feelin' and sounds

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alan hodge

alan hodge

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ok enuff crowing about my 72/73 project's looks....this afternoon I rode it to shop that did the paint so they could take pic for facebook page...….this was about 30 mile round trip at about 55 mph...bike ran great..however...at speed I noticed whirring noise from primary side..as far as handling..road was in not so great condition and bike seemed like riding race horse kinda twitchy but as I relaxed and gave it its head was ok...I have a total of 100 miles of commando seat time...is sound from primary side 'normal' or should it be perfectly quiet? at idle no sound comes from primary side at all..chain is at 5/8-'3/4 tension.. my 72 Triumph T120 is not twitchy at all ..my 68 BSA A65 twitchy.....the commando has avon roadrider tires......thoughts?
 
Alan did you check primary chain after ride or before .... I don’t usually hear anything from chain case ...
 
Got oil in it? Just asking. I don't have quite that much play in mine, but have no noise that I discern, but there's so much other racket it probably doesn't stand out.
Strange thing about chain drives is that from my years with them is that some are quiet as a mouse and others make the whirring you describe. I tend to write this off to the rollers clicking in the sprocket. I could be wrong and it wouldn't be the first time, but I just can't seem to look fast enough as they go by to pick it out.
 
got a few ounces of ATF...the sound is not very loud but i have become focused on it and worry primary side might grenade at speed...as i said i am just learning the sounds, feels of this bike since i have only seen one other living breathing commando in my life(belongs to a friend who has since parked it) and rode it a whopping 1/8 mile around the block ...on the other hand the engine on my bike is very quiet and smooth...it's just when i glance down at primary side and tune in/focus on it that i hear the sound....ps i am worry wart/type A personality squared.
 
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Alan , think you running primary chain a bit loose .... book say 3/8” total up and down movement , that what I strive for even though counter intuitive as it do seem a tad tight ... never my fave job as always end up fooling with drive chain too .... wait till it cold and check your primary chain free play again then slack off drive chain and make your primary adjustment .... once you re-do drive chain make sure to confirm primary still good .... hope this helps
 
Could be a bit too tight drive chain since the sound is only present while scooting along. The drive chain could also be just barely rubbing on the inner primary cover especially if it's a brand spanking new chain.
 
Alan you got lots to look at now .... when you say a couple ounces in primary , you really mean the 200cc/mils right .... I did have an episode several ( 10 ) years ago now , the re-use of the dog bone shaped washers in front primary got the blame .... my rotor and stator cooked when I was 'bout 5 kms from home .... bike didn't quit so I headed to my shed , boy did that mess stink should have left it outside .... ended up replacing inner primary , stator and rotor all because I didn't wait for the new washers to get here in the mail .... you must have a manual ,right ?
 
Sometimes you need two adjusters, one each side of the top bolt of the gearbox. If the box moves backwards, the primary chain can become too tight. If it was loose, it would probably rattle. If there is no oil in the gearbox, that is scary.
If you are not used to riding the bike, it can feel skitterish because you might tend to hold onto the handle bars too tightly. Also certain tyre sizes and road surfaces can make the bike feel like that.
 
I run the 20-50 in the primary.....never considered using atf. When did the use of trans oil become popular in primary cases because to me it seems rather light for a roller chain drive? As said before I've been out of touch on Commando activities for some years and have queries of my own.
 
Been around here since late '05 ATF type F has been recommended since before I was on here .... it what was in my primary when I got bike prolly been in it since early `80`s
 
put everything together as carefully as possible...chain and clutch and engine sprocket i got 'gently used' from guy who went to belt...but...primary chain adjustment nearly used up to get tight...hmmm...mebbe need new one.....as far handling i compare to horseys...the A65 is like pony....the T120 like frisky stallion...the norton like Arabian race horse very fast and with more sensitive handling than the other two...at least that's my impression so far..
 
Things I would check are making sure the sprocket and clutch basket are running parallel by placing a straight edge along the outer gear teeth between the two. Shims are available to correct the rear basket. Check that you put the 1/8" thick spacer to the top bolt of the gearbox and that it is in the correct location (inside of the engine/gearbox cradle).
Cheers,
Thomas
 
If it was my bike I'd suspect a too tight or misaligned chain. Either primary or drive since the only time that you hear it is under load
 
will recheck everything but tried to get it right the first time....maybe i am overthinking this.. a habit of mine.. plenty of time to ponder/check as more 'lovely weather' on the way.....yesterday was sunny 55F so i played a bit of hooky from work and rode to body shop
 
Hmmm. I'll stick with my old manual on the oil anyway. If all checks out and you have no issues materialize as to cause of the noise I'd just don some good earplugs to prevent stress.
On the handling subject after years off of mine I found her to be a rather lively filly with a mind of her own...give it a quick kick, lean, & hang on because it's going, and doing so real fast. Sitting high I believe kind of amplifies the sensation of a twitch sending them into a quick responsive turn, but I also am of the opinion this is nimbleness is what originally made them such great machines....Still great machines.
 
I have read all the wisdom on steering dampers on here , but a few years ago I got one and put it on as a trial , the more I rode the more I liked it , so it still installed .... no negative affects just sort of gave me more confidence in the old girl at speed .... ... Alan I always use ear plugs and really mostly what I hear is exhaust .... it could very well be a chain rub as mentioned above , sometimes it is the simple stuff , eh?
 
area of noise located.....I went to the garage and turned off the radio and heater so it was perfectly quiet...got down on my knees and gently turned rear wheel...…..heard scratching sound from primary/clutch area...took clutch adjustment plug out and put ear to hole while I turned wheel..hear light scratching scratching scraping noise for sure.....turned wheel back and forth...sound only happens in one tiny part of the wheel revolving...primary coming off this week to see exactly what it is but sounds like chain rubbing or clutch rubbing or something rubbing somewhar in thar/that region...….
 
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