CR 80 Compression Specs

[bluemarlin04]

:mad3: :mad3:
I got a 1993 cr80 and when I got it it would rev fine in neutral but put it in gear and it would stall and bog out. I rebuilt the top end with new piston, ring, and gaskets and it does the same thing :mad3: !!

I checked compression and it came to 123 psi. Is that normal???

I think the carb is fuking up some how Im just not sure

Anyone got suggestions Im open for them. Peace

[SeaBass44]

what does your manual say?
you got one of those right:)

[bluemarlin04]

what does your manual say?
you got one of those right:)
uhh yea, I mean no

[vegasjeep]

:mad3: :mad3:
I got a 1993 cr80 and when I got it it would rev fine in neutral but put it in gear and it would stall and bog out. I rebuilt the top end with new piston, ring, and gaskets and it does the same thing :mad3: !!

I checked compression and it came to 123 psi. Is that normal???

I think the carb is fuking up some how Im just not sure

Anyone got suggestions Im open for them. Peace

your compression should be higher then that. Your clutch is probably the problem.

[stupidfast]

this has nothing to do with the clutch, lolololololololol. its not your compression either. it might be your reeds, or your reed cage. its got a rubber coating on it and it might be cracked or damaged. replace them with boyesens if so, or go stock replacements if its just a 93. a 93 isnt competitive in any racing series anyways. either that or your carb needs adjusting. it is most likely that. check for any debris or dirt in the jets. take off the bowl and blow it out, along with the jets. if the bike was bought in your area new, then the carb should already be jetted for the local enviroment/climate, so you shouldnt have to change anything out, unless its been screwed with before. but before you ever do any carb adjustments, make sure you air filter is clean and oiled and taking in the most airflow it can, or else you will just be tuning your carb to be running off a dirty filter. mess with the air screw. it will adjust how it handles at mid rpm range. if its bogging before it hits the power band, thats the scew to adjust. screwing it out lets in more air, screwing it in lets less in. the slow jet contols low rpm performance. im not sure if larger or smaller will fix your problem. the main jet controls higher rpm performance, and the needle controls up to mid rpm performance as well (depending on the tapered angle of the needle). the needle also has a clip on the top. raising this clip will lower the needle more into the main jet, and making the air/fuel mixture leaner. lowering the clip will make it run rich. better rich than lean. too lean can cause piston/ring/cylinder damage and overheating. too rich will only tend to foul plugs and get black goo spitting from the silencer. adjusting all these may not even be nessesary if they are all still stock, but they all very in sizes to restrict the amount of fuel is mixed with the air that comes in. it could also be your float valve. pull the pin out and pull the float out. the float valve will have a hoop that will be around a tab on the float (the float valve is very small, dont drop it). inspect the rubber tip. if there is a groove in it (will be like a ring groove), replace it. while your doing all of that, you may as well empty the gas tank, and remove the bolts that hold the fuel petcock to the tank. there should be a filter on the other end in the tank.. there are probly tons of little fibers and lint and shit (suprisingly) all over it. you can just pick it off. if its damaged, replace it.. AND, you may as well cut a small section of the fuel line out and slap on a fuel filter that u can get at a bike shop for under $3. now theres a funny thing with carburators... sometimes you dont even need to adjust anything. sometimes taking it all appart and putting it back together will fix it... its not a big project.

[vegasjeep]

this has nothing to do with the clutch, lolololololololol.

You right it would never have anythign to do with the clutch. He pulls in the clutch which pushes the plates apart and puts it in gear with a slipping clutch and it would kill the bike without proper adjuatmsnt or friction thickness......

it oculd be other things as well but the clutch is where I would start.

if its just a 93. a 93 isnt competitive in any racing series anyways

your right, cause with a fresh rebuild it is the same motor used up until 2002. The 80 class has not changed much in over 10 years.... I would know a little about the class before telling people their bike is not competitve....

[vegasjeep]

one mroe thing youll need to kick the bike over at least 7-8 times with the throttle wide open to get an accurate compression reading on a two stroke.

[stupidfast]

he says that the bike bogs. it wouldnt bog if it was the clutch. if it was the clutch he would have mentioned that the bike lurched forward, and then stalled, or the bike would travle with the lever pulled in. the clutch has nothing to do with it, but if i really am wrong, take off the basket and file off the grooves. the grooves are what keep the plates from seperating = bad. without seperating, the bike will move with the clutch lever pulled in, dont bother adjusting it, becasue the groves in the basket are still going to keep the clutch plates in place. but thats only the problem if the bike is lurching forward with the clutch lever enguaged. otherwise, its still the carb or the reeds. and no, a 93 ANYTHING isnt competitive in any class.. the improvements since then are astronomical. i was racing minis up untill this year. i would know.

[bluemarlin04]

Ive rebuilt the carb and the jets are fine, not clogged or anything. The reeds are ok, not cracked but maybe ill check the rubber piece, I checked the ignition and it sparks fine, Im gonna go for the reeds tomorrow and see if thats it. And I think it could be competitive, its all about the rider. Not like im racing it anyways, its my playbike. :flipoff2:

[vegasjeep]

he says that the bike bogs. it wouldnt bog if it was the clutch. if it was the clutch he would have mentioned that the bike lurched forward, and then stalled, or the bike would travle with the lever pulled in. the clutch has nothing to do with it, but if i really am wrong, take off the basket and file off the grooves. the grooves are what keep the plates from seperating = bad. without seperating, the bike will move with the clutch lever pulled in, dont bother adjusting it, becasue the groves in the basket are still going to keep the clutch plates in place. but thats only the problem if the bike is lurching forward with the clutch lever enguaged. otherwise, its still the carb or the reeds. and no, a 93 ANYTHING isnt competitive in any class.. the improvements since then are astronomical. i was racing minis up untill this year. i would know.

WEll you were misinformed. Until the motor change on the YZ in 02 the YZ80 went unchanged SINCE 2003.

the CR was updated suspension wise in 96 but the motor also went unchanged until 2002. The suspension still is the ole suspension from 96

The Rm80 also ran the same motor since 1986 until the 85 class update in 02. The suspension changed I believe in 03 to upsdie downs and other then that that bike went changed until then

the Kx has had off and on changes but they simply bored the cylinder out a bit to get an extra 5cc but that motor went unchanged since the late 80s. suspension wise it was updated in 01-02 as well.

So your saying that the 02 bikes are also outdated?

In a serious class where your a top notch rider then maybe youd notice the difference. But those same top notch riders can ride that 93 bike almost as fast. It is a great bike.

[SeaBass44]

WEll you were misinformed. Until the motor change on the YZ in 02 the YZ80 went unchanged SINCE 2003.

the CR was updated suspension wise in 96 but the motor also went unchanged until 2002. The suspension still is the ole suspension from 96

The Rm80 also ran the same motor since 1986 until the 85 class update in 02. The suspension changed I believe in 03 to upsdie downs and other then that that bike went changed until then

the Kx has had off and on changes but they simply bored the cylinder out a bit to get an extra 5cc but that motor went unchanged since the late 80s. suspension wise it was updated in 01-02 as well.

So your saying that the 02 bikes are also outdated?

In a serious class where your a top notch rider then maybe youd notice the difference. But those same top notch riders can ride that 93 bike almost as fast. It is a great bike.

Ouch! That is going to leave a mark :laughing: :laughing:

[stupidfast]

the power and handling differences are way to much better in every 85 vs its last gen 80. the kx received very little, the cr got a powervalve and 5 more cc's, and the rm got suspension and the motor, but everything else was almost all redesiged on the last two. the yamaha was almost completely redone, and the ktm was brand new. they perform much better than their last gen. in a professional class, a large difference would be noticed.. easily

[bluemarlin04]

Like I said before the rider makes the bike. Im sure RC could spank people on a 1980 rm 250 if he wanted too :flipoff2:

[stupidfast]

lol.. im just going to give up on this one.. rc would loose even on a 96, and hes the fastest racer in the world...