Where did you get a larger oil feed line??? I just recently rebuilt my piggy because of this very problem: fried the cam lobe and corresponding rocker assembly because I believe that dinky little oil feed line just doesn't deliver enough oil to that big head. I've changed the oil three times since the rebuild and I've got magnetic drain plugs at both locations and each time I've changed the oil, the plugs have a considerable amount of microscopic metal shavings on them. This leads me to believe its doing the exact same thing it did before. I use great oil and always change the oil/filter every couple of rides and the air filter everytime. I run it HARD, but it has always been taken care of and properly maintained. I figure the next time she needs a rebuild, I'll go big bore, but there has got to be a better way to deliver alot more oil to that head to properly lubricate that stuff. Thoughts???
I did put a bigger oil tube feed line on it this time to see if it the cam an rockers will last longer.
XR600R top end tic tic tic
Posted March 28, 2008 - 09:45 PM
Posted March 29, 2008 - 06:52 AM
pwrpapa, question you said Where did you get a larger oil feed line??? I just recently rebuilt my piggy because of this very problem: fried the cam lobe and corresponding rocker assembly because I believe that dinky little oil feed line just doesn't deliver enough oil to that big head. I've changed the oil three times since the rebuild and I've got magnetic drain plugs at both locations and each time I've changed the oil, the plugs have a considerable amount of microscopic metal shavings on them. This leads me to believe its doing the exact same thing it did before. I use great oil and always change the oil/filter every couple of rides and the air filter everytime. I run it HARD, but it has always been taken care of and properly maintained. I figure the next time she needs a rebuild, I'll go big bore, but there has got to be a better way to deliver alot more oil to that head to properly lubricate that stuff. Thoughts???
The bike is pretty robust but suffers from inadequate oiling at start
up in cold temps. I will attach a reply as to the fix below- but you
could probably get by with running thinner than specified oils when the
temperture is below 45F and by insuring a good warm-up before riding the
Re: Oiling Mod for the XL600R
Here is a bit I wrote up a little while ago- it was
under an XR650L oil pressure thread if you want to see what else was there.
Yes, this is a mod you have to make your own parts for, but it really
isn't that hard if you have a little bit of experience with this sort of
thing. If it looks beyond your capabilities, I will be happy to add
more detail and answer any other questions. If you elect to leave things
as they are, I would reccomend you run a multiviscosity motor oil with
the lowest first number you can find coupled with the approperiate last
number- say a 5-50 or there abouts. Then make sure to warm your engine
completely before riding. I suspect that Honda changed the oil pump
volume as the years have gone on, but I still feel that the below is a
worthwhile mod. Good luck and let me know if I can be of further
" I had a lot of problems with cams and rockers on my XL600R motor
(which has the same oiling system) - to the tune of five sets before I
figured it out. You may have had a high speed oiling problem but my trouble
was all start-up related. At lower temperatures (below 50 F) there is
insufficent oil flow to the head through the itty-bitty oil pipe,
leading to oil starvation and gallling. Once the engine produces a little
heat and thins the oil everything is just dandy. The result is your engine
runs for a few minutes with little or no oil to the head every time you
start it up. Much has been written about worn oil pumps and high flow
aftermarket replacement pumps, but there is a better way. I replaced the
line to the head with a piece of Aeroquip braided hose and a few 1/8"
NPT fittings into the case and head and ran the bike another 35,000
miles with nary a problem- and it only required valve adjustment once. And
this was using a high lift cam without hardened rockers
I only deduced the cause of the failures after a local aircraft
mechanic told me about a similar problem with Lycoming airplane engines-
unless properly pre-heated in the winter these engines would gall their cams
in exactly the same way as my Honda, only it cost a LOT more to fix.
After modifying my motor I began ice racing it (in temps down to -20F)
both to prove my alteration was valid and to have a way to play with
bikes in the winter.
I think the oiling to the head is insufficent on all of the Honda RFVC
engines and I would not run one without making the change. I've
modified three engines and none of them have had a subsquent cam or rocker
problem. It's relatively cheap and easy to do, and you will never have to
worry about the top end ever again."
Also this from "XR600 Race cam"
"The quick answer- you tap the case and head to a 1/8" pipe thread and
use a standard pipe to flare fitting (90 drgree bend at the head and a
45 at the case) and attatch the two with a larger pipe- I used Aeroquip
braided stainless hose on all of the engines I've done as it was
available at my local supplier- but you could just as easily use soft copper
and buy all of the parts at Home Depot.
The object is to increase flow by enlarging the pipe- you are replacing
the tiny supply pipe that Honda still fits to all of it's XR600/650
engines. There are some built in restrictions when using the off the shelf
fittings so I don't think you will be in danger of using a pipe that is
too large. I also increased the preload on the oil pump over pressure
spring by streching it about 20%- primarily to increase available
pressure when the engine is cold, (start-up) which seems to be when the most
Be careful when taping the case cover and installing the fitting as the
case is a magnesium alloy and there is not a lot of material there- it
is possible to crack the case and then you will have to make a few
weird parts to set things right- if it comes to that I an send you a few
diagrams. NPT is a tapered jam fit and forces material apart when
tightened- so you need to just get it snug enough to seal. If you apply a wrap
of teflon tape you may not have to tighten it as much to get the seal
I suppose it would be possible to do all of this with the engine
intact- but I would reccomend taking it apart to make sure no shavings or
chips get into the motor. I also had very good results from polishing the
contact points on the sub rockers where the tappet adjusters hit- use a
sharpening stone to flatten out any grooving or pitting from the
adjuster tip and then buff to a mirror finish. If you can, do the same to the
tips of the adjusters as well. Use a hand stone and don't over heat
things so you maintain the proper tempering. I did my adjusters in a
unimat lathe so I could maintain the radius of the tip- but a drill press
set to it's lowest speed would work as well. This allows you to set the
tappet clearances more accurately, reduces running friction, and reduces
The last area of failure on these engines is the little end bearing on
the connecting rod- if you find yours has worn significantly the best
bet is to replace the rod (you will need to have a machine shop do this)
with a "hot rods" kit from XR's only or White Brothers. These rods have
a bushed little end which will take more abuse as well as an additional
oiling hole- and the oiling holes are larger. If you want to make a
full house racing motor you can opt for a Carillo rod, but I think the
"hot rod" will suffice for most applications."
Posted March 29, 2008 - 01:39 PM
Posted March 29, 2008 - 03:27 PM
Nailpounder sent me this info. about the oil feed line...He's a member here.
Posted March 29, 2008 - 05:01 PM
I've had four of 'em- they will do anything a KLR will, and are more powerful. The early ones had a tendency to spit the carrier bearing out of the case and into the 2nd gear cluster (symptom- hard shifting, particularly into and out of 2nd, gear whine in 2nd, lots of swarf in the oil as the thrust bearing is worn to dust) and ALL of the Hondas with this engine variant (XL600, XR600, NX650 XRL650L)will gall the cams if not warmed up and if run in the cold without switching to thin oil. Ask me how I know. Switch to 5-30 if temps will be near freezing an allow a good warm-up or bad things will happen.
They are pretty reliable otherwise, and should you encounter the bearing issue or galling issue there are fixes (I designed a new oil feed system for mine after the first 5 cams and rocker sets and cured the problem for good). The XL doesn't have the off road chops of the later XRL but it is at least as fast and if the price is right you'll have lots of fun with it.
Posted March 31, 2008 - 02:02 PM
Posted March 31, 2008 - 02:56 PM
The assemblys smallest dia.is the systems max flow.
I'm going to do the same at next change thanks for sharing.
Posted January 12, 2010 - 02:32 AM
hey Micknmeld i think i bought that lemon (or one like it)
my motors out this week end for a strip down and assesment
Posted January 12, 2010 - 11:39 AM
Shit nearly 2 years on and this thread is still usefull:thumbsup: ....
hey Micknmeld i think i bought that lemon (or one like it)
my motors out this week end for a strip down and assesment
Holy old threads batman!!!
Yeah since then my brother bought a diffent XR and ran it out of oil:bonk: and toasted the motor. He then bought another XR with a rattly top end and it turned out to be toasted cam and rockers. I am an expert at rebuilding top ends now!!
Good luck with your bike dino. There are very few XR's that are lemons,there are a few that have been neglected and they just need to be loved again:thumbsup:
Posted January 12, 2010 - 11:50 AM
Posted January 12, 2010 - 12:01 PM
Ha Ha yeah mate old i know, googled xr decomp and this was one of the threads it pulled up. engines out tommorrow so hopefully be able to pick up prob quick smart...
What's it doing to make you want to take the donk out?
Posted January 12, 2010 - 12:12 PM
Posted January 12, 2010 - 12:15 PM
Keep us posted.
Posted January 16, 2010 - 06:25 AM
so what does this mean? well if changing to -4 AN hose and fittings seems to solve the top end oiling issues, then i believe that it is not the hose that is solving the problem, it is the change in fittings. on my motor, both my banjo bolts for the oil pipe have only one small hole in the side of the banjo bolt. i have redrilled both for two larger holes as well as enlarging the main oil hole on each. i am not sure if this is enuff.... so i am tempted to bend a new line up using some 5/16" hard line and silver soldering some banjos to it. but that leads to the question that since you are removing restrictions in the top end oiling and thus increasing flow, at what point are you going start affecting the flow to the bottom end since they are sourced from the same location.....
Edited by SoCalXR600Rmonkey, January 16, 2010 - 07:37 AM.
Posted January 16, 2010 - 07:58 AM
So it's indeed only flow, and flow restrictions.
Some guy at ADVrider.com installed a flexible hose with some elbow fittings.
He stated that the hose was 2x as big as original, but the elbow joints were not much bigger then the original ones.
See this page and the page before:
Im also going to enlarge the banjo bolts after reading all of this. Maybe even install a bigger flexible hose, but i don't know if the oil line resistance is that much of a problem.
Posted January 16, 2010 - 08:33 PM
Enlarging a tube gives more pressure but less fluid speed, while restricting a tube gives less pressure but more fluid speed. This is Bernoulli's principle.
But what about viscosity in relation to oil line diameter?
When we look at Hagen-Poisseulles principle which calculates pressure drop as result of viscosity in relation to pipe diameter we see that diameter is ^4th power. This means that increasing pipe diameter pressure drop becomes a lot less! http://en.wikipedia....euille_equation
Also when you scroll a bit down the page you can see that fluid move a lot quicker at the center of the diameter of a tube than at the wall, because of wall friction. This means that enlarging the tube between the banjo bolts actually makes difference in resistance!! ( ^4th power remember)
When the oil pump pumps cold oil, and there's a big pressure drop, the amount of pressure (drop) shows at the pump side and needs to be overcome by the pump. The crank oil passage could be bigger and cause a lot less pressure buildup. This means oil will flow to the crank when cold, but not to the head, untill it warms up and pressure drop becomes less....
Enlarging the oil pipe will decrease this pressure drop a lot, and cold oil will flow to the head more easily.
Just my 0.2$
Posted January 17, 2010 - 02:43 AM
dont forget that the pressure drop is after the banjo bolt and there is some pressure before.
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