Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Wenman on May 28, 2017, 09:51:46 PM
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I have a CB550F running 4 - 1 with pods! (Yes I know pods)
I have 40 pilots and 115's mains and needle clip 3rd down.
It runs really good, idles fine and picks up well through the range and doesn't back fire!
My problem is it gets very hot!!! I cannot touch the rocker cover after a short ride and if I spit on it it frys it straight away! Now I don't know how hot these engines are supposed to get and I may be paranoid but it doesn't feel right to me. The points cover stator covers everything to hot to touch!
It may be running slightly lean as the plugs are slightly white but can't believe I'd be putting bigger jets than the what I have! Timing fine too!!
I also have the exhaust headers wrapped in heat tape!!
Any ideas please??
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If it's running weak mixture it will get hot, exhaust wrap won't help either, the wrap keeps the heat in the pipes rather than letting the air from motion cool them. Always worth checking the ignition timing as well.
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Thanks
Ignition timing is spot on when testing in the static method.. should I throw a timing light on it?
To richen it any more would mean upping the jets to 120's 125's and I've never heard of any cb550f requiring any bigger than 115's???
Thanks Al
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All factors of modifications to the engine/exhaust have an effect on jet sizes. Different makes of pod filters often require different jetting, and then the issue of make/ type/ how baffled (or not!) the exhaust system is. It is a case of trial and error until you get it near as you can to what works best. Be aware, changing jets can be a pain, but nothing like as much hassle or expense as an engine rebuild if it damages a piston or valves running too weak!
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Thanks again!
I just feel like putting bigger jets than 115's in will be over compensating for something else? Think I'm going to check all the other things that could effect the leanness first!
I did a top end rebuild on this and wondering if maybe the cam is a tooth out? Would this cause it to run lean? I assume it wouldn't pick up like it does and allow me to staticly time it if the cam was out?
Went to the bikeshedmc show in London at the weekend and really inspired! Just want to sort this issue out now so I can take my project for a ride further than the end of my road! 😡😡😡😡
Alan
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The cam being out would not affect the ignition timing directly as the points operate from the end of the crank. If you fitted new pistons and rings it may get hot until properly bedded in and settled (500-1000 miles) The engine will run with the cam misaligned by one tooth either way, but it will run hot, so certainly check cam timing (at least it can be done with the engine in the frame, unlike their 750's!)
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Do you have any means of checking the temperature?
You can get oil temp dip sticks and colour changing stickers, or even just an infra red thermometer.
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Ordered a temp gun! I'm hoping it's just me being paranoid! Can anyone tell me if they are able to touch parts of their engines after a ride out! The rocker cover is untouchable as in scalding hot!
Going to check cam timing as I think it's the last thing which could be causing this issue!
Thanks for all ur help
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Ordered a temp gun! I'm hoping it's just me being paranoid! Can anyone tell me if they are able to touch parts of their engines after a ride out! The rocker cover is untouchable as in scalding hot!
Going to check cam timing as I think it's the last thing which could be causing this issue!
Thanks for all ur help
NO,
they all get hot,go with the plug colour,a pale tan is lean enough !!
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You've quite a few things in the mix there, some diligent work to get anywhere is ahead of you I think.
Cam timing as you are going to check should be easy and at least put your mind at rest to eliminate it. It may not be the cause though as there are some quite well documented changes made in this respect for these engines to get a desired result, but in the absence of good reason it's likely to be a best starting point to be assured it's std.
The main jet sizes are more open to interpretation I feel. The jet numbers give a correlation to the flow they will allow, but don't take account of the changes in effective vacuum which come about by removal of the std airbox etc.
The odd effect that is often not considered is that the engine (loosely speaking) still requires the same amount of fuel as std to run correctly. But by changing the intake come vacuum, the same jet will flow a different amount of fuel in response. It's this you are trying to correct.
For example, if you simply run with a dirty air filter, the engine will head toward richer running with no change in jetting. Just the air quantity went down, corresponding vacuum went up and higher venturi vacuum means more fuel is pulled through the same jet (assuming max jet volume is not reached).
With pods, you create the opposite. Loss of vacuum means less fuel is pulled through the same jet for a given engine speed, so you have to use a bigger jet to get the fuel back to the same flow level. The outright numbers may not be consistent with another setup as you have no idea what airflow or vacuum changes you've achieved.
The original intake bellmouths also, when removed, change the fundamental flow through the venturi. Firstly their length is tuned to whole engine setup and helps to improve engine output across its rev range. Secondly, they broadly align the airflow to more effectively pass the required flow through the critical part of the carb. Without them, most carbs will simply flow less air at maximum volume than with them fitted.
I don't know which plug you are running to give heat range but it will obviously affect plug colour.
Also, it's becoming more apparent that with ethanol in fuels you will most likely get the plug showing whiter than we've seen in the past, so less accurate as a good signal of jetting than before.
Some good info in this link, it's been updated to indicate that point about plug colour also.
http://forums.sohc4.net/index.php?topic=7401.0
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Maybe you can fit an oil cooler?
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Id rather fix the problem ta!
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Im not sure there is a problem, these engines do run hot, as all air cooled engines do.
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Both my fours run F hot and both run on rich side. Burnt my wrist on one of the downpipes of my 400 last week and it came out in a massive blister Ouch. Shame we haven't got a Nurse on here.... Could have done with a little sympathy ;)
Peter.
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Still waiting for temp gun but this is how hot it gets...
Rocker cover, head fins, points cover, stator cover all are untouchable! I mean even if I was to touch them for a fraction of a second I would leave my skin on them!
This is after a 20 minute run light to moderate traffic uk!
Checked my cam and it may have been one tooth out, this has been adjusted l, valve clearances re done, static timing bang on, 40 idle 115 mains needle on 3rd notch!
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You old boys worry too much. All my air heads are running hot at the moment, it is called the weather ;)
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Both my fours run F hot and both run on rich side. Burnt my wrist on one of the downpipes of my 400 last week and it came out in a massive blister Ouch. Shame we haven't got a Nurse on here.... Could have done with a little sympathy ;)
Peter.
Unfortunately I don't do Telemedicine Peter so cant see your bister but I do sympathy.....mainly because I have burnt my arm on down pipes in the past and it bloody hurts. Never mind, I'm sure you have another arm so you'll be just fine.(keep it covered and dry until blister dries up ;))
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Oh, and going back to the original thread my CB400/4 runs that hot, the engine almost glows red !!!
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Still waiting for temp gun but this is how hot it gets...
Rocker cover, head fins, points cover, stator cover all are untouchable! I mean even if I was to touch them for a fraction of a second I would leave my skin on them!
This is after a 20 minute run light to moderate traffic uk!
Checked my cam and it may have been one tooth out, this has been adjusted l, valve clearances re done, static timing bang on, 40 idle 115 mains needle on 3rd notch!
If you are going to use a thermal imaging camera make sure you have the emissivity set correctly or the readings will be way out.
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It's not thermal imaging just a temperature IR gun. Point it with the laser at parts of the engine and it gives a temp!
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I have a 500 and a 550 going at present. The 550 has only been for an MOT and I am waiting for the reg docs (import). When I went for the MOT I feel it was running much hotter than my 500.
Anyway point is, I was given one of those IR point and shoot guns but never used it on the bikes. Don't have 100% confidence in their accuracy and believe they can give false readings on reflective surfaces, but will give it a go tomorrow on the 500 and then the 550 when I get a number.
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I have one of those ir guns bought against the day I get the bikes I care enough to check get back up and running. On my cb500 and the tiddler ca125 and cb250 - all aircooled sohc Hondas I always regarded the engine getting hot to the point it smelt hot and you could feel the heat off the engine on your legs as a problem needing resolving. My cb500 covered somewhere past 180,000 miles of sidecar tugging abuse over a fair few years in all weather with her original engine, with a slightly weepy head gaskett the previous owner pointed out really needed doing. In all that time it only got really hot a few times, and each time I pulled over and let her cool off, cause was pretty always the same, stuck in stop start traffic on a hot day for a long time, unable to filter due to the chair. Getting hot to that point seemed to use fuel and oil quite badly. Only other times I can recall a sohc of mine getting that hot and I ignored it, kept going I had a con rod jurnal size up completely. That said I do live somewhere where traffic jams are rare so could always afford to keep moving at a decent pace so hot engines not genrally a problem.
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Ok, traffic round here as normal..awful. But after about 15 miles these are my readings with the IR gun.
Between fins on head at front between 2/3 110 deg C
Front top left head fins 95 Front top right head fins 90
Back top left head fins 90 Back to right head fins 90
Front left crankcases just below block 70 Front right crankcases just below block 76
Back left crankcases just below block 74 Back left crankcases just below block 82
Have to aim at the less shiny bits. Measurements taken on shiny bits pretty useless (downpipes etc)
As said earlier I think my 550F runs hotter.