350scabarat Posted July 25, 2009 Report Posted July 25, 2009 Hey guys i bought a shee about a week ago and the clutch was molested so im busy fixing it. . I noticed that the crank cases hav bn sealed with silicone, the carb boots aswell. .my question, silicone isnt petrol resistant? So arnt the cases and boots gana leak? Quote
Overboost Posted July 25, 2009 Report Posted July 25, 2009 RTV black silicone is what they use to seal most rear end cases and transmissions in cars. impervious to oil, not so much gas after a while but will work interim. of course, it is not correct to fix a crank seal with, and will leak regardless, carb boots may be fine until you find some new ones, but the seals, they are going to leak probably very soon. Quote
Paul M Posted July 25, 2009 Report Posted July 25, 2009 (edited) Gas will eat the silicone ! take it apart and use Yamabond! a little work now or alot of $$$ later Edited July 25, 2009 by Paul M Quote
350scabarat Posted July 25, 2009 Author Report Posted July 25, 2009 No i dont mean crank seals? When u split the 2 cases. . .the mating surface? They used silicone, u think the petrol will eat away? Cause the cases mate so closely? Ah damb im jst tryna cumfort myself. . Haha im gana hav2 split it. . .damb. Thanx guys Quote
slopoke Posted July 25, 2009 Report Posted July 25, 2009 thats what you use when mating cases together. Like it has been said black is most common. I try to use yamabond when i can. It cleans up easier. If you have a Kubota dealer nearby they have the best sealant. The japaneese believe in sealant and few gaskets due to the tight mating surface. The key to it all is do NOT go overboard with any sealant. What you see squeeze outside also squeezes inside and can create issuses stopping stuff up, more so on a 4 stroker. Quote
350scabarat Posted July 25, 2009 Author Report Posted July 25, 2009 No not on a 2stroke crankcase that has petrol in it all the time. . Quote
slopoke Posted July 26, 2009 Report Posted July 26, 2009 yes that is what cases are put together with. Yamabond or something of equal. Black rtv will work fine. Quote
2strokespirit Posted July 26, 2009 Report Posted July 26, 2009 No i dont mean crank seals? When u split the 2 cases. . .the mating surface? They used silicone, u think the petrol will eat away? Cause the cases mate so closely? Ah damb im jst tryna cumfort myself. . Haha im gana hav2 split it. . .damb. Thanx guys Scabarat, buy threebond (from yamaha or where ever from) or Bostic BLACK GASKET MAKER is a PETROL RESISTANT silicon....... Quote
swrbansheeboy Posted July 27, 2009 Report Posted July 27, 2009 not to be a total dick but.... dont you think that if silicone or silicone based sealants were acceptable for this application that yamaha would be using them? i mean that given the price comparison and the volume of bikes yamaha (and all the other bike mfg's) builds yearly dont you think that if silicone was a acceptible substitute for yamabond/threebond they would be using it just to cut there bottom line? if it was a good substitute i'm sure they would be using it, you figure $1 per bike they produce in a year and thats alot of savings. they use yamabond/threebond for a reason and you should also.... it amazes me that people will try and save $2 to assemble an engine that will cost them $500 to tear down and re-build later.... Quote
slopoke Posted July 27, 2009 Report Posted July 27, 2009 First I'm not being an ass but it amazes me stuff people say without knowledge. Yamabond is a silicone base sealant. DUH It is MADE IN JAPAN hence it is cheaoer there!!!! DUH Why don't you leave those great stock pipes on that banshee? They cost more if you buy them new than cpi's HUH There are plenty of rtv's and silicones that work fine for the cases but dont get the idea that 3 bond or yamabond isn't silicone because it is. It cost more here because it has to be imported. Use what ever you want because the beauty of it is it is yours. Do some research by googling and come to your own conclusion as someone will always dissagree. Thats nature. Quote
slopoke Posted July 27, 2009 Report Posted July 27, 2009 oh and i like to have proof as to what i say here ya go Yamabond 4 Motorsports Yamabond 4 Motorsports is a silicone-based liquid gasket that fills gaps on a flange surface and prevents leaks. When cured, this product forms a rubber-like body that resists heat and seals joints subjected to high temperature. Gear- and engine-oil resistant, Yamabond 4 Motorsports sets in 60 minutes. Not for use on copper or copper-based alloys. Yamabond 4 Motorsports, 3 oz. Tube (Dealer Order Qty.=1) ACC-BOND4-MC-00 Quote
slopoke Posted July 27, 2009 Report Posted July 27, 2009 here ya go they may not have been dumb Permatex Quote
old roost Posted July 27, 2009 Report Posted July 27, 2009 hey guys, well this weekend i finally had time to remove the engine and split the case,(i want to replace all gaskets and seals before rebuilding the top end) Shee has been sitting out in the elements not run in about 5-6 years(before i had it sputtering about 3 weeks ago) i was amazed at how good the lower end looked! the gear set and inside of the case looked brand new, i could not find any metal filings anywere!! i figered i would a see little here ant there. the crank looked to be good also i did not see any pitting or cracks, i am just going to clean it up and reinstall. My question is do you have to buy the crankseals seperate or do the come with the whole gasket kit? and to add to this topic it seems that i am the first one to crack this case apart and it looks to have almost no sealent on the case halves, i did notice a very very tiny amount of gray rubbery sealent. could this be the factory sealer? Quote
slopoke Posted July 27, 2009 Report Posted July 27, 2009 yes that is factory. it will squeeze out Quote
old roost Posted July 27, 2009 Report Posted July 27, 2009 yeah that is what i thought thanks slopoke. Quote
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