The time has come to make some mods to the 500 Scrambler. I have read all the posts, read all the magazine articles, seen many aftermarket products in use and have made my descisions. I currently run a K&N filter (more of requirement than modification). My bike seems to be a little faster than the normal 500 Scrambler, so my results may not be the same as what others experience. Modification #1: Last week I order the FMF Megamax II. I have heard nothing but good about it & last weekend when riding with Steve Thompson at Brown Mountain I fell in love with it. Steve is running all the disks without the core. Its not loud, but man does it thump! Makes your chest pound! Suppose to deliver much more low end torque, which is what I want.
Modification #2: Last week I also ordered the K&N Jet Kit. Read posts from here that were very positive, plus I know with the pipe I will probably need to rejet anyway.
I'm supopose to have everything before next weekend, so I'll let everyone know how goes it. I'll install the pipe first & run it a while. A friend has a GPS so we'll do some wide open runs and some 100 & 300 yard runs. Then I'll install the jet kit and see what happens. I was going to wait until I installed it to post something, but I was really too excited to wait. Plus I figured I might get some good install advise from you guys that have done it already. I can't wait!
These are really the only 2 modifications that I have seen that seem to be worth the money. After-market clutch is out of the question. I trail ride. Purely. No "out of the hole racing" or top end racing. Only racing through the trails. I like a cluth that hooks up low, even shimmed my stock one down to get an even earlier hook-up. It wants to go as soon as you think about hitting the gas. Got to use all that torque! I rode a roller clutch & could not tell the difference. Rode with a guy at Brown Mountain that had the roller clutch, he said he couldn't tell any difference either. Rode a 500 that had about a 1800 RPM stall on it...launched hard, but hated keeping my thumb on the throttle all the time, also killed the engine braking. Anyway, if anyone has done anything else that improved the engine performance, please let me know. Next mods will probably be straight wiring the fan so the ignition doesn't have to be on for the fan to run, then Aaen Steering dampener, then split brakes, then.........

Jerome Coker
'99 Scrambler 400 & 500

PS - Top 3 things I have learned from my experience on an ATV:
1. Only modify your quad to improve YOUR riding style.
2. NEVER compromise realiability for anything.
3. Always modify your wifes 400 first.

 

Well Jerome, unfortunately the first thing i would do is install a roller clutch kit from Aaen. You don't have to change the weights and springs to gain the benifiets of a roller clutch which would be reduced friction, less heat, no PVT dust, faster backshifting and improved accelaration. The only reason i say this is because all the power you can ever squeeze out of that engine has to go through the PVT. I have the roller clutch setup with different springs and weights and i do mostly trail ridding.

For the setup you are going for you won't have to do any thing but change the exhaust. The only way you are going to get more power while maintaining lots of torque is by increasing the displacement of the motor by 50cc's or more.

I found that the bike has plenty of torque and i would like more horsepower. After speaking with Olav Aaen the 400 is perfered maching to hop up because of the availbility of parts and simplicity of the motor but the 500 has a lot of potential. For one the cylinder head was originaly designed for duel type exhaust like on the Honda 400ex and then was changed at the last minute due to manufacturing problems and costs. Due to the poor current configuration of the head further motor mods are pointless. He has actually modified the 500 head with a valve job, hotter cam and a port and polish. Then installed a .30 over Wiseco lighter and stronger hyperutectic type piston for faster revs, lighter reciprocating mass, higher compression and reduced piston to wall clearace. Finally installing the megaphone exhaust and a 42mm carb. 60+ horsepower can be achived with even more torque than stock but the cost is considerable more than it would be on a 2 stroke. On the flipside reliability and motor life should be a good as stock with the new and improved parts. Unfortunatly the trans cannot handle more than 70 HP.

For now motor work is on hold till Olav starts offering serious mods for the 500. Since the 500 is new and there are way more people with 2 stroke polarises the 500 takes a backseat for now. As far as other mods sounds like you are on the right path.

I might take my bike to get weighed this week if my schedule allows me and i believe it will tip the scale at an estimated 520 or so with the current mods. The reduced weight also helps.

Chris Picciotto
99 Scrambler 500

 

Its late & this is short & simple but...Just installed the FMF MegaMAX II. First impressions... awesome!!! Well worth the money! I installed it with core out, all disks in. The tone is deep & hard. It is not LOUD. It is louder than stock, everyone will know you have an aftermarket muffler, but its a good sound, not just noise. Just enough backpressure to prevent backfires & gurgling. My power band seems smoother all throughout the RPM range. Strong steady power. No dead spots. No surge areas. Good steady power, more noticable on the bottom. No loss on top end. More responsive. Strong acceleration, I'd guess 3-4 Mph gain on top. Haven't took it out of the yard yet, but so far very satisfied, (have a big yard with long drive). Will update after first trail ride. Installing K&N Dynojet tommorrow night, can't wait to see what else this 500 can do.

Jerome Coker
99 500 scrambler

 

Way to go jerome, I told you, youwould like it. Wait until you hit the trails

L8R,

Steve

 

If you choose not to get the roller I would invest in aftermarket button for the stocker. Check out www.startinglineproducts.com ,they sell sled hop-up, but some are ATV applicable. Jack turned me on to them. They have two different sets of aftermarket buttons that should fit your clutch. Trust me the stockers are crap!

I would think that your next step would boe in the handling dept, maybe new tires-damper-different springs, you'd be amazed at how much a difference a new set of handle bars will make (providing have'nt already done any of these). A small carb bore might also be worth the $$.

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Jerry Goodman '99 400L, '98 TBlazer