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Post by nakedgoose on Aug 5, 2024 0:17:24 GMT 1
could it be the wrong pistons fitted and the Skirt tab causing this ZiG I sure hope not,
I have a athena head gasket on the way, it'll probably be 3 weeks or so before it gets to New Zealand but I will update if this solves the issue I'm having,
I can definitely feel a lip with the current head gasket when I run my finger up the bore so I think that's the likely issue
I should add that I'm using Mitaka 350lc pistons and I ordered the ones specified for my bike so shouldn't be issues unless I was sent the wrong ones, unlikely though
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Post by chrisg on Aug 5, 2024 18:57:34 GMT 1
Food for thought: Cylinder bores are honed specifically to fit oversize pistons and pistons "off the shelf" , even though they same the same size, may not necessarily fit. The clearance should be between 2.4 and 2.6 thou (inch)
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Post by 4l04ever on Aug 6, 2024 15:53:04 GMT 1
Food for thought: Cylinder bores are honed specifically to fit oversize pistons and pistons "off the shelf" , even though they same the same size, may not necessarily fit. The clearance should be between 2.4 and 2.6 thou (inch) The clearance can vary between different types/makes of pistons, so check with the supplier/manufacturer. Also, forged pistons usually have a bigger clearance than cast
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Post by chrisg on Aug 6, 2024 18:58:20 GMT 1
Food for thought: Cylinder bores are honed specifically to fit oversize pistons and pistons "off the shelf" , even though they same the same size, may not necessarily fit. The clearance should be between 2.4 and 2.6 thou (inch) The clearance can vary between different types/makes of pistons, so check withe the supplier/manufacturer. Also, forged pistons usually have a bigger clearance than cast Thats very true. I was referring to the Mitaka's. 👍
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Post by Tobyjugs on Aug 12, 2024 14:31:25 GMT 1
Hi guys,
Finishing up the engine rebuild on my '80 rd350lc, trouble I'm having is with setting my timing,
I'm trying to get the engine to TDC, but it always seems to spring/jump past TDC, I get to about 2.7mm before TDC and then the engine will jump forward past TDC by ~2.5mm's, it seems to do this no matter how fast or slow I turn the engine over, plugs are out and dial gauge is down the left spark plug hole,
This issue originally appeared as a hard spot before TDC where I can't turn the engine past it without either a breaker bar, or a fair bit of momentum with my 1/2" ratchet, this only appeared once the head was torqued down, I've taken the head on and off a few times now to confirm this, the squish is above 1.6mm as my solder was still intact when measuring so I don't think that the pistons are contacting the head either,
The jump feels like its compression related but this is my first engine rebuild so not really sure,
any got some ideas I could try?
Is this all sorted now?
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Post by nakedgoose on Aug 13, 2024 0:56:31 GMT 1
Only just got the new head gasket in the post a few hours back and have just finished installing it thankfully it solved the issue, have set the timing without issue this time around, also checked the squish band and its still at 1.4-1.5mm so it must of been massive with the OEM head gasket
I should be good to put the engine back in the frame once I do a leak down test, having minor issues with that due to a stuck exhaust washer/spacer but I'll carry on with that tomorrow, hopefully it'll just need some heat to come out.
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Post by chrisg on Aug 13, 2024 19:10:55 GMT 1
Good luck, hope all goes well.
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Post by Tobyjugs on Aug 14, 2024 8:24:44 GMT 1
Only just got the new head gasket in the post a few hours back and have just finished installing it thankfully it solved the issue, have set the timing without issue this time around, also checked the squish band and its still at 1.4-1.5mm so it must of been massive with the OEM head gasket I should be good to put the engine back in the frame once I do a leak down test, having minor issues with that due to a stuck exhaust washer/spacer but I'll carry on with that tomorrow, hopefully it'll just need some heat to come out. To be honest I have run engines with 0.9 mm squish height and then swapped over to a standard cylinder head and gasket and the squish height was 2.20 mm. I did not feel any difference in power. Only noticed a slight increase in cooling water temperature.
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Post by nakedgoose on Aug 15, 2024 4:59:31 GMT 1
Only just got the new head gasket in the post a few hours back and have just finished installing it thankfully it solved the issue, have set the timing without issue this time around, also checked the squish band and its still at 1.4-1.5mm so it must of been massive with the OEM head gasket I should be good to put the engine back in the frame once I do a leak down test, having minor issues with that due to a stuck exhaust washer/spacer but I'll carry on with that tomorrow, hopefully it'll just need some heat to come out. To be honest I have run engines with 0.9 mm squish height and then swapped over to a standard cylinder head and gasket and the squish height was 2.20 mm. I did not feel any difference in power. Only noticed a slight increase in cooling water temperature. Good to know,
I wont be chasing the squish band clearance any further, was just keeping tabs on it as my head was resurfaced along with the thinner athena head gasket.
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