cr85r expert mods?

[robertmoto10]

hey guys i just got a new cr85 and i was wondering what mods i should get?

 

[01HondaCR]

Practice

 

[_JOE_]

Maintenance.

If it's a brand new bike get a few spare air filters, a couple tires, a few bottles of pre-mix and tranny oil, a sheet of muffler packing, a couple levers and a top end kit. That should get you through a season.

If you have any money left sign up for a riding school. If you don't have a local school check with a local track and they might know of someone who could help you. Your skills will have a MUCH greater effect on your lap times than a shiny exhaust pipe.......

 

[_JOE_]

And get the bike jetted right....http://www.dirtrider.net/forums3/showthread.php?p=1340315#post1340315

 

[helio lucas]

there are some mods that work well. porting is the better mod on that bike. or a big bore 100cc.
other than that and fine tuning is a wast of time and money for a non-expert rider.
i have a fast cr80 and my buddy can beat me on a slow chinese junk pit bike.
practice until your body is hurting for a week... then practice more. riding time is the key...

 

[robertmoto10]

well i bout it used about a week ago i like it but i want to get a little more bottom end power out of it and i have been riding for 4 years

 

[Patman]

It's not a bottom end bike, if that's what you were looking for you should have looked at a power valve bike like the KX or RM. Having 4 years of riding experience doesn't mean you are fast or even near fast. Go to a track and enter the Novice or C class ans see where you place. If you don't lap the field learning to ride better should be your priority. Sorry if it sounds mean but that's just the way it is.

 

[_JOE_]

Your best bet would be to rebuild it with a complete top and bottom kit. Replace the reeds and repack the silencer. As Helio said, you can alter the porting to shift the power a bit but that's about all it'll do, shift the usable power lower in the rpm range. It will still have next to nothing down low with a healthier midrange and less top end pull. On a non-powervalved small bore you're better off to just leave the throttle wide open and use the clutch to feed power to the wheel.

 

[robertmoto10]

iv never raced and i have only been to the track twice cause i mostly go out to the desert but i want to get into racing some more

 

[robertmoto10]

what are some good premixs cause i dont want to get a realy crapy one

 

[robertmoto10]

ya and now that i think of it if in the rocky sections if i feather the clutch it handles fine

 

[_JOE_]

Any premix from dirt bikes at your local powersports shop should work fine. Pro Honda, Maxima, Amsoil, Yamalube, Klotz, Bel Ray, etc, etc.....

You ride an 85 in the desert and want more low end? Sounds like you need to adjust your riding style or buy a different bike.

 

[Patman]

There is no best premix. Use the search feature to see them 1.6 trillion threads on the subject. Pick an oil & fuel supplier, jet the bike for it and you should be fine. On a small bore in the desert I would think more oil is better so maybe 20:1 or 24:1 would be a good choice.

 

[robertmoto10]

ok thanks pat man but isnt 20 and 24 like sorta off from like 32 and 40

 

[Patman]

It's just a higher concentration of oil. More oil means more better for your engine.

 

[_JOE_]

With the RPM and heat in that tiny little engine you can use all the extra protection you can get. Thinning the mix (40 or 50:1)won't help anything. Some try to use it as a bandaid for poor jetting only to make the jetting even further from ideal. If you're not sure stick to the factory recommended mix, should be 32:1 and jet it properly. I would run it a jet size larger, maybe two, over ideal to add a little margin of safety in the desert heat and frequent full throttle runs.

 

[RM85rider123]

you are definitely going to be flying through top ends in the desert. Make sure you buy at least 1, and change it after about 17-20 hours of riding.

 

[robertmoto10]

thanks guy and should i jet it myself or take it somewhere for a pro to do it cause i do most of my own matinece

 

[RM85rider123]

thanks guy and should i jet it myself or take it somewhere for a pro to do it cause i do most of my own matinece

If you know how to jet it, then go ahead.
here is a jetting guide-

A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. If you have never jetted your bike correctly, you will almost certainly gain some performance at some point in the bike's powerband. A cleanly jetted pilot circuit can be the difference between having to clutch the bike out of a turn or not. The needle can make all the difference in the world for the power of the machine in most situations, as it controls the throttle range that most riders spend most of their time using. A correctly sized main jet could mean the difference between being able to rev out high enough to not have to shift one more time at the end of the straight, or the power falling flat on top and requiring you to make that extra shift.

Are you fouling plugs? Many people will tell you all sorts of band-aid fixes, from running less oil, to running a hotter plug. Both are incorrect fixes for plug fouling. It's all in the jetting.
The only way to know what jetting changes you will need is by trial-and-error. No one can give you jetting specs, because every bike is different, every rider has a different style, and jetting is totally weather dependent. Unless the person telling you what jets to use is riding an identical bike, on the exact same track, at the same time, his recommendations are meaningless.
Jetting is fairly simple, and is a useful skill to learn if you ride a two-stroke and want it to perform at it's best.
It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving.

Before you start to rejet your bike, you need a clean air filter, a fresh plug (actually you need several plugs to do plug-chop tests for the main jet), and fresh fuel. One important detail: Make sure the engine is in good mechanical condition. If your engine has a worn top-end, fix it first. Trying to jet a worn out engine is a waste of time. The same goes for reeds that don't seal properly, and a silencer that needs re-packing. Worn reeds will mimic rich jetting, and worn rings will mimic lean jetting.

Before you start the jet testing, install a fresh plug. Set the float level to the proper specs, an incorrect float height will affect your jetting all across the throttle range.

Warm the bike completely, and shut it off.

As already stated, start with the pilot circuit. Turn the airscrew all the way in, then turn it out 1.5 turns to start. Start the engine, and turn the idle screw in until you get a slightly fast idle, or hold the throttle just barely cracked, to keep the engine idleing. Turn the airscrew slowly in, and then out, until you find the point where the idle is fastest. Stop there. Do not open the screw any farther, or your throttle response will be flat and mushy, and the bike may even bog. This is only the starting point, we will still have to tune the airscrew for the best response.

Now is the time to determine if you have the correct pilot installed in your carb. The airscrew position determines this for you, making it very simple. If your airscrew is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet.

Once you have determined (and installed it if it's necessary to change it) the correct pilot jet size, and tuned the airscrew for the fastest idle, it's time to tune the airscrew for the best throttle response. Again, make sure the bike is at full operating temperature. Set the idle back down (the bike should still idle, despite what you read in the Moto Tabloids), and ride the bike, using closed-to-1/4 throttle transitions. Turn the airscrew slightly in either direction until you find the point that gives you the best response when cracking the throttle open. Most bikes are sensitive to changes as small as 1/8 of a turn.


The airscrew is not a set-it-and-leave-it adjustment. You have to constantly re-adjust the airscrew to compensate for changing outdoor temps and humidity. An airscrew setting that is perfect in the cool morning air will likely be too rich in the heat of the mid-day.

Now, it's time to work on the needle. Mark the throttle grip at 1/4 and 3/4 openings. Ride the bike between these two marks. If the bike bogs for a second before responding to throttle, lower the clip (raising the needle) a notch at a time until the engine picks up smoothly. If the bike sputters or sounds rough when giving it throttle, raise the clip (lowering the needle) until it runs cleanly. There isn't really any way to test the needle other than by feel, but it's usually quite obvious when it's right or wrong.

Last is the main jet. The main jet affects from 1/2 to full throttle. The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan.

Once you have a little bit of experience with jetting changes, and you start to learn the difference in feel between "rich" and "lean", you'll begin to learn, just from the sound of the exhaust and the feel of the power, not only if the bike is running rich or lean, but even which one of the carb circuits is the culprit.

The slide is also a tuning variable for jetting, but slides are very expensive, and few bikes need different slides, so we won't go into that here.

 

[robertmoto10]

cool thanks rm85rider i think i could do it now

 

[flyingfuzzball]

yeah learn to do it yourself. Its one of those skills that you will use over and over again if you keep riding. Especially for when you ride in varying conditions.