I put a TAV-2 30 on my Doodlebug. I run a HF 200 on it and at modest RPMs I get a slap from my drive belt bumping the cover. At more RPMs it runs good but, under some conditions it slaps. Sounds like a motor boat. Rub marks on the inside of the belt cover are at the mid point between the pullies-on both top and bottom sides. The belt is on correctly and the belt fit is tight-so tight it is a bit hard ( not too hard) to install it. Any help as to how to solve this?
Tav-belt slap
- Thread starter Dudlydoodleright
- Start date
- Tags slap tav-belt
My first thought was that the compression setting for the driven is set too stiff. It may be forcing the belt beyond the OD of the pulley intermittently causing the slap-slap sound you are experiencing. Anytime the RPM falls below the driver engagement point, it will cause slack at the driven pulley sheaves, basically flopping around on the top of the pulley sheaves especially if the belt is longer than required.
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I don't understand this.
How can it slap?
On decel the secondary drives the primary until you are nearly at a walking pace and the primary has fully opened and there is no contact on the belt
When in motion under power there is not slack, when dynamic breaking there is no slack.
All I can think of is the secondary does function properly.
Here is a link to an old thread that might have some useful information, its all I have to offer.
http://www.oldminibikes.com/forum/mini-bike-discussion/63090-tav-mixing-springs.html
How can it slap?
On decel the secondary drives the primary until you are nearly at a walking pace and the primary has fully opened and there is no contact on the belt
When in motion under power there is not slack, when dynamic breaking there is no slack.
All I can think of is the secondary does function properly.
Here is a link to an old thread that might have some useful information, its all I have to offer.
http://www.oldminibikes.com/forum/mini-bike-discussion/63090-tav-mixing-springs.html
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^OK, well OP witnessed rubber markings on the guard. OP did not report witness marks on the driven pulley sheaves. Wouldn't this be indicative of dynamic-braking on a defective driven? I can agree that the driven may not be working properly.
If it weren't for the fact he saw marks on the guard, I wouldn't be saying what I am. However, "Motor-boat" noise can occur on decel on a driven that is not sliding back/forth properly. The other thought is that it is not slapping at all. Perhaps the guard is not positioned properly to begin with along with a defective driven. Still need to know belt#, C-to-C, etc..
The link you provide is for spring matching to high(er) RPM engagement of driven. This issue, IMO, deals with mid RPM engagement and possible a spring preload selection that is too tight. OP said that this noise diminishes with spring position on the driven. I can attest to this but only as it relates to the decel noise.
If it weren't for the fact he saw marks on the guard, I wouldn't be saying what I am. However, "Motor-boat" noise can occur on decel on a driven that is not sliding back/forth properly. The other thought is that it is not slapping at all. Perhaps the guard is not positioned properly to begin with along with a defective driven. Still need to know belt#, C-to-C, etc..
The link you provide is for spring matching to high(er) RPM engagement of driven. This issue, IMO, deals with mid RPM engagement and possible a spring preload selection that is too tight. OP said that this noise diminishes with spring position on the driven. I can attest to this but only as it relates to the decel noise.
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How about some pictures of the TAV.
In case you were not aware you have to clean and lubricate the primary of the tav with something like this product
Loctite Moly Dry Film Lubricant - Henkel.
I also use it on the bushing in my secondary.
Could be as simply as a sticky clutch
There are also buttons on the secondary that might be worn out or broken that could case things to hang up or shift improperly. ( the cam slides on these )
Have a look at those too!
In case you were not aware you have to clean and lubricate the primary of the tav with something like this product
Loctite Moly Dry Film Lubricant - Henkel.
I also use it on the bushing in my secondary.
Could be as simply as a sticky clutch
There are also buttons on the secondary that might be worn out or broken that could case things to hang up or shift improperly. ( the cam slides on these )
Have a look at those too!
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Problem solved! The belt slap (yes belt slap) was tracked down to an improperly seated drive shaft end bolt. The forward sheave would pulse in and out. The bolt torqued and the lock washer compressed but it was still more than a 360 turn to fully seated! Now I have lost the ID marks on the outside of the belt-so my belt number is ???????!
I lubed all the ware surfaces with anti-fling dirt bike chain lube. Sprayed on and wiped off the excess before the solvent drys---The bronze bushing I put motor oil on the ID and dry on the OD----Correct me if I'm wrong on the lube job.
I lubed all the ware surfaces with anti-fling dirt bike chain lube. Sprayed on and wiped off the excess before the solvent drys---The bronze bushing I put motor oil on the ID and dry on the OD----Correct me if I'm wrong on the lube job.
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OK, now I'm not understanding. You said it was slapping the cover. How can the belt go so slack just due to the outer pulley sheave travelling a bit? Belt alignment stays the same (assuming your driven nut torque wasn't out to lunch as well) and belt travel on the driven isn't going to move up on the pulleys. Below 2200rpm, that belt should be loose as it's gonna get on the crank shaft/bushing. I still wonder what length belt you are using.
Your lube description sounds about as far from mfg. standard practice as it gets. Wear surfaces?? Such as? Absolutely no wet-type lubrication should be carried-out. The only lubrication should be Comet dry lube and only on the outer cover to centrifugal assembly interface. Nothing but a cleanup job on the belt contact surfaces.
Your lube description sounds about as far from mfg. standard practice as it gets. Wear surfaces?? Such as? Absolutely no wet-type lubrication should be carried-out. The only lubrication should be Comet dry lube and only on the outer cover to centrifugal assembly interface. Nothing but a cleanup job on the belt contact surfaces.
Clone clutch probably shipped without directions so your lack of understanding is forgivable.
Driver must not float.
Use moly dry lube.
This link will take you to a great resource for your TAV system.
Just follow the rules for best results.
I would add that I do things differently myself.
I use a drop of oil now and then on the bushing, but I make a point to never wet it.
Too that end I also have used moly grease more often than oil.
I do not use the OEM bushing I have a modified TAV system and use a longer one than comet or the Chinese make.
The trick is never let the bike idle and wear out that bushing.
Drive it or turn it off.
The secondary has a bushing too.
I put some dry moly on that when it gets stripped and cleaned.
read and good luck
Comet 30 Series Torque Converters | Comet Parts - Clutches
Driver must not float.
Use moly dry lube.
This link will take you to a great resource for your TAV system.
Just follow the rules for best results.
I would add that I do things differently myself.
I use a drop of oil now and then on the bushing, but I make a point to never wet it.
Too that end I also have used moly grease more often than oil.
I do not use the OEM bushing I have a modified TAV system and use a longer one than comet or the Chinese make.
The trick is never let the bike idle and wear out that bushing.
Drive it or turn it off.
The secondary has a bushing too.
I put some dry moly on that when it gets stripped and cleaned.
read and good luck
Comet 30 Series Torque Converters | Comet Parts - Clutches