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dohc versus sohc
Posted: Sun May 20, 2007 12:47 pm
by Georgios Georgios
Hello,
I would like to understand what are the advantages or disadvantages of the
Double Over Head Camshaft system in comparison with Single Over Head
Camshaft system. I ask this because before I buy my KLR650C I used to use a
HONDA XL500S which gave me no problem. So with my KLR now I have a better
system or worse?
Thanks for any information.
Georgios
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dohc versus sohc
Posted: Sun May 20, 2007 2:39 pm
by Al
Dual overhead cam design has some advantages over single cam design.
First, it allows four valves per cylinder motors to run at higher rpm
than four valves per cylinder with a single camshaft.
Another advantage is creating more of a hemispherical combustion chamber
by having wider valve angles. The spark plug can be located in the top
center of the combustion chamber.
After riding a KLR more than 80,000 miles, I don't see any disadvantage
of the dual overhead cam design. It was the bottom end bearings on my
KLR that wore out.
http://auto.howstuffworks.com/hemi1.htm
http://auto.howstuffworks.com/question562.htm
http://en.wikipedia.org/wiki/DOHC#Double_overhead_camshafts
http://www.streetracersonline.com/articles/camshafts/2.php
Georgios Georgios wrote:
> Hello,
>
> I would like to understand what are the advantages or disadvantages of
> the
> Double Over Head Camshaft system in comparison with Single Over Head
> Camshaft system. I ask this because before I buy my KLR650C I used to
> use a
> HONDA XL500S which gave me no problem. So with my KLR now I have a better
> system or worse?
> Thanks for any information.
>
> Georgios
>
> _________________
>
>
>
[Non-text portions of this message have been removed]
dohc versus sohc
Posted: Sun May 20, 2007 3:38 pm
by tlh
So Al,
How many miles did you have on it when you did the bottom end?
albatross
----- Original Message -----
From: Al
To: Georgios Georgios
Cc:
DSN_KLR650@yahoogroups.com
Sent: Sunday, May 20, 2007 3:38 PM
Subject: Re: [DSN_KLR650] DOHC versus SOHC
Dual overhead cam design has some advantages over single cam design.
First, it allows four valves per cylinder motors to run at higher rpm
than four valves per cylinder with a single camshaft.
Another advantage is creating more of a hemispherical combustion chamber
by having wider valve angles. The spark plug can be located in the top
center of the combustion chamber.
After riding a KLR more than 80,000 miles, I don't see any disadvantage
of the dual overhead cam design. It was the bottom end bearings on my
KLR that wore out.
http://auto.howstuffworks.com/hemi1.htm
http://auto.howstuffworks.com/question562.htm
http://en.wikipedia.org/wiki/DOHC#Double_overhead_camshafts
http://www.streetracersonline.com/articles/camshafts/2.php
Georgios Georgios wrote:
> Hello,
>
> I would like to understand what are the advantages or disadvantages of
> the
> Double Over Head Camshaft system in comparison with Single Over Head
> Camshaft system. I ask this because before I buy my KLR650C I used to
> use a
> HONDA XL500S which gave me no problem. So with my KLR now I have a better
> system or worse?
> Thanks for any information.
>
> Georgios
>
> _________________
>
>
>
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
dohc versus sohc
Posted: Sun May 20, 2007 4:53 pm
by Al
I sold the 2000 KLR at 81,000 miles. The guy I sold it to in Birmingham
finally opened it up at 85,000 miles. If I remember right, he said the
bearings had .060 inch slop and the crank was shot.
I first noticed a noise in the engine in July 02 at about 73,000 miles
on a ride to Colorado. In September, I rode it to Sebastopol CA, down
the coast to Morro Bay, and to Texas on the way home. When I rode
across the Mojave, I was looking at every call box incase I had to walk.
That motor went another 5,000 miles after I thought it was going to break.
BTW, at 80,000 miles the top end looked great, the cams looked new. The
top was the first place I looked for the noise.
Guess I shouldn't have gone 11,000 miles on the oil and air filter when
we rode to Alaska.
I don't have a KLR now, I just wanted to see what you guy think about
the 08 KLR.
Al
tlh wrote:
> So Al,
>
> How many miles did you have on it when you did the bottom end?
>
> albatross
>
>
>
>
>
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dohc versus sohc
Posted: Sun May 20, 2007 10:26 pm
by Mike Peplinski
As far as I know, and that isn't very far, it really doesn't really make all
that much difference. The DOHC setup uses 2 seperate cams, usually one for
intake and one for exhaust. They usually work directly on the valves so
there really is no "valve train". The SOHC has, obviously one cam that has
both intake and exhaust bumps on it. The valves are activated by levers or
"rockers" as they are known. I think y ou can ultimately get more HP out of
a DOHC setup because you can work with each cam and its timing individually,
where the single you have to change the cam. You can probably get more RPM
on the dual cam setup because there is less moving parts to move but really,
in the application we have, with our lightly tuned engines, but that would
only come into play at really stratospheric RPM's. Setting valve lash is
easier in a single cam. Typically you just adjust a screw or some sort. The
dual cam requires changing shims. Although some SOHC engines also use shim
and bucket adjustment. I"m thinking it really doesn't matter. Its all just
so technical.
>From: "Georgios Georgios"
>To:
DSN_KLR650@yahoogroups.com
>Subject: [DSN_KLR650] DOHC versus SOHC
>Date: Sun, 20 May 2007 20:46:07 +0300
>
>Hello,
>
>I would like to understand what are the advantages or disadvantages of the
>Double Over Head Camshaft system in comparison with Single Over Head
>Camshaft system. I ask this because before I buy my KLR650C I used to use a
>HONDA XL500S which gave me no problem. So with my KLR now I have a better
>system or worse?
>Thanks for any information.
>
>Georgios
>
>_________________________________________________________________
>Don't just search. Find. Check out the new MSN Search!
>
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>
>
>
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fred rocks
Posted: Mon May 21, 2007 4:13 pm
by Tyson Stephenson
Got my stuff lightning fast. I even changed the order midstream and it all
got here.
Thanks fred.
[Non-text portions of this message have been removed]