Thread Repair on GS1000 2v Exhaust Threads

[massakins]

What are the options for restoring a strong thread into the exhaust port bolt holes (8M x 1.25 thread) on a GS1000 2v cylinder head? Head is off the motor on a work bench.

Looking for something more durable than a Helicoil type since the exhaust pipe is removed and replaced frequently.

I've heard of Keenserts and other styles but am not familiar with them. Any recommendations?

Thanks, Pat

[RobGS850L]

I've seen the demo and they seem to be pretty darn good. They were a bit pricey though. But I think Helicoil is about the same actually. The Keenserts were actually threaded and wedged in where a Helicoil may pull out easier because of the dependancy only on the coil threads. The Keensert folks say that a Grade 8 bolt will snap off before the insert pulls out. I didn't get to see that part. :roll:

[robinjo]

When you take off the exhausts alot I would use studs instead of bolts no matter if you use Keensert or Helicoil.

[AOD]

I agree, replace with studs!

[massakins]

Guys,

I know all the KZ series Kawasaki's have studs but it seems that a couple of the studs on my GS1000 2v might be so close to the frame downtubes that a header flange might not have enough clearance to fit.

Has anyone used studs and found no interference problems?

Thanks, Pat

[duaneage]

Use studs that are just a tad longer than need be and you should be OK. The exhaust bolts are a real problem on these old bikes, I have a spare engine that broke off two of them . In order to use it someday I will first have to repair the holes. :x

[jhw84]

In order to use it someday I will first have to repair the holes. :x

I didnt feel like messing with it, and bought a new head on ebay for $50.

But, my present holes are messed up pretty bad. It appears that the original holes were stripped, and someone tried to weld them shut and drill and tap them, however, they did a poor welding job, then drilled the holes crooked, then tapped it SAE.

Hence the new head.

[bucketsofgs1000]

Open up the holes and use M10 bolts instead. Maybe that will solve your problem.

[massakins]

Let this be a lesson to those of you that still have a GS1000 2v cylinder head with 8 good threaded holes at the exhaust ports. Replace those soft OEM bolts with a Grade 8 fastener or equivalent while you can still get them out. Otherwise, you'll be facing the same dilema of those above.

I've got five cylinder heads in total and three of them had broken OEM fasteners; I was able to successfully remove one of the four broken fastners with the resultant thread condition at 100%. The other three holes are not as good as new and I'm looking for a solution.

Hey Big Jay, how can you help a guy out with this?

[duaneage]

I think the best solution for ravaged holes is to install helicoil and permamently install studs into the helicoil. i would use a bonding agent in the holes to hold the helicoil and stud to the head.

For bolts i would look for cap nuts that protect the threads from the elements. I have an engine to experiment on and when the weather breaks i intend to find a way to repair it.

I am scared as hell to loosen the bolts on my 650. When the day comes I plan to have a spare head ready (I have one of those that needs a little valve work but otherwise has good exhaust bolt holes) so I can minimize the downtime.

On the upside I replaced pipes on a 82 650L and all of them came right out with no trouble. But if any were tough I would have stopped right there. I use an impact screwdriver (like what is used to get phillips head screws out of the case) only mine accepts a socket as well. Using this tool I can work them out if at all possible. Either they come out with a few hits or it's a slog.