Tim's XS project - 750cc rephased ported head titanium valve hot cam craziness

Re: Tim's XS project - October 2011 - ENGINE UPGRADES COMING :D

This beautiful bike thread ended kinda abruptly.

Any recent news on this gem?

The valves look different. Are the intakes Ti or both exhausts and intakes?
How much bigger did u end up going?

Tim said:
More pics of the head! It's done, along with some awesome intakes! Cam and crank being sorted now.

xs650webcam008.jpg

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It didn't end - not sure where you read to. Page 66 I think has me firing up the new engine for the first time, and I've been riding it since. 113MPH is the fastest I've had it up to at this point.

I don't have the specs on the valves handy. The head was ported and valves enlarged by 707 Racing, and I honestly don't know if I ever found out exactly how much larger the valves are.

All 4 valves are titanium, as are the retainers.
 
Yeah, that was iteration #1 of the bike - turn signals and all. Deals Gap back in who knows when - 2010 maybe? Not sure. Still need to change the pipes.
 
Christ Almighty

Watched the vid of your bike being started up - ears are bleeding and soul is rent asunder
 
...and all things must end.

Sold this bike yesterday. Topic #448 of DO THE TON, started April 1, 2007 - just 2 months after I put the site online.

Almost exactly 10 years from the day I brought it home to the day I sold it.

It went for a solid price, but not outrageous considering the value of many of the components and work in the engine.

Seemed like an appropriate way to celebrate the first 10 years of DO THE TON, and move into the next decade unburdened from the last.
 

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So, when it's appropriate, can you relate why this bike was a burden to you?
Looking for practical advice owning a classic motorcycle. Yours looked like a keeper.
 
I own the following motorcycles:

1966 Honda CA95
1971 Motobecane moped
1973 Honda ST90
1975 BMW R75/6
1978 Yamaha SR500
2011 Vooodoo Vintage custom w 1978 XS650 motor
2011 Suzuki TU250X
2013 Kawasaki KLR650

Of those the Honda CA95, Motobecane and Voodoo are all non running projects in various states of assembly/reworking.

The BMW is in the shop getting a complete engine overhaul with new Siebenrock 1000cc powerkit, new valve train, clutch, swingarm replacement.

I've had the XS for 10 years and have done everything I wanted to it and have enjoyed it. The only regret is not having run it on the salt in Utah at the BUB Speedtrials. That was on the agenda and I even have a set of custom Vanson leathers specifically for the run.

Maybe I'll borrow it or buy it back when I'm ready to run it there, but I did manage 115+ mph on it on the road in Alabama.

It was just time to pass it along and the right buyer arrived. Since building I've never so much as blown the single 10A fuse in it. Ridden regularly it is as reliable as my BMW or KLR.
 
Thanks.

Do you think the /6 will be as good or better than the XS? Different.
I've never ridden an XS but have a neglected /5 I've been meaning to get around to. Riding that briefly feels like riding a 70's Cadillac.
 
jcw said:
Thanks.

Do you think the /6 will be as good or better than the XS? Different.
I've never ridden an XS but have a neglected /5 I've been meaning to get around to. Riding that briefly feels like riding a 70's Cadillac.

Apples and oranges. Stock, the BMW compared to the Yamaha is kind of like comparing a BMW car to a Honda. Both get the job done, and properly set up, the Honda will perform well. But, there's a distinct and noticeable difference in quality.

My Yamaha XS was far from stock. It had about the best possible suspension you could put on an old XS, had been lightened and stiffened, and had a race-spec motor in it. It would trounce the BMW on the road and around a track.

Your 45+ year old /5 probably is running on original suspension components. My /6 has Progressive springs, I rebuilt the front forks 8 years ago and it has Works shocks. It's getting a larger, stiffer swingarm from a 1981 R100 and I recently put a new brake rotor and pads on it.

So, it handles much better than it did before I upgraded the completely worn out old components, as it should of course. It's a great bike to ride long distances, but it's not going to compare to any modern sport bike. I've ridden it confidently at 90+ MPH through twisty roads, through the Tail of the Dragon and for a 2 week 2500 mile trip, and that was before upgrading the rear shocks and front brakes.

Now with all the upgrades and the bump to 1000cc forged pistons with nickasil cylinders, and all new BMW OEM valves/guides/springs (one piston was down to 110 PSI and the valves/guides were worn out), it should run like a bat out of hell. I also just put on a Jim Cray spec Keihan stainless exhaust system on it which are basically lightly baffled open silencers, so it's going to sound as good as it runs :)

The BMW is an investment and should last me the rest of my life with all the new bits. All my other bikes will be rusty hulks by then (except the 1966 CA95 baby dream which lives inside the house).
 
I'm running Mikuni VM32's. It's not so much hopped up as just turned into an R100. It's not high compression or a lumpy camshaft - just more displacement. The R75/80/90/100 are all the same engine more or less with different pistons and cylinder bores (and carb jetting).

It was running a bit rich before, so I'm hoping the carbs are more or less right for the 1000cc along with the improved flow with the exhaust. I have plenty of jets and a bunch of VM34 bodies if I want to increase the carb size too.
 
Looking to get 100hp maybe?

I just look at that spindly frame and the bolt on rear subframe and think how in the world did this thing evolve into a winner of IOM and Daytona superbike.

Looking to put the race fairings on?
I should just wait for the build thread. Lol.
 
I don't think any airhead has ever made 100HP. You'd have to turbo / nitrous / supercharge the thing. Stock R100 is around 60HP.
 
Dual plug heads, high compression pistons, high squish heads with clearances set just right...

90hp at the crank?

LOL?
 
Maybe I'll hunt it down and buy it back ;) But first I need to build my shop at the cottage so I have somewhere to put it.
 
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