Topic: Rebuilt engine too tight

[fmctm1sw]

A couple folks have seen that GL650 I'm putting together in the project forum.  I've run into trouble with the motor.  After it was reassembled, it is too stiff for the starter to turn over.  My (two) starters have gotten a clean bill of health from a local starter/alternator shop.  It's possible I did something wrong on reassembly but I'd say it isn't very likely.  I plastigauged the connecting rod bearings and marked them so I'm certain they are back on properly.  It was assembled with a moly based assembly lube.  I know I checked the ring end gap too.  I turned things as I put it together and have everything torqued to spec.  The guy that did the honing did all my other bikes so I have no reason to believe anything is amiss there.

As for the voltage, I get about 6.5VDC at the starter when cranking it.  I had it jumped off my truck and the jumper cables will get hot.  I can turn the motor over with a torque wrench, it isn't seized.  I took the pushrods out of it so it was only turning the crankshaft/cam/plugs and it cranked.  The voltage was at about 9.5 VDC.  It will turn fast enough like that to bring up the oil pressure.  Add the valve train and you can forget it though.

According to what I've read, it isn't completely out of the realm of possibility for a motor to be stiff after it's rebuilt.  As a comparison, I sat my 550 on it's centerstand and put it in 5th gear.  I can turn the motor over by turning the wheel.  I can do that on the GL too but its MUCH harder.  Some of the things I've seen to address this is (mostly car sites):

1)  Using marvel mystery oil in each cylinder followed by periods of cranking (over days even).  (I tried this in a limited capacity and had a big mess out the exhaust.  I didn't let it sit long though)
2)  Putting two batteries on the starter (series.. as in 24 volts)  (might be fine to turn the starter but I want to start the motor)
3)  Towing it in gear behind a car (dangerous.  I have pushed it around my driveway a while with the plugs out... exhausting)
4)  Turning it over with a wrench for a while (exhausting)

I think what I'm going to try is pulling the plugs and devising some sort of way to continuously turn the rear wheel for a while.  I guess the lesson learned for me is to periodically put a torque wrench on it during the rebuild and see what I get.  It takes 20-25 ft lbs to turn this motor with the plugs in it.  For this application at least, I guess that's too much.  The valve train is pretty heavy duty, there's 4 valves per cylinder and there's two valve springs per valve (one smaller one inside the big one).  The thought crossed my mind to take the inner one out until it loosens up.

If only I had a kickstarter....   Thoughts welcome...

[faux fiddy]

Myself , I live for danger so towing it behind a truck can't be all that bad. If you're sure nothing is going to clunk or a wrist pin keeper  come out, spin it up enough to  get the oil pressure up. Make sure it is getting to the head before you go too far. It might turn out to be a really good tight motor.

[fmctm1sw]

Myself , I live for danger so towing it behind a truck can't be all that bad. If you're sure nothing is going to clunk or a wrist pin keeper  come out, spin it up enough to  get the oil pressure up. Make sure it is getting to the head before you go too far. It might turn out to be a really good tight motor.

I'm hoping.  They used the same starter on the 500 and 650 and supposedly the 650 was really hard on the starter and starter clutch.  Perhaps a fresh rebuild is too much for a 30+ y/o starter that was pushing the limit to begin with.  Or maybe I'm screwed...     I'll try to look at it this weekend.

[Don R]

 Have you tried to eliminate the wiring with the jumpers? Does the starter interchange with any others? I read a cb900 falls right into a 750. I had a 56 chevy with this issue, a bearing got put in wrong and the tab wasn't in the notch. It ran for a couple years before it spun.

[fmctm1sw]

Have you tried to eliminate the wiring with the jumpers? Does the starter interchange with any others? I read a cb900 falls right into a 750. I had a 56 chevy with this issue, a bearing got put in wrong and the tab wasn't in the notch. It ran for a couple years before it spun.

Don, I've gone straight to the starter with my cables, same thing.  The starter on it is the same as the CX/GL 500s and CX/GL650s.   One of the tips over on the CX forum is to try to find a 500 starter since they are generally less abused.  One of the starters is off a CX 500, courtesy of ebay.  Interesting thought on the bearings, I'll have to look at my photos to try to remember what I did with them, if anything.  I know the plastiguage measurement was good.  Thanks, I always appreciate the thoughts of the old timers here...

[754]

I know its late but next time after bolting cases together, check that it turns freely, pistons on , check turning, cam in check turning, etc

Then you may have caught it..

[faux fiddy]

The more I think about it a wrist pin retainer might be out, but I don't think you could turn it at all if that happened.  I know they can leave a good notch when they come out at speed.  Not sure how long the one I saw was run after the fact.

[fmctm1sw]

I know its late but next time after bolting cases together, check that it turns freely, pistons on , check turning, cam in check turning, etc

Then you may have caught it..

I did all those things.  I guess what I need to do is develop a better feel for what's normal turning effort and what's not.  As it is, it's about 20-25 ft lbs to turn with a torque wrench. 

[754]

Itsa tough call.. Hard to say wether its ok, and will run in nicely, or something is actually amiss.
 If it were a 750 I would probably just run it,, stock parts being plentiful and cheap.
Are you thinkng of trying to fire it, could run it a few minutes, and see if it gets tighter. Then let it cool off.. If its still tight, then, I would be opening it up.

[ekpent]

Its a water pumper so keep an eye on the oil etc. The only thing I think of when I read this is that the engine would be tightest when totally new and I feel that you think something is amiss. Best to follow you first impression or gut instinct maybe.

[faux fiddy]

Asked a friend about this. He says fresh motor should spin, and race motors get broken in on practice lap. Suggests something is amiss and that he would start taking things off, loosen the cam sprocket, try to turn it  and go from there.

[MCRider]

Asked a friend about this. He says fresh motor should spin, and race motors get broken in on practice lap. Suggests something is amiss and that he would start taking things off, loosen the cam sprocket, try to turn it  and go from there.

I gottta admit, doesn't sound good to me. Even if you need a wrench to turn it, you can "feel" if somethings not right. And this doesn't feel right. 

[azuredesign]

As it is, it's about 20-25 ft lbs to turn with a torque wrench. 

 What's torque with the spark plugs out? Any chance you're spinning the final drive and tranny as well?

[grcamna2]

As it is, it's about 20-25 ft lbs to turn with a torque wrench. 

 What's torque with the spark plugs out? Any chance you're spinning the final drive and tranny as well?

I tend to agree here,you may want to check your clutch/primary

[fmctm1sw]

As it is, it's about 20-25 ft lbs to turn with a torque wrench. 

 What's torque with the spark plugs out? Any chance you're spinning the final drive and tranny as well?

I tend to agree here,you may want to check your clutch/primary

Yeah, that's everything.  Transmission in neutral...  I should have some time this weekend to look at it again.

[fmctm1sw]

Here's the results of my first test:

Plugs out/transmission in neutral:  5 fl lbs to 20 ft lbs max.  the max value was observed as the left cylinder intake valves were on the way down and the right cylinder exhaust valves were on the way down.  Hard to turn at the rear wheel but able to turn.

Second test:

All pushrods removed/plugs removed/transmission in 5th gear:  5 to 7.5 fl lbs.  Easily turned at the rear wheel.

Third test:

All pushrods removed/plugs installed:  Ft lbs seemed to vary.  The faster I turned my torque wrench, the more I felt resistance.  After an initial hesitation, the starter turned over the motor fast enough to build oil pressure.  Turning at the rear wheel was hard. 

[HondaMan]

When I do the Fours with new bearings, I usually must lube them with oil (20w50) instead of assembly lube, or the engine will not turn over by electric start. I've found that if the bearing clearances are less than 0.015", this also applies. If I can get it to crank long enough to bring up the oil pressure into the crankshaft (and rods), then there is an immediate doubling of the cranking speed when it finally arrives.

When I did my own engine last year, I decided to experiment a bit and used assembly lube on the [new] rods and oil on the crank. When I went to crank it for the 'oil up' portion, I had to BOTH stand on the kickstarter AND crank the electric starter, using a big car battery I keep around for the purpose, just to get it turning at all: it would not budge until then. After a few brief runs at it and the oil pressure arriving, it finally washed out the assembly lube and the cranking speed flew. Then I put the plugs back in and was rewarded with a 1-touch startup.

[fmctm1sw]

HM,  I appreciate the insight.  I was hoping once the oil got flowing I'd be good but it doesn't seem so.  I don't think anything is wrong on the bottom end with only 5 fl lbs needed to turn it.  I wouldn't mind taking the heads back off but I had all the valves out when I rebuilt it so I know they weren't bent or anything.  Ah well, I'll just try to keep chipping away at it.

[Jerry Rxman Griffin aka MuthaF'er]

Ring end gap good. What about ring side clearance?

[fmctm1sw]

Ring end gap good. What about ring side clearance?

End gap 100% good.  I honestly can't recall if I looked at side gap.

[rb550four]

I had a stiff engine once, didn't feel right,  took it back down, found a bent over wiper ring.
It was worth it to me to get to the bottom of things , have  the answer and make the repair before trying to start it.
 I don't want to be the guy with the ruined rebuild saying " I knew it and didn't do anything about it." and then tried to fire up it anyways?!!
  You don't think that you might have pinched a ring do you?