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cylinder head bolts

  • pat631
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cylinder head bolts was created by pat631

I have a 1970 dt1250c I removed the head to mesure btdc and since then the head bolts keep loosening. At first I torqued probably not enough, manual I had said 18 ft lbs.

Then went to 25...still loosening. Now trying 30lbs. I have two manuals, both are very poorly writen in regards to assembly. Do these bolts need loctite?

Maybe 30ft lbs will work?
09 Jul 2019 18:14 #1

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Replied by RT325 on topic cylinder head bolts

I probably do mine 'that' tight but gotta be something unusual going on with yours. Can't think what--but is the gasket material in the sandwich type head gasket squeezing out. Never seen that happen but apart from studs pulling in the case which i've also never seen--i'm out of ideas!!. Good solid steel washers under the long sleeve nut heads. they're 10mm studs so can go pretty tight. One more thought--is the base gasket squashing out--or in. Was it a new gasket & settling down--re-torque etc. I've got a 250 DT1.
Edit to say--just had a look in my DT1 original service manual & says 25.3 to 28.9 ft-lbs. Going by that i'd guess i probably did 40 ft-lbs--but don't tell anyone lol. I just do em up tight till my elbow clicks--they're strong studs. Problem 'is'--why does yours come loose with about correct torque. I'll take a pic of the manual DT1E but same horse.
Last edit: 09 Jul 2019 23:44 by RT325.
09 Jul 2019 23:23 #2

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  • pat631
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Replied by pat631 on topic cylinder head bolts

Your manual is a bit better than the ones I have. Its a brand new gasket. Second one actually...after the first time it loosened up I put in a new <<sandwich>> type. Stock was a flat copper style.

28.9 ft lbs is pretty close to 30. I will ride it a few hours like this and see what happens. Not a fan of the idea of loctite on these bolts...at some point it will for cause issues IMO. Its a bit of a last resort.
10 Jul 2019 04:46 #3

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Replied by RT325 on topic cylinder head bolts

Ok, that interesting. I've only ever seen sandwich original gaskets, but would have preferred a solid copper one. Hope you have some luck as is a bit of an unusual situation.
10 Jul 2019 06:37 #4

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Replied by meadeam on topic cylinder head bolts

I think you guys are talking about different things... pat361 seems to be talking about the cylinder head, RT325 seems to be talking about the cylinder jug itself. Not that it explains the loosening.

I put my cylinder head on with split lock washers, and 18 ft-lbs according to the torque specs I found on this site. I used a copper head gasket. I haven't been back to check the torque settings, but the bike isn't running yet so I'd be shocked if it changed much.
1974 DT360
1975 RS100
2007 FZ6
Fort Thomas, KY
10 Jul 2019 07:44 #5

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Replied by pat631 on topic cylinder head bolts


The way I understand various manuals, 18 ft lbs is for a different type of head bolt. They came in various sizes I guess. These are big, socket is 21mm. If they come apart again, i have another head and bolts ordered on ebay. I will also check if the head is straight...maybe do a leak down test.

I thought this might be a more common problem. So...it might be down to just not torqued enough.
10 Jul 2019 08:05 #6

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Replied by Swoop56 on topic cylinder head bolts

I've had a similar problem with my DT1. Using the sandwich style gasket ,
it seems to need a retorque after a couple of heating and cooling cycles ,
and then stabilises . I torque to 30 ft/lbs .
10 Jul 2019 13:45 #7

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Replied by pat631 on topic cylinder head bolts


Nice! thanks for the info.
10 Jul 2019 13:58 #8

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Replied by RT325 on topic cylinder head bolts

Ok, someone up there 'meadeam' thinks we're talking at cross purposes, but what 'meadeam' is missing is that the older DT/RT's have long head sleeve nuts i call them, that hold the head & cylinder on in one go. Meadeam your pic looks like a DT360/250 which has separate nuts for the cylinder & the head. All good though. Cheers.
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Last edit: 10 Jul 2019 18:35 by RT325.
10 Jul 2019 18:33 #9

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Replied by meadeam on topic cylinder head bolts


Yep, that was exactly my misunderstanding. Carry on!
1974 DT360
1975 RS100
2007 FZ6
Fort Thomas, KY
The following user(s) Liked this Post: Snglsmkr
11 Jul 2019 18:37 #10

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