The New And Improved Unofficial R65 Forum V2
General Category => General Announcements => Topic started by: MatBat on January 06, 2011, 06:20:12 AM
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Hi there,
I'm Mat from West Sussex in England.
I'm looking to buy a 1979 R65.
It seems more or less together however the seller states "Running but engine needs attention; think it's big end shells as bottom end knocks under load." How likely is this to be shells and is that a big job to do?
Also I wondered what things I should look out for when buying an R65 as you guys all seem the be the collective wisdom on these great bikes :-)
Cheers and happy riding!
Mat
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Hi Matt,
Have you seen the classifieds...
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Matty , there is a possibility that the seller of the bike is using fuel with a lower octane than these bikes require. under load the pre-ignition makes a bad knocking. so problem might not be crank, however you can blow a hole in a piston and other things with this condition. If the seller is willing to drain the fuel and you put in a couple of liters of high test the knock may well be gone ,can't know if much damage has been done a lot depends on how far the bike was ridden ith knocking.
Best regards John Muir
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Thanks for the great advice,
What Octane should be used? Here in the United Kingdom the lowest octane is around 95RON and the good stuff is 99+
I did look at the classifieds though they seem to all be US based bikes so shipping would kill my budget :-(
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We do have a fair number of R65ers in Britain - there might possibly be one or two not too far away from you who might offer hands-on assistance.
The knocking of crank/conrod bearings is -to me- a more hollow, low pitched sound that often only shows up at RPMs a little above idle, even without engine load, whereas spark knock/pinging is rather RPM independent and only under engine loading conditions and could simply be bad gas, plugs, and/or misadjusted carbs.
What is the mileage on the bike - and does it seem to be accurate/reflective of the condition of the bike? Has it been sitting, unused, for many years? Do the frame serial number (on right side headstock) and engine number (above oil dipstick) match? If you go to check it out, bring a digital camera with you and take plenty of pictures. Don't be afraid to lie down and take pictures of the underside of the engine/oil pan, cylinders as well as the prettier topside bits. You can post pics here and we can help with trying to determine the condition/repair items based on visible leaks, rust, etc.
The European octane measurement formula and the United States octane formula are different, resulting in lower numbers for the US octane measurements for what would be an equivalent fuel formulation in europe. However, I don't know if the european communities have 10% ethanol in their gasoline, which we have pretty much in every state in the US. This adds other fuel issues/challenges as it is for us, and now the EPA is planning to raise the ethanol percentage to 15%.
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95 ron appears to be equivalent to around 90 octane , 99 ron is around 93 octane
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Welcolme Mat
I'm in the uk, quite a long way from West Sussex though.
My engine will ping slightly on our 95 octane fuel but it's only audible at low revs under significant load say up hill and can be tuned out with 1 or 2 degrees retard on ignition timing. Bear in mind that any fuel stored for some time will have an even lower octane rating due to loss of some of the volatile fractions.
Although I've only had a big end failure on a car engine I don't think you could mistake pinging with a big end knock. For me it was a much more obvious lower pitched knock under load compared to the lighter metallic sound of pinging.
I've only done big ends on cars and old British bikes, not on an airhead. If it really is just shells and the crank journals are ok its probably straight forward enough. Replacing the crank is more involved and the guru's say you shouldn't attempt to grind them. Check out Motobins they recently had new R45/65 cranks on offer at a very low price.
http://www.motobins.co.uk/displayfinal.php?s=0&function=show&subs=500a&title=2+VALVE+TWINS&model=&bike=
Something to think about .... by all accounts it's very difficult to wear out an airhead crank so if it's worn prematurely due to some problem with oil pressure (dare I mention the 3000$ O ring) then what else is also worn ?
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Wow thanks for the great advice, what a great forum!
I'm hoping to take a look at the bike tomorrow so I will be sure to take the digital camera. I'm pleased to hear that the engines are hard wearing.
I'll try to get some video of the knocking noise too.
Wish me luck!
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I have experienced bad pre-ignition from improper fuel and the knocking under even light load was scary . I stpped immediately and parked the bike. I came back later the same day with an empty jerry can and emptied the gas tank,refilled 91 octane and the bike ran well again.
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I wouldn't run the engine without emptying the old gas in the tank and carbureters and adding a little high octane fresh gas.
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Yes, it could be old/bad fuel. It could also be the timing is off.
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I wouldn't run the engine without emptying the old gas in the tank and carbureters and adding a little high octane fresh gas.
Hi.Welcome.good advice dump the fuel.
I am up in Yorkshire i run mine on standard unleaded without additives and have had no problem with pre ignition.Most likely fuel/timing as we havent had many folk on here with crank/bottom end problems.
A video would be useful best of luck.
Lou
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Hi Lou
Do you run yours without any lead replacement additive's?
Ian