Not at all the same as letting it idle.  You'll have much more oil pressure and airflow for cooling at 90 mph.

justin_o_guy2 wrote on 11/05/19 at 10:18:39:


Good point.   Through the air box, right?   I've taken to bringing supplemental oil with me on long hard rides.   If I put a thousand miles on in a week end, it's going to want a drink.

Oh, no- that seems... extreme.   I doubt I have the concentration for it.   I could see holding 70-80 actual mph for the contents of a tank, though, on the right roads.   20 hours of riding in a couple days happen on occasion, holding 70+ for 3-4 hours at a stretch... well, with gas breaks.

I wonder, if lubrication and overheating are in check, does high speed operation have other unavoidable impacts on the engine?  Indicated 90 is closer to 82 actual- I'm just looking for educated expectations.

Look at Drag Bike Mike's breather thread. One smart way to reduce oil consumption.
IIRC, if you reduce a bearing's RPM by 10%, you double it's life.
So, revving the crap out of an engine isn't a good thing.
Having said that, these bikes rarely see 7,000 RPMs, which isn't much for a modern motor.
Real oil, deal with the breather, and ride...

Eegore wrote on 11/05/19 at 16:09:26:


By "rear pulley", do you mean swapping out the belt for a chain and sprockets?  I'm clueless as to the front.   Or maybe clueless, full stop.

I would strongly urge you to make sure you've jetted the carb correctly before running at higher highway speeds , 75mph (actual) all day,   is not beyond the bikes capability and will leave you some throttle to maneuver/pass  . The danger exists if your running lean, you can over heat and drop an exhaust valve , or blast metal off the dome of the piston to the point of holing it. Running slightly rich will make the motor run cooler , you may have a bit of carbon build up on the plug (it can be cleaned and reused)  you'll have less chance of after fire  and no serious damage of any kind.  All jets are cumulative, if your running lean at anything passed 1/4 throttle  ,you'll still be lean at 90. I completed a  round trip from N. Y. to  Tn.  2,100 miles in 4 days under just the conditions we're talking about here. Be sure to do the spacer mod ,it will cure your lean mid range and improve your actual top speed to 85-87 mph.

Looks like I can get most of my photos back if I use Google Search.

https://www.google.com/search?sxsrf=ACYBGNTkjkexnkKPF_oqaIQi919eEZS57g:157312...

Below is a 25T Kawasaki pulley modified to replace the 23T Suzuki Pulley.  It won't increase your to speed - it reduces the engine rpm at cruise in high gear.