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Carbs in front
- Thread starter JRay77
- Start date
Hi JRay,
I've seen photos of a reversed head XS650 motor right on this site so yes it's possible. (That, or it was the best photoshop fake ever.)
But why, eh? Why?
Or why stop at reversing the head? Gut the transmission, fit a variable swash plate hydraulic pump in it's place and lace two rims onto rotating case hydraulic pumps to get two wheel drive with infinitely variable gearing in forward and reverse.
Ideal for those who can't get along with shifting gears and using a clutch.
And for those who are happy with shifting and clutching but don't get along with electricity there's the XS650 Diesel conversion with acetylene lights.
I've seen photos of a reversed head XS650 motor right on this site so yes it's possible. (That, or it was the best photoshop fake ever.)
But why, eh? Why?
Or why stop at reversing the head? Gut the transmission, fit a variable swash plate hydraulic pump in it's place and lace two rims onto rotating case hydraulic pumps to get two wheel drive with infinitely variable gearing in forward and reverse.
Ideal for those who can't get along with shifting gears and using a clutch.
And for those who are happy with shifting and clutching but don't get along with electricity there's the XS650 Diesel conversion with acetylene lights.
i've seen a honda 4 cylinder that had this done. I seem to remember it was only good for short rides, or looking at. With the exhaust in the back it tended to run pretty hot.
Max Midnight
XS650 Addict
Last edited:
Not much there hasn't been thought of, done by now.
Why not? Duh, because the exhaust side is the hot side and if the machine with its air cooled motor is to be ridden in the real world (as opposed to being shown in Fantasy Land bike shows or run for short blasts down a drag strip), the hot side needs to be in the breeze.
I like you. A smartass with an extensive vocabulary. Very knowledgable. Now you have me thinking, why not put an XS motor on a zero turn mower?
For sure. I've thought that too. Then again I see a lot of straight pipes and two into one not set up right either.
I have seen motorcycle engine powered sawmills and once a video of an XS650 powered table saw.
FLEA
XS650 Guru
was a old racing trick with triumps ,back in the early 80s came across a trumpie on the rd with reversed heads , it was his main means of transport , swore by it but reckoned it was a mongrel to tune the carbs , went on a 150 mile run with him and a couple of other bikes and it seemed to go ok but then I wasn't riding it ,has been done to a xs650 but only seen photos
Is that a Magura hydraulic clutch setup?
Yamaha TZR250 3MA had reverse cylinders in 1989, which is no problem at all on a watercooled engine. And on a 2 stroke, the rather bulky exhausts are easier to accomodate that way. On the other hand, ensuring clean, dry air for the carbs may be tricky.
A reversed Bultaco...
that link got moved, here's the text
Before and after shots of Andy's unusual reversed head bobber
How To Flip Your Head ( without a pain in the neck )
There’s basically two ways to be able to run your intake in the front and exhaust in the rear.
One way is to have a custom ground cam with four new lobes that open and close the opposite valves at the right time.
If I had a cam grinding machine I might experiment with that a bit, but I don’t.
The other way is to flip the rocker arms to the opposite cam lobes.
To do this I built me a fixturing jig to hold the rockers, cut them and weld them in the new location.
I then needed to install oil delivery tubes to the rockers to oil the cam lobes.
The next thing you need to do is modify the head at the head gasket sealing area.
I welded a ¼” thick aluminium plate to the front and back of the head to fill in for the gasket, had the head machined flat and drilled a bolt hole.
Install the head backwards with a new head gasket, cam goes in the normal way with the threaded end to the right.
Install rocker arms in top cover the same way as normal.
Put the top cover on and torque the head.
I needed to drill and tap two mounting holes to mount my ignition plate on the left side.
I took an 1/8” plate to cover the breather opening to have clearance for the main oil tube.
A little grinding on the front of the head where the rear bolt use to go through will give you enough clearance for the tube.
I took the rocker inspection cover with the four bolts, drilled a 3/8” hole near the top and bolted in a hose barb for my crankcase vent.
There’s lots of options for intake and exhaust . I had to use a jack to give me a little more room through my front frame.
That’s how I did it,
Andy Wolfskill
Hmm. Is cutting and welding rocker arms going to hold in the long run?
Same thing I was wondering....
https://www.motorcyclespecs.co.za/Techinicale/Ram_Air.html
at 100 mph probably less than 0.2 psi
at 200 mph it gets innarrestin...
Better do cooled air with the tooters as found behind the head. That can be done with alcohol and water evap at airbox inlet, or even with additional special modifications of tooter. (Buy/build a flow bench... ') ?? Naw... ) I did it on a 1600 air cooled VW in a bus, in 1977 or so. It added a noticeable bit of push in hot weather, and it iced in cold weather. It was a 'speriment. Worth the trouble to find out. Not worth the trouble to keep the alcohol/water tank filled.
I did a blowthru on the same bus with bleed from the cooling fan, with the alcohol and water it worked pretty well on a long hill at WOT.
The research on the alcohol/water gag is mostly on aircraft.
Now a supercharger on an XS would be very trick.... hint.
and then you might well need the alcohol and water...
Of course just doping the gasoline...
Best of luck and it's a good thing to ask many questions before picking up wrench. Kudos.
at 100 mph probably less than 0.2 psi
at 200 mph it gets innarrestin...
Better do cooled air with the tooters as found behind the head. That can be done with alcohol and water evap at airbox inlet, or even with additional special modifications of tooter. (Buy/build a flow bench... ') ?? Naw... ) I did it on a 1600 air cooled VW in a bus, in 1977 or so. It added a noticeable bit of push in hot weather, and it iced in cold weather. It was a 'speriment. Worth the trouble to find out. Not worth the trouble to keep the alcohol/water tank filled.
I did a blowthru on the same bus with bleed from the cooling fan, with the alcohol and water it worked pretty well on a long hill at WOT.
The research on the alcohol/water gag is mostly on aircraft.
Now a supercharger on an XS would be very trick.... hint.
and then you might well need the alcohol and water...Of course just doping the gasoline...
Best of luck and it's a good thing to ask many questions before picking up wrench. Kudos.
