How to add a torque converter to a Baja Warrior Mini Bike
 

Many people have wanted to know what's involved in doing this so I'll show you how. First things first, this is not a drop on and go mod. It does require some grinding. I use a 4" grinder. If the engine on your mini bike has a rear facing dip stick tube, you also have to trim it too. I am using a Comet TAV2 torque converter.

The first thing you have to take care of is one of the jack shaft webs on the back of the torque converter will need to be ground down to be able to clear the rear dipstick tube boss. How much you have to grind depends on whether or not you have an acutal tube in place or if there is just the tube boss. My mock up engine had the tube but the engine on my actual mini bike did not. Of course I didn't realize that until I was done with my mock up and went to install the converter so I ground a little more than I needed to but if you have the actual tube in place, you need to grind it down as much as shown in the second picture. So, look at the first picture for what it looks like before grinding, and then look at the second picture for what it looks like after the grinding is done.

If you don't have the actual tube, you only need to grind from the end of the web up to about the halfway point to the jack shaft. I ground almost all the way. Remember that these webs reinforce the jackshaft so leave as much meat on it as you can and still be able to clear.

The next piece of grinding will be the lower rear cover bolt boss. When this thing is in place, it fits right up against the frame. This boss is about 1/4 inches thick and will not allow you to mount the TAV flush so it has to go. Grind it off and even with the back of the TAV. The third picture shows what it looks like with that boss ground off.

To make sure the grinding is correct, we now need to pull off the old clutch and gear reduction system. Remove the side cover. Remove the front chain masterlink and remove that chain. Remove the bolt that holds the clutch on and remove the clutch.

For the existing gear reduction system, there are four bolts that hold it to the case and one bolt that holds the rear section of it in place. Remove those bolts and the entire reduction system will come off.

You will need to remove the heat shield around the head to be able to use the torque converter. There are three bolts that hold it on, one of them being a bolt that also holds on the lower left pull start cover. When that is off, place your TAV backing plate in place and loosely bolt it on. (you will need bolts that are longer than the ones that came out that were holding the original gear reduction plate in. I used 8mm x 25mm in length) There are two areas on the rear edge of the mini bike frame that need to have mild grinding done because of interference with the frame. One area interferes with the chain cover mount, and the other with the frame itself. Use a sharpie or something similar to mark those interfering places. Remove the TAV backing plate and gring those areas down to where they will no longer interfere when the plate is mounted. The fourth picture below shows how my backing plate looked after I did this and yours should be similar.

That should be it for the grinding. Now you will need to remount the TAV and re-check your clearances. If all looks good, go ahead and tighten it down. If all is correct, the tav will be butted up tight to the frame where it drops below the frame and the webbing grind should look similar to picture number 5 below.

Believe it or not, the stock chain will work find. Go ahead and put it on and adjust as necessarry. I will tell you that you should leave it on the loose side. I don't think my rear sproket is accurately round and my chain goes tight/loose over a full revolution. Check your tension over a full revolution of the back wheel and adjust accordingly.

At this point you are free to put the TAV together completely. I pulled the rear chain guard off prior to putting the TAV cover on so I could trim it. You will need to trim the TAV cover to allow clearance where the chain enters and exists from the rear. Once you have the cover on (remember it will only be held on with 3 of the four bolts since we had to grind one bolt boss off) you will then likely need to trim the forward edge of your chain guard slightly so it can clear the TAV cover.

Otherwise, that's it folks!

that took a while very neat info

does anybody know where to buy a comet torque converter tav2 30? i have read that they went out of business. thanks seahawk108

im gonna save u time and money, the tav 30 is a piece of crap. I got no directions, no parts list, and missing parts.And once i got all of that figured out and put together the driver came apart and damnear took my head off.KEEP YOUR $200.00. BEN FUKTOVER

I'd have to say that it wasn't installed properly. If properly maintained and installed, it's hard to beat this mod. Comet made a great product.

Sorry to hear that you had bad luck with your Tav system-I agree with Buggymaster. It's one of the best/reliable units out there and we have several that have gone hundreds of hours without a failure- never had a driven come apart.

I just bought and installed the Tav2. I was able to use the heat shield by just grinding down and hammering the top side of the shield where it was touching the Tav2 cover mounting boss. Question: The driven came assembled on to the backing plate, are the two sheaves supposed to be 100% round? Seems they have a slight wobble to the sheaves but the shaft is 100% straight. Package was undamaged in shipment and I never dropped the Tav2, always handled with care.

Lastly, the Driver outer sheeve, the part with the springs wound around it, seems to slide outward toward the cover, away from the motor quite far. Is this normal?

Yes they should be round- the belt doesn't like to wobble very long till self destruct (got to remember your new part was shipped from somewhere and moved with equipment and humans!). The drive/clutch when installed properly shouldn't slide freely at all. assembly- spacer next to engine (this may vary in thickness, lines up back pulley with driven back pulley)- back pulley over crank shaft-brass bushing over back pulley shaft-belt with the flat side of it towards the engine-keyed shaft sleeve-clutch (part with the springs & pins)-clutch bell/cover- thick washer-bolt into crank shaft- If this doesn't match how your's is assembled you might have missing parts. Any chance you can post pics? It's so much easier to troubleshoot assembly when you can see it!

So I had it all ready to ride, left the cover off to watch it work on my test drive. The snap ring on the driven popped off and the outer sheave was wobbling all over the place. I took off the nylong lock nut and guess what? No brass bushing on the driven!!! I'm calling ******* tomorrow to have them send me one asap. Probably where the wobble came from that I was seeing before I installed it. Very frustrating and mildy scuffed up the inside bore of the driven outter sheave. The one thing I still don't know is how to re-assemble the driven clutch once the new bushing comes. Do you rotate the spring at all to preload/ build tension or just compress it and install the snap ring and nut without pre load? One last thing, do you know what the holes labeled 1,2,3 are? I understand it's applying more pre load to the spring, meaning it will stay in a lower ratio longer during acceleration?

Pre-load is light, meaning about a 1/4 turn. The holes are for more or less shifting options,I only use the center hole as I couldn't tell a difference when put in 1-2 or 3. If you buy the heavier spring then you'll feel a BIG difference. There isn't a brass bushing on the driven unit as the belt rides at the top of the puilley during idle and goes closer to the shaft as you speed up- there are rivets close to the shaft that will shred the belt if it ever goes that low.

im new here, just wanted to know, if i can put a torque converter onto the old jackshaft... as i am looking to save all the money i can.

sorry if i overlooked anything. thanks guys.

yeah that didnt work haha, i got a used setup from a manco kart and its been abused all fall. what a difference.

Great, another Warrior guy from CT

Its Matt from the OMB forum.

I know, recognized your SN immediately :hooaray:

i know some mods dont like newbies bringing back old forums but im about to anyway. Im from the diy forum and am new here after reading this guide, im saving to buy a genuine comet TAV that i found for 187 shipped from mfgsupply . Now i want to do at least grinding as i can and i have a habit of taking things apart and not being able to put them back together the right way. im looking at the best way to do this, and me and my neighbor are going at it together, i have a baja heat

If you buy the stamped backplate and not the cast one there is no grinding on the TAV, that is what I have on my warrior

Picked me up a supposedly 1 year old Baja Heat yesterday for $250. Bought a torque converter lastnight. I hope it wont be much work to install this sucker. I also need to take the carb apart and clean it out. Guess i need something else to do now that my buggy is fnished.

I could use a little info here if you don't mind Buggymaster. I installed my knockoff Tav2 this weekend and noticed no difference at all. I haven't done any other mods to the bike as of yet. I have an intake and header coming in, but im starting to think i will need to take the governer off to get any torque or speed from this bike. I wanted to leave the governer on as i was thinking of letting my stepson ride it from time to time. I notice the belt that came with the setup is quite big and you can actually take it off of the pulley if you wanted to. How tight is your belt on the TAV2? Also my variator does not close all the way while riding, it only closes far enoug to push the belt about half way up the variator and the belt remains at the top of the pulley. My belt size says 725 on it. Any information would be appreciated.

Did your speed as in top end at least double?

to my knowledge, no. I did not notice any difference, besides less torque. Is there something on the engine i should adjust to make sure full throttle is working?

When we built ours, we used an actual Comet torque converter. I am not sure how the chinese knock-offs work but even with the governor on, we went from the original top speed of 18 mph to 30 mph and that was leaving the governer in place. If you have the converter cover off, look at what is going on with the CVT system and make sure that the variator is raising the belt up noticeably as it speeds up. If not, then something is going on with it.

Here is what ours looked like in proper working form:

Actually, now that I think about it. We did not test the speed with just adding a torque converter. We went from 18 mph to 30 mph when we took the governor off. So I am not sure what it would do with a torque converter and the governor still on. Be aware though that if you take the governor off you will be running outside of what the engine was designed to do and you risk the engine coming apart and this could hurt you! Do this at your own risk.

Dang, that vid makes me want a mini bike now, good thing I'm saving the 150cc from the yerf.

Yeah, the belt is not raising up more than half way and it is not dropping at all in the rear pulley. I purchased a TAV2 yellow spring and a 9 tooth sprocket to try and help with the issue. Got some advice off some guys on OldMiniBikes.com

Well i got the problem squared away and i still have the governer installed. All i did was adjust governer screw on top of the block. It enabled me to basically double my speed and raise the belt all the way up the driver.

That's great. What was the problem?

It seems that the governer screw wasnt backed out far enough to allow the bike to reach full capacity. The silver set screw on top of the engine that stops the swing arm attached to the throttle cable.