Hello everybody,

Thank you for a great forum and wealth of info, I stumbled across it yesterday and felt compelled to join up with others who have chosen the 'The Way of the K'. I'm a real fan of the build quality, efficiency and 'all-engine' look of these bikes!

I have just got my 1985 K100 on the road after a 2 year gap and am enjoying being back on two wheels again, despite it not running 100% yet. It starts OK and seems fine at lower speeds but top end it runs out of steam and stops accelerating at 85-90mph. I will be changing the fuel filter in the hope that it is clogged.
I also have a second K100 which has been raided for parts by me and my brother (who has a 1983 K100) but which I hope to make into a lowrider/streetfighter in the future.

I started off my biking career at 14 with a Honda C50 'step-thru' field bike and have had several different bikes over the 30 years that I've had a bike licence. I still have a 1976 Harley Superglide and a 1966 Triumph TR6SS both of which are unfortunately off the road at the moment.

I'm looking forward to reading more 'K-tech' here and hopefully contributing if I can help.

All the best,
Neeilix

Greetings Neelix
Another from 'East Angular' way eh?
Wedge is over that way IIRC

Neelix, neelix, where have I heard that name before?
( pause while he googles it...............)
Aha! now I remember.
Is this you?
you should get some ointment for those spots y'know

Welcome to the forum Neelix.
Glad to see another family were the K100 is the bike of choice (my brother has a K100 too)
Hope that you will enjoy this forum and find all the answers to your questions.
As you have some experience with the K100, you will find that it's very rewarding helping other K100 owners solving the problems with their bike. Nobody is an expert, but when we all work together we (most of the time) find a solution.

Cheers
Bert

Thanks for the welcome fellas,

Yes reg, I do look very much like that only I have more spots than he does, and a bit more hair! Thanks for the tip, I'll try some ointment as the Clearasil doesn't seem to be doing the trick

Yes Bert, I'll keep an eye to see if I can offer up some help where possible.

My own bike problems seem to have worsened as I went to go out on it today and was only just able to get it to start. It wouldn't even try to start unless the throttle was kept shut and there was no choke. I last rode it Saturday when it performed as described in my introduction above. I went down the road a bit and it wasn't responding well at all so I had to turn round, come back home and use the car instead
Any suggestions are welcome, thanks.

Neeilix

Maybe check/replace the air filter...I've heard of mice nests etc in there if the bike has been sitting around.
Check/replace the rubber tubes/pipes/bits that are on or near or connect to, the engine. Rubber doesn't last forever.

Clean every electrical connection on the bike. Don't let me hear you whinge about it...just do it!

When they're running well, they are such a nice bike to ride.

Welcome to the forum.

Welcome aboard there are a bunch of really friendly people here. Good on you mate, I have a bunch of in-laws who live in the Norwich area. Good spot for riding too.
Regards,
K-BIKE

neelix
Its sounds like its been laid up for a while ?
so a big ditto for cleaning all the electricals.
new fluids and filters will do it no harm at all

A pal of mine bought a K with no fuel filter
Yep NO fuel filter and it was running very poor
65-70 flat out
he stuck a filter in at a rally and rode home on a very different bike
so its maybe worth checking inside the tank

Hopefully you're already using fresh fuel right? Splash of injector cleaner won't hurt either.

Other potential cheap fix when they've sat for a while is to cane the **** off it for 20 miles, obviously this isn't gonna be an option if it barely starts so this is something to do after you've taken everyone elses excellent advice.

Hi sorry for the delay in replying, a lot going on ATM.

Thanks to you all for the welcomes, helpful advice & suggestions, hoping to get a proper look at the bike over the weekend and try to work out what's going on with it.

The bike has been sitting there for a year and a half or so and was more or less doing then what it is doing now. I did check all the electrical connections at the time and couldn't find anything amiss. I ended up getting despondent with it and gave up on it for a while, which turned into a long while!

Yes there is good fuel in there.
Hopefully I can find something out in the next day or two, thanks again.

Neeilix

Neelix
In case you havent done it already
you have to whip the tank off to get at the important ones
I had an 85 Rt that been stood outside for 4 years and
did bugger all until I scrupulously cleaned all the connectors
(many of which were green)
Went like a good un after that
Dont forget the earth commoning point on the central spine
Some Electrolube or similar switch and contact cleaner helps too

Thanks for the info reg, I did thoroughly check and clean all the electrical connections to try and cure this problem when it first occurred a year or so back but unfortunately it didn't make any difference. The bike has always been standing in a garage so connection-wise I don't expect there to be much wrong already but I will be re-checking. I'm hoping to get to look at it tomorrow (weather permitting) as I need the bike outside to be able to get around it properly.

Your problem sounds like a problem with the MAF (air flow sensor).
If you open the throttle air is getting into the cylinders, but as the MAF doesn't or badly signals the position of the vane to the EFI computer no extra gas goes through the injectors. This would explain why the engine is starting with the throttle off but not when you open it. Have you checked the electrical connector of the MAF? Also, as noted earlier, check the 4 rubber caps on the throttle body as well as the breather hose which has the tendency to crack over the years.

Have you read the page on the EFI troubleshooting?
Here is the relation between the EFI and the MAF:
Air traverses the air filter and goes to the air flow sensor. When you open the throttle, the depression is moving the internal vane of the air flow meter and a bigger amount of air is sucked in by the engine. The movement of the vanes will turn a variable resistance. This variable resistance will tell the EFI computer how much gas it has to send to the injectors to balance the mixture air/fuel.

The volume of air drawn in by the engine reflects the condition of the load. The precise measurement of this parameter is essential to determine the exact volume of fuel to inject.

Thanks Crazy Frog for the info & advice, is this the EFI troubleshooting page? - http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm
I took the airflow meter off my other K (which used to run fine) and fitted it but unfortunately it is still doing the same thing 90-100mph flat out and not too good on mid-range response, it did start a little easier (but still not how it used to), OK at low speeds tho'. I'm hoping a new fuel filter (when it arrives) may do the trick.
The rubber hoses all look fine.
I may swap coils & HT leads from the other K tomorrow to eliminate those just in case something is breaking down.

Now that you swapped the MAF, would it be possible to swap the EFI computer?
I wanted to edit my previous post as the MAF could be bad, but it could be the other end too. It could be the EFI computer not responding to the signal of the MAF. This is a good thing that you have spare parts. At least, we could eliminate a fault with one of the major electronic components which will leave you to a corroded connection or something simple but very difficult to find.
Your problem is not easy as so many things could go wrong. We have to work on the process of elimination.

Sorry, but being a cyber mechanics is not an easy task and I never got any formal training on engine repair. I just have a particular interest to keep the K100 running.

Thank you for the interest and assistance, I've never had any training either other than having had many different bikes which have had various problems over the years and also friends/family with their bike problems! This is a lot more complex than any previous bike I've owned and obviously makes a problem trickier to find.
I did swap the EFI computer way back when this problem first occurred and it didn't make any difference but I could easily confirm that by doing it again hopefully tomorrow.
In my last post was that the correct web address for the EFI troubleshooting page you mentioned? or were you meaning a different webpage?

It's great to have a pile of spares to be able to chuck at a problem, tempting as it is. One thing I try to do when diagnosing a problem with my bikes is to try one thing at a time, taking note of any change, and then move on if no good result came of it. How many times have we given something a 'tune-up' then she's just not right a short while later?

Bert, for a non-trained mechanic I'd say you've a fair amount of useful information to impart to the rest of us. Thanks for all of it, mate. Cheers!

[quote=Bert, for a non-trained mechanic I'd say you've a fair amount of useful information to impart to the rest of us.[/quote]

I've got formal training in industrial mechanics and robotics but now I work in the IT field.
There is not a lot of difference between an engine and a computer network. Everything is logical. You start your troubleshooting by one end or the other and persevere in the same order that you started. Checking all over the place doesn't bring any good result. This is why we have flow charts or production process plans. Stick to your original plan if you want to conclude with results. (I have a hard time to teach that to my 'professional technicians')

With the information posted by many good members of this forum, the majority of K bikes owners can maintain and repair their bike on their own (if they are persistent). Thanks to everybody for their input. Every opinion count even if they contradict each others. We (and I do too) learn a lot by debating about the best solution. A simple question from a new owners deserve an answer from the more experienced riders. At one point in our life (when we were wearing our birthday suit), we were all ignorants. Since then, we learned by having somebody teaching us.
Lets not brake the teaching/learning chain! Everybody gets satisfaction. the teacher and the student

Bert

Finally got to replace the fuel filter yesterday and no change in performance, I also changed the fuel pump too and again no change.
The symptom/feeling is like a rev-limiter cutting in at between 6000-7000 rpm where the engine just goes 'flat', remains unresponsive and won't pick up speed. It will stay like this until the throttle is backed off and the speed drops down, opening up the throttle again just allows it to pick back up to the 6000-7000 rpm point again. Does anyone know if the HET could cause this? Thanks.