Pulse Air System / Yes or No?

[Mike V]

I wanted to get some background from you experts out there. I'm relatively new to the 650 world but growing more enthusiastic as every day passes. I'm doing a complete restoration on a 1981 R65 and am nearing the home stretch. During my search for replacement parts for the Pulse Air System I've learned the manifold flex tubes are no longer available (11 71 1 337 165 & 166). During my search I've received recommendations to plug the system with some belief the system was harmful to the heads especially exhaust valves by introducing cool air at the exhaust valve stem. At this point I've ordered a plug system from Ted Porter in anticipation of removing the system along with dashpots, air valves and plumbing within the air box.

So...just wanted to open up the forum to get some knowledge, opinions and recommendations from you who have extensive first hand knowledge and experience of BMW's attempt to emission control regarding this secondary air system - Pulse Air.

Thanks guys!

Mike V. / San Diego

[Bob_Roller]

I plugged my system, when one of the valves in the airbox went bad .

That was in 1983, about 75,000 miles ago, and no problems to report .

Just for informational purposes, there are drain plugs on the oilheads, that will fit the hole in the head, when the plumbing is removed, they have an allen key head, so there isn't a concern about clearance between the fins on the head, and a socket while removing the OEM union, and replacing it with the drain plug .

Remember to put some anti-seize on the threads before installation .

[montmil]

Along with Bob's comments, I'd like to add that there may be a degree of difficulty in removing the larger steel plugs from the aluminum heads.

Much like the dreaded exhaust "spider" nuts, the Pulse Air fittings in the cylinder heads are susceptible to corrosion and a near impossible removal after decades of bonding. Damaging the heads internal threads will require large applications of cash to repair or replace.

My 1981 R65 has the Pulse Air removed. The plumbing fittings remain in the head along with a very short section of the steel tube that has been welded shut. Of course, all the Pulse Air junk has been removed from the air box and openings closed to unfiltered air.

The 1983 R65 is still equipped with the Pulse Air system. It, too, is scheduled for removal as soon as I can stop riding the freshly painted and upholstered beauty.

Personally, I'm concerned about possible irreparable head damage. [smiley=2cents.gif]  Check Snowbum's site for his extensive chat on this subject. It certainly gave me pause...

Monte

[Mike V]

Monte,
Thanks - all good points. I've also been communicating with Oak. As usual he comes up with the intelligent comments and thought processes I seem to overlook. Oak wonders if the removal of the system will in some way void the CA required emission standards.  Other resources say it's a federal issue and not state specific, although experienced opinions are DMV never checks or inspects the systems.    Looks like more research and answers to questions on my part.  I'll go to Snowbum's site next.

Mike V. / San Diego

[nhmaf]

If everything is working properly, I don't think that the pulse air system does anything "bad".   But, if things do start to fail with it, such as the valves inthe airbox sticking open, then the system can cause "issues", including backfiring/excessive popping  under deceleration/closed throttle situations.   My bike still has it on, but if it does start giving problems I will be taking it off.  Clearing out the inside of the airbox of those large snorkel valves inside would be a blessing for all future repair/maintenance work involving airbox removal, too.   Some of the fittings on the heads aren't that tightly bonded, so yours *might* come out quite easily.   I'd treat it to several nightly soakings of Kroil or something prior to attempting to remove, to put the odds in your favor, just in case.
If you do remove it, I think that one can get some spare rubber bungs for the timing inspection hole in the engine case, and with a bit of RTV compound they can seal up the holes in the sides of the airbox.

The emissions concern could be of some significance, depending on your state's testing requirements.   Our state doesn't do any tailpipe testing of bikes this old, so even if I removed the system, no one would know by how much the emissions may have increased.   IF your state does do some sort of tail pipe emissions testing even on these older machines, removal of the system would cause some change to the emissions - that is the reason the Germans put it in there to begin with.

[Ed Miller]

Mine was working fine and not causing any problems, but I removed it because it makes more hassle when it's time to remove the airbox for tranny spline lubes, clutch changes, and what ever.  Since I had to pull the tranny back 3 times in 3 years it was getting old.  Removing the system hasn't altered the running of the bike at all, and no carb changes were needed.

We don't have emissions testing where I live, but if we did I would fail because I eat beans, not because of my modified bike.

[Justin B.]

Whack it!  The only issue you might have is with the overzealous California Smog Nazis come inspection time.  IF you remove it in such a way that it doesn't LOOK removed then you may be OK.

We don't have it on any of our bikes anymore.  I removed it because something deep inside my feeble mind whispered it wasn't exactly a good idea to have cool air ducted to just one side of a hot exhaust valve.  I guess I just feel better without it plus it looks better...

I use the rubber timing plugs to cap off the airbox holes, oilhead drain plugs for the heads, and screws w/fiber washers for the vacuum ports on the carbs.  If anybody needs some of this stuff I think I have extras and would be willing to put together a "kit" to do this with...

[Mike V]

Thanks all! Much appreciated for the background and opinions. Done deal...it's coming off, actually it's already off and the manifold pipes were tossed during disassembly due to them being slathered with silicone from the PO and the flex portion was badly cracked and decomposing. There was obviously a previous problem with them before I acquired the bike.  I'll keep the airbox valves and gutts on hand after removal just in case it's tested when I get the title cleared up (like a dumbshit - I never filed a Non-Op certificate on it). I have plenty of the timing hole plugs on hand they work great as pads for the Krausers on the luggage racks. Can't wait to show the bike off to you guys when it's done - this has been a long arduous process and I'm having a great deal of fun with the whole thing. Riding it won't come too soon.  Today it's the carbs, then the motor.  I'll keep in touch with all of you and forward links if you're interested in viewing the pics.  This Forum has made the job much easier and pleasant to say the least. And the new friendships are always a bonus. My sincere thanks and appreciation to all of you!

Here's my photobucket link, the individual albums are at the left of the page.

http://s428.photobucket.com/albums/qq8/gruntyman66/81%20R650%20Restoration/

Mike V. / San Diego

[Bob_Roller]

When I moved from Chicago to Phoenix, the bike had to through a Level 1 inspection, and passed with no problems, also, the bike is subject to annual emissions testing, and the bike has usually passed with no problems, except for the last time, with really worn out carbs .

As long as you don't need exhaust emission testing, you shouldn't have any problems, as most DMV locations don't have high quality employees, their just putting in time for retirement .

[montmil]

Emission inspections? Safety inspections? We dun need no stankin' 'spections. Not any more for my R65s.

Here in The Great State of Texas, riders with motorcycles over twenty-five years old can purchase a Vintage Motorcycle license plate, valid for five years, for a mere $51.00.

Registering the younger scooters annually will cost well over $200.00 in that same time period plus there's the yearly $12.50 inspection sticker "tax". There's no emissions test for Texas MCs. The bonus round winning prize for antiques is the exemption from having to pass and pay for the annual state inspections. That's another $62.50 over that five year period. We're now bumping hard up against $300.00 in taxes for those five years.

Sure, there are those silly little niggling unenforced details about using the bike for exhibitions, club outings, parades and riding it to a maintenance facility and... blah, blah, blah

I saw a vintage BMW Airhead at the recent Teaxs Motor Speedway Tech Daze event that carried an Antique MC tag along with an early 1990's Texas inspection sticker! Owner said he's never been stopped and questioned about it.

Dump that Pulse Air system and ride on.  

Truth. A motorcycle addicted co-worker -BMW 'brick', Vincent, two Turnips, a brand new expensive Vespa, HD SuperGlide... well, you get the picture- buys just one Antique Motorcycle license plate and simply rotates it onto whatever he riding that day! Both my R65s are over 25 years old but I ain't talkin' in this here den of inequity.

Monte

[Yikes]

I had to  pull my Pulse Air sysrtem off of my engine when I replaced the heads with some used ones that were plugged.  The only difference I can tell in the bike is that it smells a little different when it is first started.  I do wonder just how much pollution reduction that thing really does.
My neighbor the retired machinist and I were disccussing emissions systems the other day and he made a great point.  The systems like the ones on our bikes are "add-ons".  The original engine design did not have all these pipes and valves on it.  While some good may be done by the emission system, it is also going to have an effect, maybe multiple effects, on the normal operation of the engine that were never part of the original design, like overheating the valves.  So our conclusion was that the engines are better of without the add-on system and that proper tuning and timing are probably more important to pollution reduction than burning unspent fuel in the exhaust system.

I'm keeping the Pulse Air components in a box so that I will have all the original parts, but when I get my original heads back on the old '82, the airbox and heads will remain plugged.
 [smiley=2cents.gif]