Low end torque build ideas?

[2SlickNick]

May I suggest just adding an 8 tooth sprocket instead of the 10 that comes with the torque converter.
I have that on two of my bikes, and there is not a hill, that I cannot traverse.
Top speed still around 40-45mph.

On one of my other by bikes are use a black mamba junior camshaft. and that is known as a torque cam, but you would still need billet rod, flywheel and stiffer springs LOL. That motor is full of torque.

I have not use that motor with the 8t - Lol.

The second bike in this video has the eight tooth.


https://youtu.be/H55L6orgcR4

 

[BWL]

I have the CL1 high torque just have yet to install. I thought about getting the custom grind but at $100+ I just have not done it yet. I guess when I paid that much for my Mikuni knock off kit it's no different. Was thinking of grinding something close using the 280 lobes with the 220 duration. I don't know the timing of the NR 280 grind so should probably look at that before paying to have one ground. One day just not soon.

I know it, man! Thinking of adding a CL1 on my little motor. I figure a little more duration would up the torque a bit higher in the RPM range where I run the motor most of the time.

I know it about these custom grinds, man! You could buy a whole new motor for the cost one custom ground cam, lol.

 

[SAS289]

From the information given on this thread for around $100 or so you could get better breathing and jet, a CL1, and a different sprocket and have a very different bike from what you started with.

 

[San Diego]

I have the CL1 high torque just have yet to install. I thought about getting the custom grind but at $100+ I just have not done it yet. I guess when I paid that much for my Mikuni knock off kit it's no different. Was thinking of grinding something close using the 280 lobes with the 220 duration. I don't know the timing of the NR 280 grind so should probably look at that before paying to have one ground. One day just not soon.

Per NR Racing article posted by Russell:

The part number of our cams tells the ICL and LS. The first number is the lift, the second set is the CL, and the last set is the LS. For example

280 0207 .280 lift 102 ICL 107 LS
252 0607 .252 lift 106 ICL 107 LS
252 0207 .252 lift 102 ICL 107 LS
252 0211 .252 lift 102 ICL 111 LS
274 0607 .274 lift 106 ICL 107 LS


280 SERIES- The original NR camshaft. King of midrange. GREAT FOR MINI BIKES & MARINE APPLICATIONS

Approx .280 lift and 220 duration (at .050). This is a nice cam that works well on both stock and modified motors. This cam produces lots of low end torque. One of the best all around cams we offer. Honda blocks may need to be clearanced to install. 26 lb springs required. Bored or Aftermarket carb needed.

•280-0611: Good Torque Cam w/ excellent power. 7500 RPM. 10.5 to 1 compression or more, 26+ lb Springs ,
•280-0211: THE ULTIMATE TORQUE CAM. Special grind for Marine and Winch Boarding applications. Extreme torque. Designed for 2000 to 5500 RPM, 11 to 1 or Lower compression ratio required, HD Springs required

 

[MJL]

Keep the cam talk coming!

I ordered an intake, but it's coming all the way from China and will not be here for a while, so in the mean time I fabricobbled this intake together using the stock filter. It definitely made a difference. I still need to take plug readings and rejet, but it certainly shows promise. I hung over the handlebars, ripped it, and had to let off to maintain control, didn't have to do that before. Can't wait to tune and see if it makes any difference in my 200 yard run. Sure is easer to get to the plug now! I could have cut or replaced the studs for a shorter intake, but didn't want to mess with them as this is temporary. Pretty cool just demonstrating what someone with access to a welder (intake could even be JB weld) can do for under $15 or so to improve engine performance.

 

[MJL]

May I suggest just adding an 8 tooth sprocket instead of the 10 that comes with the torque converter.
I have that on two of my bikes, and there is not a hill, that I cannot traverse.
Top speed still around 40-45mph.

On one of my other by bikes are use a black mamba junior camshaft. and that is known as a torque cam, but you would still need billet rod, flywheel and stiffer springs LOL. That motor is full of torque.

I have not use that motor with the 8t - Lol.

The second bike in this video has the eight tooth.


https://youtu.be/H55L6orgcR4

Is the 8 tooth harder on the chain? I think I read that somewhere. I've got a 9 and 70 on now. Even with stock gears, it would climb any hill I cared to ride on! All the torque improvements are for the 200 yard straight away, hump jumping (hopefully!) and coming out of corners hot. Interestingly enough, the gearing changes didn't make as much of a difference as I thought they would. I guess the TAV adapted?

 

[TheDullCarbide]

Is the 8 tooth harder on the chain? I think I read that somewhere. I've got a 9 and 70 on now. Even with stock gears, it would climb any hill I cared to ride on! All the torque improvements are for the 200 yard straight away, hump jumping (hopefully!) and coming out of corners hot. Interestingly enough, the gearing changes didn't make as much of a difference as I thought they would. I guess the TAV adapted?

You'd have to be going pretty damn slow for that gearing to improve a 200 yard sprint. For me, a TAV2 7 inch with 9/60 gearing on a 19 inch tire creeps at an average walking pace. My $0.02.

 

[MJL]

You'd have to be going pretty damn slow for that gearing to improve a 200 yard sprint. For me, a TAV2 7 inch with 9/60 gearing on a 19 inch tire creeps at an average walking pace. My $0.02.

Well, I have to stop at the end or risk going off a 10 ft bank, so I'm only into the throttle for 150 yards or so. I'm not really looking for the shortest ET or highest top speed, just a good hard pull when I get on it. If I top out at 25mph, so be it. I do use my GPS to measure top speed to assess changes in engine performance, but acceleration is still subjective at the moment. Right now, I'm just going by how long the front end is light when I crack open the throttle. The ability to do a rolling wheelie at 5-10 mph without yanking on the front end, and jumping little humps by blipping the throttle are really what I am after. I know I could slap on a bunch of goodies and probably get there in a hurry, but I'm going slow and cheap, for now, on the improvements just to make the fun last!

 

[DeadPixel]

From the information given on this thread for around $100 or so you could get better breathing and jet, a CL1, and a different sprocket and have a very different bike from what you started with.

I have a lot of parts already hahaha. Once a person has most of the cheep mod parts its time to venture out on the " Fun to have parts " But ya your right I would recommend what you said over a $100 cam. The high torque NR280-0211 that San Diego posted the specs of looks like a dam good choice though if a person was looking for the best cam for torque and not worried about cash.

I like your intake idea MLJ. If you use a brigs 9-13 HP air filter they are about the same size as the aftermarket round filters that come in the kits. There paper though like the stock filter so don't flow as well as the aftermarket. You could also double stack 2 stock filters and mount them like you have. You would have to cut the center out the top of the bottom one. Just an idea for the next build... I thought about doing something similar but making my mount out of wood and using acrylic to seal it. I modded my stock air box and added a larger filter but the air box it self is part of the problem and it was not worth the mod. Looks cool though. Would like to know if your set up makes more power than mine. Whats the larger restriction, the air box or the filter???

 

[MJL]

I have a lot of parts already hahaha. Once a person has most of the cheep mod parts its time to venture out on the " Fun to have parts " But ya your right I would recommend what you said over a $100 cam. The high torque NR280-0211 that San Diego posted the specs of looks like a dam good choice though if a person was looking for the best cam for torque and not worried about cash.

I like your intake idea MLJ. If you use a brigs 9-13 HP air filter they are about the same size as the aftermarket round filters that come in the kits. There paper though like the stock filter so don't flow as well as the aftermarket. You could also double stack 2 stock filters and mount them like you have. You would have to cut the center out the top of the bottom one. Just an idea for the next build... I thought about doing something similar but making my mount out of wood and using acrylic to seal it. I modded my stock air box and added a larger filter but the air box it self is part of the problem and it was not worth the mod. Looks cool though. Would like to know if your set up makes more power than mine. Whats the larger restriction, the air box or the filter???

Thanks! I cleaned up the zip ties a bit and spent a couple hours swapping jets this morning to get a final tune. Ended up with a .032 with the 140 tube. Prior to the intake and muffler, she was a scootch rich even with the 140 tube and a .028. I tried a .034 and it bogged of the line even though I got a good plug reading. The sweet spot had just a little touch of tan.

I didn't pick up any additional speed on my 200 yard run with the intake, so the filter is probably still holding things back. Once I tuned it with the NKG plug, I swapped in an Autolite 3932x. While warmer than the famed 3910x it still took a good 10 minutes of hard riding before the plug was warm enough for a good burn. Cold plug (but warmish engine) was only good for 28 mph, but once it was hot, I was back up to 32 mph.

Coolest part is I now have the ability to jump humps! A real tangible difference from the stock muffler/intake.

 

[MJL]

Just checked, and the 7 inch pulley should be here today...

 

[MJL]

Just checked, and the 7 inch pulley should be here today...

Despite showing out for delivery, it never showed up. Called the post office and they, honestly, said that it was left behind.

Bike is running great, though! I had a problem with the Chinese brake shoes coming out of adjustment for some reason and dragging, so I swapped out some Hondas and it stops much better. I need to do another 200 yard speed run to make sure the brakes weren't holding me back. I'm very pleased.

I made a video, but can't seem to get it uploaded to YouTube as I'm missing the proper cable connector. Go one ordered, and should have it up in a few days.

 

[2SlickNick]

I have not had any issues with the eight tooth, and I have them on two of my bikes for over a year. One of my bikes I even run around 7000 RPMs.

Good luck with your builds and post some cool videos of your progress.

 

[MJL]

Thanks, Nick. I'll see where the 7" pulley gets me and go from there. Getting the ability to jump was one of my main goals, as our riding area has a dirt ridge around 18 inches high or so that is a blast to catch air on. Our clutch equipped, mostly stock, 200ex does it with ease, but the Baja/TAV just didn't have it until the intake and exhaust where added. Launch wheelies are plenty strong, to where I can't just crack the throttle wide open anymore, so I'm good there. I still don't have rolling wheelies without yanking on the handlebars, but I weigh 225, so it might take quite a bit more to get there. I'm at the edge of my safety zone as it is, so I probably won't go there anytime soon. There is no real plan for where this thing will end up, just something to keep me entertained. Next items in the works may be a homemade seat (springer?), and a front fork rebuild.

 

[MJL]

Got the 7" pulley on. I can definitely tell that it is a better ratio for the engine. I hit a new top speed of 34 on my straightaway and it was still pulling. I let off because I adjusted the govenor a while back, but it could never pull past the 6" overdrive so it didn't matter until now. My tach should be here in a day or two and I see what things look like. I butchered my TAV cover a bit to get it on, but better that than my leg. I'll work up something nicer when I get a chance. Seems like I lost just a touch of wheelie and jumping ability, probably due to the slightly looser belt. I might try the next size down and see how it works. I can also move the backplate out an 1/8" or so using the play in the bolt holes. Got my first warning from a neighbor. He's deaf, so the noise doesn't bother him, but he wanted us to take it easy on the grass next to his house as it keeps the dust down in the summer. The bike doesn't seem to tear up the grass much though, I'm too old for donuts, and I like my tires to last!

 

[TheDullCarbide]

Got the 7" pulley on. Seems like I lost just a touch of wheelie and jumping ability, probably due to the slightly looser belt. I might try the next size down and see how it works.

Try the next size down. The belt riding low in the driver pulley is the key to low-end torque. While you're at it, order a spare bronze bushing.

 

[MJL]

Ordered a Comet 91 and a knockoff 90 to try. Since the 70 tooth sprocket there hasn't been a hint of belt smoke, but I whacked it on a couple high tree roots on the trail today, once hard enough to knock the chain off. More air pressure would probably solve the problem, but at the expense of my back. A 60 tooth would be a good compromise, but I'll probably stick with the 70 and just be more careful.

 

[MJL]

Might throw my yellow spring in the 7". The 6" smoothed out a lot with it.

 

[MJL]

[video=youtube_share;wtGtNhwK0rg]https://youtu.be/wtGtNhwK0rg [/video]

 

[MJL]

Finally got a video to post!