As many of you probably know this is my first big twin. I know the sportster has a primary chain as well, but no compensator. The noise I am talking about is if you let off the gas and then get back on it, there is a loud clank. Dealer said its normal because of the way the gears are cut.

I have not ever noticed it on any of the new bikes I test rode. It feels like pure slack being taken up in primary chain. The level of clank is pretty substantial in my opinion. I have dealt with bikes and auto manual transmissions for many years so I pretty much know normal or abnormal. This bike has done this since I got it in April.

My service manual finally arrived but its at home. Does the whole primary cover have to come off the check tension? If this is just an adjustment I want to do it before it breaks something.

 

Check drive belt tension first. If that's OK then go after the chain. Not sure what year bike you have? That would tell if you have to pull the entite outer cover all together or the chain adjuster access cover?

 

Yes the outer primary case has to come off. you'll have to take the derby cover off to add primary fluid. Refer to your manual.

 

You can just remove the clutch cover, use a flashlight and a long screwdriver to check for chain over tightness.

Here's a little video I took:

 

my 2012 does the same thing, It is the transmission gears most likely, Put some redline heavy shock prof in the tranny and it will help a lot.

 

+1 on redline I put that **** on everything... put seriously its good stuff. Spectro is another awesome one tooooo.

 

IMHO...

If I remember correctly... Harley uses straight cut gears for 1st thru 4th, and helical cut gears for 5th & 6th... in your transmission... some trans only have the top gear as helical cut gears..

The reason is the straight cut gears are cheaper to make, but noisier... meaning they can clunk going into/out of gear but mostly they whine at rpm...

The helical cut gears are more expensive to make, are stronger (some argue they just transfer added pressure to the gear case), but they are quieter...

HD uses the more expensive, quieter gears in the two gear ratios, 5th & 6th, they believe most riders will cruise in... to reduce whine and service calls/complaints...

I do not believe the cut of the gears causes the clunking you hear...

It could be a loose primary chain... so checking it only costs a quart of primary oil and some time. You can almost always reuse the primary cover gasket unless it is damaged when removing the cover...

Most likely, again IMHO, it is the spring pack in the compensator...

The compensator, in most basic terms, is a spring loaded ramp between the output shaft of the engine, and gear that drives the primary chain... it is suppose to create a "cushion" between those two... smoothing out the pulses from a big V-twin engine...

The primary chain gear has spokes that slide up the ramps, attached to the engine shaft, to engage power and down the ramps when power is reduced... If you lug, or on/off the throttle a bunch, the clank you hear is the spokes slamming against the ends of the ramps...

The Rushmore bikes, '14-'16, have the better of the late twin cam compensators.. they are much better than their predecessors which have have numerous problems and redesigns from 2006 through 2014...

The Rushmore bikes, however, have had issues with the springs in the clutch pack of the compensator going weak/soft, which will lead to more pronounced and less dampened movement of the gear spokes along the ramps...

There is a process (see below) where you can measure the preload in the spring pack, and shim it to cut down the clunking noise if out of spec....

Some opt to just dump the HD compensator altogether, to remove this issue from getting worse after shimming, or recurring if the whole comp is replaced with another HD comp...

If you dump the HD compensator, there are few good choices... Many like the Baker compensator, but it is expensive and had it's issues... DarkHorse Crankworks has just came out with a compensator they have been testing for several years... If I didn't have a solid engine gear (I have an S&S lower crank, cases, and left side bearing) I would be using the DarkHorse Man-O-War Motorsprocket for sure...

Good luck with the repair...


In this pic.... you can see the compensator on the engine shaft... if you look close, you can see the spokes on the primary gear and the ramps they ride on..




This is how to measure the compensator spring pack preload for shims..

 

Its not the drive belt, 1, tension is good, 2, the clank is plenty loud, and is definitely from the primary side.

 

Some great information here. For touring models, all gears minus 1st are helical cut since 2010. 1st and 5th were straight (with 2,3,4,6 helical) in 07-09. All gears were straight cut in the 5 speed.

As already mentioned, if you find a lot of slop in the drive train, check the chain tension, the chain tensioner, and comp. 2007-2014 auto chain tensioners were notorious for ratcheting up too tight (which is the opposite of slop) - still check it just the same.

While in there, also spin the clutch hub and output shaft around to check the clutch hub bearing and the trans output shaft/bearing.

Take in mind, there will be slop between gears when rotating the shaft forwards and backwards. It's normal stack up. Lots of moving pieces, gears, bearings, dogs rings, etc. with large tolerances so they mate together spinning at speed...

 

Hattitude,
Thanks, thats exactly the feedback I wanted to hear. I doubt I will get to the point of pulling the comp since its under ESP, but I won't rule it out completely at this point.
At least when I went by the sporty manual, it never listed tools or size tools, what special tools will I need? Pretty sure there is some sort of tool to hold the sprockets from turning, so anything else?