I think you will find you've fitted the crank seal in the wrong way round
.Don't forget you also want to keep the crankcase pressure in the crankcase.
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| 79 cr250 elsinore smoking like crazy and carb screw settings https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=1812 |
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| Author: | digitalbrad [ Sun Mar 30, 2008 4:16 pm ] |
| Post subject: | 79 cr250 elsinore smoking like crazy and carb screw settings |
was just wondering if anyone would have some more insite for me. I bought a cr250 a few months ago and finally got to working on it, when i first bought it i took it for a quick boot and didn't smoke at all. when i got to changing the oil, there was maybe 100ml in it, i filled it back up untill oil came out the oil check plug on the RH side (about 850ml). I fired it up (in my garage by my stupidity) and man did that thing smoke!. was quite smokey in there and in the house!. tried letting it run for a while to see if it would clear itself out and no luck. So would i be correct in assuming that one of the seals are gone? would it be the one where the crank comes through into the tranny. any more ideas would be graciously taken!. also was wondering what the standard screw settings are on what i am assuming is the idle screw and fuel air screw? thanks!! |
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| Author: | ricortes [ Mon Mar 31, 2008 9:36 am ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
The clutch side oil seal is one of the prime suspects. Unfortunately the center case seals have a tendency to go too, letting transmission oil in. If it is the center seal it is worse news since you will have to split the cases and it isn't a trivial exercise. The good news is everything is available and fairly cheap if you are looking to keep cost down. Gasket kits are about $50 and you can get made in China bearing and oil seal kits for less then $100 on eBay. Rick |
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| Author: | woosh [ Mon Mar 31, 2008 9:59 am ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
My mt250 was puffing a lot of white smoke when I split the case it was the clutch side crank seal that was bad but dosnt mean yours is could be another. I am affraid of the chinese bearings and seals are they as good as the japanese ones? I spent two weeks traking down the mt bearings as a few were discontinued I am just more comfortable with japanese parts. |
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| Author: | dogger315 [ Mon Mar 31, 2008 4:50 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
I feel the same way about "made in china". I wouldn't want to put all the time and effort into a bottom end rebuild just to have a failure a short time later due to a bearing or seal produced with little or no quality control. Bearings and seals are cheap. Only use domestic or Japanese, that way you know you are at least getting decent quality and a little extra peace of mind to boot. dogger |
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| Author: | digitalbrad [ Mon Mar 31, 2008 9:16 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
i work at a honda power equipment dealer, I ordered up the seal today, so i'm guessing that it is used somewhere in one of their pieces of power equipment. i hope if i need any more parts they reference over too!! and hopefully when i tear off the side cover i don't find a bunch of other stuff wrong. |
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| Author: | digitalbrad [ Sun Apr 06, 2008 11:49 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
alright well i went and got a seal but it's not an exact replica of the original honda seal. the honda one had a spring on both sides while the one i got was still a double lipped seal. i installed it backward because i figured like seals on everyhting else you put the lipped side to the side you want to keep the oil on. there was also an o-ring that i replaced with a non-oem one. the one i put on fit tighter and was a bit fatter which made me feel better cause the one on there seemed just barely tight. Does all this work that i've done seem to be okay to you guys? Does it matter if i put a full synthetic oil in there or just stick with a regular 10w-30 or so? well atleast if i did anyhting wrong, i'll be faster in taking it apart i guess. heh |
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| Author: | spannerman167 [ Mon Apr 07, 2008 11:47 am ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
I think you will find you've fitted the crank seal in the wrong way round .Don't forget you also want to keep the crankcase pressure in the crankcase. |
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| Author: | dogger315 [ Tue Apr 08, 2008 9:14 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
I've been following your progress because I am also rebuilding the bottom end of my '79. Spannerman is correct, it's all about keeping the pressure in the crankcase on a two stroke. I'm assuming the O ring you are talking about is the one that fits inside the primary drive collar. It's probably not a good idea from a durability standpoint to install a non standard O ring around a crankpin that will spin at 10,000 + rpm as well as heat and expand to over 250 degrees. I would locate and purchase the correct seals (OE or equivalent) and O ring. Put everything back together using new gaskets then perform a leak-down test. If your engine can sustain 8 psi for one minute (longer is better), you are in good shape. A lot of the startability and inconsistent running problems can be traced back to leaks in the seals or mating surfaces. Like I said in a previous post, bearings and seals are cheap - get the right ones and save yourself some headaches. Good luck, dogger |
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| Author: | digitalbrad [ Mon May 19, 2008 8:43 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
UPDATE to make a long story short well i have installed the proper honda seal and o-ring and it's still smoking. The install couldn't be any better as we I've put a speedy sleeve on the collar that goes inside the seal so that i don't have to worry about any grooves in it, and also made sure that the o-ring was mating up good to the inner race of the bearing. and so the unit it still smokier then a chinese poker house. So the engine is comming out and am going to look at the crankcase gasket and install in new bearings. Kind of a pity that it came down to this but least i'll be able to see everything now and know the exact shape it's all in. |
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| Author: | dogger315 [ Tue May 20, 2008 4:31 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
Sorry to here the "easy" fix didn't work. Like you said, at least now you will be able to assess the entire bottom end and may even catch something else getting ready to let go. Buy yourself a complete engine gasket kit, new dowel pins, snap rings and thrust washers. Also, I would replace all the 30+ year old bearings and seals while I had it apart. The cases can be stubborn, just resist the urge to pry them apart with a screwdriver. Remember, while you are wailing on the cases with a mallet trying to get the rusty dowel pins to give it up, how satisfying it is to be working with your hands - kind of therapeutic. Have fun. dogger |
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| Author: | digitalbrad [ Tue May 20, 2008 10:04 pm ] |
| Post subject: | Re: 79 cr250 elsinore smoking like crazy and carb screw settings |
luckily i have a friend with honda tools as he used to work in a honda dealer. So he says he has a crankcase splitter which is super good. yeah i figured all the seals and bearings would be good to replace once you are that far in. I'll have to check into the thrust washers and snap rings and no doubt i'll be taking lots of pictures so i don't have any "spare parts" in the end  i'll try and give another update in a couple weeks
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