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#1 |
Join Date: Nov 2020
Posts: 18
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Vader 125 loud metal pinging sound HELP!!!!!
I installed tbolt 141 bbk, now the bike is making a loud sound and broke valve rocker. I bought a new head hoping that would be an easy fix I timed it with t mark and notch on head. Should be perfect. I adjusted valve clearance 0.03 and 0.04. still making the noise don't know what to do at this point. Don't want to put old jug on just to find out it didn't fix anything. Anyone else know what it could be it's not timing and it's not valves. What could be the fix? Is the piston hitting valves? when I replaced head the piston looked fine.
Last edited by Kurticus; 02-26-2021 at 04:18 PM. Reason: Uploaded youtube video |
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#2 |
Join Date: Nov 2020
Posts: 18
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Picture of valves on old head
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#4 |
Join Date: Nov 2020
Posts: 18
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Yx140 cam. Has 2 bolts.
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#6 |
Join Date: Nov 2017
Location: Marseille, France -> Conakry, Guinea
Posts: 1,481
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Does it have a manual or automatic cam chain tensioner? Was the YX cam a stock or a racing cam? How much lift over stock? If the cam chain has good adjustment, I would see what swapping back to the stock cam does in terms of noise.
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#8 | |
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Join Date: Oct 2016
Location: Houma, La.
Posts: 11,656
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#9 |
Join Date: Jul 2018
Location: nw of atlanta
Posts: 169
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The shared picture shows contact spots on the INTAKE valve, not the exhaust valve. That also happens to be the rocker arm that was broken.....
If this is like some of the Honda designs, the rocker arms ride on shafts that can be put in upside down. Some have a clearance groove in the shaft that positions the shaft and keeps it from rotating. It can be installed upside down, which may affect how things fit. The groove is positioned so that the bolt passes through the groove. Installing a new head should preclude installing the rocker shafts... if the head came with rocker arms.(and they were pre-assembled.) As I think more, the Honda design was also used to adjust the valve clearance. Does this engine use that adjustment method? If rotating the rocker shafts adjusts the valves, you might try adjusting them 180 in the other direction. I would like to see the piston, but I think it would make a thud-like sound rather than the clink/clank you are getting. Most valve-piston contact occur with the edge of the valve whamming into the piston crown(top). If the piston had some unusual reliefs cut in, it could make some different contact. tom
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vertical and above ground - my daily goal |
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#10 |
Join Date: Dec 2018
Location: PNW
Posts: 983
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It would appear to be something to do with the valve, valve train, cam, or timing chain maybe the chain tensioner. I would take the cover off timing chain, spark plug out, and turn it over roll it slowly and inspect the whole chain to see if it is rubbing anywhere and confirm there is nothing abnormal about how it rolls. Stethoscope might get you to the exact area of the click then its a matter of deduction or close inspection, failing that, the head would have to come off.
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#11 |
Join Date: Nov 2020
Posts: 18
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Update on valve to piston contact
Update
The piston has the letters "IN" on the intake side. Correct orientation I took the whole kit apart and reinstalled it, retimed it too. Still makes the noise I think I going to try flipping the cam tomorrow. Maybe it is 180 degrees off not to sure yet |
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#12 |
Join Date: Aug 2009
Posts: 551
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Can you tell us which specific kit you used from TBolt?
Also, which head (and valve sizes) you used? I'm hoping your valve numbers above were a typo, and that you set them at .003" and .004" |
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#13 |
Join Date: Jul 2018
Location: nw of atlanta
Posts: 169
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Did you aee any marks on the piston? If you did, you may have valve-piston interference problems.
Did you check that at TDC, the piston did not go higher than the top of the cylinder? Cam can be installed 180 out, but I don't know how. Piston/crank TDC is TDC every time, while cam will be 180 from where it started... exhaust or firing, crank & piston don't care, they are in exactly the same spot for eache... which are 180 different in cam timing. I would take out the plug, and rotate the crank by hand, feeling for some sort of rough spot where the noise is generated. Could be wrong rockers/cam followers, with incorrect geometry, but you replaced the head. Were ALL head parts replaced, or some put into new head? Was installing the cam chain difficult or did it go on easy, and tension up nicely when the tensioner was installed? The crank shoud rotate nicely through 720(tow full turns) with plug out. Watch / feel the cam chain as you slowly rotate 2 turns, feeling for binding or difficult to move 'spots'. tom
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#14 |
Join Date: Nov 2020
Posts: 18
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Update the piston was correctly installed I never found the problem, but intake valve was hitting the piston I'm not sure how to resolve the issue. The timing was dead on and don't know if there is a tensioner on venom x20. I did replace everything with a new head. All parts but cam were pre installed. I'm buying a nother new head to hopefully fox the issue. I'm losing hope this bike may be sold as broken if I can't fix it by the 10th. I'm closing on a house and don't plan on moving the bike
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#15 |
Join Date: Oct 2020
Location: Flower Mound Texas
Posts: 904
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Maybe try a thicker head or base gasket?
Now I'm not going to suggest anything here but... if you knew the cam was installed correctly... the marks where the valve have hit the piston are there. So ...and I'm sure I'm gonna get some hateful responses for what I'm gonna suggest.. you have an outline of where to remove a little material from the piston top with a dremel or similar. Use allot of tape across the piston top so the shavings cant fall in. Steady hand and a couple minutes and the clearance issue is fixed.
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Tags |
141cc, big bore kit, boom vader, ticking |
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