2 stroke questions

[exrider12]

i bought a cr85 today and the guy put a new top end in the bike ( certified mechanic) and it has1 hour on it.He said the silencer could need repacking and that could cause blowback is this true? and what is blowback?

thanks

[klutch]

For some reason i can't help but feel he meant backfiring... but i dont know much about two strokes...

[exrider12]

all i know is theres oil or something black where the pipe meets the cylinder. o and how do u repack a silencer?

[250rAL]

I don't know what he meant by blowback either but a silencer that needs repacking isn't going to hurt anything(but your ears) although I've read that it can cut your maximum horsepower. The sludge at the pipe/cylinder junction is common with two strokes and is nothing more than a mess. You can get aftermarket manifolds with O-rings that seal better.

[exrider12]

ok thanks and how hard is it to repack and wat tools do u need?

Originally posted by exrider12
all i know is theres oil or something black where the pipe meets the cylinder. o and how do u repack a silencer?

thats normol on a 2stroke... blow back is when the pipe is not working right an is sucking oil that it blows out back in the head

[ZeroLogic]

http://www.motosport.com/offroad/product/TM-DESIGNWORKS-NO-LEAK-EXHAUST-COLLAR/?prodId=225009&cartItemId=4489574&sMMY=YAMAHA;YZ125;2003

[KXRida]

Originally posted by exrider12
ok thanks and how hard is it to repack and wat tools do u need?

take the silencer off, take it apart, pull the baffle out, throw the old packing away, clean the baffle core with brake cleaner, wipe off oil and gunk, roll new silencer packing around baffle, (some use strips of tape to secure the ends or you can just hold it and put it back in the silencer casing), once baffle core with new packing is in the silencer, put the end cap back on, tighten it, put it back on the bike.

Not hard :eek2: lol

[exrider12]

k thanks guys

[exrider12]

well i got it today and rode it around it runs fine but a slight bog (sat all winter). well i wash it put in to much gas and it overflows out of the gas cap and now it wont run. any sugestions?

[exrider12]

anyone?

[KXRida]

too much gas in it and it won't run? :huh

look somewhere else for your problem. Check you plug first off and make sure it's not fouled. Better yet, put a new one in. Make sure your floats aren't stuck open or anything or your jets don't have any dirt in them. Does it have good compression?

[exrider12]

its a brand new plug the first time it was used was today. it has good compression and a brand new top end. it ran fine before i washed it, could it be something electrical? could i have flooded the engine with gas also?and how do i check the floats? and wat r they? lol:confused:

p.s.it sounds like it wants to start but wont

[UNBROKEN]

have u tried pop starting it , or starter fluied

[exrider12]

il try pop starting it tommorow

[KXRida]

Originally posted by exrider12
its a brand new plug the first time it was used was today. it has good compression and a brand new top end. it ran fine before i washed it, could it be something electrical? could i have flooded the engine with gas also?and how do i check the floats? and wat r they? lol:confused:

p.s.it sounds like it wants to start but wont

it could possibly be flooded. If you let it sit for a little bit, try it again. Also, try turning the gas off as well. Could be something electrical, but everything should be sealed in shrink tube. The floats are in the bottom or "bowl" or the carb, they set the correct fuel level in the carb.

See if you're getting spark to narrow your troubles.

[exrider12]

il check the spark plug. so it started after a tiring amount of tries then itll run for 5 seconds then bog and die? :mad:

[exrider12]

how do i check the floats? also could it need a carb cleaning it sat all winter and what do you recommend on how to clean it?

[KXRida]

Could probably use a carb cleaning, but it's hard to say. Is the gas on? Sounds like you're not getting fuel.

[exrider12]

just pulled the plug is was a dark color which means its running rich? which makes no sense. has a spark but not that big of one? which way to raise the idle also?

[KXRida]

if it's a brand new plug and it's dark already something's wrong. Go try an absolutly brand new plug. Like one that's never been ran and get back to us. Sounds like either a fuel/spark issue. Try a brand new plug. It may save yourself a lot of headaches.

[exrider12]

well what do i check, the plug had black liquid on it i nkow theres a like fabric part but didnt see it. what kind of spark plug should i buy ( i know i want a hotter burning one) are they all same and will fit in any bike?

[exrider12]

please help i wanna ride this thing! if it helps any it ran fine with a slight bog before i washed it idk if i got something wet?

[flyin#5]

clean your carb. look at your pilot jet (smaller jet you will see when you take the float bowl off.. will probably have to remove with a flathead) its probably clogged. blow all passages with carb cleaner then compressed air.

[Premis]

take apart all the electrical connections and blow them out with air, there could be water in them. Check your air filter, did you clean it after you washed it? If the spark plug was black it is running too rich, that could be the pilot jet, main jet, or needle. Also, I assume it takes a pre-mix, did you mix the gas and oil right? anything more than 16oz of oil to 5 gallons of gas is too much oil. That would cause it to bog and run like crap and make the plug black.

If it is flooded, pull the plug out and kick it over a dozen times, if a bunch of unburnt fuel comes out that could've been your problem.

[KXRida]

Originally posted by Premis
take apart all the electrical connections and blow them out with air, there could be water in them. Check your air filter, did you clean it after you washed it? If the spark plug was black it is running too rich, that could be the pilot jet, main jet, or needle. Also, I assume it takes a pre-mix, did you mix the gas and oil right? anything more than 16oz of oil to 5 gallons of gas is too much oil. That would cause it to bog and run like crap and make the plug black.

If it is flooded, pull the plug out and kick it over a dozen times, if a bunch of unburnt fuel comes out that could've been your problem.

just general knowledge for everyone, it's not the oil that fouls the plug, it's the gas. Changing your ratio does nothing but make jetting inconsistent.

Like I said, first try your plug. If it's black, that's not good. What plug are you running? Before you go tearing half your bike apart and running a hotter plug try what you have now. A B8 (b8es, br8es, br8eix, etc) series plug should work fine. I personally don't run anything hotter than an 8. A b8es will by far be the cheapest at no more than $3. If it is infact your plug, then rejet your bike.

[exrider12]

im gonna bring it to a dealer ship and have them take the crab apart clean it ,inspect the rest of the bike clean the airfilter and all that. so il get back to you guys

[KXRida]

cool deal, but did you try the plug first. Also shop labor is $60 an hour I believe, so be prepared for a bill. Hopefully you shop is good to you. Any more the only thing I have shops do is fork seals if I feel lazy ($50 for the entire job seals included isn't bad at all), other than that, I hate putting tires on and I end up either chewing up my rims, pinching a tube, sending a tire iron into my nads, or something of the sort, so I don't deal with tires haha.

I really wouldn't take it to a dealer just yet. Try some of the cheaper alternatives first and if you narrow it down to one specific thing, then take it in. Also, cernic's suzuki charges $18 to clean on oil a filter, just throwing that out there. If you have the money, that's cool and all, but you can buy like 3 bottles of filter oil for $18 and do like 30 filter cleanings/oilings :eek2:

carb wise, check your jets first! It's easy, I'll take you step by step to checking your main/pilot. Turn the gas off, disconnect the fuel line, loosen the hose clamps on the carb boots, loosen the top cap on the carb with the cable in it. If you want to, you can take the slide and needle out, but it's not nessicary to check the pilot/main, pull the slide up a little towards to top of the carb so you can tilt the carb and gain access to the bottom drain bolt, take of the drain bolt (most seem to be 15mm or something close), careful, gas will come out, so do it somewhere where you won't get yelled at (not in the driveway), once the gas is drained out, you will see the main jet (has a hex shape, should be a 6mm socket I believe) and pilot (has a slot in it for a flat head screw driver). You can then take these jets out and look for any obstructions. To take the bowl off, most have three or four little screws and the bottom bowl comes off, this gives you more access to the pilot if you need it. Follow all the instructions in reverse order to put it back together. Also, do you put your jets in with a ratchet. Finger tight or you'll snap them off. Not loose that they have play in them, but don't tighten them a lot or they'll break, I've done it. Sadly that'd probably cost your $30 at a shop. All of that can be done in about 15 minutes or less.

Here's another question, when was the last time you changed your oil? See if it's a red color (unless you are running gearsaver) red tint usually indicates coolant in the oil, which usually is due to a bad water pump seal. Happened on my kx 85, ironically it wouldn't fire after I washed it and I had to troubleshoot all of this. Like I said, TRY A PLUG FIRST. It can only be so many things. When was the last top end, what compression reading are you getting. Is it hard to kick (well for an 80).

[exrider12]

i get tired after a little while of kicking but im not sure cuz this is my first dirtbike. I looked for the oil and there was almost none in the engine! i almost added a whole bottle of oil to the (transoil) but u said its tinted red and a brand new bottle of the transmission oil is red? i would do the carb thing myself but my dad wont let me and wants it done right:rolleyes: o and it has 1 hour on a new top end. but il trya plug. thanks

[KXRida]

Belray gearsaver is red, but if you have conventional oil in it and it comes out red (and you're loosing coolant) it's a water pump seal. I would check you manual, because I can almost guarentee an 85 does not take 1000cc of oil. Most 250's only take 800ish. Put the right out amount in. Too much and the crank whips the oil and it foams up. Like I said try a new plug first and see what happens. Kicking and kicking usually doesn't do much. The only time I'd keep kicking is if the bike atleast tryed to fire some. What year is the bike? What's done to it?

[exrider12]

alright replaced the spark plug and now it runs fine but its shooting oil out of the exhaust? any ideas? and its stock

[exrider12]

o and some transmission oil is coming out of an overflow tube from the engine so i think i put a little to much in? its olny dripping a little.

[exrider12]

anyone?

[Caseys 300ex]

It could be that your oil to gas ratio is to much so the extra oil isnt being burned and just coming outta your exhaust. Youll have to change the plug everytime it fouls. My 250 fouls the plugs and i cant get it to start on a cleaned plug.. just a new one.

[exrider12]

i put 8 oz of 2 stroke oil in 2 gallons of gas which is 32:1 right?

[exrider12]

anyone?:huh

[exrider12]

i need to know by tommorow afternoon!

[KXRida]

rejet, that is the only way to solve it. DO NOT, I repeat DO NOT keep switching ratio's. Pick one, stick with it, and jet for it. You are fouling the plugs, so you're going to have to lean up the jets on it. Follow my steps above and you'll be fine. ;) I haven't fouled a plug on any 2 stroke in over 4 years. Drain the oil you have in it, and put the correct amount in. Stick with something around 32:1. The extra oil will help with the constant revs of the bike, but it sounds like you're still pretty new to bikes, so I don't think it will be revved out. With my 200sx I run 40:1 just because I'm not revving it as high as my 125's. I was pretty sure you needed a new plug. You want the insulator to be a medium to dark brown, not black or white. Also, a "properly" jetted 2 stroke should only really smoke during warm up. At opereating temperature, they should be little to no smoke. When you see the bug foggers out there, they probably go through about 20 plugs a day. Jetting is all trial and error. That's the only way you can do it right. Yah you can take it to a shop and have them jet it for the conditions right now, but what happens when it gets hotter this summer and it needs rejetted again? Changing mains/pilots take 5 minutes TOPS if you're slow. Moving the clip takes about 10ish. It's not hard, just learn to do it. Jetting is not a one time set it and forget it kind of thing. If you want your bike to run properly and get the most power out of it that you can, jetting is essential. Lots of guys throw pipes and reeds on bikes and never rejet them. If you're going to spend the money on them, spend the extra couple of minutes and rejet for the new mods.

[exrider12]

im going to check the plug tommorow and see what color it is. If its black or white i will rejet it. the thing is it shoots some oil out of the silencer and builds up on the rear fender. It doesnt really smoke alot when i get riding but does during warm up. so 8 oz of oil in 2gal of gas is 32:1? and i do rev it and ride it hard!:blah:

[exrider12]

??

[KXRida]

well if you're fouling plugs, that is a pretty good indicator that you need to rejet. Did you ever end up repacking your silencer?

and yes 8.0 oz. to 2 gallons is 32:1. 4.0 oz to one gallon is 32:1 and I believe 3.2 oz to one gallon is 40:1.

[Old Dirtbiker]

I agree, get rid of the lower crank oil. The 85 Honda's if I'm not mistaken require right at 1/2 qt., no more.

It will also have a bolt on the right side of the engine case.
This should be removed as your filling the crank to allow air to vent and keep you from overfilling the engine case.

Your bike needs to be posted against a wall or tree so that its not leaning over when re-filling the oil level.

Depending on your riding habits, the lower crank oil may require changing fairly often. This oil bathes the clutch disc. As the disc where down the particles stay in the oil. So the oil may look okay but can still be pretty nasty and cause early engine/clutch failure.

The vent bolt & drain bolt may or may not have a small copper washer that helps seal when tightened down. Try not to lose it.

You have some good responses and some not so good.
Use caution, ask questions, and don't get in a hurry.
The riding season is just now coming in.

[Old Dirtbiker]

Oh ya exrider, another thing.

You have one of the finest 2-smokes ever made.
Your bike has more all around torque for its weight than a lot of larger bikes. The front of my Sons 85 seemed to always be up!!!

They are also very easy to service, maintain and will provide you loads of fun without breaking the budget.

There are all kinds of easy inexpensive upgrades available once your ready.
Smaller front sprocket, v-force reeds, Fmf pipe,and a shorty to name a few.

I would suggest that you replace the factory hose clamps on all coolant hoses with a heavier type as the originals "will" break.
When that happens, expect to do another top end rebuild.
Not overly expensive but think of the down time.

Another thing to remember is even though its water cooled, it still needs to get rid of the engine heat. Keep the fins clear of packed mud, treat it like a freind and it will return the favor.

Something else I would suggest is to get yourself a "CLYMER" manual for your particular bike. They are chock full of pictures are a wealth of knowledge, and should be handy when riding in case of a unexpected failure.

Good Luck and have FUN.

[KXRida]

Originally posted by Old Dirtbiker


Something else I would suggest is to get yourself a "CLYMER" manual for your particular bike. They are chock full of pictures are a wealth of knowledge, and should be handy when riding in case of a unexpected failure.

Good Luck and have FUN.

ah some clymer manuals are good and some not so good. Honestly, you CANNOT beat an oem honda manual. Very very descriptive and detailed. Best oem manual IMO.

As for the 85's when I raced them, it was pretty much pick your color. With the smaller bikes, they are all so close to being the same, the most riders can't really tell the difference. When I was running 85's the biggest difference I could tell was the ktm. More power than the others, but it turned like crap. Other than that it was an amazing bike. TM's on the other hand were amazing. I got the chance to ride one, it was nice.

The 250f's are getting the same way now. They are all getting so close, that there isn't a bad one and they're almost the same. Yes they differ in spring rates and suspension, but for a novice rider, they can't really tell.

[KXRida]

One more question for ya and hopefully a good response... What premix are you running? please don't say weedwacker oil.

[exrider12]

its honda 2stroke racing oil and any reason why it shoot oil out of the exhaust? and its leaking a little tranny oil so i think i over filled it ( out of overflow i think). but its going to a shop tonight so it should be alset. and no i did not repack my silencer im gonna have them do that to. thanks guys for all the help

[KXRida]

well the extra oil could be from worn out silencer packing and the oil not being completely burnt (rejet!).

if you're leaking out the overflow I would assume just by the name, that you have too much in. Glad to hear we helped you, but my next question is, why would you still go to a dealer to have them change your oil and repack your silencer????? :eek2:

dealers are not cheap when it comes to service and they always find something extra to tack on the bill (lubing cables, adjusting chain, etc). I don't know about you, but I don't feel like paying XX amount of money to have someone adjust my chain when I can do it myself in 2 minutes.

[exrider12]

its more my parents want to make sure its save to ride:rolleyes: and ready to ride because im going to start racing.

[KXRida]

well what are you going to do when you go to a track and you have you bike jetted for a 60 degree day, then in the summer it goes up to 90? Call the shop? :p

Learning to do these simple things are part of riding. So you're saying it's not safe to clean you filter or repack you silencer by yourself? :confused:

[Flyin-Low]

Originally posted by exrider12
its more my parents want to make sure its save to ride:rolleyes: and ready to ride because im going to start racing.

Let your parents know that they are doing nothing but hurting you by not letting you work on the bike yourself.. If you ride in dusty conditions you'll need to clean your air filter AT LEAST every couple of rides, so your bike will be in the shop a lot lol.

And the day someone gets badly injured because they didn't clean their air filter or put new packing properly let me know! :rolleyes: