| Vintage Dirt Bike Q & A https://vintagedirtbikeforums.alp-sys.com/ |
|
| Torque specs for 75 Cr 125 head bolts https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=4731 |
Page 1 of 1 |
| Author: | SCALECRAFT [ Thu Feb 02, 2017 5:36 pm ] |
| Post subject: | Torque specs for 75 Cr 125 head bolts |
H All I have a DG performance head that I am using. After about 10 min, the head bolts came loose and engine shut down. Head bolt specs with OEM head and with DG Sunburst Head?? Anybody?? Thanks Steve |
|
| Author: | rayivers [ Thu Feb 02, 2017 9:45 pm ] |
| Post subject: | Re: Torque specs for 75 Cr 125 head bolts |
The Honda service manual indicates 16.6 ft/lb max, but I've used 18 ft/lb with no issues (both head types). With a copper head gasket, I'd also recommend using a copper-type sealant. I'd also check to make sure the studs aren't sticking too far - or not far enough - out of the head. Neither of the two DG heads I own (CR125M and MR175) use the same height at the stud as the stock heads, and many DG heads I've seen on eBay appear to have been machined, either for more compression or to remove combustion-chamber damage. Ray |
|
| Author: | SCALECRAFT [ Fri Feb 03, 2017 8:43 am ] |
| Post subject: | Re: Torque specs for 75 Cr 125 head bolts |
Thank you. The DG head is OEM specs. I will have to put Helicoil repair in the cylinder on 2 posts. I will if possible, stack the inserts. They are rated at around 30 ft/lb per insert. Thanks Again Steve |
|
| Author: | rayivers [ Fri Feb 03, 2017 9:55 am ] |
| Post subject: | Re: Torque specs for 75 Cr 125 head bolts |
Just a couple suggestions FWIW: 1) I'd use single inserts the full length of the stud threads on all four of your stud holes (if two stripped out, the other two may be almost there), and 2) I'd also make sure the top of the insert is @ 2mm below the top surface of the cylinder. The Honda engineered studs are designed to bed into the cylinder aluminum, and could spread/damage the insert if it's too close to the top. Ray |
|
| Page 1 of 1 | All times are UTC - 7 hours [ DST ] |
| Powered by phpBB® Forum Software © phpBB Group https://www.phpbb.com/ |
|