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Post by wayne on Jul 6, 2020 2:50:04 GMT -5
Dead cold start, never managed it before. Is that telling me something??  |
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Post by typ110 on Jul 6, 2020 4:09:29 GMT -5
Probably that you gained some weight during the years :-))
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Post by timpa136 on Jul 6, 2020 9:04:47 GMT -5
Nothing to the sound of that start indicates low compression. It explodes to life so to speak. Low compression would slowly catch
and blurble up to speed. Not to worry.
Tim
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Post by hudson on Jul 6, 2020 9:17:01 GMT -5
Curious if you have a compression tester, Cold- -VS- running temp. How many miles ? Anyway good to see you. 
Brian
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Post by janski on Jul 6, 2020 10:14:46 GMT -5
Amazing what effect a lock down has, must have a go, could be a sprag saver?
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Post by wayne on Jul 6, 2020 21:17:43 GMT -5
Amazing what effect a lock down has, must have a go, could be a sprag saver? Yup, I reckon COVID's got something to do with it. Added a few kg and that "what am I gonna do now" feeling. The bike is actually pretty good compression. 130 psi last I checked which was only about a thousand miles ago. I have been able to start it hot in the past but never dead cold so that was a genuine attempt with no idea if it would work or not. At some point Brian I did do a cold vs hot compression comparison but can't find those stats. It would be interesting to know so I'll do it again and post. |
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Post by wayne on Jul 18, 2020 23:34:22 GMT -5
Curious if you have a compression tester, Cold- -VS- running temp. How many miles ? I dragged out the compression tester. Here's the trace and the compression written in red. Guess my bike survived 4 years in the museum okay. Last check I did was also around 130. Wide open throttle for test cold and hot. Re the difference between hot and cold, as you'd know Hudson there's a contribution from rpm and a graph from memory. I don't have any way (at the moment) of accurately measuring cranking rpm. Suffice to say, the cranking rpm dead cold was noticeably less than at operating temp. Interesting the uneven compressions and how they come together when warm.  |
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Post by hudson on Jul 19, 2020 15:20:02 GMT -5
Wayne
I did a cold -VS- Hot comparison also,after I asked the question. You beat me to the post.
I noticed that the cold graph does crank slower ( as you mentioned) evident by the spacing of the peaks and returns closer to 0 between peaks. I did a test with a known pressure applied to the tester to compare with the graphs pressure scale and there is no correlation. Approximately 100 P.S.I. of constant pressure applied to the tester will cause the graph to register appox. 142 P.S.I. My conclusion is the calibration has to be factored with the speed of the rise in pressure and the volume of the hose and fittings and is at best a good approximation,( as also mention here on this boards pages) But a very good indication of evenness of individual lobe sealing. Just had to scratch my curiosity itch.
Brian
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Post by wayne on Jul 20, 2020 1:37:31 GMT -5
Hardly any difference in yours re total psi readings and only a small difference in the smoothing of peaks (your cold engine peaks are smoother than most RE5's I've run the test on).
Yet big difference in mine. Wonder what gives?
Thanks for posting.
PS, Wide open Throttle on mine as well.
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