CB350 Sly... Now with 2 finger braking!!!

Re: CB350 POS... with video to prove it

rockcitycafe said:
what's that godawful tapping noise?

that and it could very well be a fuel issue, check the idle circuit on the right carb, and check them for sync, on any 350 I do, I drill 2 6mm threaded holes into the intake passages so I can use a vacuum gauge, you may want to do that too. I had a bike that ran like that and it actually turned out that the right side carb fuel line was somewhat blocked, so it wouldn't fire at lower rpms, only at higher where there was enough vacuum to suck fuel from the bottom of the bowl
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godawful tapping is the left intake rocker... must have been bent or something and I can't get the gap nearly as small as it should be. it's on my winter to do list to swap it for another one. ya it's loud but the left cylinder is the one that still works flawlessly so it's not part of my current problem...

I've swapped the carbs from side to side and the problem remains on the right side which made me think it's not carbs?

I'll have a look at the fuel line tomorrow but it's clear line and there's no visible issue...
 
Re: CB350 POS... with video to prove it

It's one of three things, ignition, carbs or mechanical. I know that's stating the obvious, but I'd try a couple of things.

Sparks: Try a timing strobe on the right side and see if it's firing steadily or if it fires and then goes dark at low revs. If it's firing OK and at the right time at different engine speeds, it's probably not ignition. If timing is all over the map or it goes dark, then it's ignition on one channel.

Carbs: If you haven't already done so, swap them over left to right and see if the dead side changes sides. If not, it's not the carb

Mechanical: Kick is fine for testing. Did you just do that on both sides or are those the readings from earlier?
 
Re: CB350 POS... with video to prove it

teazer said:
Carbs: If you haven't already done so, swap them over left to right and see if the dead side changes sides. If not, it's not the carb
Click to expand...

that's a really good idea, I never thought of doing that but with the 350 you can, lucky you. also, try swapping the spark plug wires and swap the yellow and blue wires, on the 350 you can cross them over through the hole in the frame that the coils sit in
 
Re: CB350 POS... with video to prove it

p.s.s. you really want to swap that rocker sooner than later before it starts chipping the valve face and seat and spalling the valve stem
 
Re: CB350 POS... with video to prove it

I just read that you had swapped the carbs already. If the ignition tests out OK on both sides with a steady spark, I think I would pull the motor and lift the head and see why it's making all that noise.
 
Re: CB350 POS... with video to prove it

Did you try swapping plugs left to right?
 
Re: CB350 POS... with video to prove it

I got it starting and running pretty decently after a LONG fight, however there remains an underlying problem of some kind as the right carb is tuned completely differently from the left in order to make the thing work. once i got it running i decided to just ride it while there was still riding weather to be had. then when it's too cold to ride take the motor out and pull the top off and see what's really wrong (seems like it must be mechanical.. I've swapped the carbs and coils from side to side and the problem remains on the right so that kind of eliminates fuel and ignition issues). so i got a couple of good rides in and was about to head out again last night and two of the 4 welds on the exhaust have cracked open... fml! this bike does NOT want me to have a good time!

that said, thanks for all the suggestions and encouragement along the way everyone!
 
Re: CB350 Sly... endlessly failing...

It'll probably make perfect sense once you find out what it is too. When I have shit like that happen I dwell on it before bed and then dream of the answer. I wake out of bed in the middle of the night yelling "That's it!". lol. It's because the problem solving part of your brain stays awake during REM sleep.
 
Re: CB350 Sly... endlessly failing... but running!

well, after getting it half ass running again, i started riding the hell out of her and THEN the left header cracked at the weld... I'll have to do something more robust over the winter for next season... meantime i got it welded back up with a big bead of ugly...

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and now I'm back on the road again!!!!

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Re: CB350 Sly... endlessly failing... but running!!!

Wow, your pipe is taking on the ex-racer patina faster than I ever imagined!
Why not add 2 more slip joints and retaining springs in the headers where it cracked? A lot of the dirt trackers do this and it seems to work. Sleeve, weld and you're good to go. Takes care of any slight misalignment and also allows some differential growth of the various parts of the exhaust system due to thermal expansion when it heats up. I couldn't tell from the photo, but is the muffler rubber mounted so there's some play?
Outstanding bike! Nice Audi too!
Pat
 
Re: CB350 Sly... endlessly failing... but running!!!

Thanks Pat!
muffler WILL be rubber mounted tonight... that was a stupid oversight on my part... i was hoping the spring joints at the collector under the bike would do enough but apparently not. if i had rubber mounted the muffler the weld might have survived! i'm already thinking about how to do a v2.0 that won't have that problem, but i'll probably start from scratch. your suggestion is in the running for sure, thanks!
 
Re: CB350 Sly... endlessly failing... but running!!!

anyone following this thread knows i don't have a speedometer so i wondered how slow this thing was... enter the free iphone gps speedo app!

so 87 (141k) isn't the ton, but i didn't redline it before i ran out of road... don't think i'll get there but it'll be close! i'm still amazed that a motor rebuilt by an accountant runs at all!

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Re: CB350 Sly... Ton-less

hope the thing doesn't vibrate into peices. Honestly i would never take my 350 >70 it's not why i built it and i don't feel all that secure on the thing. Fun to ride in the 35-60 range though
 
Re: CB350 Sly... Ton-less

axeugene27 said:
hope the thing doesn't vibrate into peices. Honestly i would never take my 350 >70 it's not why i built it and i don't feel all that secure on the thing. Fun to ride in the 35-60 range though
Click to expand...
yay for nylock nuts and blue loctite! (and a torque wrench!) no sign of vibrating apart so far!
ya, i definitely didn't build it because i was interested in 'doing the ton' in spite of the fact that i'm on this site... but with no speedo on the bike i was curious...
that said, it felt suprisingly good at that speed. it's the brakes that are the weak link for sure... gonna try and do something about that this winter...
pretty sure if i want to crack the ton i can do it on my CBR1000RR with 160hp :)
 
Re: CB350 Sly... Ton-less

thearcticsea said:
Where'd you get the pipes? I need some for my 450.
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built them myself with some mandrel bends and a buddy with a welder...
here's something quite similar specifically for 450's...
http://omarsdtr.com/exclub.html
 
Re: CB350 Sly... Ton-less

axeugene27 said:
hope the thing doesn't vibrate into peices. Honestly i would never take my 350 >70 it's not why i built it and i don't feel all that secure on the thing. Fun to ride in the 35-60 range though
Click to expand...

You need more experience then, if your not feeling confident on it, something is wrong
They thrive on rpm, change down, open up ;D
 
Re: CB350 Sly... Ton-less

crazypj said:
You need more experience then, if your not feeling confident on it, something is wrong
They thrive on rpm, change down, open up ;D
Click to expand...

+1

My bike loves to bounce off the redline.
I know my 360 is a little different, but it's not worlds apart from the 350.
 
Re: CB350 Sly... Ton-less

perhaps after some newer tires upgraded brakes and suspension i will feel better about pushing it,but honestly id rather go 50 through the curves then 100 in a straight line
 
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