New here looking for some tips to restore my 85 k100. 27,000 miles but needs a tune

WelKome!

http://bit.ly/new2kbikes

Welcome!  27,000 miles?  Still needs breaking in!  Check all the rubber stuff for cracks and stiffening.  Get a can of Deoxit and go through every switch and electrical connection, especially the grounds.  Change the brake fluid!

Last year I got an 83 one with 29,000 miles. Lots of rubbers replaced, needed full brakes job, services, coolant expansion pipe, tyres, still needs a few things one being that the water pump will give out and eventually the rear main seal too. But a lovely bike to ride too and very happy with it.

I've had plenty of Ks that never had WP or main seal issues.  Yes, then CAN fail and need replacing, but not always.

St Augustine FL... Mmmm... I love that place! Been there three times.

Welcome Antbmw

duck wrote:I've had plenty of Ks that never had WP or main seal issues.  Yes, then CAN fail and need replacing, but not always.

I bought a K100RT back in 2013 at 36,000 miles. A year later it needed the WP [original] done and then another year later at 78k miles the rear main seal [also original] and slipped in clutch etc too.. I have no complaint but realise buy an old K you may need to do them. I still have it.

Duck,
Good morning my main issue is consist running. I feel like the return fuel line is clogged at the tank. I’ll get the engine running which is sometimes hard with out using the starter button to get it warmed up. But once it’s warmed up I can’t just turn the throttle I have to do it really slow to build rpms. Then when I run to long it just seems like all my work goes to a waste. Must be back pressure on the return line. I think I’m going to run a return line straight to the top of the tank temporarily just to see if that’s my problem. After replacing everything in the fuel system I thought I’d be there by now. Any suggestions are always welcome

Have read through the fault finding guide (it's on the Portal Page).

Have you measured the water temperature sensor when cold. 

Mike

No I haven’t the fan kicks on but it does feel hott

A bad engine temperature sensor will make the fuel injection run rich and can flood the engine.  It's an easy check, but a bitch to replace. 

Return line back pressure can be caused by the check valve at the spigot where the return line enters the tank.  They have been know to stick closed.

Have you replaced the fuel filter.  NAPA 3032 is the one to get.

You may want to run some fuel system cleaner through to clean out any varnish that may have formed in the injectors.  Techron by Chevron is good stuff.  About 6-8 ounces in 5 gallons of fuel is a good mix.  If the bike isn't rideable, I will start it up and run it until the temperature gauge starts to move.  If no gauge, 4-5 minutes is about right.  I'll go out in the garage and do this a couple times a day for a couple weeks.  The idea is to let the cleaner soak for a while and then flush it out while the injectors are being pulsed.  I've only had one bike that didn't respond favorably to this regimen.  In that case it may be necessary to remove the injector to have it cleaned.

Another source of problems is the crankcase breather hose A.K.A. the Z tube.  It's behind the throttle position switch (TPS), and is a very common source of problems when it cracks and allows an air leak in the air box.  It's not expensive and is the first thing I check and replace when I get a new bike.

Hi,

Having written this once it seemed to get lost when I posted it:

The Water temperature sensor has two functions:

1. An input to the EFI (pin 10). If this is faulty, it will send a wrong signal to the EFI, and usually results in rough running. If you measure between Pin 10 and earth on the EFI connector (NOT THE EFI MODLE), then at 20C it should be in the order of 2.5k ohm, and at 80C around 300 ohm. If you get a low resistance when cold it will over fuel, leading to it being difficult to start the bike

2. The other side of it is connected to the temperature switching unit via a connector. 
 
The TSU is located with all the other relays. It controls the fan and the over temperature warning light. The fan is activated first, then at a higher temperature, the light is illuminated. If the bike is running at this stage, then it will still be able to run. If however, the engine is stopped, then with temperature light illuminated, the bike will not be able to be started. It will remain in this state until the engine cools down sufficiently for the temperature light to be switched off.

 
Mike

Welcome

work around for petrol tank check valve removal by Sidecar Paul

[url=http://www.kforum-tech.com/how-to/Modification for early gas tank.htm]Modification for early gas tank[/url]

if you get a 404

-start here http://www.kforum-tech.com/

-under "How-to from the forum"

-"Modification for early gas tank"

Thank you all. Yeah new fuel filter, injectors,z pipe, pressure regulator, and fuel pump. I’ll check into the temp stuff. I completely removed in cleaned the tank but the return fuel line still seemed to have a blockage afterwards

With just 2 gallons of fuel in the tank can you see fuel returning when the engine is running?

There should be a pretty obvious flow in the tank forward of the filler.

Antbmw wrote:Thank you all. Yeah new fuel filter, injectors,z pipe, pressure regulator, and fuel pump. I’ll check into the temp stuff. I completely removed in cleaned the tank but the return fuel line still seemed to have a blockage afterwards

You don't mention the vacuum pipes and the vacuum caps. They all need to be good.

As yours is 85 you may have a fuel pressure sensor as ell as a fuel pressure regulator, located beside the fuel pressure regulator.

It doesn't do anything and you don't need it, but it does have a vacuum line that goes around the front of the throttle bodies. Remove the vacuum line and replace it using a vacuum cap same as the others on the throttle body spigot.

At the rear end of the throttle bodies near the Z pipe there is the vacuum line to the fuel pressure regulator....got to make sure that's good and not cracked.

Smooth idle? A basic thing, not related to fuelling obviously, but have you had a squiz at the short, elbow-shaped engine oil breather hose that runs up into the the left rear corner of the airbox? Squeeze it, looks for cracks. A test of this hose is to let the engine idle (trusting that it's smooth initially) then slowly unscrew the engine oil filler cap and watch the idle change. If it changes from smooth to rough the hose is in good nick. If it is cracked and you're slowly turning the throttle and experiencing misfire or stumble, perhaps it's having a hard time simply because this hose is leaking excess air. Worth a quick look.

OEM part number 11 15 1 460 480

Z pipe is new. Anyone of you guys live near st. Augustine fl.

Maybe a blockage in exhaust or air inlet, or both, especially if it hadn't been started in years.

Antbmw wrote:Z pipe is new. Anyone of you guys live near st. Augustine fl.

I'm in Orlando. Just finished 21 day quarantine all clear of the K-19

pm your address I can come over whenever