XL cylinder head:
(translated from Marc 2003)
(translated from Marc 2003)
XL driver doesn´t know it, what has begun with a light film of oil, often ends
in the total mess. Machine and also driver cannot save themselves from hot oil.
typical problem at almost all XL 500 models is the thick area between valve- and
cylinder head. By thermal problems it comes to leaks at the outlet side. The
valve head cannot be tightened and also not evenly be attracted correctly,
favored by weak, torn or faulty threads.
the solution (yes, there is a !!!!) I did some measures:
first i have removed the upper engine mount. Attention!! HONDA warns of this
step from an official side. Frame break and change of the road performance can
be the consequence. Within the former 13 years I have driven some tracks, have
not spared my XL in any vacation and joined in some Enduromeetings. Also after
the most exact examination of the frame I haven't been able to discover a weak
I have renewed all threads in the cylinder head. Where it was possible I
employed M8 Heli-Ceul thread instead of M6 threads. Where the place didn't
suffice I built in M6 thread inserts. I have put carrier bolts into all renewed
threads instead of screws. To ensure the right length I extra manufactured them.
An exact analysis of the rocker box cover is necessary here. This must be
altered correspondingly. It is partly possible to leave the upper thread of the
carrier bolt with M8. For this the corresponding drillings gets on-drilled.
also have got tips of other XL 500 drivers:
February 13th, 2001:
can say to you how I have solved the problem with the cylinder head. Because the
preholder of my XL didn´t have much knowledge about an XL (so i suggest) he has
turned off all carrier bolts. What to do in this case. To solve this problem a
fitter turned new carrier bolts: At the bottom, into the cylinder 8
mm, at the top (cylinder head) 6 mm. Therefor it is necessary to calibrate
exactly the depth of the threads in the cylinder. Leave the threads by 1-2 mm
shorter, so one can screw the bolts quite in and therefore prevents a turning
off the course of thread. Don´t use Helicoil but drill the cylinder and drill a
thread into it (very carefully). Because of the bolts, which are (at the top) 6
mm one can put on and screw on the cylinder habitually (without drilling). As
sealing I take a sealing which is used by Mitsubishi. But be careful, there are
two different sealing of Mitsubishi, one is only the mass and one has metal dust.
This one with the metal dust is the better one. My XL is completely dry. With
kind regards Günter.
the enoiose topic cylinder head and its lid:
sealing miracle is called ELASTOSIL (Company Wacker Chemie)
transparent silicone, against which all other so-called thick masses (e.g.
etc. are bad, and even the "XOel" shuts up) Combined
intact, at the best bushed threads in the cylinder head, the cylinder head
problem is solved for all times (to drive with or without motor suspension
matter of taste). I would not recommend Helicoil for a final thread repair. It
is not made for repeated screw in and screw out . For small money there are
Thread busches which you can use without special tools.
July 7th, 2000 23:26
have just read the page about the cylinder head, simple and good designed engine
but the execution is partly lousy.
offers a replacement kit (cylinder head with valves). All carrier bolts and
threads are amplified and what is even better the thick area is approx. 30%
taller. Prize 2 years ago approx. DM 850.
real option, especial when you consider that a new normal cylinder head costs
approximately the same amount without valves.
have to ask your dealer whether the Kit is still deliverable.
look 2000 00:38:56, 20
just read about the mess making cylinder heads. I built
in three XLs and don´t agree, that this is not for eternity.
machines are thick for three or four years. A stupid preholder had built in
into the cylinder head and cut corresponding threads (6.25 mm.) I asked Böllhof
(manufacturer of helicoil) whether this is still recoverable with helicoil. The
answer was yes, the nuclear hole drilling may be 6.3 mm too.
mass is “Elring”, not hardening, on silicone base.
Harz, Georg-Fröba Str.9, 64347 Griesheim
has become sort of “religion war”, what XL-drivers tell one another about
the leak problem of the XL.
advice: the upper engine mount doesn't have to be removed as long as you take
the drilling of the hold disks to flight with the frame mounts. Furthermore a
flat head as well as lid is important eminently. When these points are adhered
you put some “Dirko” (as thin as wafer) on the cylinder head and its lid
which must be as clean as possible and puts everything together. Ready. Till now,
I never had a oil mist at the engine!