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Not convinced it’s running right…
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Re: Not convinced it’s running right…
So here’s what I’m thinking. Please keep in mind this is the first time I have EVER worked on an airhead. I’m used to flat fours, inline fours, etc with Mikuni carbs. The boxer and the Dellortos are French to me. But I’m thinking that I want to pull off the air intakes from the back of the carbs and glance in there and look at the accelerator pumps to make sure they are working.
Then I want to check valve clearance and timing. I’m assuming there is a bolt or nut or something on the front of the engine to turn it over with? Clockwise or counterclockwise clockwise? Timing light hooked to left cylinder or right cylinder? Points set to .016?
Thanks for any and all help you can give. Everything on this bike is foreign to me at this point. I’m learning, but I’ve got a long way to go. And I can tell you that the way it’s running now ain’t gonna work! I couldn’t even make it up the moderately steep hill at the end of my road. Had to stop and turn around. Now THAT is sad.
Thanks again!
Chris
- schrader7032
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Re: Not convinced it’s running right…
Timing light: can be hooked to either plug wire...both cylinders fire at the same time. You should see only one S mark. If you see double images, it could indicate a timing differential with the cylinders reaching their firing point at a slightly different time. If the distance between the two images is less than 0.25", it's OK. More than that, might take some "adjustments".
Points gap: nominally 0.016" is used, but the gap can be a wide range and still run OK. Set it at 0.016" and see where you are. Ideally, you would then adjust the entire ignition backing plate to bring the timing into the window. But if you turn the plate and it runs out of travel, don't hog out the holes in the plate, just go back and tweak the gap. A small gap change can make a big difference in timing.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- srankin
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Re: Not convinced it’s running right…
While he is not covering a R90S, some of the videos and information will cross over for your bike and may prove useful to you in learning the ins and outs of the bike.
Boxer2Valve is selling downloadable videos for a R90/6, again, it is not exactly the same as your bike but the basics are the same. https://www.boxer2valve.com/service-vid ... rials.html. I have not viewed any of this video series but have watched others and they are also well done.
Both sites beat the heck out of how I learned to do stuff on my bikes, Chilton's, Hayes, and factory manuals were the thing. The internet has opened new doors for learning, sometimes LOL, depends on the teacher. These guys are good. St.
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Re: Not convinced it’s running right…
I went back out to the garage and pulled the left intake tube off. I wanted to look in there and see what was going on with the accelerator pumps. I twisted the throttle and NOTHING happened. The right hand slide went up, but the left slide just sat there looking stupid. It had come off of the cable. That explains why the temperatures were the same at idle. Both cylinders were idling just fine. Anything over idle and the left cylinder wasn’t pulling his share of the load.
Anyway, fixed that problem and it’s like having a whole different engine! What a sweetheart! I haven’t ridden it yet because I still want to check the valves and the timing first, but I can tell you that I’ve found the problem!
With that being said, I’m still not happy when I open the throttle any faster than a snail. It bogs. I remember reading somewhere, possibly on here, and possibly on Snowbums site, (That man is incredible!) that when you reassemble these carbs you must be very careful how you put the pumps back in and you have to prime them or they won’t work. That’s something I have to check out also. Has anybody heard of this? And by ANYBODY, I mean either of you.
Thanks again, and I’m going to go back and reread your last responses.
Chris
- srankin
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Re: Not convinced it’s running right…
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Re: Not convinced it’s running right…
The bike was bogging pretty bad! Enough that I KNEW there was a serious problem that I had to figure out. So, this time I pulled the intake tube off of the right side, saw nothing causing a problem, so I pulled the slide out of the right carburetor. Sure enough, the clip holding the needle in position wasn’t holding the needle in position, so it was just floating around in there doing whatever it wanted. Ive ordered new clips for both sides as these seem kind of weak after 48 years. For now it’s holding the needle just fine, so I’ll be okay for a week or so waiting for the clips.
Took the bike out for the first time, other than up my short road and back, and went for a 17 mile ride. I wanted to at least try it as it’s supposed to rain for the next three days and I knew I wouldn’t get a chance. The bike ran like a TOP. Everything worked pretty much flawlessly, with the exception of the speedometer needle. It was flopping around all over the place! It would go from 30 to 120 and everything in between. I’m going to pull the speedometer cable off and check it. Hopefully it’s just that and it will be an easy fix. If not, we will do whatever we gotta do to get it working better than that. My GoldWing speedo is off by about 10 MPH, but it’s steady and it’s rather consistent, so I can deal with that. This thing is all over the place!
Oh, and the timing was also off. When I hooked my light to it, before making any adjustments at all, it was sparking just before the OT mark on the flywheel. I set it back to spark at the S mark, and everything seems fine now.
Today is valve adjustment day, rocker arm end play adjustment day, speedometer cable checking day, and oil leak finding day. I think my push rod tubes are weeping. Is this a relatively easy fix or do the heads have to come off? I haven’t checked into that yet.
Once again, I thank you guys for your guidance in getting this thing roadworthy. I see a lot of good riding ahead of me with this bike. It won’t replace my R1200RT, but it will certainly be an entertaining alternative.
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Re: Not convinced it’s running right…
- srankin
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Re: Not convinced it’s running right…
Unfortunately to change the push rod seals, the rocker arms do have to come off, however, you do not have to mess with taking the heads or jugs off, they will slide on the four bolts far enough the rings are not disturbed, the head gasket is not disturbed. There is just enough to wiggle new seals in.
LOL, you don't even have to take the carbs off the cables, just unhook them from the head and let them dangle, no, seriously get a strap to hold them out of the way while you work.
Good luck, St.
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Re: Not convinced it’s running right…
The speedo cable is weird. I pulled it loose at the transmission and hooked the cable up to my cordless drill. (In reverse) The speedo seemed to work just fine. It went up to around 10-12 MPH on low speed, and around 68 or so on high speed, and just sat there as pretty as you please. That tells me that the cable AND the speedometer are working fine. Once again, this is gonna take some trouble shooting.
I did get the valves adjusted today, and the rocker arm free play, and retorqued the heads, so if it ever stops raining, my butt is headed up into the mountains for a GOOD shakedown cruise. I will let you guys know how it goes.
- srankin
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Re: Not convinced it’s running right…
You can get a decent cable from EME for about $50, so second, I would replace the cable. If that fails, the problem will be in the speedometer itself. LOL, if you get a new cable, you will have one more new part, if the old cable is still good, keep it for a spare or reuse it later. St.