Author |
Message |
Sgthigg
| Posted on Thursday, March 06, 2008 - 09:21 am: |
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I know these motors are very noisy. But what would cause a knocking sound to start after the bike is ran till hot, shut down and then restarted? I find this happening all the time on my xb12. It runs strong but I am wondering. I run a drummer loud and can here knocking at idle over the exhaust at about 5 feet away. When I rev the rpms a little the knocking picks up too. However at 15 mph plus I dont hear anything, well atleast not over the exhaust. Any suggestions? |
Jaydub
| Posted on Thursday, March 06, 2008 - 09:24 am: |
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check and see if the primary chain is too loose - mine made a knocking noise, and it was the chain rapping against the case... if not that there is a compensator nut? not sure where but the guy who did my primary said if it wasn't the primary could be that.... |
Deadduck
| Posted on Thursday, March 06, 2008 - 11:00 pm: |
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you may have to take the primary cover off and re-torque (220ft./lbs) the nut on the front primary sprocket. if its a knock that sounds like the bottom end of the motor is about to crap out, that is probably going to be it. mine did this about 2 months ago and left me stranded atop blood mountain. man that was a long day............ good luck Deadduck |
Jos51700
| Posted on Thursday, March 06, 2008 - 11:14 pm: |
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A loose primary crank nut will make you think your motor is about to die. Damage only results if you don't fix it promptly. Just coming loose doesn't hurt anything. (technically, it's not a compensator nut, that's on Big Twin engines) These are all good places to start that offer good inspection, without alot of cost or time. If knock continues from there, then it's probably serious. Or, ride it till it breaks! These are noisy motors sometimes.... |
Typeone
| Posted on Friday, March 07, 2008 - 09:53 am: |
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+1 loose crank nut. happened to me, sounded awful. retorqued to new spec and all was well.. . (Message edited by typeone on March 07, 2008) |
Deadduck
| Posted on Friday, March 07, 2008 - 11:34 am: |
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thanks for posting the service bulletin with the new values. 240-260 ft.lbs to correct my post above. I love the "generously apply red locktight" in fact just poor the entire bottle on it. What is this part like on other H-D motors? is the sprocket splined or on a key way or anything. Surely they didn't do all the motors like this. |
G234146
| Posted on Friday, March 07, 2008 - 01:11 pm: |
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+1 on the nut. You must tighten your nut!
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Pwnzor
| Posted on Friday, March 07, 2008 - 03:58 pm: |
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What I don't understand is, HOW COME IT DOESN'T HAVE LEFT-HAND THREADS so it CAN'T come loose...?
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Pwnzor
| Posted on Friday, March 07, 2008 - 04:05 pm: |
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side note: I've finally acquired the four bolts needed to mount my new stator, and am about to button up my bike once again. I'll be applying the newly spec'd torque value of course, but I'd been riding on the original for over 40k miles with no problem. Taking it off was no easy task, I can assure you it was not in danger of coming loose. I realize others have not been so fortunate. I've always sort of enjoyed the fact that my engine sounds like a blender full of nickels. |
Sgthigg
| Posted on Friday, March 07, 2008 - 08:05 pm: |
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Thanks Gents, I brought this to the attention of pensacola HD/Buell about 2 years ago(13000 miles ago) when I first heard of the Bulletin and it was in for other warranty work. I brought them a copy and they said they had no idea about it and they could not find it in their "system". However the said the will go ahead and do it. They charged it under warranty. Anyway, I have always had this sound and I really kind of wonder if it was ever even done. Or maybe it has came loose again. I dont know. I guess to be 100% sure I will do it my self. I got the manual, know what size the socket is? And what do you use to clean the oil/fluid off the shaft with so the locktite sets up correctly? Thanks guys, |
Pwnzor
| Posted on Friday, March 07, 2008 - 09:29 pm: |
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That nut is 1.125" (1 1/8") and you can use brake parts cleaner or other solvent and a wire brush to clean out the threads. Make sure it is completely dry and clean and apply the loctite. (Message edited by pwnzor on March 07, 2008) |
Jos51700
| Posted on Friday, March 07, 2008 - 09:47 pm: |
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"What I don't understand is, HOW COME IT DOESN'T HAVE LEFT-HAND THREADS so it CAN'T come loose...? " Think about the way the nut is loaded, and that should answer your question. The crank is trying to twist (Counter clockwise as viewed in the earlier photo) and the rest is resisting that twist. Assume everything but the crank was stationary, and the crank was still twisting. Would the nut tighten, or loosen? How does this apply to the LH nut on the clutch hub? "What is this part like on other H-D motors? is the sprocket splined or on a key way or anything. Surely they didn't do all the motors like this." The BigTwin motors (only) use a nut with a sleeve on it, and a set of cone springs, and a set of two opposing ramps. THIS is the true compensator, and it's nut. The herky-jerky motion of the engine is smoothed out by the two ramps sliding against eachother and the ramps' "ramping" motion pushes the ramps against the tension of the spring pack. If the springs are completely compressed, the assembly still cannot slip over to the next set of ramps, and so forward motion is still guaranteed. The net result is smoother low-speed operation, and it does actually make the bike sound different. Some rubbies install solid front sprockets to make the bike cackle more on decel (The compensator alters the decelerating forces as well.) In the compensator system, the front sprocket is not mechanically fixed to anything. 2006 and later Dyna's, and 2007 and 96-inch BigTwins use a simpler, but similar setup. I'll try to find a picture/exploded view. |
Jos51700
| Posted on Friday, March 07, 2008 - 09:54 pm: |
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The splines lock the upper (outer) ramp. The lower ramp is a part of the floating front sprocket. Turn your monitor on it's left side to see how it looks on a bike.
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Jos51700
| Posted on Friday, March 07, 2008 - 09:59 pm: |
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The guts.
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Jos51700
| Posted on Friday, March 07, 2008 - 10:01 pm: |
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On XLs and Buells, the front sprocket is fixed to the flywheel/rotor, and the whole assembly is splined to the flywheel. The nut holds it all in place. Nothing slides around. |
Pwnzor
| Posted on Sunday, March 09, 2008 - 04:35 am: |
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Holy crap!!! thanks for all the info dude! |
Jos51700
| Posted on Sunday, March 09, 2008 - 10:37 am: |
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I aim to please |
Deadduck
| Posted on Sunday, March 09, 2008 - 10:51 am: |
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Thank you Jos.. very well explained with the 8x10 glossys and a paragraph on the back of each one ....... |
Spatten1
| Posted on Sunday, March 09, 2008 - 03:24 pm: |
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"What is this part like on other H-D motors? is the sprocket splined or on a key way or anything. Surely they didn't do all the motors like this." My second post of the day about Harley non-engineering. This is a pet peave of mine. 250 ft/lbs with red loctite is a band-aid for a stupid design. Now on the Buell drive gear nut, we have left hand threads and an over-kill gigantic locking plate. So, the guy who designed the right side of the Harley engine/tranny should have talked to the guy that designed the left side of the Harley engine/tranny. By the way, this level of engineering and forethought was probably fine when the sporster engine made 45 horsepower. Problem is, the engine is now making twice that, and some of the legacy 1950's design/engineering is still present. (Message edited by spatten1 on March 09, 2008) |
Jos51700
| Posted on Sunday, March 09, 2008 - 04:31 pm: |
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I kinda do and kinda don't agree with Spatten. Could it have really hurt to put a lock tab or something on there? But, would it have really held up? I've seen them strip all the splines out of the stator hub. But the locknut was still tight. They did change it on the '07 and later Harleys.....I'm sure there are more reasons for what they chose to do than what I know. I often wish I knew all those reasons.... |
Sgthigg
| Posted on Sunday, March 09, 2008 - 09:29 pm: |
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What size is that bad boy? I plan on doing this myself a precaution. I got Tq wrenches out the yin yang but I highly doubt this socket size is going to be in my tool set. Is the also metric equivalent? Thanks |
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