Unofficial Royal Enfield Community Forum
General Discussion => Campfire Talk => Topic started by: j byrd on December 14, 2009, 02:01:59 am
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Hey, gang, anyone know if a carb for a 500 single like our Enfields would be big enough to put on my wifes 500 Honda CB 4 cyl. after I fab up a log type intake? I want to put a single carb in the middle of a log-type manifold and get rid of those "auto-clogs" that are on it now. We have had a few multis and they all have carb trouble if they set for any time at all. Don't need a lot of extra performance or anything, just something that will start and run reliably at gentle speeds. Come to think of it, I believe I hear my 6 cyl. CBX downstairs stopping up now- -that'll take a Holley to feed that thing! Thanks for any suggestions, and if anyone knows where to buy an intake like I'm talking about, that would be even better. ( for the 500 4 cyl.) J Byrd
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Instead of going through all that Bravo Sierra for a dubious solution, why not drain the carbs prior to storage - or store the bikes on heavily treated fuel? I use the Klotz Octane Booster to store a lot of my "long term" bikes on - using that for a fuel preservative and draining the carbs has worked well for me for years. ANYTHING you put on the bike, carb-wise, is just going to clog with the dismal goo that the oil companies call motor fuel. Why not preserve the bike and circumvent the work - AND the goo - by treating the fuel?
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Hi, Scooterbob, We have tried Sta-bil, 104 Octane booster, running it out of gas, wd-40 sprayed in the float bowls, etc. It seems like the 500 has such tiny passages that unless we leave it running constantly, it just won't stay free. Also, the taking off, apart, and back on is MAJOR surgery for me on this bike. I have not tried the product you suggest, and will look for it next trip to town, so I do appreciate that. Maybe it will help the other bikes. I am just so sick of the multi setups with their tiny-hard to access parts, just seems like one carb would be soooo nice. I don't have the trouble on my 2 cycle bikes, is it the oil mixture that keeps 'em starting? We have had the 500 since 1981, so this isn't necessarily a lousy gas problem, tho I do agree that todays goop should be ran up- -well, never mind, it is lousy tho'. I seen a couple of 750 Honda CB's with one carb on the end of a log back in my chopper days, they seemed to work, but I always wondered about lean/rich conditions with it on the end. Thanks so much, J Byrd
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I did a twin Del Orto set-up on a CB 750 chop in days gone by. Think I had 44 mm carbs on it. Was a real pain to get it right. Only reason I did it that way was it had no carbs/intake when I picked it up and had the Dels' laying around. Can be done but I had plenty of time and a bored mind ;D. Looked good and sounded cool but like Scooter Bob said lots of re-engineering the wheel to make it work.
Probably when I started using Marvel Mystery oil most of the problems went away on multi's. Had 2 CB350-4's I'd treat with it and no more problems. So the two-stroke theory might be what helped then and now. Ounce per gallon hasn't hurt anything so far (wouldn't suggest it on a fuelie engine however). Will.
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HMMMM, I guess I will pull the 4 little suckers off one more time, do a super-clean including ultrasonic, add some of the mentioned additives and give it one more chance. Then I may kill it and get her an Enfield also if it don't work. She loves her bike tho, I painted it Candy Magenta with flowers, Unicorns, castles, all the girly stuff years ago, so she thinks it's special. I do too, but in an entirely different way. I might try to get her to just hang it on the wall. Thanks fellows, a little encouragement sometimes helps, and the ideas sound logical, J Byrd PS, if you're not familiar with it, magenta is pink. Keeps me off of it!!
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If you're going to pull them off anyway you could leave them off for the winter and reinstall in the spring. Keep them in a warm/dry location and see if that helps. Couldn't hurt to try. Will.
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There used to be someone that made a 4 into 1 intake manifold for the old CB750 sigle overhead cam engines.
Jon
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Automobiles had single carbys on a multi cylinder engine since the beginning.
For storage purposes we are fond of 100/130 LL AvGas.
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Automobiles had single carbys on a multi cylinder engine since the beginning.
For storage purposes we are fond of 100/130 LL AvGas.
You cannot get any better than that - I use the stuff on my LONG term storage junque - two kicks and it's always going again. If the FAA says it's good for five years in a sealed wing tank - then it's good for FIFTY years on the ground as compared to the crappola that is called motor fuel THESE days ..... It will also soak off the crud of "new, modern, wonderful" motor fuel if you put your "dirties" in a sealed container of it. Be VERY careful of the stuff, tho .... it actually WILL burn - and vigorously at that .....
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I've found on the multi carb 4stroke outboards that are not used much or in long storage. Just run the carbs out of fuel. there is not enough fuel left in there to screw anything up. Maybe your not running them completely dry on the bike. Most of the carbs I see are Kiehn probably the same type on your bike. ERC
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I do a LOT of these kind of bikes. The project you are contemplating will suck more time and money than 10 years of carb cleaning. And the chances of it running well or reliably are slim. I have seen a couple of decent conversions on GL1000's and a Sonny Angel Moto Guzzi using automobile carbs. These involved a lot of engineering and fabrication.
I don't know were you live. A lot of times it is inconvenient or uncomfortable to ride in the winter, but not impossible. If you can get in a couple of 1/2 hour rides a month most of your issues will not occur. Other wise I would be more aggressive in your winterization program. Some good suggestions have been offered.
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Hey, Vince, I was kidding about putting a Holley on the CBX, but yesterday when I went down to ride each of the bikes like I do as often as I can, it poured gas out of the little tubes that run between each carb. That was a new one for me. I always run my small engines out of gas before putting them back up, they live in the basement and seems to be no smell mysteries that way. I agree there are good suggestions, am going to try the Marvel if I ever get the 500 CB cleaned out, and by the way, the trusty little Enfield did its usual thing, fired right up and ran great, as did the other bikes except the two Honda multi-cylinder ones. And I do like those, just get so tired of them constantly giving carb troubles- - but- - I'm not beat yet !! Back to work, John PS, I am in Alabama, so can usually ride short distances in all months.
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It sounds as if you have one or more float valves that are sticking or not shutting off. When it reaches this point the overflow often goes into the combustion chamber and washes down past the rings into the crank case. So check your oil for gas!
I would think your problems relate as much to moisture as to gasoline. Alabama was pretty humid the time I was there. Whenever there is a temperature change condensation will form on any metal part. The inside of the tank and carbs are particularly prone to this problem. If you do not have the luxury of a climate controlled garage you will have continuous problems. One way to address them is to put a 100 watt light bulb under the carbs and a cover over the bike. this will minimize condensation. Also, I have found that a customer's idea of clean often does not match mine. Every jet must be removed from the carb body and individually cleaned. You can't leave ANYTHING that is green or discolored. Use steel wool to scrape every trace of contaminant off the jet and carb body inside and out. At this point you also must replace the float valves. The 500cc probably has replaceable seats, but the seats for the rubber tip needles in the CBX must be polished. Saturate a Q-tip with a metal polish. Put the Q-tip in a drill motor and polish to a mirror finish. Thoroughly clean the seat before installing the new float needle. Remember to re-set the float lever if it is adjustable. Do NOT disassemble the carbs from the bank they are on. You don't want that headache. Trust me.
Proper cleaning of a typical 4 carb bank will run 3-4 hours including removal and replacement. Your CBX will take 4-5 hours.
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Vince, the floats are OK, it is the transfer tubes between each carb I was describing. The carbs had been rebuilt earlier this year at a dealer, they have been doing well, the only thing they didn't do was put the overflow tubes back on, which I did a couple of months ago. If the tubes are not transfer tubes, then I have two carbs which suddenly from last week to this week have cracked. Not likely. I have my basement the exact temp-ac and heat- as the rest of the house. The overflow tubes are NOT stopped up, and no gas comes out of them, it doesn't have time to even fill up the float before the carb to carb tubes start leaking. Runs great, tho', after I shut of the new petcock and runs till the bowls are empty.! Guess I will just ride round the house a occasionally till I decide to fool with this one, gotta get the brides 500CB working first. Thanks again for the tips/suggestions, life as a fellow with too many bikes is never easy, and when you start selling them, they tear up in self defense- -don't wanna' leave the basement. John
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I misunderstood. The transfer tubes you speak of sound like the the fuel line: the fuel line from the petcock goes to a junction, then the fuel flows between the carbs via passageways cast into the garbs and connected between carbs with these tubes. If these are leaking it is not an easy fix. The parts are probably not available. Hopefully they are not cracked. The tubes are sealed in each carb with o-rings. These can dry and crack with age. The fix is to dis-assemble each carb separately from the bank and pull the tubes out to replace the o-rings. Do all of them even if they are not now leaking. They are all the same age. You will probably have to match them up from open stock. There are tiny linkage pieces (including springs!!) that must be re-assembled just so for the carb bank to work. With age, corrosion, and factory lock-tite this is a tedious job. You will have to re-sync after the work.
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Good stuff...
Call me lazy, but when I worked for a month getting my KZ650 running I went through the same types of issues. After pulling the carbs for the 4th time to adjust the float on the or some such I realized why I love my RE so much....
On a side note I put a new petcock on the thing from Z1 and the rubber rotted inside of a month because of the ethanol in our gas.. They replaced it free o charge, but the gas eats everything.. Luckily I had put an in-line filter on the rig or those rotten bits would have screwed everything up. As it is I only found that the petcock went bad when I pulled the tank to balance the carbs.
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nothing wrong with stock carb set-up. i have 4-bs 32's on my gs and the re-build formula is probably far easier than a manifold set-up. first, see if you can get a complete o-ring set from www.cycleorings.com. The kit includes ALL o-rings you need: fuel tubes, vent lines, chokes, mix screw, etc. and they are very inexpensive, but of the material demanded by a carb. Airtight carbs will make a huge difference.
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Does your set-up have the vacuum fuel petcock. That one part on multi-Honda's (especially) always causes problems. Weak diaphragm and all kind of stuff goes wacko. Cracked vacuum hose can do the same thing. Will.
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Does your set-up have the vacuum fuel petcock.
good point! :-\
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Evening, folks, I'm enjoying all the replies, just don't get on very often sometimes. Neither of the bikes has a vacuum petcock, only one of those I've had is on my 500 Suzuki Titan. Accurate info on the "O" rings and vacuum leaks, had those problems before, thankfully learned that lesson already. As I mentioned in an earlier post, thank goodness for the single carb on the Enfield, as well as the Harley and old 250 trail bike. Never any trouble, but this is what you get with technology- -even if it is 70's tech. My Honda buddies hate it when the old paint shakers start and the multi's won't. Of course, I do too, but they have quit teasing me about my HD and that "funny old looking bike" as they call the Enfield. Oh, well, I love 'em all, so I'll get 'em fixed. Thanks again, supposed to be in the mid 50's here tomorrow, so let's ride a bit !! John
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Hey there, gang, I decided to soldier on with my single carb project for my wifes 500 Honda. This turned out to be an easy exercise and we are extremely pleased with the results. I bought an old chassis with the engine still in it, fab'd up a manifold out of square tube using the spare engine individual runners, a piece of scrap pipe, and a carb off a 500 Yamaha trail bike. So far I have nearly $90.00 in this project, and it does something none of our 4 cylinder bikes has ever done- - starts and runs instantly!!! It is much more responsive, especially at low speeds, pulls strong, idles smoothly. PLUS- -it has been fun for about 3 days. This bike had not ran since 1986, so she is a happy girl. Gona' try to send construction pictures, sure am pleased with the results. And yes, did put Marvel Mystery oil in, fresh 93 octane gas, checked all items I could think of. The small vacuum line to the outboard Left manifold runner made all the difference in the world- -neat carb. John
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Looks like a nice job to me.
I think it will be just fine, and it looks good too.
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Thanks Ace, this has been fun, the throttle cable even hooked up with no mods!! We are supposed to have two days of 60's temps, so she will be able to try it out for herself. I have not changed anything on the jetting or mixtures yet and am aware we may have to, but it fires instantly hot or cold, and doesn't surge, so we'll give it a couple of more trial days. Thanks for your response, means a lot, John
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That looks really good. I built one for an old 750 honda years ago and it ran great with a single carb, I think I used a bendix zenith carb from a Sportster on it.
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What size/model carb you end up with? Nice job on the fab.
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Thanks guys, I'm so satisfied now, that if we were keeping the 79 CBX we have, that I would try a side-draft weber or such on it to get rid of six carbs! Since I'm not keeping it tho', won't try that. 1Blackwolf1, the carb is a Mikuni 34 mm off a Yamaha single- -seems like it is an 85 model. Knew no history about it, it just looked clean, so I fastened it on. I knew one would be easier to take completely off and re-do than to even get the air box off the 4 carbs that were on it, so blind luck was with me on that one. Now my wife says tomorrow she's gona' blow the doors off my Enfield. I hate it when they're right. HA !!! Thanks again,John
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Time to make a bet with her winner buys dinner and drinks. ;) Then see who's faster.