Hi all,

I've started a major overhaul on my bike, and I have to say, the information and community on this blog is amazing. I'm a complete novice and having this resource saves me many gray hairs.

A few months ago is when my bike started to act very funny. At 90mph the engine aggressively hiccuped and then eventually lost power (did I mention my wife was on the back?). I was able to start it back up but it has not run well since. Being the novice I am, I brought it to a BMW certified shop where I promptly waited 2 MONTHS to get my bike back. Long story short, it still doesn't run well.

This is the work I had done at the shop:
New vacuum caps to address a leak
New spark plugs
Carbs synced
New air filter
Valves realigned 

The shop also said my plug wires were shot and replacements were "unavailable". In order to replace the plug wires I'd need to replace ignition coils and new wires.

Most of this is straight from the shop ticket. This could be an easy fix for all I know, but it's all over my head.

Do any of you have an idea where I can source new plug wires? And if so, is this an easy job a novice can perform?

Thanks in advance for the help. I'm sure I'll many questions in the coming weeks.

When they say CERTIFIED that has absolutely no connection with their ability to work on a motorcycle.
Firstly the need for new plug leads does NOT mean that new coils are necessary (that is a con)
And when you say Major overhaul what are you planning to do in an overall picture.

Model, year, miles?  (it helps if you put the year and model in your sig, or at least the post)

Major overhaul in, I'll drop a new engine in this thing if I have to. That and I'll be stripping away weight that no longer function (i.e. ABS) and giving the bike a bit of a makeover.

It's a 1990 K100 LT. Odometer reads 66k but has been a little faulty as of late. Maybe closer to 75k.

GeorgiaK wrote:Major overhaul in, I'll drop a new engine in this thing if I have to. That and I'll be stripping away weight that no longer function (i.e. ABS) and giving the bike a bit of a makeover.

It's a 1990 K100 LT. Odometer reads 66k but has been a little faulty as of late. Maybe closer to 75k.

So you probably will be pulling it apart to do a rebuild to a cafe job.
Best to do things as the rebuild takes place and pay careful attention to how the air box/plenum/ injection all fits because the 8v bikes are very prone to air leaks in that area and it upsets the injection no end, it has extra air that has not been accounted for and will run like a dog.
The hiccup could well have been caused by a bad lead/plug and then the pressure of that causes leaks.
I would suggest take it from there and when you start it next see how it goes.

GeorgiaK, I'd steer clear of that shop.  It's clear the folks there are less than honest, and they may well be incompetent too.  Even though you may not feel like you're wrenching skills are what they might be, you'll probably be better off doing your own work.  There are plenty of resources here and elsewhere available to support you. The WWW is your friend.

errr am i the only one who thinks that having 'carbs synced' does not sound right.

To the best of my knowledge BMW bikes have not had carbs for a long long time and K's never had carbs.

Mike

crikey !!!
how the hell do you realign the valves ???

I wonder if we are talking here about interpretation of what they said..... to what you understood  or  what they likened the process for you to understand ?
 there is a different terminology between what some folks understand so far, until they become accustomed with the correct terminology and function on the fuel injected "k " (no carbs ) that we may use in here ( the forum )

New vacuum caps to address a leak    (total possible, common and recommended )
New spark plugs                                (definitely a good start and recommended )
Carbs synced                                     ( just a terminology issue  we call them throttle bodies )  
New air filter                                      (standard practice )
Valves realigned                                 (  hmm   perhaps this was valve clearances  "
adjusted"                                            with  replacement shims ?)

there may be a correlation between ignition issues found in your area of the country ...
for us aussies in the "big dry country" we don't see too many coil failures ...but I could imagine in different climates "coil " failure and ignition issues with leads could be associated with moisture issues  and premature failure ....experience may be good and predictive correction for the resolution ..in your area .

have a look at "realm engineering" for plug leads at a very reasonable price ...ngk also make a quality set for our bikes ..besides the " oem " bmw high price" replacements  

for many of us, the fact that we are prepared to do the work ourselves and parts are available ...makes the "k" a very reasonable offering to the home mechanic .

we have seen some major restorations in here by those that do not do the work themselves .... I shudder to think how much they spent , getting workshops to do the work for them ...but still amazing results for those afflicted with the bug ..

there are many alternatives to just giving it over to the mechanic to find a timely ( for him ) solution that may cost you a packet In dollars ,,whatever .

if you have the inclination, many contributors in here can help you on the self help path ...if that's what you need or want.

it may not be easy for some ....but the reward is an amazing feeling of self accomplishment

there are not many things that haven't been attempted on the forum ....so give it a go ....

good luck ! 

cheers

Haha. Loving all your responses.

A cafe job would be cool, but I'm trying stay a little truer to K bike. Not going to alter the bike too much. After all, I have no idea what I'm doing  . Any suggestions onto fairing alternatives are welcome. I really like the look of the 'bubble' fairings on r90s and some Italian bikes but I'm ok to go minimal as well.

Definitely not going back to that shop. Living in Texas now, any who. I had taken the bike to two different BMW specializing shops. One guy knew his stuff but his wait list was so long, the poor ol K bike hardly got any attention. The second was a dealer and don't seem to care about any bikes with age.

Carbs synced, valves aligned….straight from the shop ticket. charlie99, your translation sounds correct to me.

The bike lived in the Southeast United States (humid and hot) for many years but it's been run in everything from blizzard to sand storm. 

Will look into Realm Engineering for plug leads. Definitely going to try to tackle the next steps myself. I've ridden this bike for too long to not really know much about the workings of it all. Also, my wife has shown a lot of interest in helping me and even spent an afternoon learning how to use a ratchet taking off the fairing. It doesn't get much better than that.

Thank you all for your advice. I'm about to leave town for a few weeks but I will keep you updated on my progress.

BTW, this is where the bike is at currently:

Do these look right for a K100 LT?

https://store.bobsbmw.com/product/plug-wire-set---ngk-k100-2-valve

They will work.  Here's another option:  http://www.euromotoelectrics.com/category-s/795.htm
I've been a very happy customer of EME for a number of years.  John is a really helpful guy, charges very reasonable prices, ships fast and he's close by to Texas.
Aside from that, there's not much to say for EME....   

Excellent! Cheaper too.

If anyone cares to walkthrough the install, I'd be really grateful. I've never touched an engine with a tool so I'm a bit hesitant/excited to get my hands dirty.

Remove the spark plug cover.

take a photo.
take another photo because the first one will be blurry.

Make a note of which lead goes to which plug at both ends. Label them?
Take a photo. (Don't forget the photo of the bottom of the coils will be upside down).

Take off one lead and if you can, replace it with a new one. Guessing the new ones are equal in length to the old ones.

See if you can see into the bottom of the coil. Should be shiney and copper coloured.
Maybe undo only the bottom nut and bolt to let the coil swing out a bit.

Repeat 3 times.

Use pliers to get the old leads off the plugs. They have a tab on top made for pulling.

Check the tops of the plugs have the little cap thingy and not just bare thread.
The plug on the right.


A good time to replace the plugs? D7EA.
Take your time and have fun.

brickrider wrote:They will work.  Here's another option:  http://www.euromotoelectrics.com/category-s/795.htm
I've been a very happy customer of EME for a number of years.  John is a really helpful guy, charges very reasonable prices, ships fast and he's close by to Texas.
Aside from that, there's not much to say for EME....   

I second that endorsement of EME. Bought plug wires and battery cable kit from them; perfection on both counts.

Kyle10 wrote:

brickrider wrote:They will work.  Here's another option:  http://www.euromotoelectrics.com/category-s/795.htm
I've been a very happy customer of EME for a number of years.  John is a really helpful guy, charges very reasonable prices, ships fast and he's close by to Texas.
Aside from that, there's not much to say for EME....   

I second that endorsement of EME. Bought plug wires and battery cable kit from them; perfection on both counts.

I third that. Bought a fuel pump from EME. Very reasonable price and fast shipping (even to Canada).

Just got back home after being away for a month. Ordered the plug wires from EME. Excited to get cranking again, it's all I could think about when I was away.

Red. Gotta work better than black.

Got the plug wires swapped out. I don't know why I was dreading that. So simple.

Bike is firing up ok now after battery charge. There was way more white smoke out of the exhaust once fired up the first time, which I suppose is expected after sitting as long as it did (3 months). And at more of angle.

It fires up, sounds ok for a second then starts sputtering and struggles to stay fired. Lots of clicks and pops. I can fight it some with the throttle but even that gets overcome after about a minute.

Any insight as to the next step in getting this baby purring?

Sounds like its loading up. 

Is the video a startup from stone cold? Are you using the 'choke' (its really not a choke)?

Yeah, flip the choke out a notch.  Rev it up to about 2500 to let it "get its rhythm" and then leave the choke on for a few blocks until it heats up.

Do not let it sit there and idle.  The owners manual says to start it and ride off.  K bikes, especially K75s, will foul the plugs if you let them idle for too long.

It is starting from cold, but temps here are warm at the moment. Choke was engaged during video.

There's a heluva lot to check, GK

Take a look at the intake boots, the rubber collars b. the intakes and the airbox. Are they cracked? Common, as age/heat degrades the rubber and if there are cracks this could be letting in extraneous air in, buggering the setup, especially during idle.
If they are they'll need replacing, or repair if you're clever enuff to bodge something together (rtv?). 

W/O shifting through this entire thread: 
have you taken a flashlight to the tank interior? Water, crud, detritus...old gas+accumulated water? 
inspected the fuel pump, inc. the intake screen? 
confirmed the injectors are producing an adequate flow/spray?

Can you actually ride the bike? Sitting awhile may require a bit of a rideout, putting fresh fuel through the system and getting everything up to operating temps. Blowing the crud out, replacing anything that's been static.

GeorgiaK wrote:It is starting from cold, but temps here are warm at the moment. Choke was engaged during video.

Looks like the choke is off to me.

Fuel issues? Fuel filter or blocked pump? Fuel line inside tank leaking pressure inside the tank?

Its turning over, firing, its running good on start up and then falling back. Lack of fuel? Fuel pressure sensor? Air leakage on intake side? Manifold perished or cracked? None of these are extremely costly items.

The Hall Sensor can sometimes cause misfire problems when it has warmed up but this normally takes 15-20 minutes to happen. A test for that is simple, use of a hair dryer on the cover for a while before firing up.

Whattya know. My choke is not engaged. I thought it was because I had done it about an hour prior with it engaged. doh.

My suspicion is the issue lies in the fuel system. After reading your suggestions I went out and played with it some more. From cold, it's very difficult to get the engine to idle. Right as the engine would sound like it was dying out, I applied throttle, and after a significant pause the engine would rev up loudly and stay alive. It's almost as if there is latency issue in the throttle. After about 30 seconds of giving it fuel before it dies over and over, the engine was able to idle. 

Not a clean idle, definitely still clicking and popping, but no threat of dying either. So I played with the throttle some and found that there's definitely some sort of lag between throttle action and engine reaction. It's like the engine is getting no fuel and then all of the sudden, it's getting too much fuel. A clog maybe? There is also some loud mechanical sounding clicking coming, from what sounds like, the front of the bike.

I'd be happy to take a few more videos if it would help diagnose the hiccup, just let me know what you'd like to see.

I think this is your problem: http://classickbikes.com/ckb.tech/0.ckb.tech.files/intakeman/intakeman.htm

That makes sense. Will definitely be my biggest project thus far. What parts should I source for this? Also, while I'm in this area of the bike, should I be on the lookout to replace anything else preemptively?

GeorgiaK wrote:That makes sense. Will definitely be my biggest project thus far. What parts should I source for this? Also, while I'm in this area of the bike, should I be on the lookout to replace anything else preemptively?

Intake manifold - 11611460408 x 4
Boots above the TBs - 11611460755 x 4

Chances are your crank case breather hose is shot too.  Part 11151460480

To me that sounds like it's starving for air, have you checked the air filter and air box for rodent nests. also give the flap in the MAF (air flow meter) a push to see if it is moving freely.

'Starving for air' was exactly how I worded it to mechanics a few months back. I checked the air filter and the MAF flap and everything there seems to be in top shape. I'll see if I can get a closer look into the air box today.

Also, I apologize if this is poor forum etiquette, but I was wondering if any of you could point me in a direction to a bobber/cafe style headlight kit that will fit on on the K. I removed the fairing off of my LT for good and would like to throw on a new headlight and blinkers. I've been having a little trouble locating a kit that for sure works on the K. Also, not sure if I'd need to replace the relay as well.

Ordering all the parts for an intake manifold swap. 

So far I've got:
Intake manifold x4
Boots x4
Vent Hose x1

I'm pretty sure I'll swap out those pesky Oetikers with something a little easier to work with. 

Anything I'm missing before I place the order?

These Suzuki clamps are good to use

48mm Suzuki band clamp  Part# 09402-48208 for TB->bushings and bushings->air plenum connections.  Cost about $4.75 each.

I might have missed your response to checking the fuel system.  When was the fuel filter and pump sock replaced?  Is the debris in the bottom of the tank or a brownish tinge to the aluminium?  How's the black rubber sleeve on the pump?  is it gooey or crumbling or solid?   Inspection is simple   Open fuel cap.  Remove the 4 screws holding the flapper in place.  Lift carefully as there may be a gasket.  A flashlight or work light is helpful to view the tank internals.   Reverse to re-install.

Seems silly that I'm just now checking inside the tank, considering a saw some gunk in the the lines when I removed it.

The cover was on there pretty good but I eventually got it off. Lots of white crust on actual gas cap. Seems to be a bit rigid, might be time for a replacement.


The inside of the tank revealed more gunk. Most of it seems to be hanging out in the crevices of the tank.


Aesthetically, the fuel filter? looks fine, I guess. Not sure.


So my main concern is the gunk. Where did it come from, how do I prevent it in the future?

One more gunk photo:

Was this bike sitting for some time?  Because it looks like a varnish build up I used to see in old outboard motors.  

Drain the gas, pull the filter and pump assembly and wipe out the inside of the tank.  Carefully hook up the pump in a small bucket with a couple bottles of Techron or Seafoam and run the pump for about 10 minutes to clean out the internals.   Save the cleaner by straining it before you put it back in the bottles. Replace the filter, sock and hoses (use submersible hose) with new.  check the rubber mount for the pump.  If it's gooey or cracked, don't be cheap, just replace it or you're in for a bigger expense.
Clean the filler cap with carb cleaner and see if the build up comes off.  If it does, after it's all clean spray it down with WD40 to keep it pliable.  Re assemble all. Add fresh high test and a dose of the cleaner you saved and take it for a long ride.

It sat for about 8 months. 2 months of that was sitting at some bozo's shop while he "figured out" why bike wasn't running well. Obviously he was unsuccessful as was the bozo before him. I've taken matters into my own hands, thanks to you guys, even though I'm a complete novice. I feel like any mechanic worth his salt would have spotted gunk in the tank, worn fuel hoses, intake manifolds, etc. after about 15 minutes with the machine. When it runs, it sounds like it's starving for fuel and air until it gets warm.

Keith, thanks for your input. I've dug in the tank a little bit this afternoon. I was able to get three fasters off on the pump, but there's at least one more I can see. My tools seem insufficient for getting into these tight spaces. Looks like I need some shorty screw drivers and maybe an angled socket wrench bit, especially for putting it all back together. Any other tools you guys use on a job like this?

One of the biggest problems with mechanics fixing K Bikes is that they see very little of them and outside of the K Komunity on forums like this and some fossils at BMW not many know much about them.

One friend here recently took his K100 to his local bike shop who had it for 4 months and gave up without charging him much at all and when I had time I called round and within 1 hour it was going as sweet as. It was the connector for the fuel pump. The guy at the bike shop was doing the usual look at all the complicated solutions first instead of using the KISS principle.

It sounds to me that you are trying to remove the screws around the plastic flange that holds the pump while it is in the tank. Much easier if you squeeze the two plastic tabs on either side in towards the centre then lift the assembly up to the tank opening to work on. The photos show my old one and then the new one in place in the tank. I took the fuel hose off the fitting on the other side of the filter to make it all easier.

You'll see that a previous owner had the pump just hanging by a cable tie.





GeorgiaK I also meant to mention that you can get an overhaul kit for the fuel cap - new seals and o rings. I had to do mine.

Cheers

aye good post gaz
just unclip the hold down assembly .
no need to do much of it in the tank at all 
except for undoing the outlet pipe from the fuel filter and the electrical termination screws on top of the pump .
after wards you can do it all out side the tank

be aware that there may be rubber bits laying around inside the tank ......these split rubbers align along the bracket that hold the pump and offers some buffering between the tank skin and the bracket ...in case of accident ...distortion etc ... i have not found a suitable replacement for these yet .....( other than manufacturing something of an internal (and immersible rated rubber hose, split to suit length and diameter ) 

good luck at the refurbishment ...

Oh wow, that made things much easier.

Everything looks to be in good shape, but there is a lot of gunk on the other side of the pump. Might be wise to replace it as a precautionary measure?

The pump electrical wires seem pretty shot though. Something I should worry about?


Gaz, whereabouts did you find the overhaul kit for the fuel cap? I'm having trouble locating one.

When you see the price of the pump you might want to just clean up the old one and run it a while longer.  Not like changing it our is a big job.  As for the wiring, It may well be worth the time and trouble to replace it now.

I too would like to know where Gaz gets the cap rebuild kit.  In the US it is no longer available.

HA! Yea, might hold off on the new pump, so long as it performs well. Just so I know in the future, what are some signs of a faulty fuel pump on a K?

Electrical is whole new level of stuff I don't know anything about. Would any cabling work or is there some immersible kit I should get? I'm not entirely sure how to remove the electrical element from the tank. That bit the wires are attached to (fuel gauge?) is severely rusted. 

Also, I'm still not sure what the gunk in the tank is. There is definitely some congealed bits that might be varnish build up as Keith said bust there is quite a bit of sand and dirt debris in the tank as well. Any thoughts as to what can cause that?

Cheap gas or buying gas at a station that is having its tank filled while your filling up is where the sand and grime comes from.  You could build a wire set.  However, BMW has a harness that handles the low fuel sensor and pump with the applicable connector (under right side of tank.  Look on the microfilm fuel tank I think.   

Warning sign of a pump going south... Gets very noisy may start to fail intermittently, performance might start to diminish.  There are some options that fit like the oem and then there are a few pumps that will require some modifications of to fit.  IBMWR has some of the options as does the Liberry on here.

Ah, this was helpful:


And I didn't know the wire unit was called a Sending Unit and it is removed via 4 screws on the outside bottom of the tank. Definitely replacing mine.

I can't remember who I purchased my fuel cap overhaul kit from, even though it was only in the last few months ( not good at purchasing records). However they are still listed from a mob in Australia who are not necessarily known for bargain basement prices but hey! sometimes that's how it is.
The company is Munich Motorcycles; link to the site below.

Munich Motorcycles

Hope you can find them cheaper somewhere in the States.

Cheers

Try soaking the fuel sender in a bucket of white vinegar over night first to see how it can be salvaged, I used carby cleaner type fuel additive and petrol to soak the pump equal parts, having firstly drowned the bottom in wd40 cleaning as much as possible the gunk off the inlet at the bottom, you should be able to see the little rollers through the intake slot, some have found after soaking the pump can be run backwards to shift any debri, then run normally.