Jack_Shaft
TY 4 Stroke Junkie
Just managed to re-assemble our RX-1 engine since we installed LC pistons and 2x Yamaha base gaskets.
We have some sort of a strange ticking sound coming from what is either the timing chain, PTO side valves (supplying piston #1) or the gear reduction at the crank. Using a mechanic's stethoscope, it seems to be coming from this general area and it sounds as though it's a valve tick.
The timing chain is plenty tight, the valve clearances are well within spec and the cam lobes are also well within spec (engine only has 40 miles on it!), so we have so far ruled that out.
Has anybody else encountered a tick coming from their PTO reduction gears? Is there any sort of alignment to do with these? There is no mention in the service manual about having to "time" these gears, even though there is a dot on the crank gear, but no corresponding dot elsewhere.
The only other thing I can see happening is maybe the timing chain is not perfectly routed, or one of the guides became somehow gouged and is hitting the chain, making the sound?
I just don't know, maybe we'll try and ride it out, but I am not very keen on running a brand new sled with a tick. If anybody else here has encountered something like this on a re-assembly, please post up.
-JS
We have some sort of a strange ticking sound coming from what is either the timing chain, PTO side valves (supplying piston #1) or the gear reduction at the crank. Using a mechanic's stethoscope, it seems to be coming from this general area and it sounds as though it's a valve tick.
The timing chain is plenty tight, the valve clearances are well within spec and the cam lobes are also well within spec (engine only has 40 miles on it!), so we have so far ruled that out.
Has anybody else encountered a tick coming from their PTO reduction gears? Is there any sort of alignment to do with these? There is no mention in the service manual about having to "time" these gears, even though there is a dot on the crank gear, but no corresponding dot elsewhere.
The only other thing I can see happening is maybe the timing chain is not perfectly routed, or one of the guides became somehow gouged and is hitting the chain, making the sound?
I just don't know, maybe we'll try and ride it out, but I am not very keen on running a brand new sled with a tick. If anybody else here has encountered something like this on a re-assembly, please post up.
-JS
Check the guides for the timing chain. There's a little locator slot for them down nead the base of the head.
Jack_Shaft
TY 4 Stroke Junkie
lakercr said:
Thanks for the note, just go tto speaking with the other mech, he said the one guide was bolted in place on the bottom, the other was between the two cast stand-offs on the bottom end, exactly where it should be.
Keep the responses coming, they're all appreciated.
-JS
ken_climb
TY 4 Stroke Junkie
What year of sled?...if its an 03 they the gear reduction is very noisy! and thats probably all it is. 
BigDog05
VIP Member
My 05 is very noisey if idle is under 1500. Sled has less than 100 miles.
I've been considering going to the dealers and listening to another one to compare. Starts to get noisey as soon as off fast idle.
I've been considering going to the dealers and listening to another one to compare. Starts to get noisey as soon as off fast idle.
Jack_Shaft
TY 4 Stroke Junkie
Mine is an 05 Warrior. The gear reduction was NOT this loud before we tore it down. I suppose it could be some additional piston slap from the re-sleeved block we have here with the LC Wiseco pistons.
Maybe after the rebuild, the backlash between the two gears is slightly greater. I hope that's all it is, we're going to try it this afternoon regardless.
-JS
Maybe after the rebuild, the backlash between the two gears is slightly greater. I hope that's all it is, we're going to try it this afternoon regardless.
-JS
Jack_Shaft
TY 4 Stroke Junkie
Went for a quick ride, it got louder and louder and louder.... sounds like a main or lower conrod brg. Looks like we have to do a full disassembly/reassembly again. Hope nothing else is cooked, that's all.
-JS (taking a break until tomorrow!)
-JS (taking a break until tomorrow!)
Buckeye
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I think we all feel your frustration.
Freak
TY 4 Stroke Junkie
Scary.... I did rods and pistons on my 03 and it got louder I thought. I even had my mechanic come back over to listen to it. Between him and the peeps on this forum 
I determined it was normal, irritating for a Yamaha to sound like a 73 Fiat, but nonetheless normal. So far 300 miles and its still there and still holding together.
I determined it was normal, irritating for a Yamaha to sound like a 73 Fiat, but nonetheless normal. So far 300 miles and its still there and still holding together.
treewhacker
Expert
That is the exact reason I bolted a turb on mine and didn't tear the engine down. I just don't want these problems.
Thrusted Vector
Expert
Bigdog did you ever check the valve clear or do a leak down test?
BigDog05
VIP Member
Attempting to make an adapter for my leak down tester. But I did turn the fuel screw out to 2.5 turns. Helped a lot on the stand, but still no snow to test.
Thrusted Vector
Expert
I took an old spark plug,broke the center out of it then welded a fitting on it for a hose adapter.
Jack_Shaft
TY 4 Stroke Junkie
Hopefully we'll be able to start the tear down tomorrow, we need to know the color of the lower conrod brgs and the main brgs in order to get some replacements sent in.
I hope it's only the brgs and nothing else is damaged !!!
-JS
I hope it's only the brgs and nothing else is damaged !!!
-JS
Jack_Shaft
TY 4 Stroke Junkie
treewhacker said:
Well, the boss already did the job on the original engine and we had to really go into the engine at that point, so we opted to install the LC pistons at the same time, just to be extra-safe.
In hindsight I think we were stupid to try and re-use the brgs after the lean burndown on one side, but everything looked so perfect - the engine didn't even seize when it failed - that we assumed it was alright.
Lesson learned: If you take it apart, NEVER put it back together with the same brgs, no matter HOW nice they look. Stupid, stupid, stupid!
