Another Cam timing thread

[Guest]

I've looked around and found some, but while I understand the answers I need to just verify that my eyes aren't fooling me. (also hopefully some clearer pictures so others can see how close it could look but possibly still be off).

Summary: Bike (1981 GS 550T )starts, idles fine and runs fine up to about 5k rpms. There something changes. I've been over the intake system, new Orings sync'ed carbs (freshly built with fresh orings), stock airbox with K&N OEM replacement filter, sealed airbox (cept where air is supposed to enter). Still does the same thing. Nerobro and I were talking and he suggested looking at cam timing, thus my investigation and the following pictures (click the pictures to see larger versions).


Timing plate lined up:




Exhaust cam pic as system is at TDC:



Another further out:



Another with flash:



There are some more pictures in the album, but they are blurry.

Anyway, I'm thinking I'm a tooth off, which makes both sides a tooth off, but I wanted to get some other opinions. The clymer has the one and the arrow more lined up and it's hard to tell.

Any of you pros out there that can say "yeah, you are off" would be re-assuring to me.

Amos

[hampshirehog]

From your photos it looks like you're a tooth out. The arrow on the exhaust cam should be exactly in line and level with the cylinder head. To make sure, line your eye up exactly on the head and look along it - easy to get it wrong otherwise.

[rustybronco]

You're off a tooth.
#1 points to the edge of the head and #2 points straight up.

[nutsandbolts]

Yesp- same comment from me. Off a tooth.

[TheBigRed]

Thanks Guys!! That is what I was thinking after looking at it this morning.

I'll tear into it this weekend sometime to correct it and report back the results.

This evening is tied up, tomorrow we have a wedding to attend, but I'm looking for Sunday to be pretty open, so A couple of hours in the morning and I should have this corrected.


Amos

[rustybronco]

Also measure the chain stretch while you're in there.

[waterman]

I agree with others, one tooth off. When positioned correctly the arrow actually looks to be pointing slightly under the gasket surface. It is sorta deceptive since it is parallel to the gasket surface when off by one tooth as your pictures show. Good pics BTW, easy to see what is described.

One of my 650 was like this and also had one tooth off between the cams. It ran surprisingly well, but didn't quite sound right. Does make you wonder what they were doing with cams out though.

[TheBigRed]

I agree with others, one tooth off. When positioned correctly the arrow actually looks to be pointing slightly under the gasket surface. It is sorta deceptive since it is parallel to the gasket surface when off by one tooth as your pictures show. Good pics BTW, easy to see what is described.

One of my 650 was like this and also had one tooth off between the cams. It ran surprisingly well, but didn't quite sound right. Does make you wonder what they were doing with cams out though.

Thanks, I was trying to get the best pics I could in the short time I had this morning, also wanted good pics so those who come after have an idea of what it looks like when wrong/right.

As for what they were doing with the cams out, here is more detail:

http://www.thegsresources.com/_forum/showthread.php?t=82482

Amos

[waterman]

Thanks, I was trying to get the best pics I could in the short time I had this morning, also wanted good pics so those who come after have an idea of what it looks like when wrong/right.

As for what they were doing with the cams out, here is more detail:

http://www.thegsresources.com/_forum/showthread.php?t=82482

Amos

Well, since I don't get down to appearance section much, (too much guilt since my bikes are half way to ratdom), I hadn't seen your project. Looks great and a great read about your travails, I sometimes wish I would document some of the stuff I have done if only so I could accurately remember it.

Especially enjoyed reading about the "group" effort involved in the resurrection. It always delights me to see how this group helps out others with our projects, even if only to razz about speed of progress.

[TheBigRed]

Well, since I don't get down to appearance section much, (too much guilt since my bikes are half way to ratdom), I hadn't seen your project. Looks great and a great read about your travails, I sometimes wish I would document some of the stuff I have done if only so I could accurately remember it.

Especially enjoyed reading about the "group" effort involved in the resurrection. It always delights me to see how this group helps out others with our projects, even if only to razz about speed of progress.

Yeah, I greatly appreciate all the help I received with the project especially there at the end and up to now, and probably beyond. As this thread shows though, something can be slightly off even when paying attention to the detail (I don't blame anyone for this error as I was there when this part of assembly was done and I missed it as well).

But I'm really hoping this fixes the issue and from here on out this bike should be able to live with routine maintenance and care.

Amos

[nutsandbolts]

make sure that you have exactly 20 chain pins between arrow 2 on exhaust cam and arrow 3 on intake cam.
best,

[TheBigRed]

make sure that you have exactly 20 chain pins between arrow 2 on exhaust cam and arrow 3 on intake cam.
best,

Oh, I forgot to mention that I did count that the way it is right now and that "measurement" is correct, but with the exhaust being off as it is pictured, that makes both of them off.

Amos

[TheBigRed]

Ok, I think I have it right now, but before I button everything down gasket and all I wanted to get some feedback. So, here are the pictures: (BTW I have the cam chain tensioner in place and have turned the engine over at least one full time with the 19mm bolt to make sure all slack is taken up)

Timing plate:




One angle (here it looks like the arrow may be too far but I'm not sure):




There are some other pics in the album, but they are kinda blurry.

I'm going to go measure the cam chain for stretch (I doubt it's out of spec), and triple check the count between 2 & 3. Hope to hear back soon to tell if I've gone too far.

Amos

[rustybronco]

Looks good!

[TheBigRed]

Thanks!! Now to clean up the gasket surfaces (blegh). and torque everything to spec, button it all up and see if the rain will hold off so I can take a test ride.

Amos