Had an 80th birthday do today......(not mine you silly s*ds)...so I haven't got any further......... Just as an aside, when I fired it up the other day, the heat was building up in the shed as you would expect, even with the doors open..... I was in the middle of adjusting the balance and had just got off the floor, and had stepped away from the bike when suddenly a flow of white liquid p*ssed through a small hole in the high level shelf immediately above where I had been lying, and it was spattering on the floor right next to the bike...... ....a quick panic got the bike moved and an investigation on what was on the shelf revealed that a plastic container of SBR had sprung a leak......dunno why........but SBR to the uneducated out there is basically a very waterproof PVA.....once it has gone off, b*gger all will remove it. .......so a wet rag was rapidly applied to the side of a hot engine and polished belt covers.....Phew! Thankfully it wasn't one of the umpteen platic containers of white emulsion on the shlef as well......and thankfully it didn't happen overnight when the bike might have had fairings back on!!. Mind you it does turn a very lovely blue while it is in the process of drying.....and then it dries clear with a hard finish (lacquer alternative maybe? Nothing will stick to it either) AL.
Effing thing is still playing up......Today, it decided to start backfiring out of the exhaust instead of the airbox....in fact, not once did it spit back from the airbox.... .....so because I thought my exhaust note had been sounding funny (a sort of splashy blip from the end cans on tickover, which it didn't do before the problem started) I thought I would have another go at the pilot screws.....I had already turned them past the recommended Dynojet setting of 3.5 turns out to 4 turns out, but it seems it was better at 4.75 turns out......backfire doesn't seem to occur and the exhaust note now booms on tickover again. .....but now the effing overflows have decided to drip again...not constantly, I think....well, I can't tell while I'm riding it can I, but they are definitely wet when I stop. Now why should altering the pilot screws a bit cause the overflows to drip.......?? Stoopid b*****d bike.........I think I might whip it up to Carl Harrison in the very near future to see what he can identify. AL.
Bl**dy Hell, Chris - that was somewhat late. That was back in 2012 and I sold the bike two years ago. But, just to clear things up - both new float assemblies were faulty, so they wouldn't seal properly. AL
How incredibly frustrating... Interesting that Factory Pro were advocating 14mm. How did you discover this was wrong??
Ah.......wouldn't you like to know? Oh, of course you would - you just asked me...... OK..... When I was trying to find out what was causing the carburation problems, I looked at loads of information on these Mikuni BDST38 carbs; because I recalled having some issues with a Kawasaki engine that was doing similar things (it was the ZZR1100 engine in our outfit). I knew the float / fuel level would partly control the primary circuit, so if the level was wrong it would cause slow running issues and/or overflowing. If the fuel level is too low the pilot screw has to be turned out more and vice versa. I remember when I stripped the SS carbs the first time, that the float levels were 9.5mm and 12.5mm which were obviously less than the 14mm. Anyway I set them to 14mm - but that is not the actual fuel level until the carb is the right way up. So once I got some non-faulty float assemblies, I set the carbs in a vice at the right angle and I spotted a line on the outside of the float bowls which seemed first of all to be a casting fraze, but I wasn't sure. I eventually saw the same carbs are fitted to TDM Yamahas. I also found a diagram of how to check the fuel level on them. So I did the same with mine in the vice - a few times as it happens, because they were way out of the Yamaha spec. I reset the float heights at 13mm and then re-checked and the fuel level was higher but not enough - I couldn't be sure about the Yam check diagram, so I set the floats at 12.5mm and the level was more or less correct with the Yam diagram ---- and the line on the float bowl. I should really have set the floats at 12mm but as it was running OK at 3.5 - 4 turns out on the pilot screw; I couldn't be bothered to take the carbs off again. Diagram below....
So you set the level according to your own experimentation plus some clues from the TDM installation and a cast-in mark on a he outside of the bowls, wow, well done. And the effect??? BTW, I ended up with a TDM pilot screw in one of my Mikunis. One of mine was seized, so I managed to gently drill it out and went to see if I could order one from a local shop. I couldn’t but they had the s/h TDM one. Luckily, although it was pretty different, the different variations were all greater, so I was able to get it pretty damned close by sticking it in a drill chuck and ‘turning’ it down to size.
Sorry for the sarcasm - are you super sure there are pump jets on Mikuni BDST38 carbs as what were fitted too Ducati Supersports? You need to take a closer look old son, before you comment.
What I found out and what I did worked but I think I could have got it better - but the carbed SS really needs to be set up properly after a few runs on a Dyno or whatever the rolling road terms are today..... AL PS. Anyway, this thread expired between 2012 - 2016, so I am not reverting to it anymore. There is plenty on this forum which covers similar issues.
