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-   -   what to look for when purchasing (https://www.horizonsunlimited.com/hubb/bmw-tech/what-to-look-when-purchasing-7924)

martync 2 Sep 2003 22:51

what to look for when purchasing
 
Hi

I'm about to take the plunge and buy a R100GS but wanted to know what to look out for in the way of engine noises and other bits which tend to go (eg drive shaft etc..)

How do you test these are OK and what noises are normal when the bike is OK as Ive not had an old bike before (used to have sports bikes but got sick of em!)

Any help greatly appreciated

Martyn

Timo 5 Sep 2003 03:35

The early Paralever drive shafts are, as Grant puts it, 'a service item' meaning that they have a working life span of +/-50000km. Lots go further, and some have quit sooner, but that is a good time to look at replacing them. Lots of good Airhead (air-cooled, 2 valve head BMW twin) on the Airheads web page http://www.airheads.org/index.php and questions can be posted there as well.

The nice thing about these bikes is that generally, they are well looked after, being outside of the typical buy it and bash it owners group. Most GS owners are knowlegable about their bikes and maintenence etc. is done properly.

I am sure others will add more specifics, but as a start I would advise having a knowlegable shop look over any potential purchases. I mean a shop or individual with specific Airhead experience, not your average corner motorbike dealer.

You will find that many GS's have been 'upgraded' in some way, or accessorized:
Quality suspension upgrades are worth paying extra for - improved fork springs and aftermarket shocks are common and necessary improvements. the front brakes are not stellar, larger rotors, dual disk, and better calipers are nice. Watch out for any damage to the wheels. look for excessive run out, an easy measurement to do when viewing a bike. the wheels are difficult and expensive to rebuild. dual plugging is a nice option to have.

As with all bikes, the engine should start easy, run smooth, quiet (noisy valve gear?) and generally breath well. check carefully into any changes to the exhaust or carbs, as not all modifications are positive.

Generally great bikes that will last a long time, if maintained properly. Buy and enjoy. If I were you, I'd spend the extra money to purchase a low km PD model, as the extra fuel capacity is a must on long trips and an aftermarket tank will run you big $.

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martync 5 Sep 2003 04:16

Thanks for the info, as i thought the usual when buying then, just wanted to know of any engine knocks to look out for as airheads are noisy anyway, also i know large tanks are a good option but have been told dual sparkers are just extra cost for low end smoothness??? and a long trip is probably better off without????
I think 30-50K out of a drive shaft is OK, you can't expect much more than 8-10K out of a chain driven bike and if you look at the cost, the old paralever seems a lot cheaper than £180 for a chain and sprokets.



Timo 5 Sep 2003 05:37

Yes, there is some added complexity from the dual spark ignition, however, the general consensus seems to be that the benefits outweigh the negatives. I think it is more about better running on low(er) octane fuel - 87/89 rather then the recommended intake of 93/94 octane fuel. Some report an increase to fuel economy and power (+/-5-10%), as the fuel is burned more efficiently and fully. I dual plugged my R100GS and noticed some improvement, but not a huge benefit. Mainly it ran better on low octane fuel - less pinging. This is a good benefit for world travel, where better grades of fuel are hard to find. The R100GS has a higher compression and a wider bore then the old R80G/S(which runs fine on 87 I might add). These are both contributing factors to pinging and detonation.

As to rough running, the R100 engines do seem rougher in general then the 800cc engines, a function of reciprocating mass and magnified by any imbalance to each side both in weight or carburator sinc. I have heard that some R100's are better then others.....

beddhist 28 Sep 2003 05:50

Quote:

<font face="" size="2">The early Paralever drive shafts are, as Grant puts it, 'a service item' meaning that they have a working life span of +/-50000km. </font>
The same goes for gear box bearings. If the bike is high mileage, factor that in. If it's been done recently make sure you get invoices from a qualified dealer.

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Salut from Southern France, the bikers' paradise,

Jenny & Peter.

[This message has been edited by beddhist (edited 27 September 2003).]


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