Thunderchild

Just a thought before I pay out for a new carb joint. Could I test it to see if it is the problem by using some high temperature RTV sealant like gasket seal, to see if it improves the issue?

I have an XVS 125 (54 plate, 6.5k). I was out riding the other week and she started to lose power when doing 50mph. It only lasted for a second like the brake was on, and then continued as normal. This repeated a couple of times during the journey. I have replaced the oil and filter and put new plugs in to see if it helped. The old plugs looked like originals and appeared black at the ends, one was slightly wet on the thread. On the way to work, she did the same thing again when I got her in to 5th gear. It was an extreme downpour at the time and I initially thought this may have been contributing to the problem and the engine was not warmed properly. However, when I pulled out the car park after work, she died completely in first gear with a total loss of power. When I opened up the throttle, she would pull off, the power would drop and eventually she would cut out with the throttle fully open. I noticed that there was a point on the throttle before she lost power, so I had to hold that position and change gear quickly to let the speed build up. I eventually managed to get her into third and limped her home doing 15-20 mph. When she is in neutral and I apply the throttle, she revs normally, reaches a certain point and the power/revs die off. I can continue to open the throttle fully with no difference and she will just cut out. Now my first thought was she was losing compression and it could possibly be the rings. Having searched through the forum, I came across this thread: I have checked my carb manifold and it appears to have a small crack in it and a bulge just above left of the crack (see pic). It doesn't open up when I rev her in neutral, but could this be the problem or is it something else? Many thanks.