idling problems
Posted: Mon Aug 15, 2016 11:21 am
After having my rear shock rebuilt by brook suspension I recently got my KR1S MOT'd and taxed, and I'm able to ride it. It rides well, corners nicely and the engine has a pleasing zing which none of my bikes have really had since I had a 2MA TZR.
However... Starting it is a total pig. It needs loads of kicks from cold which I kind of understand. It seems to need to be put onto prime for a few seconds before you give it a go. It will often fire and then runs hideously until it's warm, when you can keep it going if you do it all first time. All of this is reasonably expected for an old two stroke, if a little on the difficult side. However the idle is very high, and takes ages to settle. I spent a couple of weekends fiddling with the idle screws, and I tried setting them to the manual setting of 1 and 1/4 turns out from fully in. When I did this, the idle was no slower than 3000rpm and it took ages to settle to this. I can actually reduce the idle with the choke.
If you think it was difficult to start when cold... that's nothing. When hot it won't start for love nor money. You can occasionally get it to fire, and then you have to be quick on the throttle to get it up to the right speed. The most reliable way to start it when hot is actually to let it cool down! This means that it's nearly impossible to ride anywhere on it.
I think I know what the problem is... but I'd like people to confirm. The inlet rubbers are surprisingly flexible, and have some cracking. My guess is that the issue is an air leak on the inlet? This is an exceptional pain as I don't think they are available from Kawasaki any more... Is there any easy way to test this? A suggestion on another forum was to wave an unlit blowtorch around near the rubbers to see if there is a leak, and it didn't seem to have an effect.
video here
https://youtu.be/wo54bHYUuA4
Someone also suggested it might be a bad crank seal... I flipping well hope not.
The inlet rubbers are cracked:
Any ideas?
However... Starting it is a total pig. It needs loads of kicks from cold which I kind of understand. It seems to need to be put onto prime for a few seconds before you give it a go. It will often fire and then runs hideously until it's warm, when you can keep it going if you do it all first time. All of this is reasonably expected for an old two stroke, if a little on the difficult side. However the idle is very high, and takes ages to settle. I spent a couple of weekends fiddling with the idle screws, and I tried setting them to the manual setting of 1 and 1/4 turns out from fully in. When I did this, the idle was no slower than 3000rpm and it took ages to settle to this. I can actually reduce the idle with the choke.
If you think it was difficult to start when cold... that's nothing. When hot it won't start for love nor money. You can occasionally get it to fire, and then you have to be quick on the throttle to get it up to the right speed. The most reliable way to start it when hot is actually to let it cool down! This means that it's nearly impossible to ride anywhere on it.
I think I know what the problem is... but I'd like people to confirm. The inlet rubbers are surprisingly flexible, and have some cracking. My guess is that the issue is an air leak on the inlet? This is an exceptional pain as I don't think they are available from Kawasaki any more... Is there any easy way to test this? A suggestion on another forum was to wave an unlit blowtorch around near the rubbers to see if there is a leak, and it didn't seem to have an effect.
video here
https://youtu.be/wo54bHYUuA4
Someone also suggested it might be a bad crank seal... I flipping well hope not.
The inlet rubbers are cracked:
Any ideas?