Yamaha FZ 07 / R7 Engine case bolts

Go the Helicoil route! You’ll be removing less material from the case and no counterboring necessary. I’ve never stripped out a Helicoil. They tend to expand slightly when torqued. In addition the stainless steel is harder than those mild steel inserts.

 

The counterbore is a very simple tool- it sets depth automatically. The only thing left to figure out is how to attach it to my hand held drill- it's a square drive like a tap. We have a good hardware store here I'm going to try today.

 

You will be good Gino! I had 12mm timeserts so I had to counterbore to make the threads match-up on the bolts. 22mm timeserts will be fine without sinking them in my opinion. While it doesn't call for it, I used high temp red thread locker on the timesert as an added precaution to it backing out later on disassembly. The tool that expands the base of the timesert does lock it in very well on its own. Good luck and if you have any questions shoot me a dm or email. My best.

 

You can use a 1/4" drive socket extension in your drill and corresponding socket to drive the bit.

 

Try to find a square socket or 8 point socket that fits the tool. Then you can use one of those socket adapters designed for an impact driver in your drill.

Also, if you can't find anything that will work at your hardware store check Grainger. They stock a lot of stuff the big box stores don't, and you can pick it up there or have it shipped to your local store if they don't have it in stock.

https://www.grainger.com/category/t...rs=Socket+Shape|4-Point|8-Point&filters=attrs

 

Well, the first timesert went in beautifully. I went slow and steady and actually used my tap driver to turn the drill bit by hand- kept shavings from flying everywhere, too.

The second one, not so much- the case came apart. Obviously, @regularguy was right, the bolt was the only thing holding it together! This was the center section of the cases. So the backup engine is going in for Laguna.

Appreciate all the help and advice!

 

Dang Gino, sorry to hear.

 

That sucks, but at least all the internals and the head are good.

 

Yeah we had a good run with this one- it could have been alot worse if it had blown up spectacularly. I'm betting the outer bolt was pulling on those threads because the inner one was weakened.

Wondering if I should time sert the new cases before the build?

 

studs

 

The R7 has additional frame bracing, doesn't it? Does that help prevent this?

 

The R7 frame brace is towards the rear- it's a bolt on piece. I haven't heard rave reviews of the R7 chassis being much better or even different than the FZ, given all the same goodies.

The R7 does come with thinner fork tubes than the R6 forks that most people race on- you would think that with front end feel being an issue, that front end might be better- but all of the front runners run R6 forks so perhaps not. Or maybe they just want it to be easier to set up and find parts?

Either way, I don't think this case bolt issue is something big to worry about. I got 10+ race weekends out of this build, and there were many more on that particular set of cases before that. And that is with a 97HP build!

 

@Gino230 Sorry to bring up an old thread but I had a built motor do a similar thing last season. The end of the season the bike developed a pretty bad vibration in the higher rpm range. We couldn't figure out what was causing the issue until the motor was pulled for a refresh and found the center support was broke off completely and the only thing holding it together was the bolt. I hadn't heard of anyone else having this problem until I saw this thread just now.

Did your vibrate more than usual? Have you heard or seen others with this problem?

Thanks

 

We had no vibration or power loss. I just noticed the oil drip and tried re-torquing that bolt, but it would not take torque.

I have heard of this happening on built motors in the past. We had almost 3 seasons on this engine and it was making 97HP so it was time!