Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > BMW Tech

BMW Tech BMW Tech Forum - For Questions specific and of interest to BMW riders only. Questions comparing which bike is best etc go in the "Which Bike" forum.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

7 Litre Camel Tank Lets You Explore More, Click to Find out More!

LinkBack Thread Tools Display Modes
Old 21 Jan 2008
Registered Users
HUBB regular
Join Date: Oct 2006
Location: Czech Republic
Posts: 21
Airhead valves

Hello all,
I'm going to change push rod tubes seals on my R100GS and at the same time want to inspect cylinder heads. The bike has 115000kms on the clock (it might be more, I own it since 70000), engine takes little oil, I'd say less than 0.1l per 1000kms and it isn't noisier than other airheads I've heard. The thing I'd like to know is if I should have valves and guides replaced and seats recut on the bike with such a mileage even if they are in their wear limits. I'm preparing the bike for a long trip and want to have everything 100%.

Please advise
Reply With Quote
Old 21 Jan 2008
AliBaba's Avatar
Registered Users
Veteran HUBBer
Join Date: Apr 2001
Location: Norway
Posts: 1,350
0.1 l oil per 1000 km is pretty good for an engine of that mileage.

If you prepare the bike for a long run tour I would have overhauled the cylinder heads. I did it at 150kkm and it was needed.

It might be smart to check the pistons and rings to. My rings and piston (R80GS) were good at 150 kkm but at 180 kkm they where far outside the tolerance – but the engine was running nice.

Timing chain and clutch should normally last a lot longer the 115kkm but it might be smart to change them if they are original.
Reply With Quote
Old 21 Jan 2008
Vaufi's Avatar
Contributing Member
Veteran HUBBer
Join Date: Jan 2004
Location: Munich, the beer capital
Posts: 814

While the engine is open, check the main bearings in the crankshaft as well. When I had to exchange the seals for the push-rods I checked my bank account and had the pistons & con-rods balanced on my R80GS. Jeez, what a difference! The engine runs so nice & smooth now.

Only when we pause to wonder
do we go beyond the limits of our little lives.
(Rod McKuen)
Reply With Quote
Old 21 Jan 2008
Registered Users
Veteran HUBBer
Join Date: Feb 2006
Posts: 1,513
I would not take apart a good running engine to do this, but seeing that you have the valves out, i would fit new exhaust valves keeping everthing else that was in specification. If you change the guides, you will have to recut the seats. I would avoid removing metal for as long as possible.
Reply With Quote
Old 22 Jan 2008
Registered Users
HUBB regular
Join Date: Oct 2006
Location: Czech Republic
Posts: 21
Thank you guys for your input.
I agree with oldbmw. I don't like to remove any metal unless it is necessary. I'll take a look at seats and I'll inspect guides using method described in repair manual. If they both look OK I'll probably replace only valves as a precaution against split exhaust valve head. I've heard or read warnings this may happen on the engines with high mileage. Is there any reason why I shouldn't fit new valves into old guides if they are in good shape?
BTW does anyone know new valve stem diameter? I know they are stated to be 8MM but I'm guessing they are slightly smaller. 7.98?
Reply With Quote
Old 25 Sep 2008
Registered Users
Veteran HUBBer
Join Date: Oct 2002
Location: Stockholm - Sweden
Posts: 316
How did it go ?
What did you chose to do ?

Ever heard of metal fatigue ?... get new valves!
Drive Safely,
Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Buying an airhead BMW in South Africa Roboyobo BMW Tech 2 12 Dec 2007 21:32
AirHead in Guatemala PeteNero TRAVEL Bikes for Sale / Wanted 0 21 Dec 2004 18:46
gs 1150 burnt valves oddbod BMW Tech 1 13 Aug 2004 13:53
Which Battery for my Airhead? Story Leavesley BMW Tech 7 23 Dec 2003 18:33
adjusting valves and carburator Mark van der Molen Yamaha Tech 0 25 Apr 2002 02:44


NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!

HU DVD Autumn Special!

Take 40% off Road Heroes Part 1 until October 31 only!

Road Heroes features tales of adventure, joy and sheer terror by veteran travellers Peter and Kay Forwood (193 countries two-up on a Harley); Dr. Greg Frazier (5 times RTW); Tiffany Coates (RTW solo female); and Rene Cormier (University of Gravel Roads).

The first in an exciting new series, Road Heroes features tales of adventure, joy and sheer terror by veteran travellers."Inspiring and hilarious!"

"I loved watching this DVD!"

"Lots of amazing stories and even more amazing photographs, it's great fun and very inspirational."

"Wonderful entertainment!"

Check it out at the HU Store! Remember to use Coupon Code 'HEROES' on your order when you checkout.

Renedian Adventures

Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!

What turns you on to motorcycle travel?

Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!

New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.

Books & DVDs


All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.

Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!

All times are GMT +1. The time now is 22:48.