Well was thinking of a Yamaha XT or TTRE for a RTW trip -but maybe the BMW F650GS is also a contender - although have obviously read some of the horror stories here about the BM. Just wonder which engine is likely to last the longest before major work the BM or Yam? What is a roughly average mileage one could expect before major work i.e. engine strip down (and I know this will vary a lot -but just a rough idea?) I'm just thinking my RTW trip is likely to be in excess of 50-60,000 miles.

My F650 ate it's water pump and warped it's head in Morocco with less that 30000 miles on the clock. Made it into Spain though.

My XT600E burned more oil that my MZ 2-stroke on the motorway. This never seemed to bother it. I traded it for the Triumph before I got to grips with serious use.

I'd go with the Yam unless you feel a need to cruise above 60 mph for any decent sections of the trip. Even for USA/Canada/Europe I'd be happy at 55 on the back roads, but not everyone is.

Andy

As 3wheelbonnie says, there are a number of known weak points for the single cylinder F650 engine when doing high mileages, although I don't know which models/years are susceptible - if you plan/deal with these in preparation then it is a very smooth engine - It is the smoothest single that I have ever ridden.
There are plenty of examples of them putting in lots of miles, including with tour companies, like the one sponsoring this forum (now switching over to the new twin cyl BMWs).
It also does 70 MPG consistently, no matter how you treat the throttle and easily cruises at, say, upto 80 MPH all day, still running very smoothly. FI will deal with altitude better than carbs, although the latter can be adjusted with a bit of effort.
The chain gang website has a bigger "database" for any issues about this bike.

I rode a TTR for a while and that was not a smooth running engine with lots of obvious vibes - a typical thumper! I found it quite tiring to ride all day compared with the F650 twin spark.

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Dave

In my opinion you cannot go to far wrong with the Yam. I had a similar decision to make a while ago, and went for the xt660r. It is very simple to use, and maintenance is very easy and straightforward. They are really bullet proof, and you can get spares very cheaply and easily. You can get a larger tank from offtheroad.de, and loads of extras from touratech among others. The bike is cheap, and this leaves you with all the extra cash you need to get the extras you really need. Handling is good. I have ridden mine on quite a bit on sand, dirt, gravel, forest tracks and highway, and it does it all fine. Not a superstar at any in particular, but does all well enough. I added a tall screen from yamaha to mine, and now motorway travel is very comfortable up to 130kmh. The seat is in my opinion better than the bmw, and the headlight is one of the best on any bike I have owned. Bump starting is no problem, and the fuel mixture can be adjusted very easily via the main computer switches on the dash, which can be a real plus, and sorts out any surging or popping that may occur with dodgy fuel, and you can easily run it on leaded fuel. I put a Touratech bash plate and some renthal bars on which protects everything nicely, and gives you a very robust bike. If you do drop it, plastics are very cheap and easy to replace.
Check this out -http://sverrirt.blog.is/blog/sverrirt/ . these guys went around the world on them and rated them pretty highly. I think they chose the bikes (ie not sponsored by Yamaha), so it is a fair appraisal. There are plenty of others who have done the length of africa on the XT, including a Dane recently, who also rated the bike highly, and had no real problems at all, despite giving the bike a pretty hard time.
Good luck, and if you any questions you can also check out . : XT660.com The #1 xt660 resource : . | The #1 xt660X, xt660R and xt660Z Tenere resource . They are a huge wealth of useful knowledge.

Just picked up on this part of your question: as you say, it is going to vary - thing is that if you give it the correct care and maintenance, it will do a good job for you, whatever single engine you have.
Any single is probably going to want some work doing after your quoted mileage. I suggest you take the view that the bike is written-off at the end of such a long, "rough-riding" journey. Anything better than that is a bonus.

Your question implies a second hand bike purchase, so you will want a low mileage (genuine, not fiddled!) bike at the start - look for one of those rather than a specific model of bike.

If you are thinking new, then the XT660R has a stable mate in the XT660Z Tenere.

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Dave

Walkabout hit a good one there with the XT660Z Tenere. Initial reports are very good, and it certainly looks like an impressive machine. The engine is certainly tried and tested, but it now has a big tank, high screen and some good protection. They have also improved some of the fuel injection. Certainly worth a look, and at the price they are going for, you cant get a better bike, with such a proven track record.

What caused the warp?

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Tacos Tyring Travels.com

It's all heat related and hard to tell which order things happened in. By the time the cooling light came on, the waterpump was a gonner, the exhaust had a leak where it entered the engine and the compression was down. I rode another hundred or so miles to get into Spain at 50 mph, spent a day dealing with the BMW dealer from Hell in Malaga (go along the coast, BMW Marbella tried calling Berlin and a KTM dealer for me), then got RAC to ship it home. On putting the head on a glass plate I found it was no longer flat, hence the lack of compression and valve clearances all over. The water pump shaft has no bearing and so runs on and wears it's seal. The water mixes with the oil, so you have an aircooled F650. I personally thing the water pump seal went first, things heated up and the head gasket went. With less compression/wrong mixture it was just a matter if time before other things started to cook.

Good news is that the waterpump repair kit is small, light and takes about half an hour to fit.

This was a 1999 bike BTW, I see nothing with the FI bikes that suggests any improved water pump design.

I'll be staying air cooled until Hell freezes over, but there again at that point all the watercooled engines will be stuck anyway

Andy

just to make sure we are all on the right page here, when you talk about the Yamaha XT which model do you mean?? the 600 or the newer 660.

Ive the newer XT660R (R for off roader, the X is the road bike with supermoto wheels). Its very much the same as the BMW but with differences. The XT660R will also return 70mpg but does drop if ridden harder, there has been cases of couriers with over 70kmiles on there bikes and have had no bother. It is slightly cheaper to buy for a reason becasue its not as well know and also some of the finishs are suspect like engine covers,paint, etc etc.

Depending on what type of terrian you want to travel will choose your bike??? The xt will cope with nearly anything thrown at it and can be moded very cheaply to suit the type of biking your doing. The only big down side with the XT is the fuel range which is around 130 if lucky before the light comes on. There is a larger fuel tank avaiable from offtheroad but it is very expensive and they are not best know for speedy deliverly. The other option is just carrying 1 or 2 plastic petrol containers with you just incase.

As someone said before have a look at the . : XT660.com The #1 xt660 resource : . | The #1 xt660X, xt660R and xt660Z Tenere resource forum as its got plenty of information about the bike and people who have done trips like yours on the XT660.

Was actually talking about the 600 engine. Don't think I can run to a XT660 or new Tenere - whilst I can probably afford to purchase one - I don't think I could meet the Carnet cost for one - thus a second hand XT600, TT600RE, or F650GS is more along the lines I was thinking.Was just trying to get a general idea of the longetivity of the engine -not really the anciallary equipment. I,ve seen on the forum some GS's reporting well over 150,000km done -but not sure if the Yam's can match that?

My '94 F650 has done almost 150,000km and is still going well. It has had two waterpumps, one at 60,000km and one as 138,000km. It has had a new cam-chain at 70,000 and that's all that has been done to it. It still has the original rear shock! It's certainly a much more comfortable bike than the XT, but possibly not as rugged. I would say of the many (100+) travellers we have had visit or stay with us, the XT would be the most reliable but the F650 range would not be far behind.

Regards

Nigel in NZ

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The XT600 engine is a nice simple lump that'll go a long time with minimal servicing. MIne's not particularly old or high mileage, but it's done over 30,000km without any problems whatsoever.

Matt

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*Disclaimer* - I am not saying my bike is better than your bike. I am not saying my way is better than your way. I am not mocking your religion/politics/other belief system. When reading my post imagine me sitting behind a frothing pint of ale, smiling and offering you a bag of peanuts. This is the sentiment in which my post is made. Please accept it as such!

I am with Matt on this one the XT lump is a winner. I had a Xt600Z Tenere 1VJ with a 3AJ barrel and it was fantastic. Tried the F650 once or twice as a dealers courtesy bike and found it busy and vibey for the amount of output and no faster in real terms than my 2T MZ.

Steve

F650 all the way so far. I moved up from the 3AJ which according to Dave Lambeth is the best they built. He built both our 3AJ's and had one of the starter one-way gear go which meant it was pot luck if it would start or not. And that bike was already hard to start, especially when the ambient was cold.

We got the last of the Dakar's and just love them. Super comfortable, and crips clean power. You really notice the 16 more HP's compared to the 3AJ. Not sure how much the new ones have.

Learn how to do the maintenance and the tell tell signs of things one their way out (like the waterpump) and you're laughing. You'll probably also be a rarity amongst the Beemer riders for doing so. But at least you can than give realistic feedback about the quality.

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Tacos Tyring Travels.com

Interesting how the complimentary statements of fact about the F650GS, including for example Nigels' last post, end up anywhere but in the BMW tech forum.
I guess we are all too busy riding the Wee Beemers to be too bothered about spreading the good news! Anyway, that will just push up the second hand prices!

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Dave