Proper traveling speed for an XJ

I've been taking my Seca 650 and 900 on 10 hour+ trips. They are a joy to ride and it seems I'm always finding some new thing to tweak or make better.

I'm curious what a good maintaining speed is to go on these old XJ's when you drive for hours on end. Personally I keep the needle between 70-75mph. However, I'll find myself in some fierce traffic at times and I have to up my speed to compete a little. Often I ride with my cousin who owns a BMW GS1200 and that thing can go 85 all day. Is this okay to do on our old Secas? Can we go this fast for extended periods of time without hurting the motor too much? "Back in the XJ's hey day the speed limit was 55mph so 75 must've seemed pretty fast back then. Now, it's considered the slow lane speed.

Eventually I'd like to go across the country one one of these bikes. I'm a simple guy who doesn't need all the bells and whistles of today's motorcycles, however, I'm sure if I owned one I'd change my tune pretty quick but for now, i'm an XJ guy.

 

Only US had 55 mph limits - a 650 plus (or even a 550) could pull 80 all day I'd hope. You'd want to check the oil level after 800 miles though!

 

Someone at a rally tried to destroy and XJ motor. I heard he jammed the throttle open although I have not seen the video. Must have been an idiot to do that.

 

How exactly did he try and destroy it?

 

In the early 90's I witnessed a guy at Loudon Speedway in New Hampshire (Animal Hill) pin the throttle lock on his 750 Maxim wide open.
The bike ran for about 30 minutes like that with a huge crowd around it.
I watched from a distance fully expecting something catastrophic with hot oil spraying everywhere.
After 25 minutes it died down for an instant, probably gas boiling in the float bowls, then slammed to redline again and went another 5 minutes.
In the morning the bike still turned over.

 

Think it is the one Simmy is referring to l have never heard of an XJ engine wrecked yet .

 

I did see that video. Its posted somwhere around here, but Ididn't save the link.

It was ad a HD rally in France. They drained the oil, then held her with the throttle open for 20 minutes before the fire started. The engine was still running when the fella had to jump off of the bike, at which point it stalled.


To answer the OP's question: 80-85 all day long is not a problem. Yamaha briefly (~3 years) ran the 750 Seca as a factory 24 hour endurance racer, in which case 100 MPH+ was not an issue either.

 

Yes bulletproof engineering.

 

Well then, I guess I'll feel much better hangin' with my cousin on his GS all day at 85.

P.S. If you find the link regarding running redlining the 750 I would love to see it.

 

Where do you find this stuff?

 

at 85 mph an air-cooled motor is getting all the cooling it needs.
City commuting with traffic jams I would expect is a much harsher environment for them.

https://xjbikes.com/forums/threads/japanese-f1-xj750-endurance-bikes-info-translated.58132/

look at the early racer prototype, even has 650 Seca side covers.

 

People post here, and I read it.
the-ultimate-chain-drive-xj-bike-that-does-exist.48461

Also, my bad. It was only for an 8-hour race.

 

Even sitting at idle an air cooled engine gets all the air it needs, because engineers know stuff (even HD engineers, though they often get overruled by the higher-ups).