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Post by elsiefan on Apr 25, 2022 15:45:33 GMT 1
Reading through it looks like we have had different experiences with OEM and pattern gaskets. My LC had pattern ones (Athena I think) and they leaked, so I replaced with OEM (no extra sealant) and have had no leaks since. But others have had the opposite issue. Plus there is the consideration of tolerances to consider. You pays your money and takes your choice. Try asking what oil you should run it on as well!! π
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Post by dougw on Apr 25, 2022 16:00:32 GMT 1
You don't mention what has been done to your barrels. I suggest you measure the squish height and inform us on this thread. Don't worry about your timing too much and set it was standard. We are all professor's with different ideas. Just try to keep to the standard tolerances unless you want more performance sorry, should of said earlier. this is what the chap told how much was skimmed off. Barrels 0.008 Head 0.010 I'm hoping that they are still within tolerance levels? Athena barrel gaskets to be used along with OEM head gasket, unless i can use the Athena gasket i have? unless something else is recommended thanks If that's a total of 0.018 inch, 0.4572 mm by my reckoning, you will PROBABLY have a safe squish clearance of greater than 1.2mm. I personally would build it with dry gaskets, torque the studs down to about 10lb/ft , and check the squish. Controversially, I currently favour permatex copper gasket spray, so if I was happy with the squish clearance I`d take the head off, use some of that , refit and torque down properly. Other opinions are widely available on this. Then re-check the squish clearance ! If the squish clearance is less than 1.2mm I`d use a thicker base gasket to get the clearance back up.
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freddie19
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Post by freddie19 on Apr 25, 2022 16:01:34 GMT 1
I'm sorry but I never understand why people would take the chance on such a crucial pattern part.
I've only ever used genuine head gaskets and never had a problem. Actually, only ever used all genuine gaskets on my bikes!
Pattern parts are cheaper yes, but they're cheaper for a reason, they're just not the same quality as genuine gaskets.
Do the job once and do it correctly with only genuine gaskets, you'll be glad you did in the long run!
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Post by dougw on Apr 25, 2022 16:16:15 GMT 1
I'm sorry but I never understand why people would take the chance on such a crucial pattern part. I've only ever used genuine head gaskets and never had a problem. Actually, only ever used all genuine gaskets on my bikes! Pattern parts are cheaper yes, but they're cheaper for a reason, they're just not the same quality as genuine gaskets. Do the job once and do it correctly with only genuine gaskets, you'll be glad you did in the long run! Flip side, since I got my first 350LC in 1983, raced that , had a few more, rebuilt mates bikes, I`ve never as far as I can recollect, used an oem head gasket . Never personally had a leak problem either.
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Post by 4l04ever on Apr 25, 2022 22:08:29 GMT 1
I have used both pattern and OEM head gaskets and both have worked fine if the cylinders and head are good. Only had issue with cylinders not being level and parallel to each other. Got them skimmed and was then perfect with a pattern metal style head gasket on a 4L0.
I use my own gaskets (Oldmoto) for everything else with no issues, as do other members of this forum :-)
Nearly 0.5mm is a fair bit off, so you may need to use a spacer with as gasket either side. OEM gasket is 0.6mm, so you would need to be around 1.1mm for the base gasket, which can be done with a 0.5mm spacer with a 0.25mm gasket each side.
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Post by damiensk on Apr 26, 2022 10:27:21 GMT 1
thanks 4LO4ever
if im reading your e-mail right, std 0.6 base gasket along with a 0.5 base gasket?
just to confirm
im not an expert on all this, hence all the questions just to make sure i get the rest right, noting that i am not after performance, just want to have it running right im going to go with OEM head gasket, right first time, spent the money getting the barrels/head skimmed, may as well go OEM. given the measurements that has been taken off. Barrels 0.008 and head 0.010, what base gasket should i buy, looking at what norbo supplies
0.25 0.4 0.5 0.6 std 0.8 0r any mixture of 2?
thanks for any help
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Post by 4l04ever on Apr 26, 2022 17:25:07 GMT 1
The gasket material does compress so the thicker the gaskets, the more the compression takes up. To reduce this, you can use a metal spacer between two gaskets. i.e. 0.25mm gasket plus 0.5mm spacer plus 0.25mm gasket if you wanted 1mm total.
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Post by Tobyjugs on Apr 26, 2022 20:51:53 GMT 1
With a standard Yamaha head gasket and standard tolerances you will be around the 2mm with the squish height. So if you loose half a millimetre you should be ok, but you should try to work out your geometric compression ratio to be safe and correct. Rob is correct about his base gaskets. If you use a big gasket from him shall we say 0.80mm you can loose 0.20mm with compression. I would go with DougW's advice and fit everything and measure. Report back once this is done and the advice from the forum will be helpful.
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Post by dougw on Apr 27, 2022 11:24:10 GMT 1
Adding to say I`m using 4L04ever 0.25 mm base gaskets , to reduce my port heights.
Good quality gaskets and no problems.
(also a home made 0.4 mm copper head gasket, 1.3mm squish on my engine , looking for reliability over power )
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Post by damiensk on May 9, 2022 10:32:28 GMT 1
Gents, bit lost on this now, still got the issue of what size base gaskets i should get for my 4LO. was hoping to buy a spacer as 4LO4ever suggested, he did send me an e-bay link but seller would only supply a 2.00mm spacer. ( thanks to Rob for all his help) so does any body know someone who could supply a 0.5mm spacer?
as a reminder, this is what i had skimmed Barrels 0.008 Head 0.010
thanks for any help
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Post by vectisitch on May 11, 2022 13:34:47 GMT 1
I used Athena with no problems
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