Vintage Dirt Bike Q & A

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PostPosted: Mon Oct 25, 2004 11:58 am 
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Joined: Tue Sep 07, 2004 7:55 am
Posts: 6
Who's been down this road before?........Started the disassembly of my newly acquired 79 250. It never ceases to amaze me - the stuff I find on these project bikes. This bike ran when I got it, but wasn't too easy to start. So I started the fun last night.... things coming apart in a reasonable fashion and only a couple of minor things made me cringe, stuff like not using a washer and burying a bolt head into plastic parts... or the wrong fasteners. I was amazed at the detail given to this poor beast. The front motor mount had a missing nut. That's ok as the old owner used a small hose clamp to hold the bolt in the bracket..... BUT, the one that troubles me is the lack of a base gasket. I found some evidence of silicon sealant as the stuff had been squeezed into the crank area........ I couldn't get the darned head nuts loose, even with heat. My fear is maybe they decided to leave the head gasket out to and really tightened the head down to compensate for the lack of gaskets? Does anyone know what thickness the base gasket is supposed to be? Other than the advice on the gasket, does anyone have an amusing story about basket case bikes?


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PostPosted: Mon Oct 25, 2004 10:08 pm 
I just took apart my biddies 79 CR250 and was amazed to find no base gasket at all. Not even silicon! But it ran when he bought it!. We also got a 78 CR125 that ran with no head gasket at all. It ran like crap and was hard to start but it would run. Just shows how these Hondas were abused over the years but kept on goin.


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PostPosted: Tue Oct 26, 2004 11:39 am 
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Joined: Fri Feb 27, 2004 10:20 pm
Posts: 906
Location: San Clemente, CA
Surprise me and tell me the swing arm pivot is not siezed too :cry:

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF


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PostPosted: Thu Oct 28, 2004 10:43 am 
My 1979 CR250 came with a women's stocking (oiled), tie wrapped around the air cleaner cage. The engine was mint.


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 Post subject: Woes
PostPosted: Thu Oct 28, 2004 12:20 pm 
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Joined: Tue Sep 07, 2004 7:55 am
Posts: 6
my 79 swing arm bolt came out easier than I thought......but it was pretty dry looking at that. It looks as though maybe the head gasket was not used either....... Can't tell yet. My fear is the idiot left both out in favor of silicone sealant......... The combustion chamber looks pretty clean, so maybe the bike wasn't run very long in this condition. At least I don't think I see any piston marks in the combustion area of the head......

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1979 Honda CR 250 R
1973 Honda CR 250 M
1974 Suzuki RL 250 Exacta Trials - 2
Model 49 Bultaco 250 Sherpa T
1977 Yamaha XT 500


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 Post subject: re
PostPosted: Sun Oct 31, 2004 7:53 am 
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Joined: Tue Aug 31, 2004 1:44 am
Posts: 283
Location: Maysville, AR
Yikes. :shock: I have found numerous things like cases screwdrivered apart.no base gasket installed on my 360 yamaha when i got it.,lol it was nearly impossible to kick over so it was likely it couldnt be started like that,despite that the piston wasnt hitting the head.my mt and my 79 cr250 engines were run with no air filter.the mt engine was pretty much worn out
when i got it and the 79 cr 250 top end has the liner peeling chrome off around the exhaust port,the head and piston crown is beat up pretty bad and at one time it suffered a four corner siezure.The bike still runs super strong and has good compression despite that.these old bikes sure are tough to suffer all that abuse and still keep going. :shock:

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(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!


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 Post subject: base gaskets
PostPosted: Thu Nov 04, 2004 5:38 pm 
I purchased a bike with cherrios cardboard box gaskets(2) sandwiching a gastly torched spacer plate....the transfer where 1/2 blocked..LOL Pictures on Marks site under "Roaches"
Actually the womens panty hose as a pre filter isn't bad.K&N sells a similar product for over there filters.


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PostPosted: Fri Nov 05, 2004 7:52 am 
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Joined: Tue Sep 07, 2004 7:55 am
Posts: 6
I saw that picture some time back! At least you had a gasket. My buddy came over yesterday to drop off something and I was showing hi my CR top end. He volunteered to get the head nuts loose and I gratefully accepted his offer as he is a far better mechanic than me. It looks as though the previous owner used Permatex gasket sealer for a head gasket....... Speaking of roach bikes, did you see that photo of Kevin Kline's Honda with the ultra cool pipe? I once had a TY 250 that had a 4 stroke header grafted to the stock exhaust. It also had a shock welded in place.... must have lost the bolts. other great finds have found their way to my garage like the TL 125 that wouldn't run. This guy flipped out, poured dirt and sand down the spark plug hole and beat holes in the gas tank with a claw hammer. I bought the bike for 45 bucks and had a ball restoring it. My problem is that I see potential in every junker I see......... oh well, like I tell the wife: it's cheaper than therapy!

_________________
1979 Honda CR 250 R
1973 Honda CR 250 M
1974 Suzuki RL 250 Exacta Trials - 2
Model 49 Bultaco 250 Sherpa T
1977 Yamaha XT 500


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