Is there a joint/clamp hidden by the pegs in the picture in post 336?
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Van Islander's TX650A - Quest for a Daily Rider
- Thread starter TX650A Van Islander
- Start date
Yes there is. I can take a better picture tomorrow.
I see you had the Athena gaskets on there, probably the Athena o-ring as well. That o-ring doesn't hold up so well. It deforms over time, turns from a round profile to a square one, and I can see yours did. The originals were red colored, probably silicone, and I've re-used originals to replace deformed and leaking Athena ones. According to this Vesrah gasket set listing, the size is 2.3mm x 45mm .....
I was thinking of trying some American sized o-rings here. 2.3mm is very close to 3/32" (2.38mm), and 1 3/4" is just a hair smaller than 45mm. So, some silicone 3/32" x 1 3/4" American sized o-rings might be the hot ticket here.
I was thinking of trying some American sized o-rings here. 2.3mm is very close to 3/32" (2.38mm), and 1 3/4" is just a hair smaller than 45mm. So, some silicone 3/32" x 1 3/4" American sized o-rings might be the hot ticket here.
Thanks very much 5T ! Will be calling around town today for those. Yes, indeed, they had become square, and hard. Only about 2000 miles and 3 years before failure.
I've got the o-rings sourced and today replaced the fork gaiters with the proper caps. I had been wanting to do that for a while. I disconnected the brake line and speedo cable and with the help of my son, dropped the forks and wheel/fender as one unit. That worked well and having another set of hands was critical.
Once the ignition is back together I'll adjust the cam chain and the valves and fire it up again for the first time since October.
Today was a great day for moving forward with the bike. I installed the breaker point/ignition housings, ignition, adjusted the cam chain, checked and adjusted the valves, replaced the brake fluid (having taken the front end off to replace the fork gaiters with dust caps) and installed the gas tank, seat, side covers. Some time with the timing light and top up the tire pressure and off for a test ride! The idle is still a bit high and I need to do a dead cylinder check of the air mixture screws but it came out ok. I sure like these "new" carbs.
Looks and sounds great…. Congratulations! 
This is what I put into the '76/'77 carbs:
Main jet is 125
Pilot jets - 25
Needle/clip - 4M1-3
I set the air mixture screws at 1.5 turns out from stop
It runs great. I only took it up to about 45 mph as I wasn't near the highway. It seems to have lots of power no issue, but
The engine is burping/backfiring/popping a bit on deceleration from speed when going back to an idle position. I turned the air mixture screws out another 1/4 turn. It might have gotten better but that could be my imagination. Ideas?
Main jet is 125
Pilot jets - 25
Needle/clip - 4M1-3
I set the air mixture screws at 1.5 turns out from stop
It runs great. I only took it up to about 45 mph as I wasn't near the highway. It seems to have lots of power no issue, but
The engine is burping/backfiring/popping a bit on deceleration from speed when going back to an idle position. I turned the air mixture screws out another 1/4 turn. It might have gotten better but that could be my imagination. Ideas?
I think you need to jet up more. What you have to realize is that the '76-'77 carb set came with the smallest mains (122.5) ever put in any 650 model. They're fine on an all stock machine but are quickly outpaced if you do any modding, and I see you have those Commando mufflers. So, I would recommend going bigger on the mains (127.5, maybe even 130) and if that doesn't fix the popping, you may need one up on the pilots as well. The larger mains may require leaning the needles a step because their bleed-over into the upper midrange will often make it too rich and cause stumbling under heavy throttle applications. If you do that then you will really need a larger pilot because leaning the needle also leans the upper part of the idle circuit. The 3 circuits in your carb overlap a bit, so changing one affects the one next to it .....
Thank you 5T. I really appreciate your expertise. I will look into my options to get them here.
Great stuff right there to file away for future use.
Are those stock head pipes with double wall or are they single wall replacements. If they are replacement single wall your exhaust is open up considerably. I had to go 132.5 main, 30 pilots and drop the needle (leaner) one notch to make my tracker run very nicely. If those are new head pipes, you may find they blue quickly with a lean mixture. Heed @5twins and go the rich side first if those pipes are new.
Just checked my notes. 132.5 mains; 27.5 pilot; needle Center position. Overall runs well. If I ride at low speed or idle too long I sometimes can foul (load) the plugs up. Through all the messing around I did with carbs and jets I’m pretty happy with it the way it is. A short higher speed run cleans up the plugs but now that we’re talking about it I may throw a new set in before springtime.
I learned the hard way, doing it wrong first...
When pilots are to small (in my limited experience) you need to open the butterflies (idle speed adjust) which causes the carb to draw on the needles and the pilots. In my experience ( limited to a sample of one) the idle speed is very touchy at this point. When the pilots are close to correct the idle speed seems to be very adjustable. My bike jetting was wildly off and I started playing mains when playing pilots would have been the "short-cut".
I could try that. Will look further into my notes to see if I’d already done that. Thx
I have stock double wall pipes. I'll check what jets I have in stock and order some others if necessary tomorrow. I was able to get some from a Yamaha dealer a few months ago for under $5.00 so hope that is still an option. Thanks for the feedback guys.
Bosco, you have the same carbs as me don't you? Think your bike is a '76?
Your bike sounds great! How’s your leg doing?
