Another Doodlebug Video

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scottisha

New Member
#1
#1
Made a quick video on Memorial Day.

Three Doodles. All with HF engines. My neighbor Bob has the new frame and my two are the last model frame.
I'm on the yellow (fastest one)..Bill is riding the camera bike and Bob on his red one. Red and green one will do right at 40mph. Both riders are 165lbs. I'm 195lbs.

You can see what a difference a better carb and the 13 tooth clutch make.

Video will play in HD if you change the settings.

http://www.youtube.com/watch?v=AuIf8PWdVUghttp://
 
delray

delray

Well-Known Member
#2
#2
you will have to get some knobbys tires for it. so you can push it little harder in the corners. knobbys will work little better in that sanding/grass ground.:thumbsup:......:scooter:
 
S

scottisha

New Member
#3
#3
delray said:
you will have to get some knobbys tires for it. so you can push it little harder in the corners. knobbys will work little better in that sanding/grass ground.:thumbsup:......:scooter:
Click to expand...

Funny you mention that... I have a set of new tires (knobbies) in my garage. Just need to install them.

We rode around for about 30 minutes that day. Lucky to have a couple schools next to my neighborhood. School's closed, we ride!

Scott
 
S

scottisha

New Member
#6
#6
Stock rear sproket on all of them. Not sure if it's 65 or 70 though.

Prior to doing the carb, air filter, and exhaust, the yellow one (has the 13 tooth clutch) would only do 41-42 with me on it. Now, it gets to that speed quick and then with enough road I've seen as high as 52.3 mph.

I ordered the sproket adapter today as well as three different split sprockets. Gonna see which one works best with the torque converter. Had to take the torque converter off the yellow one cause I couldn't keep the front end down.

Hoping a taller rear end sprocket will help with that issue while also giving me a higher top end.

With the torque converter on the yellow one, I could only hit 41 mph. Swapped back to the 13 tooth and I'm seeing 50's again and it's tame down low.
 
B

bwt

New Member
#10
#10
The thing about torque converters that a lot of people don't realize is that while they are smooth and provide great off the line performance, they also use up more horsepower due to belt friction and the force required to overcome the spring in the driven unit. For example, I have a db30 with a 6.5 clone, billet flywheel, stock carb, 90 jet, 140 emulsion tube,18 lb springs, 1 inch header with rlv silencer, .060 milled head, UNI air filter and adaptor, comet tav 30,front and rear disc brakes, and 3300 rpm stall springs on the driver unit. The rear sprocket is a stock 70 tooth. The bike has tremendous acceleration off the line, yet it tops out at 45 mph. At that speed, the engine is turning around 5700 rpm. the fact is that a standard clutch and chain is more efficent than a torque converter setup, and as you have found, will give a higher top speed. But I am willing to give up some top speed for smoothness and acceleration.
 
B

bwt

New Member
#11
#11
Just a few additional comments. With a 70/13 sprocket combination like you are running, your final drive ratio is 5.38:1. With a 12 tooth on the tav30 and a 70 tooth rear sprocket, my final drive ratio is 70/12 times .9 overdrive, or 5.25:1. So my final drive ratio is already taller than yours, but I can't hit 50 with the torque converter setup. Keep in mind that with the standard 14" tire, the rear axle has to turn 1200 rpm at 50 mph. With your drive ratio, the engine is turning 1200 times 5.38, or around 6450 rpm to do 50 mph. By the way, I have checked to see that the tav30 is going into overdrive, and I have removed the governor on my engine, which is one reason I run a billet flywheel. I have run the engine both ways, with the torque converter and with a standard clutch and chain with the same ratio, and it definitely revs higher with the standard clutch and chain.
 
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