Not sure why those have given you issues, the version used on the DOHC 450s are pretty foolproof compared to lots of other CV carbs and with no diaphragm to go bad like the 350/360 carbs. Once they get old and have been rebuilt a few times they can get wonky, perhaps that's the experiences you've had.
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Modern bikes are amazing, but they kinda suck
- Thread starter Shinyribs
- Start date
The no diaphragm part is nice, for sure. But man are they fussy. If you keep the air box/filter and exhaust bone stock they're perfect. Any deviation and they're a tuning nightmare. I can dial in a carb pretty easy but those things have completely thwarted me every time 😁
Do miss my battery-less bikes. Kick and go. Very relaxing.
Danno
Well-known member
That is why I like the atv tire bikes. Pull and go. No cdi and no battery.
Actually, the biggest thing to avoid with them is blocking the ports at the perimeter of the air cleaner side of the carb's bell, it directly affects how the slides work. I've run long round or oval K&N filters (not the cheesy short cone-shaped ones that all cafe guys seem to love for whatever reason) on them and they work fine, just far less restriction so of course the jetting has to account for it along with the change in exhaust if any. The only real challenge with them is slide needle adjustment, there isn't any provision so you have to improvise there. Mikunis or PWK Keihins are the better way to go for mods on an older twin. I have a pair of 36mm PWKs that I'll be using on my built 450 engine for the drag bike project, hopefully running this fall.
EricV
Well-known member
Yes, once upon a time I could afford that. Not now, and the XSR700 I ride was rather less than that, $8k when I bought it. I did the math and taking an older bike and bringing it up to the spec I wanted was more $$ than buying the new one with all LED, etc. I paid for it by selling another more expensive bike that was paid for by the usual method of hard work, OT and payments, plus some savings. I only wish I could afford some of the bikes people say nice things about. And you can find the used XSR900s for fairly reasonable money. Sure, perhaps not your budget, but I can't know these things.
The CB1100 is just a UJM, but that's the style you like. They have been out since 2010. There have got to be some deals on 13 year old bikes by now. I won't bother you with my opinions of Triumphs and their parts network, or lack thereof.
I've heard nothing but good things about PWK's.Actually, the biggest thing to avoid with them is blocking the ports at the perimeter of the air cleaner side of the carb's bell, it directly affects how the slides work. I've run long round or oval K&N filters (not the cheesy short cone-shaped ones that all cafe guys seem to love for whatever reason) on them and they work fine, just far less restriction so of course the jetting has to account for it along with the change in exhaust if any. The only real challenge with them is slide needle adjustment, there isn't any provision so you have to improvise there. Mikunis or PWK Keihins are the better way to go for mods on an older twin. I have a pair of 36mm PWKs that I'll be using on my built 450 engine for the drag bike project, hopefully running this fall.
I had a pretty hotrod twin cam CB750 once. 1983? Sitting on Hurricane 1000 forks, raised rear shock mounts, CBR F2 wheels/brakes and a braced frame. Clutch and transmission from a 900. Longer 900 rods with a spaced cylinder. Full Kibblewhite valve train with titanium everywhere it was available. Custom ground cams. Bored to 823cc and compression was raised to around 10.5:1. I had fits trying to get the stock carbs to work. Grabbed a rack of 900 carbs and didn't have any luck with those either. Finally fitted a rack of Mikuni's from an air cooled GSXR. I think from an 1100? They had rubber diaphragms and tuned in pretty easily and had fantastic throttle response. I might have just finally gotten lucky with the Mikuni's, but I felt like the aluminum pistons in the stock CV's were just heavy and slow to lift, so they couldn't respond like they needed to. I really can't say, though.
That bike was a hoot when it was happy, but man was it fussy. Hated being in town and would overheat and soft sieze. I thought the starter motor was going out on me 😂 It was something to power wheelie clicking in to third on an old air cooled CB that was eager to spin up past 10k rpm.
Those CB1100's you mentioned are beautiful. I've heard that with some really basic fiddling that they'd make really good power, too. Hell, they torquey stock. I think around 70ft lbs.
🤔 That could be a cool sidecar rig...
Danno
Well-known member
I think the modern ujm is the vstrom/sv line. Older bikes are affordable. Plenty of know how and parts. Enough power for most riders. But not nearly as smooth down low like the original 4 cylinder bikes. And a wonderful midrange sound. The last of the classic would be a nighthawk 750 or maybe a ninja 500. I like bikes with long production runs. The tw200 is a perfect example.
I handle servicing a buddy's '92 Nighthawk- I've been steadily de-ratting it over the last few years. Its a really nice ride- a fair bit of easygoing power, very pleasant. There is some general guidance around for fork oil level and needle shimming which really improve the bike. The biggest problem is all its owners have left it to live outside- my price of working on it is that he at least put it under a tarp.
Still waiting for him to bring it around for new sprockets and a chain...
Still waiting for him to bring it around for new sprockets and a chain...
A lot of what they call nakeds or hyper nakeds now is just a UJM to me.
Upright bars, no fairings and mid mounted foot controls. Naked sounds edgier though, for that street cred.
I've been tempted to look for a used CB1100, and I realize it's just a plain old UJM but the style and close enough to 100 hp would make it pretty enjoyable for me if I could find one affordable (seat/pegs relationship to be determined, haven't had an opportunity to sit on one yet). My wife bought my 900F for me a couple Christmases ago, I couldn't have afforded the cash outlay myself and she knew I wanted a bigger bike to replace the VF1100S I'd sold a year or so prior. The only reason I was looking at the Speed Triple was knowing the experience of a friend in Tampa who has many bikes and really loves his, and I've ridden with him while he was riding his as well so I know how well they run and handle since I was chasing him the whole time on my VF1100S. But in the end that doesn't matter since it's out of my reach.
I've lived a lifetime of budget constraints so I'm pretty much used to either waiting for what I want or letting go of the desire to have something I'd like but is out of reach. My father used to often say "when my ship comes in" I'll get this or that but his ship never came in, and I really don't expect any financial miracles either. I went to talk with a guy who has a home-based bike salvage operation yesterday about 35 miles from me because he needs someone to tear down and part out bikes, and I would have taken the opportunity (short-term to help him out until he finds someone permanent) to make some extra cash, but the working conditions are way too difficult for my old body so I won't be able to do it (entirely by myself as he's not there most of the time during the day, working off the floor with no lift, limited space in a small garage with only a fan in Florida now-summer heat, have to carry my own tools back and forth, and all non-running bikes parked all over his back yard and down a trail into the woods, many of which are behemoths like Harleys and Gold Wings for $60 to $100 a bike flat rate). Life goes on and I have to be content with the blessings I already have.
Danno
Well-known member
I suggest a new thread ...modern day ujm. The thread would be some vast bikes...Some how I see a goldwing and a tw in the mix.
EricV
Well-known member
You could limit the definition to EFI and multi-cylinder, that thins the herd a little. Better still, top out the buy in price at $3500 or so with an example required. That still covers a lot of ground. We're crazy around here, I'd get mildly excited over an updated CX/GL500 with EFI and a better charging system.
Don't think we can discount thumpers in the UJM category.
You can't get much more universal usage than an old dual sport 😁 Old XL500S was as happy at 3mph as it was at 70mph. With a 5 speed. Whatever Honda did right on that bike, I wish they could remember and tell the other guys. 270'ish lbs, 65+mpg at speed and cruise the interstate with ease. Why are modern dual sports 150 lbs heavier, less powerful and use more fuel? I don't get it.
Charging system was useless.
You can't get much more universal usage than an old dual sport 😁 Old XL500S was as happy at 3mph as it was at 70mph. With a 5 speed. Whatever Honda did right on that bike, I wish they could remember and tell the other guys. 270'ish lbs, 65+mpg at speed and cruise the interstate with ease. Why are modern dual sports 150 lbs heavier, less powerful and use more fuel? I don't get it.
Charging system was useless.
Make it a GL650 and now you're talking. A local riding buddy named Ray had a GL650 when we first moved to the area, I met him at the local Sunday bike hangout just south of me. He spent a lot of time doing simple mods and some more advanced stuff that didn't cost a lot of money, just effort (lightened the flywheel, ported and shaved the heads, flat slide Mikunis under "Flywheel" in this link) ran mid-12s at the drag strip (I was there) and regularly kicked my 450's ass. So EFI and a charging system to handle it would make that pushrod v-twin even stronger I'm sure.
See, there's a bike with more than decent suspension travel and it isn't jacked up like a modern sport bike.Don't think we can discount thumpers in the UJM category.
You can't get much more universal usage than an old dual sport 😁 Old XL500S was as happy at 3mph as it was at 70mph. With a 5 speed. Whatever Honda did right on that bike, I wish they could remember and tell the other guys. 270'ish lbs, 65+mpg at speed and cruise the interstate with ease. Why are modern dual sports 150 lbs heavier, less powerful and use more fuel? I don't get it.
Charging system was useless.
The CV carb relies on an airbox with a fairly specific filter restriction and volume to counteract the CV carb's slide weight and return spring tension in the way they intended. Take that volume away with pod filters or velocity stacks and the vacuum at the throat changes causing the slide to operate sluggishly and less predictably off idle. No amount of jetting will fully restore the low end response w/o serious mods to the carb. Ironically the CV equipped bikes almost always performed better with the airbox intact then with it off, you could mod the airboxes with some good results but yanking them off rarely improved much.
IMO CVs are great on a stock or lightly modded motors but I wouldn't trade my FI for it.
Yep, at VHT we tell people to leave their stock air filters in place, particularly on the SOHC 400/450 models which have more of an actual airbox than the earlier twins and more like the 4 cylinders. The only thing that seems to help them when someone goes custom with the airbox removed is to extend the hose connecting whatever aftermarket air filter they're using to provide more collective restriction and less chaotic flow. Honda knew what they were doing, unlike so many videos on the internet where they claim that certain things done 50 years ago are better done their way now, LOL. Those idiots know who they are (cough Common Motor), and they apparently don't know anything about Honda's massive success in GP racing back then or they'd have more respect for what Honda printed in their service manuals.
I raised that bike over 3" by the time I was done with it 😁See, there's a bike with more than decent suspension travel and it isn't jacked up like a modern sport bike.