Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: guest564 on February 18, 2010, 07:22:11 PM
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I read somewhere that Honda uprated the oil pump on the later RFVC engines. Does anyone know if this is correct and if so which pump do I need?
Cheers
James
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Ooh. I hadn't heard that before. I haven't got the access to the 'fiches anymore to check sorry.
GC
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I read somewhere that Honda uprated the oil pump on the later RFVC engines. Does anyone know if this is correct and if so which pump do I need?
Cheers
James
Aye James,
Does this thread and URL from the XL600R - The XL Board help?
" (Date Posted:05/16/2007 00:16:56)
Here is URL to comments posted by a 1984 XRL owner regarding cam oiling problem and solution
http://www.advrider.com/forums/showthread.php?t=51126&highlight=flow+head
The content is cut and pasted below. I just noticed the post below had noted the different diameters of the banjo bolt holes.
from Tim McKittrick:
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 pip, leading to 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 fitttings 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. "
My regards, Bill.
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I can't say that I've had a problem, but if an upgraded pump was available I would go for it, it might improve cooling. The head has oil wells built in that keep the cam lubed for some time after start up, the first time I rebuilt my engine fully I failed to prime the oil pump and it ran for some time before it seized, there was no significant damage to the camshaft. I used to change my oil after every race meeting though.
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...the first time I rebuilt my engine fully I failed to prime the oil pump and it ran for some time before it seized,
Been there done that. Out of interest how do you prime your pump?
In the past I've had lots of trouble trying to get the oil through a freshly fitted oil line into a dry pump. My solution (and this may sound mad) was to connect the flow line at the crankcase end, fill it with oil, place a handpump on the oil tank end (using a tapered adaptor to make a seal) and pump. After a couple of strokes you hear a pop as the air lock is forced through the pump.
EVERY time I do an oil change on an RFVC engine I loosen off the banjo on the head to check that oil is being pushed around.
GC
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What I did was to lash up a funnel to the oil line from the tank and fill it with oil, then turn the engine over a few times to draw it through, an awkward job with no kick or electric start, then reconnect the oil line. Like you I loosen the oil line into the head to ensure that the oil is coming through.
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Older RFVC have a pump with 48 teeth sprocket (for example all XBRs and GBs, oder NXes), later it has been changed with 47 teeth and the cooperating crankshaft sprocket of course too). It is easy to change - if you have the older solution.
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What models do you find those on?
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You can compare this two pairs of sites:
1:
http://www.partzilla.com/parts/detail/honda/HP-15105-MG3-000.html
and
http://www.partzilla.com/parts/detail/honda/HP-15105-MN1-671.html
2:
http://www.partzilla.com/parts/detail/honda/HP-15130-MG3-000.html
and
http://www.partzilla.com/parts/detail/honda/HP-15130-MN1-670.html
It is not a complete list of models (for example there is no XBR, only GB - the same engine). Comparing you can notice for example that in the case of XR a change had place in 1988.
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Thanks. I haven't seen my XBR for two years but I will havea new garage by the end of this year and then I will have somewhere to work on bikes again :D
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Well, you can always take your engine home, as I do (for winter).