72 CB350 For the Daughter

Nice, can't wait to see the pretty bits all on her!

Harsh I really like your color choices for this bike, really different.

Harsh said:

Soldered the pipe and it didn't leak overnight so I am calling that a win.

Unfortunately, the fight continues.
I printed and cut out the tank logos, but when I went to apply them to the tank I had bits of white around the edges and it looked like crap. Printed two more sets and cut them out. While they weren't as bad as the first set they still looked like crap. I think I am going to have to call a buddy that owns a decal shop locally and see if he can print them on vinyl for me. They will be thicker which will leave a raised bump at the edges once they are clear coated over, but I really don't have much of a choice other than having them painted on. Which at this point, since the tank is already painted, might prove to be a bit difficult and would certainly cost me a chuck more money. I really need to get them on today so I can get the tank back to my painter because he is going out of town on Thursday.

Click to expand...

I bury vinyl decals under clear pretty often.. trick is to get enough clear on there to wet sand it back and polish it back up.
This black Triumph logo is a vinyl decal... no bump after cutting back and polishing.

Frustrating afternoon. I get everything together to set the timing. Fire up the bike and as expected the timing is off. I adjust the plate and get the left side adjusted in spec. The bike starts to idle a bit high so I adjust the idle screws a tiny bit to get it back down into the proper range. Go to check the right side and it is off the oposite direction as the left side. So that means the individual board(s) needs to be adjusted. Turn the bike off and loosen the screws. Fire it back up, but now the idle won't hold. It will stay at 1700, but if I adjust it ever so slightly to drop the idle it will get to 1000 hold there for a few seconds then drop and kill the engine unless I give it some throttle.

From here on out it doesn't matter what I do the idle or timing is off for both cylinders. Try and give it throttle and it bogs a bit and once I get it to 4000 or 5000 it won't hold and drops down and I can see a bit of smoke coming from the right exhaust. I also noticed the left exhaust isn't as hot as the right. I presume it is a carb issue, but what I don't know if it is an air leak or something within the carb.


And the icing on th cake...I messed up the front fender. I was looking for a bolt on one end of the work bench and I guess I bumped it enough that it caused the fender to fall off. It has to be repainted.

So two things I think I may have found.

First: Somehow the choke got moved during my adjustments from being completely open to closed. I am sure that had something to do with the issues with idling and not wanting to run well at higher RPM's. The only thing I can think of is that the lead from the battery to the timing gun grabbed it and moved it.

Second: I noticed that the plastic piece on the left carb on the throttle arm moves about 1/8" in and out. I think the felt washer that is supposed to be behind it is no longer there. That felt washer, when oiled, stops air from entering at the throttle arm causing a vacuum leak. I usually don't pull that arm out since it is a royal pain in the ass. So I guess the carbs will be coming off again and will be opened up a bit to check and see if the felt washer is in there.

Not my pic, but it shows how the plastic piece (yellowish piece) could move in and out if the felt washer isn't there or has deteriorated to the point of being virtually non existent like in this pic.

Noticed a slight oil leak yesterday from the left side engine cover. It has been on and off a few times when I was messing with the starter so it doesn't really surprise me. So it looks like I get to pull the cover off again to replace it. I guess when I get home today I will pull the carbs and start taking them apart to oil the felt washers and re-adjust everything to get them back to a good starting point for tuning.

Took the carbs apart to oil the felt washers. They were dry as a bone and soaked up a fair bit more gear oil than I thought they would. Carbs are back on, adjusted evenly, and synced.

I don't know what the hell is going on now. Start the bike wwith no choke and it instantly jumps a bit above 3500 rpm's. Back the throttle set screws completely off (not touching) and it only drops a tiny amount. Fuel mixture screws were set at 1.25 turns out. Turn them to 1, no change. Completely loosen the throttle cables at the carbs and throttle, no change. It will rev up if I give it some throttle.

Decided to check the timing, well just because. With the plate rotated to the full retraded position and both boards moved to the full retarded position the timing marks are still showing a good 5/8" advanced.

The only thing I did was pull the throttle shafts to oil the felt washers.

I really have no clue what else to do.

Did you possibly throw them out of sync?


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Oh they are out of sync now since I have completely loosened the throttle cables to make sure they weren't opening the throttle plates. However, as it sits the idle set screws are not touching which has the throttle plates completely closed. The only thing I can think of is a vacuum leak. I am going to take everything back off today and see if I notice anything.

What I don't get is the complete change in how the carbs behave. I would have thought that oiling the felt washers would have alleviated any vacuum leaks and allowed the bike to run a bit smoother.

symptoms sound like vacuum leak for sure, but I was wondering if they are CV carbs and if the shafts you pulled out to oil the washers can go in more than one way and are holding the butterflies open on you. If they are mechanical slides then that wouldn't be it. Tried to look at a parts fiche to see what those rods do, they are mechanical carbs but the pic was terrible. My guess is vacuum leak somewhere.

The shafts could go in more than one way, but then the idle set screws and attachment to the throttle cables would be on the wrong side of the carb body. I did one carb at a time so as not to accidentally swap parts between carbs.

The rods attach to the throttle cables. As the cables are pulled they open the butterfly valves.

ok could they be out a few degrees rotation causing the butterflies to not completely close? I had an issue on a set, looked like the butterflies were completely close but they were actually open slightly, was a bugger to figure out but what it ended up being was the PO had removed the butterflies and then re-installed them on the wrong side of the shaft. I had to look at pictures of carbs to figure it out. Caused the bike to never idle lower than 3K rpm no matter what I adjusted.

OK...I took everything apart tonight. Checked the butterfly plates and they look to be seating very well. Checked the cables to make sure they were seated in the plastic housing. Cleaned the mating surfaces of the carb and rubber parts. Put everything back together and gave it a go. Starts up and the idle is at 2700. I tweak on the idle set screws and get the idle down to 1100 and purring like a kitten.

Awesome, now to check the timing. Still off. Each cylinder is right at 20 degrees advanced. I don't know if the unit is bad or if there might be something off.

ok got the whatever was off fixed, that's good, I am guessing you are using electronic ignition? Depending on the model some use the mechanical advancer for advance and it may be stuck, if it uses it you can pull them and clean them to free up the weights to move out and in. If it has built in advance it could be faulty.

I am using a PAMCO electronic ignition. So no mechanical advancer. If I can't figure it out today or tomorrow I am going to give Pete a holler and see what he says about his unit.

OK, I've heard Pete has great customer service so reach out and ask for some help. He'll take back a unit, test it and if new and faulty he'll make it right from what I've heard, if used and warranty is done, he'll fix or replace for reasonable.

I have read good things about his customer service as well. I purchased it a while back when I bought a whole mess load of parts to have at the ready, but haven't actually tried to use it until a few weeks ago. I will provide him a link to my build thread so he can see when I actually used it for the first time.

I am just getting into a time crunch now. I have a trip planned to Deals Gap in a month and really want to take the bike with me.

Before I call Pete I need to verify if the unit is bad. I can swap the points back in and try and time the bike that way. I have the points and the mechanical advancer, but I don't have a set of condensers. OR I can pull the PAMCO out of the wife's bike and install it on this bike and see what happens.

I am not keen on pulling things off of a running bike, but it might be the easiest option in this case.

Yep, id put the known good unit as its not a lot of work to pull, test then you know 100% its the unit or something on the bike.