81 XS650 running but have issues


So after replacing coil and ignition i was still having issues. I think i nailed it down to a leak at the intake boot. Mainly the left side. Before i wasn’t using the intake gasket i was just using rtv instead. So i put in two new gaskets from mikes. Still seems to leak, and i also had one of the barbs pull all the way out when trying to check the plug if it was tight or cracked. I superglued it back in but not sure if that’s going to work. This video is after all of the above. I do have my old set of intake holders that were wiring ok, i may put those back on or try and find two better ones new. These that are on there now are new from mikes but quality seems iffy. Bike starts and idles fine, will rev out but bottom end is i think just sucking in all that air making it run like crap
 

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If you haven't replaced them, the butterfly shaft seals could be bad too. If you do go looking for another set of manifolds, try to find the ARS brand. They were the original supplier. You'll see their logo stamped on the manifold lip .....

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If you haven't replaced them, the butterfly shaft seals could be bad too. If you do go looking for another set of manifolds, try to find the ARS brand. They were the original supplier. You'll see their logo stamped on the manifold lip .....

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The butterfly shaft seals are new. I’m going to look for that brand for the holders. I feel pretty good about getting this last piece hopefully fixed. Seems like that vacuum barb shouldn’t have just pulled out like that it must have been sucking in air pretty good. I could kill the engine with that starting fluid sprayed around it. For now I’m going to put my old holder on and see what happens. I’ll order good holders. I’d pay for the best ones i could find seems like an important part. Also i seen a post you did about those Uni foam filters, mine are the capped ones and i seen where you mentioned about getting 4in open ended ones. I’m going to search for those as well i think. I just replaced my clutch friction plates and springs now also so i hope that helped my clutch slipping
 
....post you did about those Uni foam filters, mine are the capped ones and i seen where you mentioned about getting 4in open ended ones. I’m going to search for those as well i think.
For what it's worth... I'm running the capped Uni's on my '80SG. They work just fine on it.
 
Trying not to be anti but thinking out loud
But what are you spraying with .. A starter fluid have better ability to fire the spark and would not stall the motor if plenty of it
If i get it right now
If I understand it right what it can do on the outside is evaporate and lower the intake manifold temperature.
That can affect the droplets on the intake with no leak.

All in all it idles fine as far as i can tell .. given the fact that these are old machines .And not having stock setup .
Everyone has their own views but looking for perfection takes time and cost money
And I did se a video earlier that was perfect with the throttle response.
Summer coming up --- if nothing worse .Perhaps accept it for now put some miles on it se what happens.
Enjoy some riding

I have used XS 650 s that would not idle at all if i did not hold the gas handle
Again I am not telling anybody what they shall do with their bikes .No Sir . But I doubt it can get much better and that with a massive effort
that is typically a winter job if at all
 
Trying not to be anti but thinking out loud
But what are you spraying with .. A starter fluid have better ability to fire the spark and would not stall the motor if plenty of it
If i get it right now
If I understand it right what it can do on the outside is evaporate and lower the intake manifold temperature.
That can affect the droplets on the intake with no leak.

All in all it idles fine as far as i can tell .. given the fact that these are old machines .And not having stock setup .
Everyone has their own views but looking for perfection takes time and cost money
And I did se a video earlier that was perfect with the throttle response.
Summer coming up --- if nothing worse .Perhaps accept it for now put some miles on it se what happens.
Enjoy some riding

I have used XS 650 s that would not idle at all if i did not hold the gas handle
Again I am not telling anybody what they shall do with their bikes .No Sir . But I doubt it can get much better and that with a massive effort
that is typically a winter job if at all
Yeah it is set up well as far as jetting and everything else. It’s just not rideable at the moment, the air leak causes such a issue at bottom i can’t ride it without basically stalling it out. If i just sit and rev it i can get past it and rev it out but it’s to big of an issue. I’ll let you know once i switch the carb holder out if that fixes it
 
So i tried switching the carb holder on the left side with my old one. Still have same issue. I dont see any cracks anywhere on motor or carb. For some reason it won’t seal up to the motor or i have a leak somewhere in the same area i can’t see. Not really sure what to do. Thought about maybe using some rtv plus my gasket and try to seal it better but i feel like there must be a reason it won’t seal
 
Run a straight edge across the intake mating surface on the head. I've seen (I've had) cases where the threads have pulled out slightly.... preventing the carb adapter from seating on it.
 
So i checked the matting surface and it’s flat, looks perfect from what i can tell. Really searched for any cracks and can’t find one. I might have to put a straw on the spray so i can pinpoint the leak spot better. Just weird that it’s the same leak with two different carb holders. I’ll keep trying to figure it out. I might try the rtv plus gasket and see what it does
 
I might have to put a straw on the spray so i can pinpoint the.....
Yes. I watched your video and that was my first thought. I use CRC Electrical Contact Cleaner. It comes with the straw and the spray is very controllable. You can pinpoint down to a loose screw with it.
 
If you're going to use sealer, use Yamabond or an equivalent (MotoSeal 1), don't use RTV silicone. In fact, throw that shit out. It has no business being anywhere near your motorcycle, lol.
 
If you're going to use sealer, use Yamabond or an equivalent (MotoSeal 1), don't use RTV silicone. In fact, throw that shit out. It has no business being anywhere near your motorcycle, lol.
Ok tossed it 👍🏼. You do the Yamabond smeared both sides of the gasket lightly? Also how is that stuff for removal later. I was trying to avoid the seals cause of the pain in the ass clean up every time but at this point i need it to seal
 
Ok tossed it 👍🏼. You do the Yamabond smeared both sides of the gasket lightly? Also how is that stuff for removal later. I was trying to avoid the seals cause of the pain in the ass clean up every time but at this point i need it to seal
Just buy some new gaskets. Replace them when they no longer seal. Or make them. No sealant.
 
Just buy some new gaskets. Replace them when they no longer seal. Or make them. No sealant.
I have two new sets of the thick gaskets. I tried one set already and it was leaking still as shown in video. I did read a previous post somewhere else that 5twins talked about tightening the carb holders and letting them sit a day then going back and tightening again before installing carbs. I ordered some Yamabond I’ll apply to the one side (boot side). Hopefully this seals it finally
 
I prefer to use thin gaskets in this application. They distort less when tightened down so less chance of any air gaps.
 
But I think the factory used thick ones for a reason, to help insulate and isolate the manifolds and carbs from engine heat. I've always used the thick ones installed as shown (sealer on one side) and never had any leak issues. I do check the torque on the mounting bolts several times after initial install to compensate for gasket compression. There is a lot of that on these thick gaskets.
 
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