Getting my 20-year-not-started 1982 750 L2 working was going great... until the carb. It is the Keihin setup. The PO drained the float bowls prior to storage (i.e., throwing a tarp over it), but the carb has been more hassle than I thought. Two main issues:
- The T-junction of the fuel intake leaks. The original 0-rings were hard as nails, so I replaced with 5x2mm I had, however it still leaks. Assuming that it is the o-ring size, I've read on here that it needs 5.5x2mm, so that extra 0.5mm ID must make all the difference? Is 5.5x2mm correct? ID or OD for the measurement?
- When reassembly of the carbs together, it seems so hit and miss getting the choke butterflies to freely move when tight. Is that just the way of it - they are hit and miss; sometimes I carefully tighten up the 4x carbs to the brackets it is fine, sometimes it binds the choke. Any trick to it?
Once this is sorted then after new chain/sprockets (530 conversion ordered) it should be a runner....
5.5 x 2.0 is the correct size O-rings for both the Tee and the fuel transfer tubes.
Try moving the choke discs around with the screws just lightly snugged until they snap shut easily. Also, keep the main carb to joining bracket screws loose too. You gotta play with the position of everything and then slowly tighten the screws to make sure the chokes rods don't bind. It's fiddly at first then you will get the hang of it.
Just for the record for anyone searching for these o-rings like me.... I tried some 5x2mm that I had in a metric o-ring set, and they still leak. I then found a supplier who does 5.6x2.4mm but they are to big to fit without a LOT of force. So my search goes on for 5.5x2mm....
Ah, yes as soon as I wrote that I realized that I should have mentioned that I am in NZ!!
Special little items like this are just terrible to find here. With my XR650R every time I need a part the answer is "special item from Japan, wait 6 weeks".
The ORing Store has them all, just not keen on the $30+ delivery to NZ for about $1 of o-rings! I'll find them sooner or later down under - many of our special engineering companies will have them, but they don't have an online presence and are still in limp mode with COVID restrictions.
O-rings arrived from the USA, however the Tee is still leaking. I bought a new fuel hose and clamp just to make sure that it's not leading from the inlet of the T, but there is so much fuel coming out it is hard to tell if it is the o-rings or something else.
That is unfortunately beyond the workshop I have, but mainly the skill. Are there other common bikes using the carbs, or parts that I could use instead like the tee from the Mikuni carbs which has two o-rings on each side?
I can make one for you but it won't be cheaper than that.
For anyone stuck on the same problem - this eBay metal T link joiner did the trick. No difference to the naked eye, but no leaks.
The other tip I've found along the way is to only ever use a non-phillips head JIS (Japanese standard) screwdriver. The most accessible to buy are the motion pro JIS t-handle. Oh, and I realize that for most of you here this is not a tip but old news! But it took me a while to find it out so maybe handy for a another novice like myself.
Thanks again Nessism, your help has been invaluable on this and other threads.