Topic: Stripped oil line bolt hole

[emlupi]

I was changing the o-rings in my oil lines today (CB750K2). When I went to re-install the lines to the engine, one of the 6mm bolts would not make torque. It made up to an intermediate step (about 5 ft-lbs), but would not draw up to final torque ( 7 ft-lbs). I immediately stopped turning when I didn't feel any more  increasing resistance.  I am guessing that the threads are buggered up in there. I had a bad feeling when I found traces of Loctite in the threads when removing the bolts. I have ridden the bike and there is no leaking or seepage at the connection.

My question is, what would be the recommended fix in this situation. It's oil tight now, but eventually I am going to have to deal with it (hopefully not till over the winter). Do I attempt to chase the threads or will I need to install a helicoil? What are your suggestions? Thanks.

[HondaMan]

I was changing the o-rings in my oil lines today (CB750K2). When I went to re-install the lines to the engine, one of the 6mm bolts would not make torque. It made up to an intermediate step (about 5 ft-lbs), but would not draw up to final torque ( 7 ft-lbs). I immediately stopped turning when I didn't feel any more  increasing resistance.  I am guessing that the threads are buggered up in there. I had a bad feeling when I found traces of Loctite in the threads when removing the bolts. I have ridden the bike and there is no leaking or seepage at the connection.

My question is, what would be the recommended fix in this situation. It's oil tight now, but eventually I am going to have to deal with it (hopefully not till over the winter). Do I attempt to chase the threads or will I need to install a helicoil? What are your suggestions? Thanks.

Yep, Helicoil. I've done many of them. Make sure to remove the chips!

[PeWe]

Or if you can use a longer bolt and use the threads still OK. The bolts used might been too short?

[emlupi]

Thanks for the replies.

Pewe,
The bolts were the stock items and fairly long. Seem to have plenty of thread engagement. The o-rings were old and dried out. There was a minor seepage out of the joint only after the bike was ridden for awhile, then it would stop. It looks like somewhere along the line somebody figured to stop the leak by just cranking the bolts down tighter and overdid it. Steel bolts in an aluminum casting and...you know the rest.

[PeWe]

OK, I should use a Time-sert or similar instead  of helicoil. I have bad experiences with helicoil that come out later on when removing the bolt. This thread is typical to be used more in the future. Different where the bolt never more will be loosened. I have replaced most of the old helicoils my CB750 has got with time-sert thread inserts. Cost more but worth it.

Valve cover threads in head, cam holder threads and 3 threads in cyl for cam chain tensioner housing are places were I have time-serts.

[emlupi]

Thanks for that info, I will certainly look into it.

[Art]

Hey em,

I ended up doing the same thing on my 77cb750f2 bike, can you help me out and point me in the right direction based on, what did you end up using? how did it work for you? where did you purchase?

Thanks

[754]

I  think this may work, and you can still helicoil if it does not work...
I Would try tapping to 1/4 NC  20 tpi. ...MAY GET ENOUGH BITE TO HOLD.

[Art]

I'm fairly new to bikes and fairly new to wrenching on them.  With that being said, I was thinking investing in time sert just because of the possibility that, from what i've heard, the helicoil will probably fail me in the future rather than the time sert. 

I had a mechanic due a top end rebuild, with new gaskets from cyclex and no leak thus far.  So I consider the top end a job well done.  I don't think I will probably be removing the oil lines any time soon, once the stripped thread is fixed.  I jumped on replacing the oil lines with Rafi's stainless steel lines and since the lines are new they dont 'have the flexibility that the old ones had.  I ultimately/ stupidly forced the bolt in at an angle and quickly pulled it out once i went in three turns.

Believe me, I'm kicking myself for doing this, but you live and you learn. 

[754]

If younonly tore 3 threads, just run a tap thru,  should be good.
may need a bit longer bolt.

[Art]

okay, I'll try that, wish me luck. Thanks 754.

[rotortiller]

Helicoils are stronger than timeserts.

[emlupi]

Hey em,

I ended up doing the same thing on my 77cb750f2 bike, can you help me out and point me in the right direction based on, what did you end up using? how did it work for you? where did you purchase?

Thanks
[/quote

Art,
I haven’t done anything with this bolt yet. It has remained oil tight thus far and I figured if it ain’t broke don’t fix it. I would probably give Frank’s idea a try before going for a helicoil or time sert.

[ekpent]

I  think this may work, and you can still helicoil if it does not work...
I Would try tapping to 1/4 NC  20 tpi. ...MAY GET ENOUGH BITE TO HOLD.

I have done that to one of my bikes.

[Don R]

 The suggestion to check out a longer bolt may be valid, There may be 2 or 3 new unused threads in the hole that could be reached with a slightly longer bolt. You would need to check the depth before just running one to the bottom though.

[Bodi]

"Helicoils are stronger than timeserts"
That's like saying Fords are better than Chevs. There are opinions on both sides.
I have had helicoils fail, breaking and/or screwing out with the bolt. May be a corrosion issue - stainless steel does not get along so well with Honda engine alloy. Helicoils are only available in stainless. Timeserts are available in carbon steel - probably better for Honda alloy work?
Anyway, I've used timeserts for rocker cover and side cover screw threads (people love to strip those 6mm threads) on many holes and had zero problems, compared to several helicoil failures on similar cover screw stripouts.

[754]

 I would be betting that many helicoil failures have to do with drill size or improper installation.
 I know of a factory, that helicoils its castings for increased reliability.

[madmtnmotors]

I have yet to have a helicoil fail. Red Locktight on the helicoil, allowed to set overnight. Chase the thread repair with the proper tap the next day (just in case) and anti-seize on the bolt threads.

EZPZ

I keep helicoil repair threads in stock of the three or four most common sizes. When I have to order one I order extras.

[HondaMan]

I was changing the o-rings in my oil lines today (CB750K2). When I went to re-install the lines to the engine, one of the 6mm bolts would not make torque. It made up to an intermediate step (about 5 ft-lbs), but would not draw up to final torque ( 7 ft-lbs). I immediately stopped turning when I didn't feel any more  increasing resistance.  I am guessing that the threads are buggered up in there. I had a bad feeling when I found traces of Loctite in the threads when removing the bolts. I have ridden the bike and there is no leaking or seepage at the connection.

My question is, what would be the recommended fix in this situation. It's oil tight now, but eventually I am going to have to deal with it (hopefully not till over the winter). Do I attempt to chase the threads or will I need to install a helicoil? What are your suggestions? Thanks.

Ummm...I just opened up an engine that had all spun crankshaft bearings (2nd one in 2 years). The culprit was: the oil intake hose's bolts were stripped. It let suction pull air into the oil line, eventually ruining the bearings and damaging the crank.

It is not hard to fix: I went to Ace Hardware (last year, for another 750 that had this similar trouble, oil light kept coming on when hot at idle) and got their 6mm Helicoil kit with drill bit (1/4", super sharp). I tapped the one last year on the bike, installed the Helicoils right there. The holes do not go into the crankcase, so all you need to do is clear away any chips that might fall into the oil holes.

[madmtnmotors]

It is not hard to fix: I went to Ace Hardware (last year, for another 750 that had this similar trouble, oil light kept coming on when hot at idle) and got their 6mm Helicoil kit with drill bit (1/4", super sharp). I tapped the one last year on the bike, installed the Helicoils right there. The holes do not go into the crankcase, so all you need to do is clear away plug the oil holes to prevent any chips that might fall into the oil holes.

FTFY   

[rotortiller]

That's like saying Fords are better than Chevs.

  No it is not, it's more like saying Toyota and Honda are better than Fords. Here is a test someone took the time to do that may help you to see clearly.