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Post by szabgab on Jun 29, 2017 14:39:09 GMT
Dear all,
I have been tinkering with my bike for nearly a half a year. I replaced valve guide seals, piston rings, a cracked lower crankcase, all the seals (apart from the crankshaft seal, guess, which one is leaking), cleaned the carb twice, taken the starter motor to bits, cleaned, etc. The bike runs OKish, but I have a really hard time to get steady idle, so it has to stay high, which is annoying. Also there is a very annoying metallic ping or ticking coming from somewhere the top (?), the warmer the engine, the more I hear it, followed by other chainy-type noises. I did replace the muffler and downpipe seals to no avail, and I tried the cigarette smoke thing - but as far as I could make out, the joints are not leaking - e.g. not moving the smoke anywhere. I kind of hoped engine knock on a badly timed machine, but the timing marks are spot on and valve clearances are great too. I did not touch the timing on the electronics, I hope, I did not move that accidentally...
Also today and the day before when I killed the engine a few minutes after cold start but near operating temperature and started it again it kind of backfired - sounded more like a hiss, like a plug unplugged and the bike let out a large puff of white smoke from the exhausts. At the first occasion I have hoped, it is just because I was taking the cam cover off before and checked oil and generally spluttered oil, petrol and other stuff all around, but this time it was a normal 'kill engine at red light' scenario. It did not do it again today, but I am not sure, what to think of this. I am running lean, that is for sure, one spark plug is between tan and white and the other is white, so I have slightly altered the mixture ratio since. Also very annoyingly in this heatwave the engine sometimes stalls upon reaching idle at hard deceleration, very handy in the middle of a sodding busy intersection.
But what annoys me the most, the bike was not this crappy before I touched it. It surely had it's share of things - idle disappearing in the hot weather, smoke because of rock hard valve guide seals and not properly seating valves, but I could trust the bike to take me where I wanted it to. Now I am listening to these unhealthy sounds and wondering, when will the engine just die for good
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Post by szabgab on Jul 5, 2017 20:48:58 GMT
Nobody has got any ideas?
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Post by wazzbo on Jul 5, 2017 21:18:18 GMT
Have you balanced the carbs? are the float heights correct? if they are badly out of balance you`l have a job getting it to run properly and tick over will be near impossible to set. if you altered the air jet mixture screw, that will only effect the slow running not richen the mixture at higher revs' If its running lean ,the pinging and knocking could be pinking which will get worse has the engine gets hotter. Have a look at this article en.wikipedia.org/wiki/Engine_knocking#Pre-ignition |
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Post by szabgab on Jul 6, 2017 16:47:49 GMT
Have you balanced the carbs? are the float heights correct? if they are badly out of balance you`l have a job getting it to run properly and tick over will be near impossible to set. if you altered the air jet mixture screw, that will only effect the slow running not richen the mixture at higher revs' If its running lean ,the pinging and knocking could be pinking which will get worse has the engine gets hotter. Have a look at this article en.wikipedia.org/wiki/Engine_knocking#Pre-ignitionHi Dave, Yes, the carbs were bench synced, so they should be reasonably close (but they are surely somewhat apart, as the plugs look different). I have been thinking pre-ignition myself, but according to a repairman it would sound differently (he have heard the bike). He suspects valve or rocker issues alongside some chain noise. Although he did not do a stellar job before on cleaning and balancing the carbs, I might take the bike in to him for proper diagnosis. I have lost faith in my own skills and I am already on the verge of getting rid of the bike, which would be a very stupid thing to do |
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ian
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Post by ian on Jul 6, 2017 20:24:29 GMT
When 5* disappeared, I spent many a happy time retarding the ignition on myTR6 bit by bit then going for a run to see if the pinking had stopped. Iirc, it only really occured under heavy load, like flooring it in a high gear. It's also quite a distinctive high pitched metallic pinging/knocking sound. On the other hand, I think cam/balance chain rattle is more noticeable on the overun - at least that's when my 400 rattles, it stops when I open the throttle, so I assume it's engine chain wear!
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Post by bodie on Jul 6, 2017 20:34:39 GMT
When 5* disappeared, I spent many a happy time retarding the ignition on myTR6 bit by bit then going for a run to see if the pinking had stopped. Iirc, it only really occured under heavy load, like flooring it in a high gear. It's also quite a distinctive high pitched metallic pinging/knocking sound. On the other hand, I think cam/balance chain rattle is more noticeable on the overun - at least that's when my 400 rattles, it stops when I open the throttle, so I assume it's engine chain wear! sounds like a good reason to keep the throttle open then Ian  |
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ian
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Posts: 5,400
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Post by ian on Jul 6, 2017 20:42:13 GMT
When 5* disappeared, I spent many a happy time retarding the ignition on myTR6 bit by bit then going for a run to see if the pinking had stopped. Iirc, it only really occured under heavy load, like flooring it in a high gear. It's also quite a distinctive high pitched metallic pinging/knocking sound. On the other hand, I think cam/balance chain rattle is more noticeable on the overun - at least that's when my 400 rattles, it stops when I open the throttle, so I assume it's engine chain wear! sounds like a good reason to keep the throttle open then Ian I try to keep it open Chris. That's why I haven't got round to painting it - according to the log book, it should be silver - I'd be going too fast! So I'll keep it blue for now. |
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Post by wazzbo on Jul 6, 2017 21:11:46 GMT
If it was mine I'd be getting the carbs sorted first as I think if they've only been bench set up they could still be a ways out of balance,re check the float heights and make sure the jets are in the right way.
If the cam chained has been tensioned using the engine running method mentioned in the Honda a manual it will probably still be loose.
Is the balancer chain properly tensioned as they are noisy when loose
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Post by mikef on Jul 6, 2017 23:08:53 GMT
Well, I have had all of those problems and have now got the answers I think, but hopefully yours is not as bad as mine.
The idle problem first.
When you cleaned the carbs did you remove the jet tubes? I went to the expense of buying an ultrasonic cleaner and when I put the carbs in I didn't remove the jet tubes. These are the tubes that the needle goes down into.
Still having problems I removed them and found that there was still a slimey sort of residue in there. So another clean with the tubes removed and then a carb re-sync (balance with the vacuum gauges). Problem solved.
I also had that pinking sort of sound above 60 MPH, was not sure what it was. It sounded too high pitched and too high up to be big end. Unfortunately it was big end. So I hope this is not your problem. Difficult to diagnose without a physical check.
Certainly a check of cam and balance chain is a step forward.
Best of luck.
Mike.
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Post by szabgab on Jul 7, 2017 12:33:31 GMT
Well, I have had all of those problems and have now got the answers I think, but hopefully yours is not as bad as mine. The idle problem first. When you cleaned the carbs did you remove the jet tubes? I went to the expense of buying an ultrasonic cleaner and when I put the carbs in I didn't remove the jet tubes. These are the tubes that the needle goes down into. Still having problems I removed them and found that there was still a slimey sort of residue in there. So another clean with the tubes removed and then a carb re-sync (balance with the vacuum gauges). Problem solved. I also had that pinking sort of sound above 60 MPH, was not sure what it was. It sounded too high pitched and too high up to be big end. Unfortunately it was big end. So I hope this is not your problem. Difficult to diagnose without a physical check. Certainly a check of cam and balance chain is a step forward. Best of luck. Mike. Hi Mike, Yes, I removed everything, followed the excellent write-up here. I did try to spray WD40 on the carb boots, it did not change anything, but today I sprayed brake cleaner on them when really hot, the bike stalled on me, so at least I have found vacuum issues, so I know, where to start first. Also there are a few annoying noises on top of each other. At idle it sounds valve-knocking (maybe issues with setting screws, as the clearances are all fine) and chainy. Upon riding the bike it sounds, like metal rattle, but I can not find anything loose. Apparently the collector box has got some welded pieces of metal inside, and sometimes they work themselves loose? This is a long shot, and I do not even know, how to check for something like this. I had the box off the bike, and nothing was rattling inside, but mind you I was not looking for unusual noises in it. Dave - I did check timing chain, and set it stationary, cover off and pushing down on the mechanism with a screwdriver. The chain is never really super-tight, it can be moved on the cogs laterally and slightly be lifted off (probably a millimeter or so). Balance chain is in very good nick, plenty of adjustments left, as the dot is at 12 and the setting piece with the cut-out for the bolt squarely in the middle. |
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