Drive "slap"

[cantolina]

Here's an interesting thing....

I've noticed that when I let off the throttle and gas it again, there is a definate "slap", as if the primary chain is too loose or something...

Its not...its as tight as I dare....

Has anyone else noticed this?

What are the chances it might be carb related? (The passages that work when the butterfly is closed...

Its smooth when I just decel...but if I go all the way to off with the throttle...it hits...then again when I accel...

Any ideas?

[RoadKingMoe]

Check the nut on the front belt sprocket. I've had it back off a bit despite the retainer.

[cantolina]

Has no one else experienced this?

That's worrisome...in and of itself...

[hoosier xlc]

Chuck, My Sporty has done this since day one. I just replaced the stator and rotor about 2 months ago and it still does this no matter what I do to the primary chain. Would like to hear who else has this noise and what causes it.
Scott

[cantolina]

Well, as an update....

I DID tighten the primary up a bit, and it DOES whine just a little..(but I have VERY sensitive hearing)...the slap is noticably less....

I will keep an eye (and an ear) on it, and see what happens..

[RedRider]

Chuck, my bike does the same thing. The noise is not as bad when I adjust the primary chain, but it is still there.

I think if we rode BT's with their compensator sprocket, we wouldn't notice this.....

I don't believe it's any big deal, and surely not worth switching to a BT to get away from it.... ;):D

[stevo]

ya got a loose nut attatched to the throttle

[cantolina]

ya got a loose nut attatched to the throttle


Yuh....Like I didn't know THAT!

:)

[Bikerdude]

Hope you guys get this resolved. I had that problem on my 85 Ironhead..two new sprockets and a new chain were what was needed. Seems so smooth now where before that slap was bad...Good Luck All..

[cantolina]

Hope you guys get this resolved. I had that problem on my 85 Ironhead..two new sprockets and a new chain were what was needed. Seems so smooth now where before that slap was bad...Good Luck All..


It seems that tightening the primary took this away...

For just a moment, I was thinkin...

First time for this word on the forum, it seems...

JACKSHAFT.....

But, I don't think so....

[XLFREAK]

Mine does it also. I've been planning on checking the primary tension but haven't done it yet. Chuck, if you have ever ridden a Polaris snowmobile, and being from NY you must have been on a sled or two, you get the exact same whine when decelerating. Not so much the slap but the whine is very distinctive. The primary is basically the same inverted tooth/silent chain set up that sleds use. Polaris is the only one that has the whine out of all the sled manufacturers but it is known to be normal. Going to a Hyvo set up will decrease the whine but its still noticable. Maybe on the Sporty's a Hyvo set up would quiet it enough so it isn't so noticable.

[cantolina]

Mine does it also. I've been planning on checking the primary tension but haven't done it yet. Chuck, if you have ever ridden a Polaris snowmobile, and being from NY you must have been on a sled or two, you get the exact same whine when decelerating. Not so much the slap but the whine is very distinctive. The primary is basically the same inverted tooth/silent chain set up that sleds use. Polaris is the only one that has the whine out of all the sled manufacturers but it is known to be normal. Going to a Hyvo set up will decrease the whine but its still noticable. Maybe on the Sporty's a Hyvo set up would quiet it enough so it isn't so noticable.

Well, I DO think I hear more than most people do....that being said, it quiets down, even for me, when it gets warm....

I do understand the Polaris thing...always never sounded right to me... :)

We'll see...I think its me, lookin fer somethin to wrench....:p

[stevo]

You will have tolerance stack up ...... basicly that's a little here and a little and it all adds up..

Try and identify if it's drivetrain snatch or just throttle/carb hesitation....

Primary chain and drive chain/belt are the only area you can really play with...

It might be worth removing the sprocket cover and then remove the keeper plate off the sprocket and check the freeplay there...there should be none on the sprocket....

[Darhawk]

.............Primary chain and drive chain/belt are the only area you can really play with.......


Put some hair around it and he'll get it figured out pdq.......................

[stevo]

prefer no foliage myself.......

ya can see what ya gettin into

[Bikerdude]

yea..My Jackshaft agrees witchya stevo!! :D oh..and so does my Dentist!