K75/K100 inlet valve clearance a bit tight

[beat]

Hi there,

I've recently purchased a 1986 K75 with genuine 68,000 km and in excellent condition.
Today I've checked the valve clearances and found that 2 of the inlet valves are a bit tight (0.10 and 0.13). Is this a concern? Or should I not worry until the clearance gets even less?

According to manual inlet should be 0.15-0.20, outlet 0.25-0.30. All my other valve clearances are spot on (on the lower end of clearance, e.g other inlet valve is 0.15, all exhaust valves are 0.25).

[Martin]

Do it, it's not hard to do, although you need special tools. You can buy them or if you have some basic tools, 4" angle grinder, hacksaw, files they are easy to make, you also need someone with a welder.  http://ibmwr.org/ktech/k100-8v-adjust-tool.pdf  You will need to remove the old shims and measure them to determine the thickness of the new shim. A workshop manual will take you through the procedure available on this site. The shims are available on line or from a dealer for around $8.00, valve cover gasket should be reusable if you are careful. Putting your location in OZ will help if assistance is available locally.
Regards Martin.

[beat]

Thanks for your reply Martin.
I have the Haynes manual, but I'm a bit hesitant to do the adjustment myself just yet.
I've just done it yesterday on my R80, but that's very easy there.
I was mainly wondering if that clearance requires attention (adjustment) right now or if I "can get away" with it for a while until I find the courage to fix it myself or bring it to a mechanic.
Cheers, Beat.

[Martin]

I would do it or have it done. See if someone will recommend someone in Sydney, we have a few members down there they might be able to help you. Once you have done it once you will be surprised how easy it is to do. I made my own tools, and adjusting the valves is really easy to do, one of the easiest I have ever done. It should not cost any more than $100.00 to get the one shim changed by a mechanic. If you want to drop in I'll run you through it. When I have done mine I set them on the widest clearance, if you need to adjust all the valves you measure the clearances, remove the shims and then shuffle the shims around until you get most of the clearances right. You then might have to buy a couple of shims, or I do have a local shop that offers an exchange service for a small fee.
Regards Martin.

[Laitch]

I was mainly wondering if that clearance requires attention (adjustment) right now or if I "can get away" with it for a while until I find the courage to fix it myself or bring it to a mechanic.

Welcome, beat! How about posting a picture of your bike?

Your intake valves are not "a bit tight" as you describe. They are too tight. You can get away with their being too tight until you can't. Valves are well known to be unsympathetic regarding a person's timidity or neglect.

This video shows the tools you need and how to use them. There are actually links to plans for fabrication of them on the site, as Martin has shown.

[K1300S]

There is also some detail on the valve adjustment process in the thread in my sig, along with great source for the tools.

[The Mighty Gryphon]

Best tune is to have the inlet valves at the tight end of the spec and the exhaust at the widest end of the spec.   Wide gap gives maximum closed time so the exhaust valve has maximum cooling through the valve seat.  The intake valves can tolerate a narrower gap because they get cooled by the incoming fuel/air mix.  The narrow intake gap helps the engine breathe better, too.

Get them adjusted.  It's not that bad a job if you get the tools.  Figure two afternoons total four hours of wrench time if you have to travel any distance to get shims.   Failure to keep an eye on the gap is probably the best way to kill one of these otherwise bulletproof engines.

[Vespa no more]

Good info there on the finer art of valve gaps


Might have another look at mine - want it running sweet


G

[beat]

Thanks for all the responses.

I'll get the special tools from motobins (UK). Just need to find a place in South/East Sydney where I can buy/swap shims.

Another question: 2 of my inlet valves are too tight. Now would you just adjust those 2 clearances or would you also at the same time increase the clearances of all the exhaust valves to the high end of clearance range, as - from what I researched - the clearances are only ever to decrease and not increase over time and use.

Attached is a picture of my K75 (along with my R80), as requested...

[Martin]

As Gryph has stated inlet valves run cooler due to the incoming charge. If they are in tolerance I would leave them, however I would probably adjust the exhaust to the widest. It's not a big deal but it is only a maximum of three shims if they need doing, and while your there you might want to for peace of mind. In 155,000 K's I have only had to adjust two exhaust valves. You might want to put a thin smear of Three Bond liquid gasket (Grey) on the gasket. If you don't have a BMW dealer locally try Kawasaki Z1300 Z1000 Z900 29mm OD shims. Possibly others out there, but apparently don't use shims with a chamfered edge as they may have a tendency to come out. I don't know how that is possible, could be an urban myth. You might also want to get a set of digital Verniers or a Micrometer to measure the new shims some have the size on them some don't.
Regards Martin.

[Vespa no more]

Not many bargains around these days


Noticed the "NSW Historic Vehicle" license plate.


$95 for rego and insurance plus $50 for Classic Bike Club Membership. Got to like that. Make sure you record in the log book before you go or the police might flex their muscle. This is a trial for one year.


What suburb in "south east Sydney"? Another forum member is at Cobbity (near Camden). There are 4 Ks in Wollongong area. Seems to be a few K bikes in the region.


You will know of the ride through the national park to Stanwell Park (check the Hindu Temple approx 2km east of Symbio Animal Park - after 10.30am Saturdays and Sundays the kitchen opens - cheap tasty indian food available and very recommended). And just a little down the road is of course Macquarie Pass, Kangaroo Valley, Jamberoo Pass. Jap sports bike heaven.


Will catch up at some stage no doubt. Mine's a dark green K100RT.


Regards


Guy

[beat]

Yes, the historic rego is the reason I have 2 bikes again. I haven't had a bike for a few years (could't justify the cost), but ridden lots before that, sometimes more than 50,000 km in one year!
I live in Cronulla and know pretty much all the good back within a days ride, but haven't been to the Hindu Temple yet... :-)

[The Mighty Gryphon]

As long as you are doing the job you might as well try to get all the gaps as close to the same as possible.  All the exhaust the same at the widest gap and all the inlets the same as well. 

It's definitely worth taking the time to do a good job.  I did the gaps on my K75RT last winter and getting them right made a noticeable improvement in the smoothness and engine clatter.

[kris]

I made my valve tools from an old electric lawn mower blade using a template available either on this site or BMWMOA. Martin has it right. Kawi shims will do and, I believe, those of other Japanese brands, given the correct OD. I believe Tim Tyler even said he trades shims with his source (some bike shop). It's not hard. A little patience and a little courage to try.

[beat]

Thanks everyone for the helpful replies.
In the meantime I have joined the BMW Touring Club NSW (Australia), where I was able to borrow their tools and swap 2 shims. All done and was easier than I thought.