GS700E_Top End Rebuild_Stuck At Camshaft Install

[Sean]

Woohoo! I made some progress! Took the front guide out and pulled up on the chain then put the cams in no problem. The only thing I'm wondering about now is the position of the notches on the right side of the cams. They are suppose to point either away from each other or towards each other, as you can see from the photo they are pointing in the same direction. How could this be? I remember when adjusting my valves before ever taking apart the engine that they matched what the guide said. And the markings on the sprocket are correct the 2 and the 3 arrow point directly up at the same time.

IMG_9629.jpg

[2BRacing]

Well done! Now for the last hurdle: the notches on the cams.

Check that the exhaust cam has "EX" identification letters on it, and inlet cam has "IN" letters on it. Have you not mixed up the cams from old / new cylinder heads by mistake? Did you remove the cam sprockets? If you did, did you re-install them correctly?

When setup correctly, the notches on both cams must point inwards towards each other.

[Sean]

Hmmm the EX and the IN are on the right ones and there is only one set of cams so no mixing up there. I do remember unbolting the sprocket on the IN while disassembling thinking that would aid in their removal so that must be the issue. When I get a chance I will check that out and let you know how it goes. Almost there!

[2BRacing]

It looks like your inlet cam sprocket is not correctly positioned on the inlet cam.

With crank set so that TDC mark for 1.4 lines up with reference mark on engine case as in previous photo, arrow 1 on exhaust cam must point to the front of the bike and be about level with the head surface. At this time, arrow 2 will point upwards, and the notch at the end of the cam will face towards the rear of the bike. Looks like your exhaust cam is correct.

With inlet cam turned so that notch faces forwards towards notch of exhaust cam, the sprocket must have arrow 3 pointing straight up. The lobe of number 4 intake valve should be pointing back towards the carbs, and not towards the front.

Remember to get the 20 pins between arrows 2 and 3 correct, with the pin over arrow 2 being counted as pin number one.

After everything has been tightened down, turn the motor a few turns clockwise and verify that 1.4 TDC crank setting has correct cam orientation as described above.

Check valve clearances by following the manual's procedure for camshaft orientation and measurement of corresponding valve clearances.

Now you should be good to go!

[Sean]

You were absolutely right. That was an easy fix. Almost done adjusting the valves, once that's complete I should have it all back together in no time. Thank you thank you for helping me get past those speed bumps. Do you know if these carbs need to be vacuum synced or will a bench sync do the job? I've been trying to find info on how to do the vacuum sync but haven't came across anything.

[eil]

Do you know if these carbs need to be vacuum synced or will a bench sync do the job?

Both. Do a bench sync after reassembling the carbs and a vacuum sync once the bike has been put back together as a bit of final fine-tuning. It should run on just a bench sync, but will run well with a vacuum sync. If you don't have a vacuum synchronizer, the favorite here is the Morgan Carbtune (google it). Ships from the UK, is a little expensive, but is simple to use and high-quality.

I've been trying to find info on how to do the vacuum sync but haven't came across anything.

No offense, but you haven't been looking hard enough.

* Your factory service manual has the procedure
* There's a BassCliff tutorial here: http://members.dslextreme.com/users/...rb-balance.pdf
* There are many threads here on the forum about it
* There are YouTube videos as well. These are usually for different bikes but the overall procedure is the same.

Also, I have a Carbtune and possibly a free day or two this upcoming weekend...

[2BRacing]

You were absolutely right. That was an easy fix. Almost done adjusting the valves, once that's complete I should have it all back together in no time. Thank you thank you for helping me get past those speed bumps. Do you know if these carbs need to be vacuum synced or will a bench sync do the job? I've been trying to find info on how to do the vacuum sync but haven't came across anything.

You're welcome! Well done for hanging in there and getting the job done correctly!

Yes, as indicated by eil, the carbs should be initially set with a bench synch, then vacuum synched once the engine has been properly warmed up (put a fan or two in front of the engine to blow cooling air while you are doing the adjustments). The synch tool must first be adjusted so that all four readouts are the same when connected to only one cylinder, and then connected to each individual cylinder.

After the vacuum synch process, and while the gauges are still connected, you can fine-tune the mixture screws by tweaking each mixture screw slowly until all gauges show the highest vacuum reading (this corresponds to highest idle method of adjusting mixture described on BassCliff).

I suggest you find out what kind of beer is member eil's favourite, and take him up on his kind offer!

Good luck!

[Sean]

No offense, but you haven't been looking hard enough.

You can offend me all you'd like as long as I keep getting all this great advice lol

Not sure why but sometimes I look and look and look and can't find what I need on the internet. You are surely a life saver... so what kind of beer do you like eil??

[eil]

Eh... I'm not cool enough for beer, I mostly drink water.

Looks like I'll probably be free both Saturday and Sunday. Slight preference for Sunday, but it may depend on the weather. Do you have a preference?

[Sean]

Taking this convo to PM check your inbox eil.

I'll update everyone and post photos once everything is back together

[Sean]

Got a couple updates on the bike. First, thanks to eil for coming by and helping out all day this past Sunday!

We managed to get the engine completely reassembled and running by the end of the day. At first it was running rough, then I spent some time with it after eil left and got the idle to settle. Took it out for a test drive that night and it rode great, rode it around my area for 30 - 40 mins. The next morning I took it out for another test drive and as I was riding down 5 mile it made a few odd noises, stalled out and refused to start. Once I figured a way to get it home I popped the valve cover off and found that the sprocket on the exhaust cam had came loose, one screw completely out, the other partially and of course a broken cam chain.

So how bad is it? Do I have to take the whole motor apart now to get at loose pieces and replace the chain. It doesn't seem like there is a quick way to do this. Let me know what you all think.

Thanks fellas,
Sean
GS700 Cam.jpg

[jimb12]

Yes you will need to split the cases. Check the crankshaft for broken teeth on the cam chain drive. Look for any other carnage down there as well.

When you put it back together, clean the bolt holes in the cams and sprockets (plus the bolts) with rags soaked in brake cleaner (evaporates) followed by a dry rag. You can use a small screwdriver to push the rags into the holes. Once they are clean, dry, and completely oil-free, then put loctite on the clean bolts and torque them into the cams/sprockets.

[eil]

Yeeouch! What a crappy thing to have happen on a freshly rebuilt top-end.

My understanding is that a broken cam chain generally means bent valves as well. You have a second head, don't you?

[eil]

Hey Sean, have you formed a battle plan for this? I might have a few free weekends coming up before it gets cold and I'd be happy to drop on by to help. (Also need to pick up my IV tank if you won't be able to use it for awhile! :P)