oh, i am going to keep an eye on the oil for my first couple rides. How much oil do these bikes typically use. I am using amsoil interceptor.

thanks

 

if you want a clean and no sticky piston stay with polaris oil,
the interceptor oil is the worse fries lube i've ever used in a 2 stroke,so fat! stuff is useless.

 

ok boys, i need some help. Just for refresher, I am new to this site and new to scramblers in general. From what i have read, 400 scramblers are suppose to be faster than 500 scramblers stock, and when you mod the 400 it destroys the 500.

Well I consider mine mildly modded. My buddy has a 2000 scrambler 500. His is stock with the exception of a epi clutch kit. Going through the trails mine feels only slightly if any faster or more powerful. On a road we are about even until 45 mph then I start gradually going by him. Mine might be 4-5 mph faster on the top, but not much different midrange or bottom.

Is that how it should be?

Any suggestions?





2000 Scrambler 400 4x4
.040 weisco
hpd trail pipe
270 main jet, 34 mikuni
hpd clutch kit
delta v-force reeds
reed spacer
.020 head milled
hpd steering stablizer
ipt wheels
itp mudlites

 

First off you shouldnt add oil to your gas if you are using the oil injector, it will only add too much oil to the mix, in turn using less gas and running hotter.

The oil lubes but the gas cools and you could be running it hot!

Second you should destroy a stock scr500, my quad is MUCH faster with the mods and will walk away easily from my sp700 at any speed, especailly above 40 mph.
With only the pipe and mild HPD clutch kit it would beat a z400 (by about 1 lenght) untuil he hit top gear.

I would say it would give a stock trx450 or YFZ450 a good run if not beat them to 50 /60 mph.
I'm trying to set up a race with a friend of a friend with a TRX450.

I don't remember the color of the primary spring but it's the one in the mild HPD clutch kit from Rick Ritter at RcR.

Jim

 

Its good to run a little fat on these bikes, you could check the oil injector by removing the line for a split second it should pulse it out.

I'm going to get a Trail Tech as soon as they have RPMs on the newer model or a Tiny Tech but no i dont know about the RPM's.

Jim

 

My 99 400 is still bored to stock specifications - all I really have is an airbox kit from Ritter (plus I added a third large hole to let in more air) plus an HPD pipe with a stock silencer - I commonly ride with a group that all have 700 to 750 4-strokes, and while we all top out at about 70 mph, I am way quicker off the line. I have to imagine I would kill a 500, so something needs adjusting - your bike should be even faster than mine!

 

ok boys, there must be something massively wrong with my bike. Every where I look on this website you guys are talking about killing 660 raptors. A race between my scrambler and a raptor would be a joke.

Here is somemore info on my bike. When the mechanic rebuilt the motor he said the v-force reeds were a little bent or something, so he installed the pedals the other way when he put the motor back in.

There is also a rattle coming from the rewind side of the motor when the bike is idling. It might just be the pipe rattling against the motor, but it doesn't sound that good. Btw the motor only has about 6 hours on it. I am hoping it is not the counterbalance shaft. After the motor was complete, but not in the bike, there was a little rattle or play in the counterbalance shaft. I took the motor to the dealer and they had never rebuilt a 400 before they said. The noise went away once you turned the crankshaft over fast on the bench, so the polaris mechanic said not to worry about it.

The motor also has 135 psi compression when hot. It has 110 cold. The head has been shaved .020 These bikes are suppose to have 115 stock according to the polaris manual. I am not sure if that is hot or cold.


The mechanic also mildly ported the cylinder. I think he mostly just cleaned up the ports a little. Would this severly make the bike slow if not done right?

The bike really is most depressing low end. My buddies and I mostly ride in mud and trail. When the bike goes through the mud you can really see how its performing. It starts off a little sluggish but when you get on it, it really really has torque. My buddies can't believe how it rips through mud, but it really only excells about 3/4 way through the mud.

I am not a atv guy, but I have driven sleds all my life. The bike seems like its loading up. The main jet is 270 right now. I filled the oil up full on my last ride yesterday, I am going to check how much oil it used and see if it is way too rich. My buddies say it is smoking most of the ride, its running amsoil which is suppose to smoke a lot less than conventional oils.

Maybe its clutching. The primary clutch is in mint shape, except it has a giant groove where the belt would sit with the bike idling. I guess it really isn't in that great of shape. Maybe the belt is having trouble getting over this limit. Are these bikes suppose to use the full primary clutch. How high should the belt ride at full throttle. With my polaris sled, I can get full use of the clutch right up to the top.

I am going to throw this bike on the radar gun this weekend to see exactly how fast it is, so i can post it, and maybe you guys can help.


please help.

 

Sounds to me if they bored your cylinder then they did a real loose job.If they did, that would explain the rattling you are hearing. It should have around 145 to 150 pounds of compression for a new top end rebuild with a head milled at .020. Another thing...if they didn't know what they were doing when they ported it.. then yes that can hurt performance too. The bad bottom end performance is probably due to low compression. Flipping the reeds is a common thing to do when they have some time on them. The big groove is from the belt riding there in slow speed situations(and may be one of your biggest problems right now). A new primary is really the only thing that will cure this problem. Do you happen to know what primary spring you are running? It could be a high engaging spring causing it to only run good at the higher throttle ranges. You can run a lower engaging spring and that will help with that but it could be your low compression. How long has it been since you had the top end rebuilt?

 

primary spring is hpd red/yellow

top end was just done two weeks ago, motor has about 6-7 hours on total rebuild.

the weisco piston said 3 thousands clearance on the piston box, we went 5 1/2 thousands because hot seat as well as some atvconnection members said go a little more because of weisco heat expansion.

thanks guys

 

Both of my 400's were done at .004. Hope you find out what the deal is..do you have another Polaris quad that you can swap primary clutches with to see if that is the problem? You may just need to let it break in a little more. My wifes trail mod is jetted at a 260 and still fat. But that's ok by me... I can outrun a 660 raptor and Banshee in 300 feet on my wifes bike no problem.