I want to increase the torque on my 06 Scrambler. From reading here on the forums i have determined that some cluthc work and exhaust work should take care of this, if done correctly. Here are the questions i have:

I called an internet retailer who tried to sell me a full exhaust system with a wider diameter pipe. Wont this decrease my torque? Arent i better getting a slip on style exhaust and keeping the stock piping? (for more torque?)

Do i need to do a whole clutch kit or just replace the two springs?

After doing the clutch and exhaust do i need jetting? (at 6000ft)

Any input will be greatly appreciatted...thanks

 

all you need to know is ritter cycle racing. You tell Rick what you want, and he will tell you what you need. His prices are pretty cheap as well.

 

It is true that in most cases adding just a slip on will increase torque (low end) but won't have much impact on top end (horsepower)......

But what needs to be considered is that torque and HP work with each other and that needs to be taken into consideration. Depending on the engine and setup in stock form...there are many variables to consider when looking for the most impact for the fewest dollars.....

An engine that likes to rev high, like my z400 for example, will benefit from a slip on more then an engine that already is designed for torque already..... The z400 in stock form, makes decent HP in the mid range and top end, (typical OHC engine) but the torque numbers in the low RPMs are not great. So a slip on, will help switch the power curve a little more towards the bottom end and a little less towards the top end..... in short, the engine will now have a little more low end, but there will be no real top end increaes.......the initial crack of the throttle will result in more power going to the ground, but as the RPMs go up the engine will fall off a bit faster then it used to.

Now, at the other end, an engine like that in a 400ex, already has gobs of low end (typical push-rod engine) and will not really benefit much at all with just a slip on. In that case a full exhaust and jetting will be desired to increase power all around, but it still won't really change the power curve that much..... you won't gain too much on any part of the curve but you will get an even increase all around........ now to get more on the top end on a push-rod engine specifically enough to really make an impact you need to get into deeper mods like cams and valves......

On your 500 engine, which I believe is a 4 valve SOHC, you will see some increase with just a slip-on and a clutch kit. But there is an argument that the clutch will make the biggest difference. I would try the slip-on, and clutch and see if you like the results...... if they are not enough, you can always add the headpipe later (just make sure you buy a reputable pipe that has an available headpipe) and then you can also jet the carb and get some more air to the box........

 

For optimal torque increase, step up your camshaft (don't be afraid off engine mods) and exhaust. DRD makes a good pipe that increases torque throughout the band, so does FMF and CT. Stepping up your exhaust usually means jetting up 2 stages, as well. Any time your bike breathes better, it needs to drink more too to keep from melting holes in pistons. FMF/Dynojet make a jet-up kit that makes everything very simple and is very affordable. A high performance clutch never hurt anyone either.

 

Don't worry about name brands... Just get a good glasspack muffler that is as big as you can fit it (long and fat). If you care about loudness, then you're stuck with SuperTrapp or stock.

Backpressure is NEVER a good thing. The idea is to keep the exhaust moving fast so that when valve overlap happens, the exhaust actually pulls more air thru the carb. They call that scavenging. The more of that you can do, the more power you can make.

Here's what FMF says, "Having less backpressure (louder), the more top end power you'll have. More backpressure (quieter), the more bottom end power you'll have." http://www.fmfracing.com/techs.../faq_detail.aspx?id=51

This is where I'm thinking a distributor is talking and not anyone that actually knows anything. Every dyno I've seen shows more lowend as well as topend power with less backpressure. The FMF pipe is pretty much an open pipe with fiberglass packing around it. That's about as close to zero backpressure as you'll get without running plain ole straight pipes.

Besides, how could you make more power by forcing the piston to work harder at getting the exhaust out? It just doesn't make sense.

Now, headers are different.... Small headers make more lowend torque because the exhaust moves faster thru them. But they also hold back power on the topend because they're so small. Large headers make more power on the topend, but they lose power on the bottom because the exhaust doesn't move as fast thru them. Some might see small headers as "backpressure", but it doesn't have anything to do with mufflers. A muffler with backpressure isn't going to add HP anywhere to the curve.

Here's 2 identical engines. One has a muffler and the other an open exhaust. Where is the loss of lowend???






If you want lowend grunt, run a small and long header into a low-backpressure muffler, run a small carb with large air filter, and loosen the valve lash to decrease cam duration. Internally, you could increase the compression ratio and shorten the connecting rod. Also, filling the intake ports with JB weld can help speed intake flow under low rpms.