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Author Topic: Best way to check for intake leak?  (Read 222 times)

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Offline raiken1

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Best way to check for intake leak?
« on: September 19, 2019, 01:33:43 pm »
Hello all,
I need to check if my carb boots are sealing properly after carb installation on my CB650. It has new carb boots on the engine head side. I am also not sure how tight to tighten all the clamps. I had heard that you can use brake cleaner or starter fluid, but I think starter fluid is too volatile and brake cleaner will remove paint. What else could I use?

Offline Dolomite

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Re: Best way to check for intake leak?
« Reply #1 on: September 19, 2019, 01:36:34 pm »
Carb cleaner. It will cause the rpms to jump if it gets pulled in after the carbs. Propane works in a pinch too  ;D

Offline Nicklopic

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Re: Best way to check for intake leak?
« Reply #2 on: September 19, 2019, 02:35:31 pm »
Using starting fluid will be okay, youre not spraying a ton and nothing around the carbs should be hot enough to be near its flash point.
Just do some quick little sprays around the edges and see if you any hear RPMS changes. Carb clean is good too, as stated
80' CB650

Offline 1976cb750f836

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Re: Best way to check for intake leak?
« Reply #3 on: September 20, 2019, 05:34:12 am »
I use wd 40, it will speed up a tad if leak, and easy to clean up, and doesn't damage rubber and plastic. I've also used soapy water in a spray bottle, it will cause a stumble or miss, and doesn't damage anything . For me start fluid and propane seem dangerous?

Offline raiken1

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Re: Best way to check for intake leak?
« Reply #4 on: September 20, 2019, 07:29:38 am »
I’m going to give starter fluid a try. I’m going to be easy with it and try not to overspray. A friend said that they use it and that it evaporates very fast.

Offline ekpent

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Re: Best way to check for intake leak?
« Reply #5 on: September 20, 2019, 08:18:41 am »
 I made a mistake recently. Got home from a ride,bike was hot and was checking out my 750 and seen a crack in cylinder #1 rubber manifold forward towards the engine left of the clamp . Grabbed a can of brake cleaner that was close by and proceeded to give them a big squirt and started a fire. Luckily I was able to pretty much blow it out + the stuff burns fast but could of been bad news if I had a gas leak somewhere. I would go with something less flammable then  starting fluid or brake cleaner  ;D ;D  Good news was no air leak  !!
« Last Edit: September 20, 2019, 08:22:10 am by ekpent »

Offline WhyNot2

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Re: Best way to check for intake leak?
« Reply #6 on: September 20, 2019, 08:46:20 am »
I made a mistake recently. Got home from a ride,bike was hot and was checking out my 750 and seen a crack in cylinder #1 rubber manifold forward towards the engine left of the clamp . Grabbed a can of brake cleaner that was close by and proceeded to give them a big squirt and started a fire. Luckily I was able to pretty much blow it out + the stuff burns fast but could of been bad news if I had a gas leak somewhere. I would go with something less flammable then  starting fluid or brake cleaner  ;D ;D  Good news was no air leak  !!

One of those.....awwww sh1t moments.....
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline ekpent

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Re: Best way to check for intake leak?
« Reply #7 on: September 20, 2019, 10:30:42 am »
I made a mistake recently. Got home from a ride,bike was hot and was checking out my 750 and seen a crack in cylinder #1 rubber manifold forward towards the engine left of the clamp . Grabbed a can of brake cleaner that was close by and proceeded to give them a big squirt and started a fire. Luckily I was able to pretty much blow it out + the stuff burns fast but could of been bad news if I had a gas leak somewhere. I would go with something less flammable then  starting fluid or brake cleaner  ;D ;D  Good news was no air leak  !!

One of those.....awwww sh1t moments.....
Ha ha - no change of undershorts but close. Checking on a cool or cooler engine would be advisable also.

Offline raiken1

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Re: Best way to check for intake leak?
« Reply #8 on: September 21, 2019, 03:19:24 pm »
Mine is revving a little too erratically to ride, so it shouldn’t be that warm.

Offline 1976cb750f836

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Re: Best way to check for intake leak?
« Reply #9 on: September 22, 2019, 05:43:20 am »
An old man when I was 16, had a hand held propane torch with the end of the burn tip cut off, attached 3/8 rubber fuel line to it bout 6ft long. He would crack the propane valve slightly, and drag the end of the hose all over the top of a running engine. Watched him find many a vacume hose leak on cars.

Offline WhyNot2

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Re: Best way to check for intake leak?
« Reply #10 on: September 22, 2019, 07:03:06 am »
Sh1t, I can't even get mine to run enough to check for leaks......getting really frustrated with this darn thing...
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

 

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