1978 GS 1000 motor to carb intake boots

[Kingjoel]

I installed an original air box. In the process I lubed the inside of all boots with lithium grease. Would that possibly cause a small air leak? The idle increases 300-400 rpm when I spray starting fluid on some of the boots. It runs great, should I be concerned? Thanks for any thoughts.

 

[chuck hahn]

Doubt the grease is the issue. I would look at the rubber for deep cracks and the orings may be shot. See page 3 here for the orings

http://cycleorings.com/

 

[Redman]

You have described the one of the test for detecting cracked boots or dried up o-rings. (O-ring between boot and head.)
Other symptom is the idle rpms going up after the engine goes from warm to hot.

And another positive comment for cycle o-rings (a fine member here providing a service to us).
Also get the replacement screw (allen head) kit. You will need them anyway as will probably bugger up some/most of the exisitng screws trying to remove them.

If the intake boots are original, they probably need replacement also. And also make things easier on yourself if also get new clamps if yours are bent up or stretched out from having been overtighted over the years. If your boots are original, they will be hard and about to crack and/or come apart at the flange. If you replace them you will be amazed at how easy it is to reinstall the carbs... and then engine runs better too.

 

[Redman]

When you say you have installed an original stock air box.... what did it have before.... pods? By a previous owner...? If so, maybe they have also swapped out the jets in the carbs. SOmething to check sometime you have the carbs off.

.

 

[Burque73]

I installed an original air box. In the process I lubed the inside of all boots with lithium grease. Would that possibly cause a small air leak? The idle increases 300-400 rpm when I spray starting fluid on some of the boots. It runs great, should I be concerned? Thanks for any thoughts.

Sounds like you're talking about the airbox boots, not carb boots to the head. In either case, the clamps can stretch or the rubber compresses and new clamps can help get a better seal. The airbox boots are much cheaper and easier to replace making it soo much easier to engage to the carbs. The others, between the carbs and head can be very deceiving. Mine looked supple and in good condition and were not hard to get carbs on and off but a very close inspection after removing them showed the rubber losing it's bond to the metal flange. Not to mention the O-rings were petrified and squished flat! If they're original you can bet you'd benefit from replacing all eight with new clamps and O'rings. I don't remember if your sync port is on the boot or the head but if those screws loosen you can get a leak there too. Another note is to be super careful not to fold one of the inner boots like on cyls 2 or 3 while reinstalling the airbox. It can be hard to see in there and I folded the edge of one of the boots without knowing it creating a leak.

If you haven't seen this thread check it out. There's a funny but pertinent mention in the first post of air sneaking in anywhere it can.
https://www.thegsresources.com/_forum/showthread.php?194050-Help!-Your-Bike-Won-t-Run-Well

I've learned so much from this forum and wanted to share a little of it. Before coming here my only thought of boots was which pair to wear while riding.

 

[Kingjoel]

Thanks to all. The bike runs great, maybe with new o rings it will run greater. The bike had a home made air box when I bought it. That's why I put original back. The very slight leak is the engine side boots. I will examine the o rings and boots (I should have when carbs were off) and go from there. You guys are a big help, thanks.

 

[chuck hahn]

I think Don is still making the intake manifolds. His are made like Kawasaki styled so they don't require an oring....from what ive been told by someone who has bought these.


http://jbmindustries.com/RubberFlange.html

 

[Kingjoel]

Thanks Chuck, I just ordered the o rings and bolts. I will inspect the boots. If needed I will order some.

 

[Kingjoel]

Update, My 78 1000 runs great with zero air leaks. Once warmed up the idle stays at 1200 rpm all day.
Thanks to all!!