Gasket Leak

I took the clutch side cover off a Honda Cub, put it back on and it’s leaking. Should I use a gasket sealant ? , it’s pretty big and kind of cumbersome. Thanks

Re: Gasket Leak

Moped Lar (OFMC) /

You should use whatever the manufacturer used when they built it.

Re: Gasket Leak

I use the copper spray stuff in both sides of the gasket and it works great. As long as it's a clean gasket.

If it's leaking, you probably shoulda replaced the gasket. Or at least make sure it's not ripped, everything's clean, and it's tightened evenly.

Re: Gasket Leak

I didn’t find anything in the repair manual but a company that sells parts recommends using Honda Ht Gasket Sealant. EBay had it for $12 a tube, it’s silicone based and doesn’t harm aluminum. Ordered a few gaskets also they were only $4.

Thanks

Re: Gasket Leak

Generally speaking, gaskets crush and seal one time. I typically don't reuse gaskets but rather buy a replacement or cut a new one from a sheet. I never had much luck with silicone based sealers either. Any auto parts store has blue, red, black or copper rtv sealers.

Re: Gasket Leak

Pushrod Fifty /

Look out for aftermarket gaskets. Many I have brought went into the trash before bothering to use. Clean both case surfaces entirely. Use a new gasket of the correct thickness and a thin swipe of Hondabond on each side of the gasket using a single edged razor. Let it set up a little so it has skinned over and wipe the excess from the inner edges. Assemble and torque the screws to spec or use an impact screwdriver with a hard plastic mallet, leave the ecxess Hondabond on the outside, and Let set up for at least 2 days before adding oil.

Re: Gasket Leak

The gasket is advertised as a Honda part made in Japan. Should I coat one side of the gasket , stick it on the cover and then coat the other side and install on the case? Also should I lay the bike on its side to keep the clutch parts, like the spring from falling off? Is it possible to not have a leak without the sealant, just curious. I’ll follow you’re instructions exactly . Thanks again. I have a 10 volt impact drill ,would that be OK ?

Re: Gasket Leak

Pushrod Fifty /

I use a piece of cardboard to lay the gasket on and apply sealant then assemble after it sets up alittle, wearing vinyl gloves. No drill only by hand. Thats what I do and I dont have any leakers.

Re: Gasket Leak

Moped Lar (OFMC) /

Make sure you follow the correct sequence of tightening the bolts when installing the clutch cover.

Re: Gasket Leak

> Moped Lar (OFMC) Wrote:

> -------------------------------------------------------

> Make sure you follow the correct sequence of tightening the bolts when

> installing the clutch cover.

...and a torque wrench.

Re: Gasket Leak

I replaced the gasket today and used the recommend Honda sealant , couldn’t find any information on the tightening sequence but I tightened it to the factory 5-8 ft lbs. The sealant takes 3 days to fully cure.Thanks

Re: Gasket Leak

Pushrod Fifty /

Tightening sequence is just a matter of torquing fasteners crosswise from each other and not in a rotational pattern. It keeps the case mated flat during the process, so it doesn't stick up on one side and introduce stresses in the cases or cover.

Re: Gasket Leak

I was careful and torqued them down a little at a time and did so in a pattern that let the cover flat The only thing I’m not sure of is the clutch adjustment . I followed the repair manuals instructions but never quite got the feel they were referring to.Thanks

Re: Gasket Leak

Pushrod Fifty /

Kind of finiky to get adjusted just right. Too loose and the clutch doesnt disengage and too tight, tne shifter binds up. Should have a little slack in the shift lever when moved back and forth by hand, if the shifter is tight, the clutch is partially activated.

Re: Gasket Leak

shouldnt need sealant but doesnt really hurt. it makes it easier to hold the gaset in place. you do need the gasket, it affects spacing some and seals best. I've hada a cover warped on one of those engines that never sealed, but that was a china lifan clone.

your new gasket should have you set tho. good call on crosswise torquing it down. I replaces mine with allen bolts just cuz those phillips heads can strip and that's a chore to deal with.

if you followed the manual clutch is probably good. we'll see i guess.

man now i want a cub again haha.

Re: Gasket Leak

I started the cub up today , ran it for a half hour and there were no leaks. The sealant must have done the trick. Now the engine pulsates sometimes and takes a while to return to idle speed. I replaced the fuel lines and eliminted the fuel filters, other than the erratic idling problem it runs strong with no hesitation when you hit the throttle. Thanks

Re: Gasket Leak

When reassembling casings I found it is easy to keep alignment of casing-gasket-casing by using a few long grub screws and threaded rod as alignment pins. Outside casings use like M6x50 grub screws in 3 positions, put on the gasket, put on the cover, thread in proper screws in the other holes, extract the 3 grub screws and replace with the proper screws. No gasket migration of pinching that way.

If you are doing the crank casing halfs, cut some threaded rod about 100mm long and do same same. No pinching, migrating or last minute gasket splitting as you knock the halfs together.

Re: Gasket Leak

That’s good advice, I think my problem the first time was an alignment issue. The sealant helps keep the gasket in place . I laid the bike on its side and put most of the bolts in place. Igota good squeeze out with the sealer. I adjusted the clutch but it’s hard to get right with the idling , surging issue.

Re: Gasket Leak

Check the float level.

Open the petcock. Use the bowl drain tube and hold it vertically beside the carb, then loosen the drain screw, the fuel will flow into the drain tube to the actual fluid level in the bowl. Should be just a bit below the flange of the carb body ro bowl union.

Might be also the emulsion tube in the carb having little specs of crapo in the tiny tiny holes on the tube.

> Tim Doll Wrote:

> -------------------------------------------------------

> That’s good advice, I think my problem the first time was an alignment

> issue. The sealant helps keep the gasket in place . I laid the bike on

> its side and put most of the bolts in place. Igota good squeeze out with

> the sealer. I adjusted the clutch but it’s hard to get right with the

> idling , surging issue.

Re: Gasket Leak

The carb was leaking when I bought the it and I took it off the bike and after the third try it stopped leaking .seemed to run fine then it sat for over a month with ethenal gas in the system. Yesterday after the idling issue I emptied the tank, cleaned the holes real good in the tank that the fuel lines connect to and replaced the lines, also got some Rec 90 fuel. Today I’ll add a little sea foam and check for vacuum leaks. Your probably on the right track with the carb. EBay has a new Jap carb for $80 shipped ,it just needs the mounting holes enlarged 1.5 mm on each side. They sell a rebuild kit but it’s $30. If there’s a vacuum leak I’ll try the Honda sealant. Thanks again

Re: Gasket Leak

Pushrod Fifty /

Check the carb flange and spacer for flatness and the oring as it sounds like an air leak.

Re: Gasket Leak

I cleaned the carb again today ,it runs great except for the surging . I think your right about the vacuum leak , I ordered a couple gaskets but I might put some Honda sealant on the gasket between the cylinder head and insulator I don’t have any O rings. Thanks

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