Knock off TAV2 and RPMs

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davidlamb78

Member
#1
#1
Okay, so I got my swap kit from OldMiniBikes warehouse, and I'm gonna go pick up a predator from the local HF. It'll be a hemi model. I'm not gonna go wild with this one yet. I have a header, breather kit, and I'm gonna run a carb that I had on my clone that is on my race cart. mostly stock carb, but rejetted and all that jazz. I'm not gonna take the gov out of this one yet. Might go there when I have enough money for the billet bits.
I have a DB30 that has some Carlisle Snow Blower tires that are about 15" tall. I was looking at the knock off TAV2 kits on ebay, and they mentioned something about topping out at 3500 rpms with the kit. I know that my motor won't rev higher than that with the gov in, but what if I end up going bigger later? Will I not be able to wind a lot higher than that with a torque a verter on the motor? My kart motor spins around 8000 rpms, and I may end up doing something fun with this hemi later. I only wanted to run a TAV because I want to ride this on trails with mild hills.
 
D

davidlamb78

Member
#2
#2
Second question. I know, you get what you pay for. Most of the time I totally get it. But, I've also been around Harleys long enough to know that this isn't always true. I was wondering if the TAV2 knock off is really a good alternative. I know I won't spring for the real thing. I can't dump that much money into something like that. I'm only about $200 into this thing with the upgraded motor and tires. I'm only trying to come up with a fun way to cruise the neighborhood with my boys and hit the trails with a buddy and his kids. I won't be racing the bike or climbing any crazy hills. Just basic riding through the woods with a few hills along the way. The neighborhood is flat, flat, flat.

3 4" Go Kart Torque Converter CVT Clutch Replaces Comet TAV2 30 75 218353A TAV 2 | eBay
 
125ccCrazy

125ccCrazy

Well-Known Member
#3
#3
I'm not a 100% sure since I've only got Comet tavs but I believe the stiffer springs that Comet offers will fit so you can change the shifting and stall points...You can also play with gearing...
 
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Havasu Dave

Moderator
#4
#4
125ccCrazy said:
I'm not a 100% sure since I've only got Comet tavs but I believe the stiffer springs that Comet offers will fit so you can change the shifting and stall points...You can also play with gearing...
Click to expand...
If there's one thing in life I've learned, it's "you get what you pay for."

The thought of having to hike ten miles out of the desert because a drive component just shit parts all over the desert doesn't appeal to me.
 
125ccCrazy

125ccCrazy

Well-Known Member
#5
#5
Havasu Dave said:
If there's one thing in life I've learned, it's "you get what you pay for."

The thought of having to hike ten miles out of the desert because a drive component just shit parts all over the desert doesn't appeal to me.
Click to expand...
can't say I totally agree with "you get what you pay for"...I've bought stuff that was name brand and paid the bigger bucks for it and it wasn't any better or as good as the cheaper stuff...one of the things I've read that people had an issue with using the knock of tav units are the belts don't hold up so good under heavier useage.... I do agree about not wanting to hike a bike out of the woods or desert but that's where everything should be fully inspected and maintained before going on such a venture along with a back up plan like someone else with a tow rope in the event anything goes wrong...
 
H

Havasu Dave

Moderator
#6
#6
125ccCrazy said:
can't say I totally agree with "you get what you pay for"...I've bought stuff that was name brand and paid the bigger bucks for it and it wasn't any better or as good as the cheaper stuff...one of the things I've read that people had an issue with using the knock of tav units are the belts don't hold up so good under heavier useage.... I do agree about not wanting to hike a bike out of the woods or desert but that's where everything should be fully inspected and maintained before going on such a venture along with a back up plan like someone else with a tow rope in the event anything goes wrong...
Click to expand...
LOL, no body needs to agree with me on anything. It's just a personal axiom I live by. Granted "name brand" doesn't skew me. However Comet made clutches for a long time, though I guess they sold that company a few years ago.

Compared to a copy made somewhere else last month. I was thinking about my next project involving trips with no backup plan. No roads, no cell phone, like life used to be. Preparedness. I wouldn't sweat it, if I were riding around the neighborhood, or on a local track.

Plenty of comments here on the knock-offs doing okay. But you never hear how they did on a 40 mile ride up hills and over rocks.
 
H

Havasu Dave

Moderator
#8
#8
davidlamb78 said:
Will I not be able to wind a lot higher than that with a torque a verter on the motor? My kart motor spins around 8000 rpms, and I may end up doing something fun with this hemi later. I only wanted to run a TAV because I want to ride this on trails with mild hills.
Click to expand...
Sorry, I derailed this a bit. I did some searching around on this site and the RPM question with the TAV's hasn't been answered anywhere that I could find.

Most of the discussion ends up being about spring engagement on the clutch at higher RPM, and some of the setups used were obviously higher performance engines.

Having said that, I haven't seen any of the high RPM drag racers using TAVs and they're spinning up past 8K. The whole purpose of the TAV is to give you low RPM, low speed torque, and still have the higher gear ratio available.

Following that logic, once you get your engine spinning past 6 or 7K, you don't need a TAV, and are into direct drive, or jack shaft.

Personally, I wouldn't want a belt designed to slide up and down in a pulley ripping past my leg at 8000 RPM. :wink:
 
Newoldstock

Newoldstock

New Member
#10
#10
tundrabeagle3 said:
I had a real comet tav2 on my mini bike and ran in to the same issues . Heres
a link to the thread


http://www.oldminibikes.com/forum/general-minibike-talk/78736-comet-tav2-issues-2.html

Unfortunately I didn't have the time or patience to solve it.
Click to expand...
I just looked at that thread.
It would have some issues with the back plate put on that way

I use Chinese 30 series because they are cheap and I can buy them break them and throw them away.
My only real issues are machining is a little sloppy but I modify them for racing.
No advantage to Comet for me except as a source of repair parts.
 
LSCustoms

LSCustoms

Moderator
#11
#11
Newoldstock said:
I just looked at that thread.
It would have some issues with the back plate put on that way

I use Chinese 30 series because they are cheap and I can buy them break them and throw them away.
My only real issues are machining is a little sloppy but I modify them for racing.
No advantage to Comet for me except as a source of repair parts.
Click to expand...
on that note, is this the same knock off that is sold on ebay? i would buy 10 if i knew people would buy the other 9, i want to play with one too!

Alibaba.com - Wholesale go kart Transmission TAV2 30 series Torque converter With 3/4" clutch & 12 tooth 35-1 sprocket

looked at shipping and i was reading it wrong, seems like they want 43/per unit to ship... i emailed them to see if the shipping quote was wrong... would still be cheaper than what they sell for on ebay, but not worth it for me to buy 10 units... anyhow, was just trying to see if they were the same units and they look like it
 
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chriscouncill3

chriscouncill3

New Member
#13
#13
ok so still what is the max rpm you can run a GTC torque converter at? I understand there are issues running to high HP but would you be better off running a mild motor at say 5000-6000 rpm or building a crazy motor to go 6000-8000rpm?
 
ole4

ole4

#14
#14
I have a hot clone with a salsbury 330 and it goes great but I have not had it over 6000rpm because when it shifts to high it goes to fast for me. I need to take a tooth off the chain drive sprocket or add some teeth to the wheel sprocket. My current project is using a Comet Tav 30 and it is not a high performance TC like the salsbury 330 and comet 340 are, so I am using a black mamba jr for more bottom and limit my rpm to 6000 or so.
 
Newoldstock

Newoldstock

New Member
#15
#15
Hard to put a number too it.
But think about this.
Many two strokes rev in excess of 6000 rpm and were equipped with OEM 30 series clutches.

Torque is the killer.

Spring for Comet 20 & 30 Series Driver Units
Choice of Blue, Black, Orange, Pink, White, Yellow

Spring Engagement Chart
For 20 & 30 Series:

link to BMI shows you the different weight and spring combinations for the 30 series.
This does not tell you what the RPM limits are, just how fast it turns when tuning the clutch.
http://www.bmikarts.com/Replacement-Springs-for-20-30-Series-Driver-_p_1015.html
 
D

davidlamb78

Member
#16
#16
Any comments on the jack shaft kit that so many people are talking about? Would it be better for something like this? I'm about 200lbs. Again, not planning any major off road trips. I may eventually do more serious motor mods, but the gov is in for now. You think the jack shaft would be a better route?
 
Newoldstock

Newoldstock

New Member
#17
#17
I did it a few years back.

Yerfdog parts.....



I admit this was a major undertaking to flip the drive around to the right side and build the special mount for the engine and jack shaft.
But for a heavy bike this has really worked well.
 
boostdoctor

boostdoctor

New Member
#18
#18
davidlamb78 said:
Okay, so I got my swap kit from OldMiniBikes warehouse, and I'm gonna go pick up a predator from the local HF. It'll be a hemi model. I'm not gonna go wild with this one yet. I have a header, breather kit, and I'm gonna run a carb that I had on my clone that is on my race cart. mostly stock carb, but rejetted and all that jazz. I'm not gonna take the gov out of this one yet. Might go there when I have enough money for the billet bits.
I have a DB30 that has some Carlisle Snow Blower tires that are about 15" tall. I was looking at the knock off TAV2 kits on ebay, and they mentioned something about topping out at 3500 rpms with the kit. I know that my motor won't rev higher than that with the gov in, but what if I end up going bigger later? Will I not be able to wind a lot higher than that with a torque a verter on the motor? My kart motor spins around 8000 rpms, and I may end up doing something fun with this hemi later. I only wanted to run a TAV because I want to ride this on trails with mild hills.
Click to expand...
The 3500 rpm is the point at which the cvt stops shifting. This will not limit the rpms of the motor. The gear ratio just remains constant at this point.
 
chriscouncill3

chriscouncill3

New Member
#20
#20
ok I am totally confused at this point.... at which point can I not use a torque converter? the reason I ask is because a jackshaft is really just changing the gear ratio to where a torque converter is like a transmission(kinda) but the ratios do change so it is better than just having no change I want to have low end torque with the high end power as well
 
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