Suzuki XN85

[Issues]

does anyone know much about the XN85? I have bought one for a cafè project. The bike has not been running for a few years and I would like some general info on it.

Are the engines the same as other suzuki's from the period, common pats between them?

Can anyone point me toward a useful informative site or workshop?

[Tony Nitrous]

Even though im a Suzuki fan,
I never liked them, 16" front and gutless.
Gpz750 Turbo used to slaughter them.

I'd still own one if it was tidy or cheap though, just for the novelty value.

Have you looked at....

http://www.xn85turbo.com/

[Tony Nitrous]

You could have a new one for $33,000AU

http://www.getpowersports.com/eddiesvintage_ontrack/preowned_inventory.asp

[Issues]

Thanks Tony. It has had a low speed crash into a padestrian, broken fairing, no instruments and a dent in the tank. I haven't picked it up yet but for $200 it should be a good project.

[Tony Nitrous]

Keep swapping bits for modern stuff and you'd end up
with a legit complianced "turbo" streetfighter...;)

[Issues]

It will be a cafè bike. USD front with spoke wheels, proberly GSXR1000 swinger, ally tail and tank. Evrything will will be at a minimum, but it will still be a heavy shit box I'm sure when its done, factory specs say 247kg.

I think a legal turbo cafe would be best for it. Being aircooled and turbo under the seat gives it good lines, I just have to pick it up.

[JackTar]

http://cgi.ebay.com/ebaymotors/Suzuki-Motorcycle-Service-Shop-Manual-XN85-Turbo-1983_W0QQcmdZViewItemQQhashZitem2ea7f86fe6QQitemZ2 00386572262QQptZMotorsQ5fManualsQ5fLiterature

[Issues]

Thanks JackTar, I bought one from the US, it arrived 2 weeks ago. The manual does not give info on what fits from different models though, or anything about what mods are beneficial.

[Wombat]

Hi did you get the bike? The engine was based on the GS650G Katana but completely reworked and would share very few common parts. Frame suspension and body work all model unique.
I might be in the market for any of the original stuff you take off the bike. Have two of these dimosaurs ....

[Jockney Rebel]

get the turbo checked and the electronics ..but nice score mate i recently took an XJ650 turbo up to dubbo completely reworked nice bike

[80s freak]

bottom ends are the same turbo and non, I have heard that gs850 barrels will fit.

[Wombat]

sorry to disagree re the bottom ends ...
non turbo is shaft drive , turbo is chain drive, with different oil pump and galleries for oil cooling jets to the underside of the pistons
for some info / knowledge on this model , try the TMIOA website
Wombat , XN85 owner

[Wombat]

genuine workshop manuals are easy to come by on ebay, $40 upwards, and parts cross reference CD also availale from the states, ebay again

[Dynomutt]

Both Suzuki and Kawasaki shaft drives of the time used pretty much the same bottom end as the chain drive. They can be converted from shaft to chain relatively easily with a few parts changes.

[80s freak]

Sorry Wombat, I was refering to the engine not the gearbox, but as Dynomutt said. Suzuki were awesome for crossover parts. The crossover CD from the states is great. I need to get another.

[Rocket]

anyone got any pics?
I cant even recall what they look like, but i remember thinking they looked cool.

[Wombat]

quote:Originally posted by Wombat

[quote]Originally posted by 80s freak

Sorry Wombat, I was refering to the engine not the gearbox, but as Dynomutt said. Suzuki were awesome for crossover parts. The crossover CD from the states is great. I need to get another.

Sorry to still disagree, crankshaft, rods, gudgeons, pistons and rings, oil pump etc etc - ALL different - not to mention oil cooling of piston crown undersides and oil cooling galleries in the head above the combustion chambers
Yesssss, the XN85 was a morphed GS650G, and almost completely different.

[Wombat]

The following is an exact quote from a Suzuki dealer booklet, printed '83 or '84 :-

Piston cooling:
Nozzles provided on the metalic back side of crankshaft spray oil on the back side of pistons to cool them. This piston cooling oil is different from the crankshaft lubrication oil. If oil pressure goes down to 2kg/cm2, the piston cooling is stopped by closing the regulator. This type of oil cooling has enabled realize light weight pistons protected against overheating.

Cylinder head cooling:
Addition cooling implements not found on GS650G are:
(1)Ram-air cover (as head cover) is provided to improve cooling of combustion chamber and spark plugs.
(2)Grooves leading to tappet chamber are provided to carry excess oil for cooling down exhaust valves, springs and valve guides.
(3)An oil route is set up underneath exhaust holes for cooling down exhaust valve seats.

Reinforcement of Crankshaft and Con'rod:
.Diameter of crankshaft pin
.Diameter of con'rod large end: 34 to 36
.Crankshaft surface treatment: Additional TUFFRIDE treatment
.Shape of con'rod small end: Area of pressure receiving is enlarged
.Shape of con'rod ribs: Ribs are made thicker

Lubrication network:
Lubrication network of XN85 TURBO
Carries the same network as that of the GS650G plus the following additions.
(1) Oil routes for piston cooling
(2)Turbo lubrication routes
Pumping capacity of oil pump is also increased to meet the above addition repuirements.

END OF QUOTE - Love the Japanese / English translation of the era !

The oil pump is a twin rotor, where the one in the GS650G is a single rotor. Looking at the oil flow charts both rotors feed the same oil galleries.
The oil system has a cooler, and flow to it is controlled by a pressure regulator. When the oil is cold it doesn't flow well, and the cooler is bypassed. Once hot enough, the regulator allows flow to the oil cooler.

Cheers
More than just a little different to the GS650G this engine was morphed from !

[80s freak]

Point taken, it sounds alot like they may have used a bottom end based on the 850 rather than the 650. haven't seen the twin rotor oil pumps before, might have to look into one for my turbo motor. Thanks for the enlightenment.