The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Adrian on October 26, 2016, 09:50:42 PM
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Hi again - the next step is to fit the steering head races - My Clymer advices putting the races into the freezer for 30 minutes or so - and the BMW genuine workshop manual - of which I have a PDF - advices a block off wood over the top of the races and a reasonable size hammer used sensibly.
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The old races got thrown way by the shop that took them out so I don't have the old ones to use as a drift. Any suggestions would be so very welcome ....... Adrian
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See if you can find a socket the right diameter... Freezing sounds good as it will shrink them a bit and you probably won't have to whomp on 'em as hard, if you are quick between freezer and bike.
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Thanks Justin. I'm also going to I heat up the frame in.That area as well. I have of all things a steel shower drain.cover that is the right diameter for the race. Fingers crossed :-)
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You can also buy an extra bearing and use it's race as a drift.
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Yep thanks George - I am thinking about doin that -)
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If you warm up the frame, and freeze the race, it shouldn't take much "persuasion" to get it installed...
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Thanks Justin - the frame is powder coated but I should be able to heat it to about 100 degrees C without damaging the coating as its put on the frame at about 200 degrees. I'm having a break over the weekend and will try on Monday :-)
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Adrian,
I do hope the powder coater man protected the hole from being powder coated. Otherwise, the Dremel is called to clean the tube to show the bare metal before trying to insert the bearing races...
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yep all good George :-)
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I'm in the process of removing mine and replacing them, so i will be interested in how you get on.
The outer race on my bike is flush with the steering head is that correct.
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I'm in the process of removing mine and replacing them, so i will be interested in how you get on.
The outer race on my bike is flush with the steering head is that correct.
Drive it down until it seats. If left slightly off the seat, you'll be stripping it within the first 100 miles of riding.
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I don't know if this is widely available, but two of the local grocery stores have dry ice for sale, it's sold by weight not expensive at all, about $2.50USD for a pound, .5 kg .
I've tried it a few times with assembling things with a close tolerance fit and works great .
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What a pain removing the bearings. I used the welder on the shells and made puller ends and extensions to pull the bottom bearing up after removing the cage.
Is an aluminium vacuum cleaner pipe good enough to drive the bottom bearing down after heating the bearing?
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Cycleworks made very clever tools for removing the races. And no so expensive.
I used them for the steering column, swing arm and rear wheel. Very good and easy job.
Do not freeze the races too deep. As heat, cold is used to temper steel.
IMHO, a freezer at around -18°C is OK. But around -100°C is not.
On the other hand, when heating do not exceed 100~150 °C.
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What a pain removing the bearings. I used the welder on the shells and made puller ends and extensions to pull the bottom bearing up after removing the cage.
Is an aluminium vacuum cleaner pipe good enough to drive the bottom bearing down after heating the bearing?
An angle grinder works a treat on the bearings, once you have the cage and rollers cut off you and either gently work over the inner race until it comes free, or if you are worried the time old method of 4 90 degree spaced cuts with a sharp cold chisel will usually expand the races sufficiently.
Aluminium Vacuum cleaner pipe is unlikely to be strong enough to seat your new bearings - Alloy/steel pipe is required. You can of course freeze the bottom yoke and heat the bearing I guess - I've always just flogged them on.
Whilst you can buy the bearings far cheaper from your local bearing shop than from any BMW parts supplier - do buy the bottom "seal" it really does do an important job.
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Thanks i will look for some stronger pipe.
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Well that was so easy to do. this was the one job on the bike I thougt I would struggle with - not the clutch removal or the timing cover removal - but fitting two bearing races.
Well leaving the races in the freezer overnight and heating up the seats on the frame to a temperature that was just too hot to touch - the top race (pic 2) just dropped right in and all the way to the seating and the lower race (pic 1) dropped in almost level with the frame and only needed a block of wood to get it level then a steel punch carefully used on all points of the compass with reasonable force but not excessive - to get it to seat.
Sometimes I am really surprised by how easy something can be on this bike :-)
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That looks a nice job Adrian,
Amazing how you can get worked up about these things, I fret about the carbs...
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I'm paranoid about my carbs when the bikes running - I'm always tinkering with them when they go off song. I have proper balancing device that's really good. My old vac gauges weren't that good.
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I often have the same feeling about tuning. It helps a little to look at what Duane Ausherman said on the topic:
A good BMW twin tuner with a lot of experience will almost never find a perfectly tuned engine. Each of my mechanics went through a "crazy period" when they were learning to tune carbs. While riding their own bikes, every few minutes they would reach down and do a slight tweak on a carb. Eventually, they learned to accept that it would never be perfect. The very best that you will ever achieve is a workable compromise. Be happy.
Duane also lists a number of reasons why perfection isn't possible:
Here are some BMW tuning considerations. Questions keep coming up about the two carbs and how to synchronize them. Do you have a "hard to start" BMW motorcycle? These are only some of the factors in tuning. This is a mental exercise only and is not intended to be important to anybody at all. The net effect will be to confuse some riders. It's amazing that they run so well with all of these factors affecting the tuning. It is only natural to want to keep your BMW tuned.
1. The BMW twin is basically two engines with a common crankshaft. In all tuning aspects, they must be treated as being two separate engines.
2. The BMW exhaust systems are of a different length, due to the staggered cylinders. So they tune differently. A cross wind can change the back pressure between the two sides.
3. The BMW twin intake is pretty symmetrical for each side, but not exactly.
4. The right side, of 1970 until about 1980, has some crap (crankcase fumes) dumped into it from the crankcase breather. This changes the tuning slightly, it's especially noticeable at lower rpm.
5. The Bing carbs are pretty consistent, but I have found differences between them, don't assume.
6. The BMW valves may seal unevenly, or may not. Same for the rings. Remember the time that you rode for 2 hours in a cross wind? That is when you changed, forever, the two sides. The cooling was totally different for them.
7. If the compression is different between the two sides, then one can't expect to balance them. Compression is measured at low rpm. At higher rpm they can act differently, and we can't even measure it.
8. Do you think that the camshaft was made with equal lobes? Maybe so, but do you think that they wore equally? Not likely.
9. Often the ignition timing is slightly different. If fact, why even think that these two cylinders even need the same timing? Proof that they don't is that when one encounters a ping (pink in the UK) it is usually on one cylinder.
10. The BMW timing advance curve is mechanically derived, not "need" derived. The ideal timing is to be retarded enough to be just under the ping timing at all rpm. To determine that, one must have the ability to independently change the timing of each cylinder under load. Then find the optimum timing increments of 50 or 100 rpm. Then what you see will be the real curve needed. There is no way to get that mechanically or electrically. The curves for each cylinder will be very different from each other and from the one provided by the advance mechanism. That's why one can find that the pinging will be slightly different in each cylinder as it goes through the "ping" rpm range. One may even find that it only pings in one cylinder.
11. Have you ever used vacuum gauges to tune the carbs and found them to be way off?. It is possible, even easy, to get the vacuum equal with the settings at idle and have them run quite differently, even badly. A deaf person would NOT be able to tune them with the gauges only. A person with experience and sensitivity can tune them faster and better than anyone with only gauges. It is natural to want a "magic" fix, but all of the gauges and level tubes filled with this and that, are a very poor way to do it. Sorry, but you need to "know something" to do the job well.
12. To adjust the cables to pick up at the same time is one way. The error in that thinking is that the two engines (cylinders) won't rev up at the same horse power vs. rpm rate. Then, at road speed they may be putting out different amounts of hp. We call that "vibration." Some vibration is normal and is due to the offset cylinders.
13. Another way is to take the engine up to 3500, or so, rpm and short out one spark plug at a time and adjust the cables for equal rpm. This won't produce equal HP (low vibration) at that rpm, but it will get you into the ballpark. The reason is that the two cylinders usually produce a different amount of horse power at any one rpm. The two sides aren't able to contribute equally to the work. Note, I really don't approve of that method of balancing the carbs.
14. The choice is easy for the touring rider. One will find that a narrow range of rpm will be normally used on the road. At this rpm, adjust the throttle cables for minimum vibration. Just know and accept that it
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What wise advice Barry!
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A bit of heat and cold and a bit of thump and it is all back together. Now for some riding without the wobble.
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Hi Adrian your information has been of help. I got my bike from victor harbour SA.
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Hi Skippy. Glad it was useful for you. Any pics of your bike mate? I hope your finding time to ride. Now I have all the money I need ~ small unexpected inheritance ~ I can finally press on with rebuild :-) Tidying up a friends garage/ shed as a workshop at the moment.
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Well the bearings made a difference the handling is much sharper than it was. Here's a photo for you Adrian