Baja warrior 212 / gearing info

[mrbeggs432]

Was wanting some advice on suggested gearing.
212 predator hemi...stage1/governor removed.
10t CC/20tsecondary?/50t sprocket/ 19x7-8 tires.
It Maxs out at about 29mph...I can feel there plenty more in the engine....usually I would think reducing rear sprocket...but with the combination of these...I want to make sure....Any advice is appreciated

 

[mckutzy]

Whats the count on the other jackshaft sprocket??....

 

[mrbeggs432]

Whats the count on the other jackshaft sprocket??....

10 tooth...

---------- Post added at 02:13 PM ---------- Previous post was at 02:08 PM ----------

 

[mckutzy]

Is it a 10-10-20-50= a 2.5:1 ratio
or 10-20-10-50=10:1 ratio... not really clear...

Here is a ratio calc.. itll help with determining what you want for ratio..
Ideally you want 6:1 to start..

 

[mrbeggs432]

Is it a 10-10-20-50= a 2.5:1 ratio
or 10-20-10-50=10:1 ratio... not really clear...

Here is a ratio calc.. itll help with determining what you want for ratio..
Ideally you want 6:1 to start..

I appreciate the info and please excuse my ignorance.....I just wanna go faster....lol

Without knowing all this ratio stuff ....Im thinking yes I may be able to pick up a few mph with a smaller rear sprocket ??? what maybe 5 tooth reduction ?

But with all these other other sprockets/gears in play..I wanted to be sure they shouldnt be changed out first before I try and reduce teeth in rear

 

[Mrmonk7663]

What he is trying to say is that you have 4 sprockets

1. Clutch sprocket is 10 tooth you stayed.
2. Sprocket that clutch chain connects to?
3. Small sprocket that attaches via chain to rear sprocket. Size?
4. Rear sprocket-50t

What size are 2 and 3?

 

[bob58o]

It’s 10 :1 gear ratio.
10 on clutch to 20 on JS.
Then 10 on JS to 50 on rear.

5200 RPM is about 29 mph with 10 :1 gear ratio and a 19” tire.

Shoot for a total reduction of about 7.2 :1 and it should reach 40-41 mph.
You could put a 36T sprocket on the back (if you find one that fits).
OR change the 10T on the JS to a 14T sprocket.

5200 rpm would be around 41mph.
2600 rpm (where the clutch fully locks up) would be around 20mph)
This means that at low speeds (less than 20mph) the clutch will be slipping and burning up.
If you start and stop often or cruise at low speeds, this would be less than ideal. If you want the best of both worlds (higher top speed AND the ability to start, stop, and cruise at lower speeds), look into replacing the jackshaft with a torque converter.

BTW, it seems like you are floating the valves at 5200 rpm. If the engine is old and/or you have been running at full speed (29mph) for long periods of time, you might want to consider freshening up the engine by replacing the old valve springs with some new 10.8lb springs. That alone might give you another 2mph on the top end.

And to address your question about dropping 5T on the rear sprocket (from 50T to 45T), you’d pick up about 3 or 4 mph. This would be the same as swapping the 20T on the JS for an 18T.

 

[Mrmonk7663]

Awesome reply. That should get the OP sorted.

 

[mrbeggs432]

What he is trying to say is that you have 4 sprockets

1. Clutch sprocket is 10 tooth you stayed.
2. Sprocket that clutch chain connects to?
3. Small sprocket that attaches via chain to rear sprocket. Size?
4. Rear sprocket-50t

What size are 2 and 3?

#2 - 20
#3 - 10

I guess on jackshaft 10T inner / 20T outer

---------- Post added at 10:14 AM ---------- Previous post was at 10:09 AM ----------

It’s 10 :1 gear ratio.
10 on clutch to 20 on JS.
Then 10 on JS to 50 on rear.

5200 RPM is about 29 mph with 10 :1 gear ratio and a 19” tire.

Shoot for a total reduction of about 7.2 :1 and it should reach 40-41 mph.
You could put a 36T sprocket on the back (if you find one that fits).
OR change the 10T on the JS to a 14T sprocket.

5200 rpm would be around 41mph.
2600 rpm (where the clutch fully locks up) would be around 20mph)
This means that at low speeds (less than 20mph) the clutch will be slipping and burning up.
If you start and stop often or cruise at low speeds, this would be less than ideal. If you want the best of both worlds (higher top speed AND the ability to start, stop, and cruise at lower speeds), look into replacing the jackshaft with a torque converter.

BTW, it seems like you are floating the valves at 5200 rpm. If the engine is old and/or you have been running at full speed (29mph) for long periods of time, you might want to consider freshening up the engine by replacing the old valve springs with some new 10.8lb springs. That alone might give you another 2mph on the top end.

And to address your question about dropping 5T on the rear sprocket (from 50T to 45T), you’d pick up about 3 or 4 mph. This would be the same as swapping the 20T on the JS for an 18T.

its a fresh hemi recently broke in.....I want a good all around dependable rider....I use T/C's on a few of my carts...but I thought those were mostly for lower end performance ?

One more question ?

If I go to 10.8 lb springs....I dont have to ad any more mods to accept them ??

Thanks for your input

 

[bob58o]

Well if the engine is fresh, then I wouldn’t worry about the 10.8 lb springs. 10.8 are the stock replacement springs. I just thought they might be worn out if you have been running at 5200 rpm for a long time. If you want more RPM, then upgrading to 18lb springs (the shorter ones specifically for the Hemi) would probably help you.
https://www.nrracing.com/product-p/dcs-an2.htm

If you upgrade to 18lb valve springs, you might be able to turn 6,000+ RPM with your current gearing. Possibly 6400 RPM (with advanced ignition timing) which would be around 36mph. At those higher RPMs, the stock connecting rod has been known to let go and went it goes, it often puts a hole in the block. So generally when upgrading to stiffer than stock valve springs, it is recommended to upgrade to an ARC billet connecting rod. Many people also recommend an upgraded flywheel as well. There have been a few known instances when the stock flywheel has either come apart or thrown its magnet. So to add durability and safety, billet parts would be recommended, but nothing else is “needed” to install the 18lb valve springs. Would just have to take the old ones out and put the new ones in. But who wants to risk blowing up the engine for a few MPH’s. So while nothing is “needed” to physically install the 18lb springs, at the very least a billet connected rod is a supporting mod that is HIGHLY recommended.

TC’s do help low end performance more than top end, but like I mentioned they allow you to gear for a higher top speed and still allow you to cruise at lower speeds without worrying about burning up your clutch. The initial reduction the TC gives you at engagement is the reason. Suppose you had a 30 series TC with 8T sprocket and kept the 50T on the back. 5200 RPM might be over 50 mph. But now, at engagement/“lock-up” rpm, the speed would be less than 10 mph. If you tried to gear for 50 mph with a regular clutch, riding at low speeds (less than 25mph) and/or stoping and starting often will significantly shorten the life of the clutch. BUT if geared for 50mph with a TC, you can cruise at low speeds and/or start and stop as much as you like without much worry.

 

[Hellion]

The TC is the de facto upgrade for the Baja Warriors, namely because it bolts right in and takes the place of the factory jack-shaft assembly.

I had a Warrior that had a straight chain from clutch to rear sprocket--it was fast but not off the line by any means. Lots of clutch slipping while it chugged up to speed. Top end was 41 or something. Crazy.

The TC allows it to have the transmission of a trail bike/enduro with a 5 speed transmission.

 

[mrbeggs432]

Thanks Bob58o and all the rest of you....for your knowledge & wisdom.....I'm gonna rob the T/C from one if my carts and start from there....just wanted a little more....but really don't want to go inside the engine.