serious rattle in top gear

[whitewing]

hey guys first post seeking to steal a little of your wisdom.

on the way back home from picking up the bike last week i noticed on the motoway that if i rolled off the throttle from around 60 there seemed to be a lot of engine braking and not a gradual slow down.

as i released the throttle theree was a pause of around a second then a loud whiring noise as engine started to brake and slow down more.

i also noticed today that if i slow down to around 40 or less in top gear it sounds like a big chunk of metal is rattling round inside my engine between my knees or legs.

i am not sure if this is all connected or could be caused be a few problems at once.

first thought of my own was driveshaft of final drive but thought i would run it past you guys first.

cheers in advance and sorry if i went on a bit

 

[mcgovern61]

A very common problem is the bolt that is in the stator comes loose. It is located on the left side on the back of the engine just in front of the battery. There is a cover on it and bolt inside. (In this pic, it is located just to the left of the stator wire coming out.)

 

[Steve83]

A while ago, I read somewhere - I think it was in the "Goldwing-The First 20 Years" book (in the Gallery) - that the Honda engineers needed to come up with a way to prevent excessive engine braking. For the life of me, I can't remember what it was...carbs...ignition...maybe just a heavier flywheel...I'll dig agound and see what I can find.

+1 on checking the stator bolt! Several members here have found them to be loose.

 

[brianinpa]

Do you hear anything at idle or slow speeds? I have an 80 parts motor that suffered what Gerry described and the stator isn't pretty. You might want to take a close look at that bolt that holds the rotor on the shaft. Any other problems?

 

[mcgovern61]

BTW, my engine does have a lot of braking. Let off the throttle and you swear I had a jake brake with how fast the bike can back down.

 

[whitewing]

checked nut and its tight. to be honest it sounds way more serious than a loose bolt. when i am going real slow in top gear when i release the throttle it sounds like something the size of a small boulder is loose inside my motor or trans

 

[Ansimp]

Could it be starter chain/drive clutch?

 

[joedrum]

hmm so when just running when parked it makes no noise .. when reving it through rpm ?

 

[brianinpa]

whitewing » Thu Apr 24, 2014 6:01 pm[/url]":1rir83m9]
checked nut and its tight. to be honest it sounds way more serious than a loose bolt. when i am going real slow in top gear when i release the throttle it sounds like something the size of a small boulder is loose inside my motor or trans

Is it only when you are in high gear at low revs? Tony may be onto something with the chain, but if you are at low revs, when was the last time the carbs were synched?

Also, that loose bolt (10) that was mentioned wasn't the concern but rather the rotor (7) that that bolt hold onto the shaft.

 

[Steve83]

Try puting the bike on the centerstand and running it in high gear. Listen all around the engine to pinpoint the sound - use a stethoscope, or a piece of hose or long screwdriver to your ear, it might help. Lightly apply the rear brake to put a load on it. Rev it a bit and release it while listening.

Just a few thoughts:

I'm kinda suspecting a worn primary chain, and possibly a bad tensioner. The tensioner is 2 pieces - one is spring-loaded and takes up the slack when running under a load. The other is fixed, and on the normally tensioned side of the chain. They both have a hard rubber surface and are covered with oil. When decelerating, the opposite side of the chain will go slack, and if the tensioner is worn, it will make some nasty noise.

How many miles on the bike? 1200's have a stronger spring in the moving tensioner, and I think the chain is also larger...

You can also disconnect a spark plug cable, causing a misfire. This usually brings out the worst in a bad primary chain. I hope this is not your problem, as the engine cases need to be split to access it! :beg:

If a transmission gear has a chip on the backside of a tooth, it could make a noise during deceleration. A bad bearing or bushing on a transmission, alternator, or output shaft could be the culprit. Too many possibilities...

If you can make a video of it as it makes the noise, it might help...

 

[Tom_Charlton]

I believe 40 mph in high gear (OD) is too slow for the engine & gearing. The 1200 is much happier if you keep the RPMs above 2500.