So Close!...
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It’s good. I really think it’s the air gap in the fuel pipe. If the motor is drinking it faster than it’s getting in, it sputters. It’s about 5 or 6 inches of airlocked pipe...
I can’t do pics at the moment cause my phone dies if you unplug it... -
Harpic is actually the Dogs Bollox at dissolving rust! As long as you keep it ‘saturated’ and don’t let it dry out it keeps on dissolving. Top Tip whoever it was who mentioned it! The outside of my second hand tank is now rust free after the previous owner sanded it down to bare metal and left it...
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Hi me! A lot of this is for future reference so I can remember the timeline until I can finally chase the bugs out of my bike..
After putting a couple tanks of petrol through the new tank I finally got it to run sweet and true with smooth power delivery. No fuel ‘lag’ problems with the new pipe routing without the airlock...
Head gasket is leaking again though
only changed it in March and can’t blame this one on the lean jetting. I gotta stop buying cheap Athena gaskets off of fleabay? Try again with a Vertex gasket...Check if it’s the same spot as well...
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@SpookDog Never had a problem with Athena gaskets they're quality parts.
I'd say something is wrong with the engine if you're having problems.
That said, I'd only get my gaskets from PJME or other reputable sources, not randomers off of eBay.
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Oh yeah, absolutely. I’m not knocking Athena as a product. They’re the best affordable option. I just don’t know the history of the fleabay ones. I don’t know if the coating on the aluminium gasket has a shelf life, maybe? They might of been exposed to high or low temps?
I wish I could find fault in the way I’ve been doing the top end rebuilds but I can’t
Sure I’ll suss it in the long run. Maybe you’re only supposed to spread the peanut butter on one side of the gasket?
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@SpookDog
IIRC:
Since I put a new barrel & piston & head on with new gasket (last August) it lasted 7 months until the head gasket went in March. I blame road salt corrosion on the head studs for that one.
This one lasted a month with new gasket, relapped head & barrel and Yamaha dome nuts and washers. I’m hoping that this time was either gasket fault or my fault fitting. I even lifted the engine out so I could get to it with the torque wrench nice and evenly. Cleaned and degreased all surfaces with Wurth degreasant. So I’m gonna have to be extra surgical next time
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@SpookDog WTF - There has GOT to be something wrong with your engine. There just has to be!
I've never had any problems with head gaskets except the cheap white ones you get off of fleabay. I've had some horrible engines in my time too and they were absolutely fine.
So this is very odd.
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I know, I don’t even ride aggressively. This is a new barrel and head since my ‘old’ problems. The first gasket on this top end lasted 7 months and rust got into the studs and nuts, so that’s acceptable. This one has lasted 6 weeks. I’m hoping it was a bad gasket (I’ve had a scratched one before) or ahem user error
We’ll see when I can be bothered to strip the top end again...I don’t seem to have much luck though, that and a painfully slow learning curve are working out worse than a Gypsy Curse!
I will get there thought. I’ve got a 93 4HW TZR project to get my teeth into yet. Can’t find any info on that thing...
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@SpookDog Definitely not putting the gasket on upside down?
You're torquing the head up evenly in a star pattern up to around 22nm? Are you using grease in the bolts as this will impact the reading you get from the torque. Greased bolts torque higher than ungreased?
Sorry if this is very basic but I'm literally baffled!
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@SpookDog did you take them head off for any reason within them 6 weeks as once you’ve tightened the head once you cant take it off again without needing a new gasket or it doesn’t seal properly, only other thing is check the torque of the bolt again once the engines heated
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Up side up,
Using a 1/4 inch drive torque wrench (and lifting the engine up to get at all the nuts evenly and unobstructed)
Studs dry and wire brushed clean.
I clean the top of the barrel and the head by gently lapping them with (180 grit I think) wet & dry on glass, then look for any high or low points with a steel rule.
I clean everything down with solvent, except the gasket which I use straight out of the plastic wrap.I seriously don’t take offence. It’s a mystery to me what I’m doing wrong, but I’ll get there eventually! It only took me 18 months to work out the jetting!
I haven’t loosened or removed the head at all. I haven’t thought about retorquing the head after running just because it’s such a pain in the ass to get at the nuts ‘in frame’
I might have to consider it though. Does anyone else re-torque after first run?... -
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@SpookDog I mean with expansion sometimes things can work loose, people heat things up when they can’t get it loose, I will probably recheck mine. I’m pretty sure when I changed my sump gasket on my landrover the other month it said on the guide check the torque of the bolts once the engines warmed up
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After I took the top end off I managed to break a head stud off level with the barrel while removing them to clean/lap the barrel! FML, eh?! I get all the luck it seems.
So I put the 3MBp00 barrel, piston & head on that I brought recently. Just for the time being. When I first rode it I thought I’d broke the power valve servo wires or such. It was so lacking the usual low down torque. Once I’d established that the servo was working I took it for a ride, it took me a while to get used to the bike feeling so very different, but man that 1mm difference rocks! It really makes the power band noticeable!
I need to take some pics of the 3mb head, piston and gasket that I took off. Once I get camera working!
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@SpookDog Your previous barrel must of been worn out and lack
of power if think 3MB00P has more power as so mildly ported, the
P stamped parts had slighty more power as had different carbs etc. The P stamped head is standard 3MB head just without the casting numbers on top..
I thought it said 12nm torque which was far too low. Still head gasket was fine to retorque even though I'd done several trips to the shops on it.