The New And Improved Unofficial R65 Forum V2
Technical Discussion => Ride Reports and Event Reviews => Topic started by: ShutterPilot on August 27, 2014, 05:50:13 PM
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So far, we hold the 650 p-pp record with an avg. speed of 94.35mph, and a best speed of 97.7mph. We'll try for our 100mph coin on Thursday
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That's cool, good luck and keep rolling!
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Great job, get to the ton!
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Wow. I wonder what it would do at sea level on pavement.
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Wow. I wonder what it would do at sea level on pavement.
Main jets for density altitude and you're good to go. Bonneville organizers have an accurate weather station on site.
Back in 1965, the motorcycle shop where I worked during college ran a 'well tuned' bone stock 650cc Triumph Bonneville at the now-urbanized drag strip at Green Valley, Texas. Best speed through the timing lights on a Saturday night was 112 mph. I know this as I picked up my timing slip on the return road to the pits.
Miss those days.
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That was also with poorer lubricants, but better gasoline, than what we have today, Monte!
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The guy I've been working for/with used to be a fairly serious race car driver. He's talked to me about some dyno testing they did with different oils. What they determined was that the only significant factor was the weight of the oil. They ran 0 weight oil in the engine and transaxle and noticed improvements in power and power delivery... but everything was due for a rebuild at the end of the weekend. Reducing oil pressure and putting external oil drains in the head further reduced parasitic drag on the moving parts.
Thinking about those discussions I figure that putting heating pads on all the oil filled compartments prior to a speed run could thin the oil a bit and get a little more power to the wheels.
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I've seen similar dyno results that demonstrated a power increase with thinner oil. Not ridiculously thin but usable and safe synthetic oil of lower viscosity. Every little helps and this is one reason I'm going too try 5W40 this winter. I always use semi synthetic transmission oil and I can feel the difference that makes just spinning the rear wheel by hand.
It's difficult to put a figure on it but we lose at least 15-20% HP between the flywheel and the rear tyre. It would be nice to get some of that back. I don't think I'd risk very thin oil but I'd make sure the final drive and gearbox were in perfect mesh for maximum efficiency. Maybe even polishing the gear teeth. Then I'd choose oil carefully.
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Update - we never did hit the ton.
With the cooler temps on Sunday, I was able to redline 5th with stock jetting so we didn't change it. I should have increased tires to 44 psi or so though.
I rejetted from #145 to #140 waiting in pre-staging Thursday as it was warmer and hadn't run into redline on my 1st return, but the event ended before we could run it that way. There was another R65, modified, that was running and his best time was 101 and change, so we weren't too far off with just a stock unit.
Part of the problem is being away from pit for 6+ hours at a time in lineup - bike's usually stone cold on first run, and this shows in my times: 1st runs 90.9 and 92 mph. Returns runs both over 97mph.
The conditions are challenging to say the least, but we left very happy and with a record: 95.332mph, with a top speed of 97.776mph
Maybe we'll see Monte out there next year?! ;)
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