the ramps on some cams. I took it by another shop today for a second (non-invasive ) opinion and the first thing this guy tells me is that S&S (which is actually what I have) cams have this ramp problem that cause them to be noisier especially when using as high of a lift as mine (.600). He suggested I try an Andrews in the .520 neighborhood. I think I'm going to try that first after I have him check all the other suggestions you guys have given first. I will definitely keep ya'll informed, thanks again.

08-26-2004, 12:28 AM
well it is good to here that you might have it figured out ...keep us posted as to the outcome

08-26-2004, 12:54 AM
Wreckerman goes to the head of the class

08-26-2004, 03:15 AM
The front cyl exhaust pushrod maybe touching the it's tube and making this noise. (the rod and tube angles are not exactly inline to one another)
Suggestion: using a wooden handle (of some sort) apply pressure to the Front Exhaust pushrod tube. experiment with angle of approach.