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- Jun 13, 2007
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so there are 2 main issues people have had with these kits
headgaskets and liner to crankcase sealing
headgasket is easy once you understand how they work.
this is what I did
FWIW apparently JBS have been using the oem Head gasket 8O
another solution for a high HP engine
the other issue is the bottom liner seal, I use threebond 1207B and lay a huge bead 12mm diam around the liner above the sealing surface as well as a coating on the cases and of course the conventional selaing surface this is to provide some integrity to the seal and is suggested by JBS you can see behind these bearings that its quite messy but it does work 100% no issues
the other more elegant solution is to run small o rings as done by Contiman and Enginehardware.
the longevity of the piston/liner are good but 5.5 thou clearence is a bit loose IMHO 4 would be perfect.
with roller mains a 2206 on the drive side and an NTN NJ206 on the ign side with 1mm endfloat lasted 100 hours and stil looked fine.
now as a review this looks quite good but if i need a new kit i will organise it myself, much cheaper, closer to what I want and I won't have to wait
headgaskets and liner to crankcase sealing
headgasket is easy once you understand how they work.
this is what I did
bushmechanic said:For whatever it may be worth the method I use for head gaskets on my 105mm bore is extremely effective, i recently found out it is the exact same method used in top fuel Harley drag bikes.
they bore out a fiber gasket to take a copper fire ring and use a wire ring in the top of the liner to embed into the copper ring.
it works because the fiber portion can compress a lot more than copper. the bolts can pull the head down closer to the liner out near the bolts while the copper fire ring gets maximum crush with the wire ring and in turn is strong enough to withstand the combustion forces.
the problem with the JBS (gaskets to go) fiber gaskets and their MLS gasket is that after about 9 hours the rolled steel fire ring gets fatigue cracks in it
the problem with the copper gaskets in the 105mm bore is that the head cannot be pulled down around the bolts far enough to get the required crush at the bore. It can work fine though on a 100mm bore and has been done already.. you can buy copper head gaskets for husabergs off eBay.
FWIW apparently JBS have been using the oem Head gasket 8O
another solution for a high HP engine
bushmechanic said:from FD racing.. no headgasket...
bottom line is that if you have enough crush at the bore on the fire ring nothing is going to get out
fdracing said:at the end of the day i decide to do the metal-ring myself , it's an square ring with 2 teeth on both side i made it on stainless steel 431 , oil pressure has it's own o-ring , and for water sealing i use an simple paper gasket.
it may give you some idea for your engine :wink:
i start the test yesterday , it seems to work well for the moment :wink:
today , hard ride , and let see what's happen !!!!
so !!! , the ring do the job !!! full throttle on 6 gear for miles , the only way i know for testing !!!! :wink:
the other issue is the bottom liner seal, I use threebond 1207B and lay a huge bead 12mm diam around the liner above the sealing surface as well as a coating on the cases and of course the conventional selaing surface this is to provide some integrity to the seal and is suggested by JBS you can see behind these bearings that its quite messy but it does work 100% no issues
the other more elegant solution is to run small o rings as done by Contiman and Enginehardware.
the longevity of the piston/liner are good but 5.5 thou clearence is a bit loose IMHO 4 would be perfect.
with roller mains a 2206 on the drive side and an NTN NJ206 on the ign side with 1mm endfloat lasted 100 hours and stil looked fine.
now as a review this looks quite good but if i need a new kit i will organise it myself, much cheaper, closer to what I want and I won't have to wait
