Dusting off the neglected square nose

I would definitely check all the other diagrams and check valves while your at it.
They've all been replaced, however, I almost like the old diaphragm that came out better than the new one I put in. Now the new one has swelled to the point of not going back in.

I should get a new carb.

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smoofers

Rockin' the SQUARE!!!!
Site Supporter
Location
Granbury, TX
When you rebuilt the carb did you use a cheap kit or genuine Mikuni ? I tried a cheap kit for my HX the other week because it was the only thing I could Amazon and have before the weekend. It's amazing the quality difference. I couldn't get the carb to seal up with the cheap parts... ever. Ended up having to use Mikuni parts to make it work.
 
When you rebuilt the carb did you use a cheap kit or genuine Mikuni ? I tried a cheap kit for my HX the other week because it was the only thing I could Amazon and have before the weekend. It's amazing the quality difference. I couldn't get the carb to seal up with the cheap parts... ever. Ended up having to use Mikuni parts to make it work.
Bought genuine mikuni kit from blowsion.

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Mike W

Infidel
Location
North Florida
They've all been replaced, however, I almost like the old diaphragm that came out better than the new one I put in. Now the new one has swelled to the point of not going back in.

I should get a new carb.

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Did you use an OEM Mikuni rebuild kit? I would never trust those off brand kits. I run nothing but ethanol free fuel in order to avoid problems like that.
 
Looks like didn't clean all the crusty stuff out of that groove where the diaphragm sits. Pretty delicate surface so I didn't want to get too aggressive with it. Gonna run the old diaphragm that came out of it for this afternoon since it never leaked there before.

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DAG

Yes, my balls tickled from that landing
Location
Charlotte, NC
Also check your return fuel line is flowing well. If the return gets plugged pressure builds and blows out the small round clear check/one-way valves on the other side of the carb. And (maybe?) push fuel around the diaphragm?

Don't think a new carb is needed just yet
 
Also check your return fuel line is flowing well. If the return gets plugged pressure builds and blows out the small round clear check/one-way valves on the other side of the carb. And (maybe?) push fuel around the diaphragm?

Don't think a new carb is needed just yet
Return line flows as it should.

Thanks everyone, I appreciate the helpful comments.

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Also check your return fuel line is flowing well. If the return gets plugged pressure builds and blows out the small round clear check/one-way valves on the other side of the carb. And (maybe?) push fuel around the diaphragm?

Don't think a new carb is needed just yet
Ashby, come to lake norman and tune this pos. I'll pay you whatever you want or I'll hang an entry door if your house needs one.

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DAG

Yes, my balls tickled from that landing
Location
Charlotte, NC
Ashby, come to lake norman and tune this pos. I'll pay you whatever you want or I'll hang an entry door if your house needs one.

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Hey Patrick, sorry to hear it's not running as well as you like. I'll be the first to admit I F###ing suck at tuning. Tried tried tried just doesn't click for me. I like building and trouble shooting except for electrical stuff. Thankfully @jo5hi3 is around that can probably set you straight if you need carbs tweeked. But if you followed the Factory Pipe jetting specs you should be really close so might have something else going on. What's it doing?
 
Hey Patrick, sorry to hear it's not running as well as you like. I'll be the first to admit I F###ing suck at tuning. Tried tried tried just doesn't click for me. I like building and trouble shooting except for electrical stuff. Thankfully @jo5hi3 is around that can probably set you straight if you need carbs tweeked. But if you followed the Factory Pipe jetting specs you should be really close so might have something else going on. What's it doing?
Haven't had it back out yet, buried with work. I don't believe that diaphragm was leaking. I smothered it in two stroke oil when I put it together and I think that weeping I found was just residuals from assembly. I bought a couple more main jets from JM along with a pop off gauge. 32psi consistently fwiw. Anyway I felt it was running lean so I put a 147.5 in it. Just scared of frying a motor and losing more time this season. Rather fatten it up till it runs wet and back down from there. Thinking about buying another complete motor to drop in in case poop happens. I'll give it one more effort with this jetting, beyond that I don't want to fuss anymore and I'd rather have a professional ride it, naturally if it shyts the bed with someone else riding it, no liability on their part. I see people attempt home projects themselves and silently shake my head, but now I'm that guy whom has no business trying to tune this thing. Reason I've done it this much so far is because I want an understanding of what's going on since I'll be operating the machine.

Not only that, time's getting short, weather is good and it took me two months to do a pipe, head and rebuild a carb. I just want it to be correct.

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Just put it back on the hitch hauler, not sure if it was swapping out the diaphragm or going up from the 145 to the 147.5 main at 1.5 turns out, but I sure can't make it run out of fuel pinned wide open.

I still want someone better than me to actually tune it, until then it works.

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