You all are likely aware of my trials and tribulations making my GS500 "just run". And my aversion to carburetors as a result. And how I have, through the necessity forged from adversity, become somewhat knowledgeable about how to make a motorcycle with CV carburetors run...

Well, you might recall I ride with my dad, it was his desire for a riding buddy that prompted me to buy a motorcycle to begin with and started this whole adventure. My dad still has a fondness for old motorcycles, those which were new when he was young. He's enjoyed the reliability of his Honda Shadow 750 and finds it to be a capable and comfortable bike, but he still had some desire for a "scrambler" as he puts it. He bought a 2011 or so TU250X that required some work to get it right, and he put a set of trials tires on it and now i's a "scrambler" and it's been his first choice to ride most of the time even though it's woefully underpowered for TX roads. We actually rode out to my parents' eventual retirement property some two hours from here into the hill country and he took the TUX and I took my GS500, which revealed the glaring weakness of the TUX. Max speed is about 65 but it can't maintain that speed if there's any incline, so the hill country and 9 miles of a 70mph highway each way was not any fun at all. That train of cars behind us as we ran that bike flat out up hills at 45 mph was not very nice.

So the plan was hatched to find a "Scrambler" that would handle gravel roads and also comfortably cruise at 70mph. And one that would be at least as reliable as his VT750. And this can't be like a KLR650 or even a DR350 because the seat height is just too tall on these dirt-oriented bikes. He needed something with size and ergos like his TU250X.

My dad is constantly cruising Craigslist in search of something that'll match with his current needs and former desires. He found a pretty well sorted '72 CL350 survivor on CL and we drove the hour away to pick it up. It's been a few weeks since he got it home and it's been a big exercise in buyer's remorse, I'm afraid. I suppose I should have talked him out of it.

First was a rash of cosmetic and quasi-functional stuff. The guy who sold it to him built it up to sell. He does this a lot, buys incomplete or project motorcycles and then adds a dash of this and that to make a complete bike and flips them. He's a retired guy who basically does this as a hobby. In this case, he kind of styled this like a hipster-themed Scrambler with real loud pipes (cheap Emgo looks like), tiny gauges (original speedo was long gone), Shinko 244s and a flat tracker handlebar plus one of these universal "cafe" type hard as a brick seats. But the bike seemed to be mechanically solid, had been upgraded to a CB450 front end complete with disc brake, ran fine and my dad brought it home.

The first order of business was turn signals, which were totally missing from the bike. Turns out I had a set that were perfect, chrome bullet type but too small for my Bonneville but just right for this bike, so I donated them to the cause. He also switched the handlebar for an alloy ATV handlebar I previously had on my Triumph. He did a "shake down" ride and the throttle cable got stuck due to a missing lock nut inside the throttle assembly, making it idle at >2K rpm. So he fixed that by putting a zip tie in place of the lock nut. Next problem was the gauges, which aside from the speedo being in kph, it was also too small for my dad to read without reading glasses which basically defeats the purpose. And he finds no need for a tachometer anyway and hoped to just chunk it. Turns out the bike has a custom (that is, made by the PO) wiring harness with none of the wiring in it for turn signals, so I'll be running wires and putting a turn signal relay on it any time now.

The PO had the bike parked on the center stand when we got there to check it out. He said he parked it that way most of the time because on the side stand, with the petcock left on (manual only), it tended to let the left carb get too full and flood, but on the center stand it was not so bad. Well, during a series of "shake down" rides, my dad discovered that the left carb leaks all the time, running or parked, leaking fuel right near the exhaust, which is a certified bad thing. So now I'm on deck not only to add turn signals to this thing, but also to figure out what's wrong with 50 year old carburetors. My guess is there's a hole in the (brass) floats, or the float needle valve is just completely not installed correctly so the fuel never shuts off.

He was supposed to come by my house yesterday and we were going to pull the carb off and let me take a look. But when he went out to fire up the old CL, one of the (non-original ... probably from TEC bike parts...) rear shocks had separated the shaft from the end, and he didn't have a spring compressor to put it back together. So now the plan is to pull the carb and bring it over to me maybe this afternoon, and he's going to cobble together a spring compressor from hardware store parts and try to put the shock back togeher.

So he's ridden it like 20 miles and spent a ton of time tinkering with it. He bought it being convinced that these 50 year old Hondas were legendary for reliability and were also very simple to work on and maintain. I contend that his 2011 TUX is a lot more simple to work on and maintain because you just have to start it, ride it, and change the oil every now and then, and that's 100% of the work you have to do on it. There's nothing simple about a motorcycle with two CV carburetors that are half a century old along with points ignition and who knows what modifications that have been done in its extremely long lifetime.

Given that it was in Killeen before and now it's in Austin (a rich market for instagram-worthy selfie bikes like this), I think he could put the turn signals on it and sort out that carburetor and sell it for more than he paid for it. Then maybe he'll give up on his desire for a do it all bike and just sell the Shadow and his DR200 which he doesn't really want anymore, put all that money together and buy a Royal Enfield 650. Fuel injection, ABS, a warranty, and the cosmetic impression of a 70s motorcycle. We'll see. But either way, I have a far more needy old Japanese twin to work on for the next few weekends.

"buys incomplete or project motorcycles and then adds a dash of this and that to make a complete bike and flips them"  =my dream retirement

"Hondas were legendary for reliability and were also very simple to work on and maintain" 

I agree, he should dump that turd to somebody with more money and keep looking!  Great read btw,..always enjoy your commentary!

Quote from: cbrfxr67 on May 24, 2021, 01:48:38 PM
I agree, he should dump that turd to somebody with more money and keep looking!

It's not about money. It's about his tolerance for fiddling with a motorcycle vs. his desire to just ride it. He wants the kind of forget about it reliability of his TU250X but with twice the power and the air of authenticity of an actual motorcycle from yesteryear.

Power to weight ratio:

'73 CL350: 33 hp/346 lbs (dry) = 0.095
'11 TU250X: 24 hp/326 lbs (wet) = 0.074

Assuming we trust the '73 power and weight figures (I don't) you are looking at a ~20% power to weight ratio improvement IF you're dad can get the CL to run as good as it did in '73.

Once you factor in the true curb weight and power loss to time/wear/poor tuning, I doubt that CL will ever outrun the TU. The juice isn't worth the squeeze.
Seems like you know this was a bad idea, why didn't you talk your dad out if buying that bike?

Well, I couldn't really come up with a reason why he shouldn't buy it.

I think the CL350 is likely making pretty much as much power as it did new in '72, maybe more, since it has free flowing exhaust and pod filters. My dad says it is a lot faster than the TUX. My guess is it has 50% more power than the TUX, maybe 20% more weight, but both bikes are also pushing my dad's weight.

I think 50% more power is meaningful. But yeah, I am beginning to regret not talking him out of buying it.

CV carbs in 1972? I thought that CV's came later than that.... Well, I just deleted 3/4 of my post, 'cause they were indeed CV's with neoprene diaphragms!


If the bike is running ok it's probably just a matter of a gasket, or the needle/seat valve...(first part I ever replaced on a motorcycle) they wear out and are easy to replace.

It's too bad that the exhaust was replaced, those old scrambler high exhausts are gorgeous.

he probably will bring it over today for me to look at if the rain holds off long enough. I agree it's most likely float needles and seats.

It has the original headers but has what look like emgo mufflers. They're loud.

FYI -- update

We did rebuild the carbs on this bike a few weeks ago. I gave it a test ride and it ran just fine. Hard to really know for sure though because I didn't ride it very fast, just up to maybe 35mph in the neighborhood. But it'll probably wheelie if you really want to.

My dad says on a long ride if you get to mid-rpm, light throttle steady cruise it kind of runs bad, surges or does other odd things. He's thinking it's the points ignition out of adjustment. That's over my head. Before my time. I even switched my 240Z to electronic ignition back in the day.

Well, it's just about time to wrap up this adventure, replace it with a much better adventure.

Catching up whoever was following this: over the past 10 months, my dad has tried real hard to make this old Honda work. He eventually had to replace the coils, which have the plug wires attached from the factory, and replaced the points, which was really difficult to get dialed in apparently. He adjusted the valves. He installed these turn signals that mount in the bar ends. I did a whole lot of wiring work with him because it wasn't wired for turn signals at all, and the wiring was a rat's nest anyway. Took a whole lot of work just to get the basic stuff to actually work: headlight, taillight, brake light, etc. Brake light is still intermittent, even with a new rear brake light switch, just because the 50 year old dodgy wiring. He also bought real vintage gauges for it, and it is basically sorted, as much as it will get. It's Real Loud. And that's the main problem, my dad hates the noise and tried to fab up his own dB killers for the essentially open exhaust, which seems to have constricted the exhaust enough to really screw up the carb tuning.

All in all, in nearly a year, I bet he hasn't put 100 miles on this thing. As much as he says he likes it when it's working, he just actually hates it overall. And it's really made him love his TUX!

So. Weekend before last he found a 2012 Triumph Bonneville SE that's pretty much exactly like mine, even the same color, for sale for $2500 under market. Only 6k miles. Previous owner reported some running issue that he didn't have patience to sort out. The PO was not his own mechanic, so this issue was something that would have required him to put it in the shop to get it sorted and he just wasn't using it enough, so he says, to justify the cost. Reading the dates and the title, this owner had the thing for 6 years and put under 1k miles on it, so I don't doubt he didn't use it much. It has some no-longer-available high end 2-2 exhaust on it, which is seriously loud, and had a K&N air filter along with minor airbox mods. And we both test-rode it, me having logged >10k miles on my own nearly identical Triumph, and I concluded that it ran rough and was way down on power from what it should be, but that it should be an easy fix. After chatting with the PO while my dad was test-riding, I kind of got the sense of the story that got the bike to the condition it was in. Cosmetically it is basically showroom mint. Almost absolutely perfect. But there was definitely a mechanical issue.

So anyway, he bought it, and we loaded it up and drove it home on my little trailer an hour or so. Then we got it off and got down to trying to sort out, real quick, if there was something obvious causing the issues. It wasn't just one thing, though. It was like a dozen little bitty things, all of which add up to just an owner who didn't really know what he was doing, and a mechanic who also didn't really know these bikes well, making fairly obvious mistakes along the way. The result was a bike that basically would not idle, and if you let it run more than a few minutes, it would eventually miss and bog badly enough that it might even stall while rolling down the road. This is an EFI bike! Should not run this way, ever.

One of the intake boots was completely loose from the throttle body, and I really had hoped this was the core problem. But it wasn't. So I went back over a couple of times over the last week and found one little issue after another. I flashed the correct map using TuneECU and my phone, or at least a good guess. Checked all of the sensor inputs on TuneECU, made sure the TBs were balanced, all the sensors were giving good readings, etc. Found a bunch of other issues. Ended up replacing the K&N air filter with a regular paper filter, putting the snorkel cover back on the airbox (leftover from my bike), replacing the leaking and cracked little rubber hoses that connect the MAP sensor tubes to the sensors on both sides and clearing the MAP ports with TB cleaner, since my theory was that oil from the K&N filter had made its way up to clog up the MAP ports (there was a lot of oil from the filter in the airbox...). We retorqued the exhaust header bolts and removed the air injection and oxygen sensors. And in the process, last night, found what I think is the last of the issues, the bike was running right as far as I can tell at least on the side stand. But the battery is shot so you really can't go ride it much until he gets a new one because it is likely to leave you stranded if you shut it off or if it stalls while shaking it out, since it basically won't hold enough charge to start the bike more than 2-3 times total until you put it back on the battery tender overnight.

So anyway, the old CL350 is about to head back where it belongs, on Craigslist, teed up for the next brown-seat-loving hipster to pose with for Instagram selfies showing off Roland Sands apparel and rolled-up skinny jeans. I think my dad got this old-bike nostalgia out of his system once and for all. And frankly, if he pulls the DIY dB killers out, it will run fine and some hipster will be able to use it daily to run down to Starbucks or whatever polished-concrete-floor "gastropub" is within 5 miles of home with a bunch of IPAs on tap. If you don't mind the noise, it actually works as well as any 50 year old motorcycle.

The irony is, my dad's "new" Triumph is probably louder than the uncorked CL. It's a whole lot louder than my own Bonneville, which is pretty loud. But I know off the shelf dB killers will quiet the Bonneville with little fanfare. My gut tells me the ECU map I put on it is probably a touch lean for this setup anyway, and if I'm going to have to re-tune, might as well do it with the exhaust sounding like he wants it to. But the main thing is, if I'm going to do mobile motorcycle mechanic service for my dad, at least it's going to be for a motorcycle that I am extremely familiar with, and in fact I have lots of spare parts for it in my garage.

It's even the same color! I guess we'll be twins riding around.

Too bad about the vintage, but I'm glad you guys figured out something that is reliable and will satisfy.

Thats a lot of work and a whole new bike to avoid having to go down a size or two on the jets for the CL350! Whatevs, as long as your dad ends up on a bike he likes its all worthwhile!

It has nothing to do with the jets on the CL350. Sheesh.

But anyway, we're sorting out the new bike. At least it has a good light at the end of the tunnel.

Quote from: mr72 on March 29, 2022, 04:31:54 AM
And that's the main problem, my dad hates the noise and tried to fab up his own dB killers for the essentially open exhaust, which seems to have constricted the exhaust enough to really screw up the carb tuning.

Isn't it the jets though? How else would you account for putting on a leaner running exhaust? When we put more open exhausts we increase the jet size to get the air fuel ratio correct again. Wouldn't it be the opposite for a more restrictive exhaust?
Have you tried going -1 or -2 on the jets with a quieter exhaust to see if it improves the screwed up carb tuning? I'm just saying it sounds like you put in a lot of work and nearly had the bike where he wanted it only to abandon everything at the last minute.

The problem is not really jetting, it's ridiculously loud exhaust an my dad has no more will to spend money trying to fix it. We couldn't find any commercial db killers to fit the exhaust, and really what it needs is reproduction silencers. It's fitted with stock jet size.

The real issue seems to be when cruising on a longish ride, it reportedly surges and hunts, which I guess drives my dad nuts. I have no idea if that's normal for a 50 year old motorcycle but something tells me running perfectly is not really possible. My far newer and more sorted GS 500 isn't much better. My dad compares it to his TUX, which is fuel injected, not a fair fight.

He seemed to be of the nostalgic belief that old motorcycles were simple and reliable and today's bikes are complicated and fragile. Now he realizes that when he last remembered these old bikes, they were new. But now they're old, and simple or not, everything is worn out and replacement parts are rare and not made the way they were. He thinks it's because China, I think it's because there's no demand for precision manufactured points ignition and vintage Keihin carb parts. Just getting it from the trailer to the show floor or down the parade route is enough. Riding a half century old motorcycle on 100+ mile recreational rides regularly is for the die hard hobbyist mechanic.

Quote from: mr72 on April 01, 2022, 04:46:41 AM
Riding a half century old motorcycle on 100+ mile recreational rides regularly is for the die hard hobbyist mechanic.

That's a good way to think of it I guess. It was probably crazy to "daily" a 1970s motorcycle even in the 70s. I recall in Ted Simon's book "Jupiter's Travels" that he packed one pannier with just spare parts, including extra cylinders and rings. That's insane by today's standards but at least he could find the parts. With the parts availability of today you would have to be a masochist to frequently ride a bike from that era.

I recently brought back to life a 1980 GS1000 and a 1984 XL600R. Both of these bikes now purr like the day they came out of the showroom and are just as nice as my 2006 GS500, but I think there is a huge difference between 1980s technology with electronic ignition and 1970s technology with mechanical points. Slightly better parts availability too for 80's machines but still not great for any parts that weren't shared between many bikes.

I don't think I would have the patience either for a motorcycle from '72. Although once you do get such an old machine running you should know it so well that it almost becomes part of your own body. You can diagnose every little hiccup because you have been through the entire bike 3 or 4 times.

Quote from: Bluesmudge on April 01, 2022, 09:02:36 AM
That's a good way to think of it I guess. It was probably crazy to "daily" a 1970s motorcycle even in the 70s. I recall in Ted Simon's book "Jupiter's Travels" that he packed one pannier with just spare parts, including extra cylinders and rings. That's insane by today's standards but at least he could find the parts.

My dad has stories about when I was little and he and his friends riding motorcycles around the small town in Arkansas where I'm from. He admits he used to have to carry a spark plug wrench with him all the time and routinely had to pull the plug and clean because it was oil fouled and wouldn't start on his '74 TY250 that was bought brand new. He had friends with these "big" street bikes like his Honda, and he has fond memories but they were out of his reach then so he doesn't have direct ownership experience. Truth be told, between 1970 and maybe 1976 he owned three motorcycles, the last he bought new: a Honda 90 of some kind, some Kawasaki 350 enduro 2-stroke, and the Yamaha. I doubt he put more than 3,000 miles on all of them combined in that time, and he worked on them all, A LOT.

It's been hard enough for us to resurrect this new Bonneville he got from 6 years of barely any use, now cleaning the tank, replacing fuel filters, etc. That old Honda he has probably has over 20K on it in 50 years, and is reasonably at the end of what was its original expected usable life. I mean, today my 7 year old Jeep is essentially in like-new condition with 60K miles on it but in 1972 60K miles was approaching the end of the lifetime of a vehicle. A decade later Japanese cars were the first that could somehow be driven over 100K miles, but it wasn't even until the mid 80s that they began putting that 6th digit on the odometers. This is just a whole new era.

My newest vehicle is my 2014 scooter. It only has 400 miles on it. It's cranky to start if it's been sitting more than a day, but at least it has one hydraulic disc brake and electric start and an ECU with actual ignition and mixture control to the extent possible with a carburetor. That's the technology and features of mid-80s economy cars, only 30 years later visiting economy motorbikes. That old Honda of my dads was not only a relic of a bygone time in terms of manufacturing technology and motorcycle refinement, and not only old, but it was also an economical vehicle back then anyway. It's not like Honda was setting the world afire with their precision refinement and legendary reliability in 1972 as they are today. They were just emerging from their entire country's wholesale economic rebuilding. Nobody in 1972 would have even thought 50 years later a Honda CL350 would still be on the road at all.

That would be a quasi cool bike to tinker with and one you'd celebrate being able to take it on a brief ride to show off that you got it running for that special occasion. The adventure is in actually getting to where you are going on it. And if you restore it and show it, people will marvel that you actually found or fabricated all of those old parts.

Speaking of which, the Handbuilt Motorcycle Show is next weekend here in Austin. I am going to recommend my dad haul the old Honda down there with a for sale sign on it, maybe someone in the parking lot will take an interest.

I loved my TU250X. Would have perfect with twice the cylinders and displacement. Did not stop me for doing a 5k kms trip.

Love that color. I totally agree, underrated great little bikes. To me, the TUX feels like a 7/8 scale Bonneville. With 1/4 the power and 150 lb less weight.

I've often wondered if a GS500 engine could be crammed in there. Actually, the DR350 engine with the TUX's EFI would be nearly perfect for that bike. But I'm guessing the old 350 couldn't be made to comply with emissions laws. A 400cc twin version of it with 40 hp would be perfect.

It's a great little bike if you are 5'8" or less and don't really need >60mph often. I ride my 125cc !Vespa all the time, so I can totally relate to the no-fast ways.

Last weekend we finally fixed the last of the little issues with my dad's Triumph. Turns out I likely created an issue in the process of fixing the others. The bike had three or four little things wrong, which all added up to it being sort of unusable. So we fixed all of those little things that were wrong, and in the process I flashed a new map into the ECU, guessing what should match the state of mods the bike was in. When it was all together, it ran just as bad as day 1. I flashed the same map back on it that it had originally and then it fired up and ran pretty much great.

My dad also was tinkering with the CL350 and he says he's got it running pretty much right. He thinks it's good to go. And go, it will. He's concluded he's going to sell it, as well as his '06 Shadow.

HMU if anyone in CenTX wants a pretty well sorted CL350 on the cheap (ish). Or a really dependable and fine running Shadow 750.

Bringing this slightly on topic for this forum, my dad is keeping the TU250X, likely forever. He's done with carburetors and the CL350 adventure made it clear just how much he actually likes the Suzuki. Considering he got it for $600, that was an even more impressive deal than the Bonnie!

"really dependable and fine running Shadow 750",........?