This page applies most directly to the 1989-1990 US-spec Honda Transalp. See http://www.ta-deti.de/ta/ for thorough technical information on all Transalp models.
Many parts from the XRV750 (RD04) and XRV650 (RD03) Africa Twins are interchangeable with the Transalp. This page (Japanese) has a full history of the Africa Twin.
Fuel Tank
RD03 and RD04 fuel tanks (identical other than color scheme) fit the Transalp frame. According to this page, "the left AT petcock is the same as the petcock for a 1990 NT650 Honda Hawk" ($55 at BikeBandit.com).
Interference
The RD03/RD04 tank's petcocks may interfere with the Transalp engine.
Blackbert says that the right-hand petcock hits the clutch cable mount, and the left-hand petcock hits the coolant line. The right petcock is larger due to a drain plug, so swapping it fixes the clearance problem on the right-hand side, but leaves the left side unfixed.
Support Bracket
Ladder106 replies that the Africa Twin tank requires a support, which is shown here.
This item may be listed on ebay as "Verkleidungshalter" (translates as "Fairing bracket"). Currently, I don't know if this is different from "Kühlerhalter" ("cooler holder") which certainly appears to be identical.
It appears in the XRV650K microfiche as
XRV650K "PIPE COMP., COWL MOUNTING" 64209-MS8-000
Fuel Pump
The Africa Twin tank needs a fuel pump in order to pump the last few gallons.
Stock Africa Twin
The Africa Twin's OEM fuel pump is electric, and it's prone to failure due to internal electrical contacts which arc and destroy themselves. The pump itself can be hardwired and controlled by an external relay, which prevents the arcing problem.
Substitute Pumps
Many people run vacuum-operated fuel pumps.
Another alternative is an electric fuel pump from Spruce Aircraft and Supply.
Swingarm
The Africa Twin has an aluminum swingarm which is is longer than the steel Transalp swingarm. It can be fitting with relatively few problems. Notably, the drum brake stopper has to be ground to fit the Africa Twin swingarm (assuming an Africa Twin disc rear wheel hasn't been used as well), and a 124 link chain is needed.
These parts diagrams indicate the compatibility of many of the swingarm parts between the Transalp and the RD04 Africa Twin. Green indicates that the part numbers are the same, while red indicates that the parts differ. Yellow indicates that the part numbers are different, but the parts may be compatible nonetheless.
SPRINGS: Single Rate (SRS), Dual Rate (DRS), Triple Rate (TRS)
STD: Standard shocks without reservoir
REZ: Hose mounted remote reservoir
ADJ Ultracross: Rebound adjustable with reservoir.
So, the shock is sold as a single unit, it's 14.69 inches long, which is stock length, it's a single-rate spring, and it's available as standard, with a reservoir, or with both adjustable rebound damping and a remote reservoir.
Brakes
Stock
The US-spec 1989 through 1992 Honda Transalps use a rigid rotor which is 276mm in diameter. The brake caliper is a floating, twin-piston unit.
This thread (transalp.org) discusses the Lenac Big Brake Kit.
DIY
Rotors for Transalps
No upgraded rotors appear to be available for US Transalps. Rotors intended for some other bikes may work, however. In Europe, various brake upgrade kits have been sold.
NT650 Hawk
The Honda NT650 Hawk uses the same bolt pattern as the Transalp. The stock rotor is a solid (non-floating) 316mm rotor (this page has excellent Hawk information), and this is probably the most common braking upgrade performed on Transalps.
Since the diameter of the rotor is larger, a new brake caliper spacer is needed. This can be custom machined, or presumably the "Lenac" spacer can be obtained.
XR650L
The XR650L uses a different bolt pattern (four bolt instead of five, I believe), so aftermarket rotors for it cannot be used on the Transalp.
Caliper Spacer/Adapter
With the larger diameter disc, a new spacer must be used to move the Transalp's brake caliper outward.
This thread (advrider.com) mentions a guy making a spacer so you can use a stock Hawk rotor (316mm) on the TA (276mm stock).
Anyway- potential very good news- I asked the guy who built a brake
kit for Honda Hawks (a 6 piston caliper and GSXr rotor- works great-
I have one on my Hawk) to look at a potential TA solution. He designed
and built a bracket that relocates the stock TA caliper so that you
can use a stock Hawk rotor which is larger (and I think a little
thicker) than the stock TA rotor. Combined with steel braided lines
and HH pads (which he thinks might not even be necessary) this should
provide a relatively inexpensive upgrade to the TA.
I should be doing this in the next month or so and will let you all
know how it works. Keep fingers crossed
This thread (advrider.com) mentions the Hawk rotor again.
Stainless brake line is a good investment. Speigler, and Galfer both offer
one. Maybe others. The trick brake upgrade is get a used rotor from 88-91
NT650 Hawk. Same bolt pattern but 40mm bigger diameter. Then you have to
machine an adapter to offset the caliper. I'm working on this now.
Also:
Steve (Fast By Big Boy) Lenac (bigboy11@sigmaweb.net) has (or will
shortly have) the full kits for this. I have one on mine (shown in
the "show me" thread) and it makes a difference.
According to this thread (advrider.com), 2001 - 2004 GSXR1000 mufflers are a relatively easy add-on.
Not quite a direct bolt-on but close. I got two 15° bend stainless steel tubes from Burns Stainless and rotated them until I got the right angle. Then I made the flange to bolt on the muffler. I attached the muffler and then tacked the flange and the two sections in place. I'm not a welder so you won't see a close-up shot. I originally had a GSXR1000 muffler on because it was titanium. But when I put the bags and mounts on, the muffler was too big and in the way. So I swapped it out for a 750 or 600 unit, shorter but not titanium. Fortunately, it weighs the same due to the shorter length.
Electrical
Battery
YTX14AH-BS
According to this thread, the stock lead-acid battery, YB12A-B, can be replaced with a sealed lead-acid battery, YTX14AH-BS. The only modification necessary is to remove the battery insulator sleeve.
NT650
The same thread indicates that the sealed battery specified for a Hawk NT650V can be used on the Transalp, but it requires a 1/8" shim underneath and possible cutting of the battery sleeve.
Repair
Fuel
Petcock Diaphragm
The petcock diaphragm develops a leak and cuts off fuel to the engine. This is a common problem. K&L sells a diaphragm repair kit. It's available here and other places as well (presumably the K&L part number is 18-2701).
Also note that the vacuum line running from the cylinder head to the petcock diaphragm (vacuum side) can develop a leak, leading to backfiring.
Accessories
Luggage
Racks
Happy Trails makes aluminum panniers and steel luggage racks. Their mounting kits are also usable with GIVI and Pelican cases.
GIVI offers topcase adapters which replace the plate on the Transalp's rear carrier. They also produce crashbars.
The E200 Monorack plate is available for 1988-1996 applications (note that the E211 may also be listed, but is for 1997-1998 applications):
The TN363 crash bars are available from AZ Motorsports and Happy Trail. Mounting these to a US-spec Transalp requires longer bolts across the front and minor trimming of the bike's plastic radiator guard.
