1150 carb synch

[Guest]

Hey all. I'm helping Trevor on his 85 1150. The PO put in new rings and valves seals, maybe more not exactly sure, but after the work he never had the bike running well. Now we're putting it all back together. So we've rebuilt the carbs and did a good manual synch. The bike starts up and idles decently actually but when I put the carbtune on her I couldn't get any decent vacuum to register. #3 wouldn't really register at all and the others would only come up to 10 at best. Didn't matter how I adjusted the carbs I couldn't get the vacuum up unless I took the idle up high of course (above 6000 or more). The first thing that comes to my mind is the valves are out of adjustment but the idle was pretty decent after the manual synch and would even rev pretty good (sitting, not under power). I've never played with these CV carbs before so maybe I'm doing something wrong?? any advice is appreciated as always.

 

[Steve]

If the engine is running, there WILL be vacuum.

Don't worry about the actual number, it is not important. What matters is that all four vacuum levels are the same.

"Idle up high" at 6000 RPM? That's not "idle", that's RACE.

Your statement about #3 not having any vacuum at all makes me wonder if you are numbering the cylinders correctly. #1 is under your clutch hand, #4 is under your throttle hand. I mention that because the vacuum line that goes to the petcock is on #2. If you number the cylinders backward, and forget to plug that line, you will think that #3 has no vacuum.

Since you have "never played with these CV carbs before", let's make sure you are doing it correctly. You will see some vacuum, even if it's low. Start by synchronizing #2 to #3. Then adjust #1 to match the other two. Finally, adjust #4. That order is not important with your VM carbs, but it does make a difference on the BS-series (CV type) carbs.

.

 

[Nessism]

Something wrong. Why are you guys messing with sync if the valves aren't even adjusted yet?

When syncing carbs I recommend setting up the idle to 2500 rpm or so.

 

[jwhelan65]

I had this same problem when I did a 700E. I put a different brand of gauges on and got the readings I was looking for. The new Carbtunes are extremely cheap I would never buy another.

 

[jwhelan65]

Another thought..did you replace the orings on the front of the intakes?

 

[TeamDar]

Something wrong. Why are you guys messing with sync if the valves aren't even adjusted yet?

When syncing carbs I recommend setting up the idle to 2500 rpm or so.

Factory GS1150 manual recommends 1750 rpm when synchronizing carburetors.

 

[Nessism]

Factory GS1150 manual recommends 1750 rpm when synchronizing carburetors.

I'm good with that. Just get them off idle a smig.

 

[koolaid_kid]

I'm good with that. Just get them off idle a smig.

When you go to synch them, you will know where the sweet spot is. It is very evident by the way it is running. Numbers are just that, an estimation.

 

[SVSooke]

I can come over and help if you guys want it.Done a few more CV sync's than you have Rob

 

[Guest]

Thanks for the posts everyone. We are adjusting the carbs in the correct sequence, middle, left, then right. It is number #3 carb, for the #3 cylinder, that isn't showing vacuum. Why we are doing a synch before doing the valves is a very good question Ed... The 1150's don't have 0-rings on the intake boots but that is a very good idea about the vacuum gauge. Last time I used it one of the balls/cylinders was acting up a bit but it still worked fine in the end. Another weird thing, we would have the idle up at around 3000 and I was attempting to even the vacuum out at about 10 on the gauge but when I adjusted the idle down all of a sudden the vacuum would jump up to 25 where it should be but it wouldn't stay there. It seemed that if I brought the idle down veryyyyyy slowly I could hit a spot, a very small spot where the vacuum would go up. Doesn't make any sense to me. I think Ed has a good point. Valves next. Never done the 16 valve type engine before, doesn't look too complicated, actually easier than the 8 with shims.

 

[koolaid_kid]

It is very easy in comparison.

 

[Guest]

Looking in the manual it says to use gasket maker as well as the valve cover gasket which looks to be silicone or something similar. Is the the consensus? as well what is the screw type that you adjust? can't see in the picture if it is an Allen head or a Philips. As long as it is not something strange that I won't have the tool for.

 

[bccap]

Are you talking about the valve adjust tool ? If so it's Roberts. About 7 bucks at your local shop for the tool. But most guys here use a wooden dowel and a Roberts wood screw. Greg's probably got one made up. Or could tell you the screw size.

 

[bccap]

This is from BikeCliff's web site on 16 vale adjustment.

To help with adjustments, make yourself a couple of tools with a couple of square head screws and a
couple 6-8" pieces of 3/8" wooden dowel. These are square head screws that are a common wood
screw - I found a #8 x 3/4" screw works pretty well. Go to the local hardware store and buy a couple
in a few different sizes and use the ones that fit best. Install the screw into the end of the wooden
dowel so that in the end you have a screw head on the end of a stick. You need 2 of these.

 

[Guest]

ha,ha,ha,ha....why oh why do I not refer to Cliffs site. Been here how many years and I still need to be told to go to Cliffs site, lol. Thanks 'bccap'.

 

[Guest]

Valves next. Never done the 16 valve type engine before, doesn't look too complicated, actually easier than the 8 with shims.

You can order the a valve adjusting tool from Dennis Kirk and feeler gauges that are designed for the 16 valve head. I would add one other thing, order some extra adjusting tappets and lock nuts just in case. I've run into some on my bike after a few adjustments they get really tight on the threads and won't adjust for crap.

 

[SVSooke]

It's a #2 Robertson head screw on the adjusters,as Garth thought I do have one made up with vinyl tube instead of a dowel since I had that.The 1150 uses the same kind of reusable cover gasket as my 750.Pays to be careful how it goes in,ask me how I know

 

[Guest]

Did you do a compression check? Switch out the guage on the one cylinder?

 

[Guest]

Checked the valves, nothing too crazy, although #3 was a bit on the tight side for the intake valves, but like I said nothing showed up that would explain the inability to obtain any proper vacuum while doing the vacuum synch. Went to bench synch the carbs again before putting them on an noticed the #2 adjuster wasn't working properly. Turns out the, 'piston', for a lack of a better work that is supposed to move when turning the screw there by moving the butterfly was not moving. Rusted solid. While attempting to 'loosen' it I broke the aluminum holding it in there...great. This is on top of the two stripped valve cover bolts we discovered while putting the valve cover back on.......lol. Poor Trevor. Well, we've put some JB weld to work and we'll see what comes out of all this tomorrow. All we wanted to do was synch the carbs...........Nothing's ever a 10 minute job. 'Chef' I really want to do a compression on his bike but being that his plugs are a different size than every bike I have every owned, my compression gauge will of course not fit, lol. Hopefully we can find some sort of adapter because we really do need to do a compression test to know what's in there.

 

[koolaid_kid]

He should have the 12mm plugs like all the other 16 valve engines. My compression tester came with an adapter, and I bought it over 2 decades ago. Not sure why yours does not have the adapter.