Cruise issue...

[Richouse]

I'm out on a bike trip and after a couple of days of riding I noticed my cruise control (ccs-100) was not holding speed very well. It was just getting progressively worse. I was thinking I had a vacuum leak somewhere. Weird thing was is sometimes it would work better and sometimes it would just suck. Buddy I'm riding with asked if altitude would effect it. I said yes I think it would, but I didn't think of that. We are out west at 6k+ in altitude. It worked great at home at 340'. I think I remember only tapping off one vacuum port when I installed it. I'm thinking now I should have tapped off more. Could altitude effect it that much or do I have a bigger issue?

 

[SLK50]

I would first clean the solenoids and see it that helps.

If theyre dirty it may not be able to hold vacuum.

 

[dcarver]

I've had no issues with my ccs-100 at altitude. The only issue I've had is bad ground, it wouldn't always 'set'.

 

[wfooshee]

If wiring was crimped in the installation, or those clip-on taps were used, cut those open and solder all the connections.

If it's already a well-connected, soldered-connections job, then move along, nothing to see here...

 

[SLK50]

Ive installed a couple of CCS-100 on a few bikes.

Over the years Ive seen two reoccurring problems

give owners fits.

If the CC didnt set, or cut out abruptly, it was usually

residual voltage getting into the brake light circuit.

If it didnt hold speed, especially on hills, its unable

to maintain vacuum.

Id check for a leak, but as I said earlier, first clean

the solenoids. They need to be clean to seal and

operate smoothly.

Electrical issues are usually not gradual.

 

[Richouse]

I’m back from my trip. Oddly enough now that I’m back to lower altitudes it’s working better. I do think altitude can effect it but usually not enough to cause ill effects. Combine that with a vacuum leak and or low vacuum and it can see how it will cause my problem.

I’ll check for a leak soon and let you guys know what I find.

 

[Mr_Canoehead]

You may need to add a vacuum reservoir to the system. It could just be that running hard at altitude is draining the available vacuum. Most of the CCS-100 installs that I have seen on BMW twins involve a reservoir and a check valve to hold vacuum. Usually, it's just a piece of PVC, capped at both ends.

 

[Richouse]

You may need to add a vacuum reservoir to the system. It could just be that running hard at altitude is draining the available vacuum. Most of the CCS-100 installs that I have seen on BMW twins involve a reservoir and a check valve to hold vacuum. Usually, it's just a piece of PVC, capped at both ends.

I have both a reservoir and a check valve in the system. Check valve might be bad.

 

[Richouse]

I hope those of you that can help me see this here. I didnt want to start a new thread. I have my bike pulled apart looking for my cruise issue. Im leaning to a vacuum issue because all of the electrical and mechanical connections are good. When I installed the unit I Td into the vacuum right there at the vacuum sensor. That way Im drawing a vacuum from all 4 cylinders. I pulled off all of the hoses to look for leaks/cracks in them. I noticed the orifice in the ports in the motor are quite small. Will this provide enough vacuum to run the cruise? Where do people usually tap vacuum from? No vacuum leaks from the engine to the cruise and the check valve is good. I did notice that the cruise servo leaks the vacuum down. It is very slow, it doesnt hold a perfect vacuum very long. I pumped it up to about 5hg and it bled off within 2-3 minutes. I figured that within specs of the servo?

Thanks

 

[Mr_Canoehead]

I wouldn't pull from the MAP sensor ports - I'd pull from one of the sync ports. As you said, the MAP sensor ports are tiny.

On the bright side, if you had a leak using vacuum from the MAP sensor ports, the bike would run poorly and it didn't.

 

[Richouse]

I wouldn't pull from the MAP sensor ports - I'd pull from one of the sync ports. As you said, the MAP sensor ports are tiny.
On the bright side, if you had a leak using vacuum from the MAP sensor ports, the bike would run poorly and it didn't.

Thanks for the reply! Why only ONE sync port? Wouldnt you get more (volume) vacuum from 2 or even all of them? If I decide to use more than one port do I NEED a check valve on EACH port?

 

[Mr_Canoehead]

Only because you don't want to connect the ports. You could use multiple ports with a check valve on each but I'm willing to bet one port would provide enough vacuum to your reservoir - certainly more than you have now with those tiny MAP ports.

 

[dcarver]

Only because you don't want to connect the ports. You could use multiple ports with a check valve on each but I'm willing to bet one port would provide enough vacuum to your reservoir - certainly more than you have now with those tiny MAP ports.

Yes.

 

[Richouse]

I decided to use all 4 of the sync ports. I used a check valve on each one and hooked all of them together and ran that to the canister. That is probably all the vacuum I will be able to get out of this motor. Hopefully that will be enough.