Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Fairview on March 14, 2012, 08:59:54 PM
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Hi, I have recently acquired a CB550 k1 as a rolling (light) renovation project. Initial impressions of the bike have been good but I hoped to benefit from the combined wisdom of forum members regarding a couple of pressing issues, I'm not hugely mechanically knowledgeable.
The first is a running problem which I think is a misfire noticeable from about 3000 revs up. Having just returned from a 120 mile round trip the problem was most noticeable on the motorway where max possible speed was about 60mph (speedo wavering between 40 and 80mph), engine sounded lumpy especially up-hill where lack of power was very noticeable, you know things aren't going well when you re overtaken by a string of artics. Fuel consumption was poor (30 odd mpg). At low revs performance isn't noticeably effected and she can be coxed up to red line without too much trouble in low gears. Starting is always great, single kick hot or cold, tick over isn't bad but engine has to be fully warm for it to settle. I'm not sure if it's relevent but it only needs choke for a few seconds when cold, and on inspection this evening the plugs are a little sooty. I put some premium unleaded in it and for a while it seemed to run a bit better but soon went back to it's bad ways. I know it could be a hundred things but if anyone has got any suggestions of where I should start I'd be grateful. It has had a recent service, still waiting for a new air filter bu the existing one has had a blow through.
The second less important problem (if anyone's still reading) is the throttle control. Despite being free moving, gripping and holding the throttle open for more than five minutes at a time is cramp inducing agony. Not sure if its down to the shiny hard grip or if there is any other means of improving things. It doesn't sound much of a problem but I'm not exaggerating when I say it made the long ride flipping hard work, especially coupled with the lack of power.
Thanks
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Who did the service and what was serviced? It may be running rich by your description and the fact that it's an old air filter. Try running it without the filter and see if it improves any.
Remove the second (closing) throttle cable if it is still there, it isn't needed.
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Done a full 6,000 service with new plugs, plug caps and possibly points? or just a 1500 oil change?
What exhaust system is it running?
K1 and 2 don't need much choke it's the K3 thats cold blooded.
Sorry Lester but both cables ARE needed (Try stopping one with the throttle stuck open!!) but new cables and grips will probably help
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The throttle spring is very heavy on the 500. We just lived with it...
Easy starts, quick off choke, lack of top-end power sounds like rich running.
Do a plug chop on full throttle and see what colour they are. Plenty of instructions for how-too if you search on here.
Steve
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Rich running definitely. Check that one or more of your carbs isn't flooding; this would give the all symptoms you describe.
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Never used the second cable...I have a kill switch. :)
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Not using the second cable can put you in a very sticky situation if the opening cable is stiff or should stick. A kill switch might save the engine from blowing, but you will have no engine braking, the bike will be freewheeling and infinitely more difficult and dangerous to stop under full control, never a good idea on a 2 wheeled vehicle! :o
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It doen't make the throttle any heavyer to operate, and besides being very handy to prevent throttle sticking open - more common then you might think especially in frosty conditions and bikes that sometimes live outdoors, I also have on occasion had to swap the cables over when the pull cable snapped on me. I'd go over all the controlls with lube to see if any inprovement, possibly consider thicker / larger diameter grips which would give mor leaverage and the main thing I did thinking back on my early 500/4 years was to fully master the art of rolling the twist grip open with my wrist not having to change angle as I think it's holding your wrist at an angle with force rather than the actual force required that causes wrist ache. I'm not sure if my expanation is entierly clear but have a go at rolling the throttle open with your fingers and then holding it there with your palm and relaxing the fingers again, after a while it's second nature and you forget the throttle is heavy. As with most of these things there is a technique that once learned is usefull for further riding on a whole range of machines, I've recently started to do some greenlaning as a job and a lot of the things my 500/4 taught me are quite usefull to offroad riding, that throttle controll method and the other is to very lightly feather the brakes, without fully applying them using 1 or 2 fingers whilst riding otherwise normally, on the 500/4 I did this too keep the front disk dry in really torrential rain, especially on motorways where you'd go miles without using brakes so they'd get very cold and wet and loose effectiveness.
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This is the only bike I've ever had with two cables so I think it's more of an H&E exercise. I shall be looking into lightening the throttle by way of a softer spring or something. Sorry for the hijack. :)
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Assuming everything is in good condition and working correctly then try one of these on the throttle
http://www.mandp.co.uk/productInfo.aspx?catRef=503589
Soft grips with a deep pattern can also help.
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Thanks for the replies everyone. I'll whip the filter out tomorrow and try it, seems too simple for my luck but you never know. If not I'll try the plug chop and see what that shows. The flooding float chamber sounds like a possibility, it's had new plugs etc. It's still running on the original 4-4 exhaust but they are tired and patched. I need to decide on a suitable replacement as not sure i can stretch to the Dave Silver 600 quid OE replacements (any opinions). That wouldn't be effecting things presumably?
As for the throttle - there seems to be varied opinion on this, the strange thing is I've got a TDM and when compared with the CB it doesn't seem to be much difference, both have double cables too. The TDM has soft rubber grips though. I accept that it might be down to technique and will give what Matthew suggests a go, but don't think it is just a case of getting used to it, I've had plenty of bikes but never had this problem. The wife rides it too and can't see her enjoying the ride with this set up. That gadget that Totty suggested might do for her.
Thanks again everyone who has replied- I'll update later.
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I got myself a chrome Motad replacement exhaust. I didn't find anything else made for it at the time. Nice pipe tho I wish it was a bit shorter.
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First thing I would do is a carb rebuilt kit. Really inexpensive and the carbs probably look like toilet bowls anyways. They I would check the jet size for the main and the pilot. Should be around 100 maybe and maybe 38-40 for the pilots. Run the engine and I got some great advice here for checking the fuel/air mixture. Run the engine hot for 10-15 min. kill the engine, pull the plugs and check the bottom. I would start here. I've realized since I have been riding motorcycles its all about the carbs!!!!! I am dialing mine in right now after adding velocity stacks and rejetting but thats a whole different project. I used to get cramps on my throttle too. I got used to it by building in up the muscle (haha) or you could get a cruise control bracket for a few dollars when you're on the highway. Also I would do what Lester said and check the filter. There are some improved AM filters for this bike that are much better than the stock ones. Try ebay. Also what matthew said about the hand placement and movement on the throttle is excellent. I gradually roll mine all over in front and back making the muscle not so stressed and more comfortable and enjoyable to ride. Hope some of this info helps!!!
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If your air filter is past it consider replacing the paper element with filter foam from RamAir, it cost £9 for enough foam to do 2 or 3 filters and they can be washed, they sell direct on ebay. It's a very easy job with a knife and a glue gun.
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A kill switch might save the engine from blowing, but you will have no engine braking, the bike will be freewheeling
Freewheeling?? why? ....I'm confused, surely if your engine is in gear with throttle stuck open and the kill switch is turned the bike just slows down like you've shut the throttle.
I know what you mean about throttle slides freezing, if I have had to ride in heavy snow (in the past, too old soft now ;D) I've used my old CB550 with sidecar and had the slides freeze open, had to get home using the kill switch as an on off throttle.
My 500/4 cafe has a Tomaselli quick twist which only has one cable which has been Ok.
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Because like it or not, your first instinct is to pull the clutch in!
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I thought the second cable was there because the throttle has a friction screw hold it open. With the screw done up the throttle will not close unless you force it to by pulling it shut with the other cable?
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No, Florence. I've had my bike since 1986 with 1 throttle cable and it works the same as any other single cable throttle.
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Florence, I think only the early bikes had the friction screw to hold the throttle open, I know only my 72 500/4 project has one on the undrside of throttle. It's perfectly rideable without the second cable most of the time, but having a spare cable pretty well fitted is a massive help for an emergency get you home measure as well as being handy in case of malfuncion - I'd rather have one fitted than not, especially on motorways or distance work. I'd simply not belive it adds to the stiffness or heavyness of the throttle unless the cable was in an awfull state. A quick actung / 1/4 turn throttle might help with not having to move the twist grip through such a wide range of movement - it's actually this that I think gives the wrist ache.
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The first 750's had a 4 into 1 throttle cable and severa; riders reported that at wide open throttle there were times when the throttles would not close, even though each carb had it's own spring.
Along with the continuous need of adjustment this prompted Honda to design (or get the carb manufactureres to design) the later assembly where the carbs were linked, the second cable is there to enable you to shut the carbs down when the return spring breaks, as they were once prone to.
In todays market with insurance companies as they are, not having one could be counted as an "Unsafe" modification that you ought to tell them about or they can, and will, invalidate your cover.
I can remember back in the early 70's that any Mini that crashed with a less than 21 yr old driver the insurance company paid to have the head removed and the bore/stroke measured to see if a bigger engine hadbeen fitted, if not they paid for re-assembly---if yes they walked away from the claim just paying for the time to strip down
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Mine has the friction screw, which I do not use I must add. I do not have the second cable fitted. Maybe I should. I will say though that it has never stuck.
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I'd agree with alot of the comments and would add:-
Stickier grips let you almost rest your hand onto it to hold in the right place and make a big difference to the effort you have to use. Seems like a small step but has significant effects.
The twin cables, I've not experienced a stuck thottle on these carbs but nor would I like to and not be able to close it. I'd also have great difficulty in trying to explain to a vehicle engineer why I had removed it if it came to that. Don't underestimate the insurance angle it's important.
The adjustment of the cables is critcal in avoiding un-wanted binding in as much as the manual usually states how much slack to have at the twist grip, this is to avoid one cable fighting against the other as the steering is moved as they follow slightly different paths.
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are the insurance people really that interested in what is fitted to machines as old as this if the item in question is not related to any incident which may occur? Do insurance companies know what should have been fitted to a machine nearly forty years ago? If it is not a MOT item does it really matter?
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Sadly insurance companies will use ANY excuse to get out of paying a claim. Supposing a car pulls out in front of you, as happened to UK Pete recently, and after several weeks of your bike being off the road, the third parties insurance assessor decides to inspect your bike closely. The one throttle cable you have fitted may well have stiffened up through lack of use, but YOU would not be able to prove that is was okay at the time of the accident, and he/she would then claim your stiff throttle contributed to the accident, as you could have stopped sooner if it hadn't been, and you'd be looking at considerably less compensation for your injuries, as the condition of your bike contributed to it :( Sounds over the top I know, but with personal injury claims costing insurers many millions every year, they WILL try and wriggle out of it, and a lot of assessors ARE bike specialists, even the aftermarket pipe you forgot to tell them about can cause serious problems ??? and if they find you have fitted little extras like engine bars, or a twin disc conversion, they need to be told about them, basically, ANY deviation from standard spec can cause problems if you don't tell them about it :'(
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Bloody odd that adding safety gear can affect your claim. Insurance companies. ::)
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As I said though, ANY excuse, they always ask if the bike has been modified, and the small print will tell you that faliure to disclose any mods may result in your policy being invalid, they just want to know all the facts, some mods will not affect your premium, but fail to inform them at your own peril :'(
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I'd have to fill in two pages of mods for the insurance on my bikes, when I explain that they say do any of the mods make the engine go faster, "nope" I say. Then they ain't bothered with the mods. As said already I think they have a good idea that bikes 30+ years old might have non-standard part here and there.
My bikes are all on an agreed value policy so whether the mods add value, like a fairing and hard luggage, won't make any difference to the amount claimed.
I do see the point about any injury compensation claims, interesting stuff.
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The insurance companies are trying also to operate without being ripped off by rigged claims which is to all of our benefit. That level of scrutiny will also uncover areas that we may think are innocent but can ultimately affect a claim for damages we may be making.
It's a good point that if you are in contention over details after an accident you will most likely find yourself up against the other party's "experts" in trying to not pay to return you to your pre-accident position.
I'm not averse to a risk of one sort or another but on this point I feel you'd be banging your head against the wall if trying to argue it.
The crux of it is that the second cable is originally designed and installed as a critical safety measure by the vehicle's manufacturer, YOU now have to try and argue against a professional vehicle engineer as to why you have removed it, what's gonig to be your answer?
I think each owner can do as they want to their bike, but would stop at advising someone to remove such an item.
Sidetracked the original post a bit, apologies.
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Glad my original post has sparked some lively debate, thanks for the advice - all of which is useful.
On the subject of insurance I also have a '92 TDM bored out to 898 and with so many modifications it is unrecognisable as a TDM (thankfully) including FZR1000 swing arm and wheel, Aprilla RS250 seat hump, flat slides, high level Renegade cans and so on and even with these declared the insurance wasn't much more than the CB. I think it is always better to declare mods as the amount of interest the insurance company take in the bike will depend on the size of the claim, if you've ploughed in to a line of bystanders at 80mph (God forbid) it would be reassuring to know that at least your insurance is valid.
As for the bike, I ha vent yet run it without a filter or with a new one when it finally turns up but I did take the old one out. I was mildly surprised to find that what I now know to be the 'gas scavenging device' had a plastic cap over the end of the steel tube. It looks like the sort of thing that would be removed on fitting. I can't imagine this is connected to the running problem as surely the engine breathes sufficiently through the filter but I'm also sure this cap shouldn't be there - any ideas?
Thanks again.
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No the cap shouldn't be there, the tube is to put the oily vapours inside the air filter so they go straight into the engine not via the paper element to clog it up
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I thought that was the case , thanks Bryan.
The new filter turned up today, I fitted it, predictably it wasn't a perfect fit, the gas scavenging tube had to be shortened to get the filter to seal against the carb air intake. Anyway as soon as I rode up the drive I knew things were better, it had warmed up by the time I got off the lanes and on to a decent bit of tarmac and then the improvement was clear, it ripped up through the gears feeling and sounding like a new bike, I even stinked an unsuspecting Pan European. It's running perfectly now and I can't believe how well i goes or how easier a fix it was, things rarely go so easily for me!
Thanks again for all the advice, ironically I don't think the painful throttle will be such a problem now it is actually responding.
Just a slipping clutch to sort now.
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If it slips a little under hard acceleration that is, I am afraid, rather hard to eliminate as they all do that a bit. Some say different oils help. I keep meaning to fit heavier clutch springs but never seem to get round to it as it means a new gasket etc and time.....
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Thanks Florence - it slips on quick revvy changes, I'd assumed it was worn plates or springs but haven't inspected it yet. I'm suprised to hear you say that they all are prone to a bit of hard revving slippage, I thought the clutches were supposed to be particularly good on the 550's? Are the heavier springs easy to source?
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I got HD springs years ago but can't remember where. I have seen them online recently tho.
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Did they improve the clutch Lester?
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I haven't had the bike running since I bought them..around ten years ago. :-\
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Agree with everything that has been said except "You have to have 2 cables". I agree with Lester on that one.
On all my bikes that have 2 cables I have binned the 'close' cable. RD500's have them aswell. I think the cable is predominantly for cold weather carb icing.
I remember now how relieved i was when I swapped my carbs way back in 82 to 550 to have a totally transformed throttle action. - from stiff and horible to light and nice. I even used a weedier spring than a stock 550.
500-4 clutch and release mechanism is dreadful. As I think I said in my rebuild thread, The K3 was generally a so much improved bike that its well worth fitting a K3 motor and carbs - if you are going to ride the bike alot. My original 500-4 motor and carbs are still sat on the floor untouched from 82. I knew I'd be riding the bike alot, so rideability was the priority not authenticity.
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The 500 cluch slips, think mine had H/d springs and was slightly better but it was fitted with a sidecar so was always going to slip a bit. 550 cluch could slip as badly if thrashed. 550K3 carbs are more fussy about being stood but give better economy. You'd be well advised to change the airbox rubbers if junking the rest of the 500 bits as I had choke cable routing issues with the k3 carbs combined with 500 airbox. K3 carbs and airbox are consequently a bit harder to squeeze in as the k3 rubbers are 10mm or so longer.
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I agree that they may have fitted the twin throttle cable for carb icing, however I can testify that it doesn't work, when I had my slides freeze there was no way you could move them either way, up or down, they were bloody solid
500/4 clutch mechanism? yep, shite ::)
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The 500 cluch slips, think mine had H/d springs and was slightly better but it was fitted with a sidecar so was always going to slip a bit. 550 cluch could slip as badly if thrashed. 550K3 carbs are more fussy about being stood but give better economy. You'd be well advised to change the airbox rubbers if junking the rest of the 500 bits as I had choke cable routing issues with the k3 carbs combined with 500 airbox. K3 carbs and airbox are consequently a bit harder to squeeze in as the k3 rubbers are 10mm or so longer.
Agree, in terms of slipping, the K3 clutch was only slightly better. Choke cable and airbox were fine on mine though. I did swap the engine top cover I think, cant remember which one I used 500 or 550. Breather Pipe comes out at an angle on one and straight on the other. Guessing I used the one to match the carbs cable bracket.
I actually found K3 carb rubbers considerably easier to fit. a) because they are longer and b) the gap between carb and airbox is larger. My airbox is stock 500.
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I think I found the choke mechanisn hit the airbox unless 550 rubbers were used. The rest of the stuff aint too bad a fit, dont forget you'd need a choke cable brakett on the bars (bolts on). I think the 550k3 crabs are more prone to issues if stood though so a double edged sword, you get better economy but pay for it if the bike gets stood or cruddy fuel is used. 550 engine and 500 carbs run fine together without rejetting in any case. My next 550 related project once the sidecar is mot'd will be dropping a 650 top end on a 550 motor and adding a su carb in an attempt to get a bit more grunt and better economy.
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650 top end on a 550? You will find that it might be slower, the 650 had a slightly longer stroke as well as bigger bores, so you may end up with a lower compression ratio, and the camchain is a duplex on the 650. That said, many years ago a mate bored out his 550 to accept 750 pistons, but had to reduce the height of the crowns by trial and error, although if you measure from the top of the gudgeon pin hole to the crown of the 550 piston, and make the 750 piston the same, it should be okay (We were skint students back then, accurate measuring tools were out of the question :(), but it did go very well! ;D
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my 550 f2 was running really rich and only doing about 30mpg the cure was a carb rebuild all the jets were knackered, fitted a carb rebuild kit to each carb