Talking of torque

[Dink]

Really Kim!! I was certain you and I both know that neither of my bikes would be following yours unless I wanted too.

Dink

[saaz]

I may have been lucky as the only noise I have in my 78 GS1000 (when it is going that is!) is the clutch noise (I have rebuilt it three times).

Cam noise is not noticeable, but this could be because of the lumpy cams without the noise deadening ramps.

[49er]

I've now done 800kms since the rebuild. Cams are quiet. I think I've definitely fixed that dam cam knock. I haven't converted the pics to digital yet, hopefully this week.
The head was re-torqued at 750kms. I plan another one after 1500kms. The carbs were vacumm synched. The bench sync was close, only 1.5cm/hg variance across the four carbs.
A compresssion test showed 155-160psi across the four cylinders. #3 still has a minor oil pass on deceleration. I may have slightly damaged the oil rings on assembly.
A Barnett clutch pack including some HD springs has just been fitted. You can really feel the extra load on the clutch cable now, but hey, no clutch slip either.
I am now able to work the motor right through the rev range. The increased torque is great. How safe are these 850's past the red line(9000rpm)? I saw 10,500 in 3rd and it was still quite willing.
To summarise, the increased capacity and CR have been hugely benificial.
The "Motoman" method of running in the motor has worked well. The only drawback being there is quite a load placed on the gearbox and transmission during the early stages, with repeated acceleration and deceleration required during the first 20-30 minutes of the bedding in process.
A set of Sport Demons are being fitted this week along with the shield I have been reluctant to fit. I love riding naked so this is a sad day. I guess if it makes the ride more comfortable and safer at speed , so be it.
Cheers
Ian

[tomcat24551]

Thanks for the update, Ian.

I've never gotten an answer I've felt I could trust on this question, so maybe you or some of the other GS mechanics can weigh-in on it: When you re-torque the head, do you just tighten the fastener from its current position or do you break it loose (counterclockwise) FIRST and then re-torque? Educate me, please.

I guess in your case, the threads, nuts and washers would all be freshly lubricated so it might be easy to re-torque without loosening first. It's the engines that have been in service for years and all the fasteners have all gotten "set" that worry me. The lubricant has long since been washed away and the fasteners don't want to turn easily. What's the proper procedure here? I'm not convinced it's necessary to re-torque a head after years of service if it's not leaking any oil or compression anywhere.

Also, you said you "reground the cams to standard specs". Do you mean you welded additional material onto the lobes and then reground them to the standard lift and profile? Or what? Without welding-up, looks like regrinding would remove lift, etc.

Any idea what your compression readings were before you did the work?

Tomcat

[49er]

Gidday Tomcat
I believe you should loosen each nut 1/4 to 1/2 turn before re-torqueing it, to avoid the chance of thread bind. Follow the normal torqueing pattern, ie from the middle of the head outwards. Loosen and re-torque one nut at a time. On my motor, the outer acorn nuts required more turns to re-torque than the the inner nuts. I think this was due to the separate oil seal inserts fitted over the oil galleys between the barells and the head on my model. On the Versah head gasket, these seals fit individually around the 4 outer studs and inside the head gasket stud holes.
The question of oiling the threads is controversial too. Some contend that over oiling is as detremental to torqueing accuracy as dry binding is.
I believe in reducing friction so I always lightly oil the stud thread.
I had my cams reground sticking with the standard timimg and lift. As this grinding process requires minimal metal removal, there is no need to weld additional metal on to the lobes. When re-grinding, the radius of the the heel of the lobe is reduced slightly which allows for metal removal from the toe without reducing the lift. As a result of this, your opening and closing ramps are advanced slightly. You need to re-shim following a regrind.
I decided to re-grind to repair the tapers left on the lobe toes by camshaft whip at high rpm.
Before the rebuild, my compressions ranged from 115-125psi. I could probably have run the bike for some time before having to strip it down.
It was getting harder to start on colder mornings though and burning some oil.
She fires up great now. I'm very happy with the 160psi, considering how short the stoke is on the 850 (56.4mm).
Any feedback on the redline/over rev safety issue would be appreciated.
Cheers
Ian