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Knocking after upgrades

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A while back (I haven't ridden in a while :smirk: ), I installed an FCR, Corked MRD-SSW, E-Cams, and an MCCT. I used the reccomended jetting for the FCR, below, and was really careful to install the cams in the same poition that the old ones came out. The valves are all within spec (although one of the intake valves is alost tigth enough to bother adjusting.

I made a post a while back about the cams I used, although I can't find it in my posting history.... they didn't have the typical lettring on the end of them, but Eddie said he thought that they were correct. When I get home later, I can check my photos of them to get the letteing again.

Anyway, the bike starts pretty easily now with half choke, although I haven't gotten it to idle w/o choke. Under any throttle, particularly at lower rpms, it knocks/detonates. At least, I assume that's what's happening.

I'm wondering if I need to change the jetting or if I somehow got the wrong cams and they upped the cmpression more than they should have.

Does anyone have ideas on what I should check to debug? i used to be more of a mtor-head, but I've spent so much time at work on the computer for the last five years, I feel pretty clueless w/ this stuff.

500 ft elevation in Northern CA -155 main jet, 200 main air jet, EMN needle, clip 3, 45 pilot jet remove pilot air jet, o-ring mod... eems like I started at 2 turns on the fuel srew, but have might have gone an extra turn at some point.

Edited by a8ksh4

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Cams look perfect assumning the TDC mark is lined up. Yes I remember a post about "C" cams. Answer was same as A & B cams which are "E" model cams. You might have a mechanical knock but not detonation at idle. No it is not jetting. Could be if under load but I think you are just talking about running the motor in the garage. Please provide more detail. What was done recently, how much it has been run, under what conditions do you hear the knock? Hi speed, lo speed, idle, under load, in the garage, on the road??? Who else can hear the knock?

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Low rpm knocking sound..

I remember something about Counter balancer / loose nut.

No expert on that tough.

Can't be compression/detonation.

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Okay, here's a photo. Note the "A" and the "C" on the ends.

2012-02-12_15-18-34_607.jpg

And the timing mark on the flywheel looks like this?

post-18851-13264038639056_thumb.jpg

Set the motor to Top Dead Center (TDC) on the compression stroke. The timing index mark on the flywheel will be in the center of the sight window (Note your looking to align the index line NOT the T next to it center of the sight window)

You did not install a piston right?

If the knocking is consistent with rise and fall of RPM

It makes me lean to, cams out of time, Piston backwards, counter ballancer nut loose/ out of time, primary nut loose.

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I'm dragging this one back from the dead... :) Haven't been riding for a while, but got the itch to at least get this thing running right. My roommate bought a bike from my other roommate and has been bugging me to get it going. I put the old cams back in just to confirm that wasn't the prob. No difference there. Timing looks good.

I figure it's just really lean and am trying to sort the jetting starting w/ the idle circuit since it's the obvious problem right now. I had the 45 pilot jet in to start w/ and it was acting lean - idling rough, rpms won't fall after throttle blip, bike gets hot quickly when not moving. I put in a 48 and it started getting better when I turned the mixture screw way out. I went and got a 50 pilot jet and at 4 turns out, it's pretty happy. I was a little worried because the size 50 pilot had a different finish/look... I wonder if this one is an aftermarket and if it's sized the same as the factory one. Anyway, I'm picking up a pilot one size larger to try tomorrow and see if I can get the idle where I want it.

I need to evaluate how the bike's doing under the rest of the throttle range after that... it sounds like the next constraint I need to tackle is WOT to get the right main jet size (not sure if that'll require changes to idle circut), and then adjust needle clip for low to mid range. I'm plowing through forum posts to figure out how this stuff works... :D

@noble - Changes, were mrd pipe, fcr-mx 39 tt kit, cams, and cam chain tensioner. My process for testing this thing is fire it up and ride around the block until warm, and then mess w/ idle circuit back at the house. I'm hearing the mysterious sound while I'm riding, with choke off, not under acceleration, at varied speed with throttle from about 1/16th to 1/8th open... I don't hear it above that.

@Jhondius - I'll check the counterbalancer nut, just to be safe. That's been on my list of to-dos. :)

Edited by a8ksh4

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I seems like your bike sits for long periods of time... could it be as simple as bad gas???

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