So Close!...
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Now I’ve got a decision to make. What extra gasket to apply to the base of the barrel. I’ve got a standard thickness of 1mm and a 0.5mm.
Do I go to 1.5 or 2? I’m leaning towards 2mm to be safe, rather a little too much than not enough. I can at least knock it off the list then… -
@SpookDog The servo side bushing on the Athena 170/125 kit is a Yamaha part, part number 31K-1131U-00. Athena advise you to buy a new one to fit the kit if you're running it on an original TZR125 as the PV and bushing for that bike (part number starting with 2RL) is smaller in OD (I think). Check it out, it's the OEM servo side powervalve bush on almost every DTR and some DT125LCs:
https://www.cmsnl.com/products/holder-3_31k1131u00/
So if you've got a 3MB cylinder with the servo side powervalve bush in good condition, you can just use that or replace the phosphur bronze bush off eBay etc. if it's worn.
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I couldn’t find a single new bush! Cheers bud! Is there a fleabay listing that sell them specifically? I need to get a proper vernier calliper to measure things. I can’t find a half decent one of those. Just Chinese things! I don’t seem to be having any luck searching from my iPhone…
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@SpookDog Those Chinese digital verniers are ace, I bought one for £5 in 2011 and I'm still using it. Exactly the same thing is around £40 in Machine Mart but Aldi/Lidl sell them cheap every now and then.
Bushes I'm not sure, I've never known a PV bush to be worn enough to replace but I guess you could take the parts to a bearing shop and get them to measure up and order you some.
Is there any way you could get access to a PC? Smartphones are excellent for what they are but it's difficult looking around for the best deal on a screen the size of a fag packet. Even if you just go online down the Library you can have 3 or 4 windows open on a big screen, makes comparing suppliers etc. a lot easier.
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I’ve got an old servo side bush that is light years better. The old one you could literally rattle the power valve!! I’ve got a 4fu (male bush) for the other side that is better as well. That side wasn’t as worn though. I’m going to try them, as well as doubling up the base gasket…
Wish me luck! I’m hopeful cause I sure as shit can’t think what else could be giving me the same symptoms…
PS! I finally got the Blaster 200 small end bearing fitted! I went the other way and took a bit off of each side of the bearing. Easier to do and cheaper if I’d fuxed it up! Easier to de-swarf as well
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@SpookDog said in So Close!...:
Now I’ve got a decision to make. What extra gasket to apply to the base of the barrel. I’ve got a standard thickness of 1mm and a 0.5mm.
Do I go to 1.5 or 2? I’m leaning towards 2mm to be safe, rather a little too much than not enough. I can at least knock it off the list then…Why you want to do that?
If you go with 1mm at the base you can use an 0.5mm on the head,will give you 1.1 squish if I remember correctly.
I made 1.1mm (2x0.55mm) at the base and with 0.55mm at the head the piston came flat with the cylinder and gave me an 1.2mm squish,all copper and handmade.
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Like I said, I had to lap the mouth of the crankcase level. I did it after fitting the head gasket so I couldn’t check the level of the piston crown to the top of the barrel.
I’m trying to get it running properly. I’m not in a position to even be thinking about tuning the squish band…—————————
Just putting it together again. Power valve feels proper again, not rattling around! Remembered to fit the banjo unions as well
It spends far too much time like this. Hopefully it’s fixed now…
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FFS! I can’t believe it but the base gasket is leaking from the same spot as before!
I think there must be a slight V at the top of where they join. I put an extra dot of sealant there last time (that it didn’t leak!)
I’m going to use silicon RTV the next time. I should of used it to seal the crankcase halves, but I used tube type ‘hermatite’ and I think I ‘washed it out’ while lapping…I’m going to test ride it tomorrow after plugging the leak temporarily. See if at least I fixed the running problem at 1/8 throttle…
Can’t seem to catch any breaks! Always fuxin something with me!
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I lapped the high side down to match the low. Then the whole thing flush. Using plate glass, wet & dry & wd40. It was only a hairs width…
You can see the problem, where the two cases join? The gasket is only 5mm wide at that point. There’s a definite gap where I’ve ‘washed out’ the sealant between the two cases. I just need to be super careful with that spot…
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I’ve been assuming that standard base gaskets are 1mm thick, but from what little I can find out it seems Athena gaskets are 0.5mm?
Can anyone tell me what the standard Yamaha gasket thickness is? Or what Athena definitely are? Be a big help!
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Cheers buddy! I’ve been labouring under a misconception!
I’m planning on using copper RTV silicon with a new gasket. 700deg stuff. I’ve had good results with it before. There’s quite an open groove at the front where the two cases join…I’ll be using it when I next put two cases together as well!
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@SpookDog If you speak for the base gasket then I advise you to go for a copper one with the Permatex Copper Spray gasket I had mentioned you in some older post here.
Yamaha's base gasket is metallic with black coating and with some melting stuff that forms a line around to seal better. -
Initial test ride is promising. Cruising at 25-30 without the previous issues. No tap-rattle and humming from the top end! Won’t know for sure till I take it on a 20-30 mile run though…
Put a spot of chemical metal over the leak for temporary/now…
