Cleaning your ISC valve

When I was installing my new ISC cover plate the other day, I decided to pull the ISC valve (idle speed control valve) out of the throttle body to inspect it, and I immediately saw that the piston on the valve had signs of carbon buildup on it.

So I cleaned the surface of the plastic piston with some brake cleaner and a rag and put it back together. When I first fired the bike up this morning I was pleasantly surprised to find that the high start up idle speed had returned to back like it used to be, as for quite some time it's always been at 1100 rpm, and now upon start up on the cold engine it's back up to around 1300 rpm, and then it drops back down to 1100 rpm after a few minutes of running.

It even seems to idles smoother after it warmed up. So after coming back from filling my bike up this morning to get ready to go on a ride, I just went online and found out that ISC valves are subject to carbon build up on the valve, and that the psiton and the inside of the valve body need to be cleaned periodically tom keep it functioning properly. So I pulled the ISC valve back out and gave it a thorough cleaning.

So as the miles get up there on your Bandit, I recommend taking a few minutes and pull your ISC valve out and clean it. I'm going to pull the one off of my car that has 150k+ on it and clean it latter today, which has also had some irregular idle speed issues with it from time to time.

I'm at 18,000 miles. I pulled mine today just because of this thread. Zero carbon - not a trace - and the idle is still dead on. I wonder if this is a gas issue from Ohio to California???

PhilS said:

I'm at 18,000 miles. I pulled mine today just because of this thread. Zero carbon - not a trace - and the idle is still dead on. I wonder if this is a gas issue from Ohio to California???

Click to expand...

Thats good.

It appears from what I found that there are two types of ISC valves, with one being actuated by a motor, and the other operated by a solenoid, which is the style used on the Bandit, and for some reason the solenoid operated ISC valves by nature are prone to carbon up.

I'm really happy that just by cleaning it my cold start up idle speed has been restored and seems to idle even smoother and it even seems to run better overall as well, and it was running great before I cleaned it.

Very interesting...Thanks for the tip!

Interesting.....

I took mine back out, pushing in the plunger which would not push in easily and would not pull out at all. It feels like a motor type. Upon reinstallation fully pulled in, the revs at idle were about 3500. Upon shut off you can hear the little motor in there changing position and resetting. I pulled it back off and the plunger was back out to normal and upone restarting, its perfect again.

Good lesson on this thing. Not really riding today so its always a good time to screw with thing!!
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I like posts like this ,gives me a chance to pull something apart.
Also to find out what part it is a how it works. I take it its the black
plastic thingo (electrics) on the RHS. TB'S (tech talk)

PhilS said:

Interesting.....

I took mine back out, pushing in the plunger which would not push in easily and would not pull out at all. It feels like a motor type. Upon reinstallation fully pulled in, the revs at idle were about 3500. Upon shut off you can hear the little motor in there changing position and resetting. I pulled it back off and the plunger was back out to normal and upone restarting, its perfect again.

Good lesson on this thing. Not really riding today so its always a good time to screw with thing!!
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When I saw that spring between the piston and the body of the valve, it looked an awful lot like a typical solenoid, but I could be wrong, as the body of the ISC valve doesn't seem deep enough to house a motor and obviously some sort of linear actuator that would be needed to move the piston back and forth.

I'll check mine again a little more closely when I pull the cover plate I made back off to install the S/S screws I'm getting.

I just checked the factory servive manual and it says this about the ISC valve.

Inspect the ISC valve for carbon deposition defects.
Clean or replace the ISC valve if necessary.

The service manual does not have any procedure for testing the ISC valve, or explain how it operates as far as does it use a solenoid or a motor.

Checked -clean-took tube and spring off, nothing else would move .

Interesting. I started the Bandit the other morning and it fired up and then died on me, very unusual. It started right back up and hasn't done it again, but I have thought the idle might be a little low on startup.

Where exactly is the ISC on the throttle bodies? I'll check it tonight, bet that's my problem.

trey

*edit* I stole this from your other thread:



Is it the thing behind the lower cover?

treybrad said:

Interesting. I started the Bandit the other morning and it fired up and then died on me, very unusual. It started right back up and hasn't done it again, but I have thought the idle might be a little low on startup.

Where exactly is the ISC on the throttle bodies? I'll check it tonight, bet that's my problem.

trey

*edit* I stole this from your other thread:

Is it the thing behind the lower cover?

Click to expand...

Yes, it's located behind then cover I made for it, and it's the only electrical thing on the right side of the throttle body.

Unplug the electrical conector from the ISC valve, and then using a T-20 Torx bit that has A hole in it to fit over the anti tampering pin on the stock 4mm ISC valve mounting screws, remove the two ISC valve mounting screws, and then carefully remove the valve from the throtlle body.

Once you remove the ISC valve, carefully clean the plastic piston on the valve with carb cleaner and a Q -tip, and then clean the inside of the throttle body housing with carb cleaner and a Q-tip.

You do not have to worry at all about removing the ISC valve from the throttle body, and doing so does not require having to reset any values on the ECM.