Author Topic: Cyclex MLS head gasket question? (Read 7038 times)

jhalldorson · « **on:** April 12, 2014, 05:54:49 PM »

Has anyone used these? I have been fighting this motor from the start.Dunno why I thought the head would be trouble free. Today I got my cylinders and head on there's a small gap on both ends. I'm using the MLS gasket and APE studs. I'm not sure if it is a normal thing, or I needed to have my head milled. Really wishing I would have had it checked now

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bytio · « **Reply #1 on:** April 13, 2014, 01:03:42 AM »

Is it a 750 SOHC? If so make sure you have the correct dowels, the ones from crankcase to cylinders are longer, and if you put those between cylinder and head then you will get the gap you see

andrewk · « **Reply #2 on:** April 13, 2014, 04:43:30 AM »

I've used the gaskets in a few different bikes. No problems here.

As stated above, correct dowels, and leave out the 8 rubber seals/dowels around the oil returns if you have a post K3.

Gasket surfaces need to be perfect.

Bailgang · « **Reply #3 on:** April 13, 2014, 05:09:20 AM »

I've used the cycleX mls head gasket on a 550 and was very satisfied, I even pulled the cyl head off twice to take care of a pesky base gasket leak and reused the same mls gasket both times. Once the base gasket leak was finally resolved there were no leaks at all at least on the cyl portion of the engine and it ran great. All of the previously mention tips is good info.

jhalldorson · « **Reply #4 on:** April 13, 2014, 09:07:00 AM »

I was hoping someone would tell me it was the way it was designed, maybe because of the ridges. Dangit! I did leave out the 8 packing seals and dowels, I never took the locating dowells out and there is nothing left as far as old gaskets. I guess I will have to pull it apart and straight edge the head and cylinders:( thanks for your input guys atleast I know I can re-use the gasket. Bailgang, were you using the steel cyclex base gasket? What was causing your leak? I was nervous about using my plain steel one with no sealer,but I did.

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PeWe · « **Reply #5 on:** April 13, 2014, 11:42:47 AM »

The head and cylinder must be very flat and have perfect surface for a MLS gasket. I grinded my cylinder and head with 400 grit paper on a flat table. I changed my mind when I did not trust the flatness. Bought fiber gasket that also do not have the 8 dowels with thick o-rings as the later CB750 got and mine had from the beginning. My 65mm (836) gasket I mounted 1987 had bigger holes for the dowels and rubbers, newer has not.

Bailgang · « **Reply #6 on:** April 13, 2014, 11:52:05 AM »

Quote from: jhalldorson on April 13, 2014, 09:07:00 AM

I was hoping someone would tell me it was the way it was designed, maybe because of the ridges. Dangit! I did leave out the 8 packing seals and dowels, I never took the locating dowells out and there is nothing left as far as old gaskets. I guess I will have to pull it apart and straight edge the head and cylinders:( thanks for your input guys atleast I know I can re-use the gasket. Bailgang, were you using the steel cyclex base gasket? What was causing your leak? I was nervous about using my plain steel one with no sealer,but I did.

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In my case the engine was already together and running before installing the mls gasket, I was swapping the cyl head on it and decided to use the cycleX mls head gasket with the new cyl head. The base gasket was standard type of paper gasket from a previous kit which up to that time was fine however while pulling the old cyl head I pulled the cyl jugs up a bit off the base and tore that gasket just a bit. Being lazy and impatient I thought I could get away with it but nope the base gasket leaked shortly after I got it back together and running. I pulled it apart again to replace the base gasket and replaced the o-rings on the far right and far left of the base as well (remember I'm talking 550 here) however I used cheap o-rings from an assortment I had. It was fine for a week or so but a leak developed around those o-rings. AGAIN it came apart with yet another new base gasket except I installed viton o-rings the last time around and that did the trick. In both cases I simply cleaned up the mls head gasket, made sure all surfaces were clean, put the mls gasket back on and crossed my fingers.

Lesson learned there is don't get cheap on o-rings.

jhalldorson · « **Reply #7 on:** April 13, 2014, 12:22:40 PM »

Pewe, are you saying your bike came with the 8 pins and orings and that you left them out? Did you mean your bike is a 77? Was the gasket made so you can leave them out or can you leave them out with any gasket? I have a composite gasket that came with my pistons. I only see this gap when I look down the sides. More so by the back corners. Has anyone ever looked to see if they have a gap? It almost looks normal the more I look at it

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jhalldorson · « **Reply #8 on:** April 13, 2014, 12:31:58 PM »

I hear ya bailgang. I am really nervous about.my orings there is a huge oring that is for the main oil galley. I couldn't find one in my seal kit that did anything but come flush with the case surface and I keep thinking I'm just being paranoid. The more I thought, I decided to just order one from Honda. I was so glad I did. It was so much different and thick. I am almost sure I would have had a leak. I had another situation like that on the countershaft bearing holder. I really don't want to do this twice!

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Jerry Rxman Griffin aka MuthaF'er · « **Reply #9 on:** April 13, 2014, 05:57:09 PM »

Be sure you install the APE studs correctly so you'll have enough threads to attach the nuts to. The gasket will compress just fine if you have everything installed properly as long as it was fine when taken apart.

jhalldorson · « **Reply #10 on:** April 13, 2014, 06:43:57 PM »

That's something I hadn't thought of Jerry. I was unsure which side screwed into the block. I screwed the side that had the most threads into it. Is that correct?

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Jerry Rxman Griffin aka MuthaF'er · « **Reply #11 on:** April 13, 2014, 09:04:44 PM »

I'm away from home and don't have my APE instructions. It'd be a week before I could get the correct info. I'm thinking Big Jay says to install them into the case at 8 lbs torque though.

bjbuchanan · « **Reply #12 on:** April 13, 2014, 09:22:27 PM »

Check height of any dowels. If you milled the surfaces you need to file down the dowel height at least as much. If not you "could" have the head held up

jhalldorson · « **Reply #13 on:** April 14, 2014, 04:29:17 AM »

Ok...thanks guys

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PeWe · « **Reply #14 on:** April 14, 2014, 05:50:05 AM »

Quote from: jhalldorson on April 13, 2014, 12:22:40 PM

Pewe, are you saying your bike came with the 8 pins and orings and that you left them out? Did you mean your bike is a 77? Was the gasket made so you can leave them out or can you leave them out with any gasket? I have a composite gasket that came with my pistons. I only see this gap when I look down the sides. More so by the back corners. Has anyone ever looked to see if they have a gap? It almost looks normal the more I look at it

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My bike is a K6 -76. It did have the 8 dowels and o-rings which I used on all gaskets before. I replaced head gasket 2 times as 736. After that 836 (65mm) and still 8 dowels with o-rings. The head gaskets I bought 2012 had both no holes for these dowels and o-rings. CycleX MLS, then Cometic fiber.
I have another new 65mm head gasket from Yamiya750 that have holes for the 8 dowels and o-rings. But I'll use the Cometic fiber without when this one is thinner, at least 0.5mm thinner which will give me more compression which I need.

This is discussed in other threads it will work without dowels and o-rings.

I'll spray my fiber gasket with Permatex Copper spray gasket to ensure the area around the oil holes and cam chain tunnel. I'll cover the area on 8 holes that will be visible for the oil. Cover with old dowels with o-rings on.

iron_worker · « **Reply #15 on:** April 14, 2014, 08:34:32 AM »

I called and talked with Ken at Cycle X about this. The 8 rubber packing pieces and 8 smaller dowels for the oil drains are not required. The MLS gasket has a raised area around each oil channel (as well as around each cylinder) that will compress as the head is torqued to form a seal.

However, the two larger alignment dowels in the corners are still required. Make sure they are free of burs and can slide into their respective holes easily.

If anyone has questions about Cycle X products I suggest talking with Ken. He is super knowledgeable and a straight shooter.

Regards,

IW

jhalldorson · « **Reply #16 on:** April 14, 2014, 08:45:03 AM »

Thanks peer and IW. IW I wondered if the channels could make it look like this. I had cleaned the locating dowells and holes. What also makes me think the Dowells are not the issue, is that the gaps are on the intake side and the Dowells are in the front of the motor. Have you looked to see if you have any gaps IW?

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jhalldorson · « **Reply #17 on:** April 14, 2014, 09:53:24 AM »

I took your advice iron worker and called cyclex. They said not to worry about it. They said its caused by the channels. Its still kinda bugging me but they said it was a question they deal with regularly and it should be ok. Jerry I did take off one of the nuts and checked the stud. I still had plenty of threads left. Thanks everyone for your help. This without a doubt, the most helpful forum I have seen and I love reading member builds. Some amazing machines on here!

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PeWe · « **Reply #18 on:** April 14, 2014, 10:28:08 AM »

One very good thing with MLS, it's reusable. Head off.... do what you need...Head on with same gasket.
There is a thread about that too. I have never done that, only read about it here somewhere.

iron_worker · « **Reply #19 on:** April 14, 2014, 10:53:05 AM »

Ken mentioned to me that he suggested if the gasket has been heat cycled (IE, you had the bike running) that he wouldn't suggest re-using it. He said if you've just installed it and need to take the head off again for whatever reason then it should be fine to re-use the same one.

IW

andrewk · « **Reply #20 on:** April 14, 2014, 02:25:45 PM »

Here's one I did just the other day. No gaps or wrinkles here. I did have the head decked. Doesn't mean yours is bad, but it doesn't look quite right to me. I might want to find out why before heat cycling the engine...

jhalldorson · « **Reply #21 on:** April 14, 2014, 02:35:32 PM »

Well crap. I can't argue with that. I guess its coming off. Thanks for the pictures.

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Bailgang · « **Reply #22 on:** April 14, 2014, 02:54:18 PM »

Quote from: iron_worker on April 14, 2014, 10:53:05 AM

Ken mentioned to me that he suggested if the gasket has been heat cycled (IE, you had the bike running) that he wouldn't suggest re-using it. He said if you've just installed it and need to take the head off again for whatever reason then it should be fine to re-use the same one.

IW

Agreed, I was pushing my luck reusing the mls gasket like I did and not something I'd recommend others to do.

KayOne · « **Reply #23 on:** April 14, 2014, 05:58:31 PM »

Can't speak for air cooled motorcycle engines but many in car drag racing reuse Cometic MLS head gaskets. I have a turbo charged SBF that sees as much as 26lbs. of boost and I have reused MLS gaskets without failure.

They cannot have been subjected to excessive heat. If the gasket shows any blueing near the fire ring or have "sprung" and the laminations are warped they are toast. I use a water based cleaner on the SBF gaskets because they have a flexible rubber type coating to seal the water passages. The Cycle X gasket has no such coating so one could use a solvent based cleaner to make sure there is no dirt between the laminations and reuse. I pay particular attention to the torque sequence and use a quality torque wrench as the embossing that forms the seals has been crushed by the first usage.

I can understand not chancing reusing the MLS as having to remove the engine or install a frame kit would be a real pain, but if it's in good shape I personally wouldn't hesitate. Lot's of racers spray a thin layer of copper coat on the internal and external laminations on the second go around.

jhalldorson · « **Reply #24 on:** April 14, 2014, 06:15:50 PM »

I used your home made mill idea pewe. I still haven't straight edged it, but my gaps sure look much better! I also wondered if some copper coat would be ok around the head or base. I was afraid of it getting it in one of the small oil passages, but there were some areas I would have liked to.

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Author Topic: Cyclex MLS head gasket question? (Read 7038 times)