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Discussion Starter · #1 ·
Hi guys, I started my bike this am and noticed a very light noise near the front of the motor it's like a soft thuding noise, hard to explain. A slight raise in rpm and it's gone. I use Mobil one synthetic v twin oil should I be using something different. I'm worried a bit about piston slap. Any ideas
 

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Piston slap noise is similar to a rocker arm noise but deeper it is a mechanical sound. The engine needs to run for awhile to allow the pistons to heat soak & grow = the noise gradually goes away.
Do you have a breather filter on the LCV hose? If so the "thud" noise could be emanating from the filter.
 

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There is a Yamaha Tech Bulletin from 2005 on motor noises that are incidental to the big cube beast motors in the Star lines. I cannot find it here anymore but here is a link to RS Clinic for now. I will grab a pdf off my home computer and put it into Documentation.


Here's a pdf. My Yamaha document pdf is from a multi-generation fax back in 2005. It's nearly impossible to read. If anyone has that Technical Bulletin in legible pdf I'm interested!

So this attachment was retyped by the guys at RS Clinic way back.
 

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Discussion Starter · #7 ·
Thanks that puts my mind at ease with the noise I explained but in still concerned with my sprage bearing for the starter, had anyone changed one and if so how involved is it
 

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Discussion Starter · #9 ·
Thanks for the warning, it's a grinding noise on the right side front area of the motor, starts fine but the noise gets worse when the bike is hot or warmed up, I guess I'll wait till I start to have starter problems, I'll get into the manual and see if there's an another gear in the mix that could be causing it.
 

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Would it help to use a mechanic's stethoscope at warm idle to listen-in and locate a likely location by comparing to component locations? Just apply the tip to three different locations around where you suspect it's coming from and it can sometimes add clarity.
 

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Discussion Starter · #11 ·
Would it help to use a mechanic's stethoscope at warm idle to listen-in and locate a likely location by comparing to component locations? Just apply the tip to three different locations around where you suspect it's coming from and it can sometimes add clarity.
Hey buddy I know it's been a while since I posted this the noise is getting worse unfortunately, now of course I know you can't diagnose or fix this problem here, it's coming from the right side by the sprage hear and accompanying drive gears, it looks like the cover is removable can it be repaired without splitting the case? I have used Mobil one since I got it, maybe try something else? Or a heavier oil. Hope you are having an awesome summer brother
 

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As you know, the anti-reversing (Sprague) assembly, sometimes called a sprague clutch, is a specific unit of assembled-gears designed to only rotate one direction. In some motorcycles it can be removed and replaced in-the-frame no need to remove the motor.

On the Warrior, the arrangement is a little different. The assembly is separated and is referred-to as the Starter Clutch. There are 6 recommended parts imo (see 5-75 items 1,2,3,4,6,7). Full job see 5-73 - 5-78.

IMO it's a mistake to selectively replace bits, they really all get beat-up. Others disagree.

The PARTS manual page C9 shows the true nature of the beast. You need items 16,17,18,19,20,21,25. You might need the 6 bolts item 22, and might need fixing bolt/washer items 24,26.

Here's the thing. Most often when this fails the motor will not start. But its robust and seldom fails (to this point in history). When the motor is running and cold I use an inexpensive mechanic's stethoscope to locate the source of the noise. If you wait until the motor is no longer running then you are shooting in the dark.

The grinding noise could be inside the starter motor. Loose magnets or failed bearings or a bad gear. So check the starter gear too (item 11) for wear or damage clues. If you replace item 11 then get items 10,12 too.

This work is not terrible on the Warrior except you really want to by a really good generator rotor assembly holder to pull the bolts without roaring the crankshaft. Plus to hold the starter clutch from rotating while pulling those bolts.

I'm certain there are tips and tricks, but the service manual covers what looks to be all the nifty tools (based on my experience with my prior vstar1100 and othe old bikes, most of which have slightly different designs). Check page 5-76 for the holders. Sometimes I invent something from bits in the garage lol.

My worry is that you might buy all the anti-reversing parts and dig-in, only to discover the trouble is in the starter or at the primary gear behind the fixed timing wheel (other side of the generator shaft where the CPS lives). Or worse, the grinding could be crank bearings.

Mechanic's stethoscope might help you identify location of noise closely enough.

I'm certain others will chime-in too.
 

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Discussion Starter · #13 ·
Thanks I did just purchase a stethoscope so that my next move, so the starter could be the problem while the motor is running. I'll get into the manual
 

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If the starter's driven gear is hanging up against the idlers that engage the starter clutch then you'll hear it on the right side of the bike, that is the drive gear end, and it'll still sound-off while running. If it's a magnet ripped off then it will grind inside the starter while starting, and might jam up enough to cause the gear trouble. These gear issues can vibrate enough to jar the frakking magnets off. But if it's the starter clutch you'll hear it behind the far right side because it sits behind the generator. If it's the primary gear you'll hear it on the left side. Yep that stethoscope will clear-up conditions.
 

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Remove the starter, cover the hole with tape etc, push start the bike.
Key on, get it rolling in neutral, jump on, clutch in put it in 2nd, clutch out it should start.
Still have noise?
 

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+1 with Churchkey's creative troubleshooting suggestion (y) and you can bench test the starter after removal for noise and wear.

Based on your OP and recent posting I suspect the Warrior Starter Clutch components are failing.
If so you'll need to remove the Generator cover, as shown below, and possibly pull the Generator Rotor.
  • The Yamaha Factory Service Manual does an excellent job detailing the proper procedures and tools required to do the task at hand!
  • Take Note that the Starter Clutch Idle Gears 1 & 2 and their related parts will remain in the Engine Case and not as shown in the photo :)
 
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