Suzuki SV650 Riders Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
199 Posts
Discussion Starter #1
I'm at 14,800 miles, doing the first valve adjustment on my 2008. I was hoping everything would be fine, but I've checked the front cylinder and they could all use adjusting. Intakes are at 0.004 and 0.005, on the tightest side of the 0.004-0.008 spec. Exhausts are out of spec at 0.006, spec being 0.008-0.012. Should I adjust to the loosest end of the spec, since mine are tight and will probably continue to get tight from what I've read?
 

·
Registered
Joined
·
199 Posts
Discussion Starter #2
So I tried adjusting the exhaust valve clearance to 0.010" and it literally did nothing. There were 1.65mm shims on both valves and I changed them to 1.55mm. Should have given me an extra 0.004" of clearance. Reinstalled the cam, torqued the cap to spec, and tensioned the chain. Rotated the crank through a few revolutions. Rechecked clearance and it's still 0.006". What gives.
 

·
Registered
Joined
·
6,732 Posts
I never go by what's printed on the shims...much better to use a micrometer and measure what they actually are. In your case...you're in the middle of the spec which is fine and the setting should be more stable now that everything has been run in. As long as both cylinders have the same clearances the cam timing will be good and you should be able to synch the TB's with little problems.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #4
So I think I got the front cylinder adjusted correctly, but now I have another problem. I didn't realize the rear cylinder had to be timed with the front in TDC. The service manual says to time the front at TDC of the compression stroke, which I did, but then it says to rotate the crank 360 degrees (which I suppose will put the front cylinder at TDC on the exhaust stroke) to time the rear. I already took the cams out of the rear with the rear at TDC of the compression stroke. So I guess that means I have to get the front cylinder to TDC of the exhaust stroke before I time the cams in the rear cylinder. Does that make sense? How do I do that? What stroke should the front be on now that the rear is at TDC of compression?
 

·
Registered
Joined
·
6,732 Posts
The SV rear cam procedure does mess up lots of people because it's a bit counter-intuitive. The front cams are checked and timed at 'F/T' on the rotor (which is TDC on front), then rotate motor 360 to get back to 'F/T' (which is again TDC on front) but now you set the rear cams in time at that position.

To check the rear clearances you must have the rotor set at 'R/T' which is only 270 from 'F/T' where you had checked the front. To me it would have made more sense to have both jugs checked and timed at their respective TDC's....but Suzuki thought otherwise so we must go with what they did.

So....TDC compression on front, spin 360 (same direction as wheels rolling forward) back to the same place (but now will be TDC on exhaust stroke)......then at that place align the rear timing marks and you'll be good to go. I think the manual has pictures of where the cam lobes should be just to double-check.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #6
The SV rear cam procedure does mess up lots of people because it's a bit counter-intuitive. The front cams are checked and timed at 'F/T' on the rotor (which is TDC on front), then rotate motor 360 to get back to 'F/T' (which is again TDC on front) but now you set the rear cams in time at that position.

To check the rear clearances you must have the rotor set at 'R/T' which is only 270 from 'F/T' where you had checked the front. To me it would have made more sense to have both jugs checked and timed at their respective TDC's....but Suzuki thought otherwise so we must go with what they did.

So....TDC compression on front, spin 360 (same direction as wheels rolling forward) back to the same place (but now will be TDC on exhaust stroke)......then at that place align the rear timing marks and you'll be good to go. I think the manual has pictures of where the cam lobes should be just to double-check.
Right, so I'll need to take the the front valve cover back off to verify the position of the cams? I was just trying to avoid doing that.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #7
Or I could just go 90 degrees on the crank and that should be at the correct "| F" mark wouldn't it? Might just be better to pull the valve cover anyway so I know for sure.
 

·
Registered
Joined
·
6,732 Posts
If you have a sparkplug out......just turn until you feel compression (on the front) then turn until the 'F/T' comes up.....then 360 back to 'F/T' which then is the timing position for the rear cams.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #9
If you have a sparkplug out......just turn until you feel compression (on the front) then turn until the 'F/T' comes up.....then 360 back to 'F/T' which then is the timing position for the rear cams.
That's a good idea. Already took the cover back off though. Should any timing marks line up on the cams of the front cylinder when the rear is in timing position? It looks like the exhaust has just come off the cams and the intake is about to start, so that would be the end of the exhaust stroke and beginning of intake if the piston is at TDC. How hard is it to slip the chain on the crank sprocket on these motors? I just had to hold the chain up while turning. I hope it's okay. I don't know what stroke the valves should be on now. I think I timed them correctly and it looks like the exhaust valves are about to open and the intake is pointing almost straight up. That indicates to me that the piston is at BDC of the power stroke, about to begin the exhaust stroke. Is that right?
 

·
Registered
Joined
·
6,732 Posts
With the rotor pointing at 'F/T' when timing the rear cylinder the front cams should be in overlap where the exhaust is almost closed and the intake just beginning to open....so the motor is in the proper position to install the rear cams. Go by the timing marks on the cams (rear) and double-check with the manual which should show the lobe relative positions just to be sure. Then rotate another 360 forward and double-check the front cam timing so you know nothing slipped in the process. Done!! :)
 

·
Registered
Joined
·
199 Posts
Discussion Starter #11
With the rotor pointing at 'F/T' when timing the rear cylinder the front cams should be in overlap where the exhaust is almost closed and the intake just beginning to open....so the motor is in the proper position to install the rear cams. Go by the timing marks on the cams (rear) and double-check with the manual which should show the lobe relative positions just to be sure. Then rotate another 360 forward and double-check the front cam timing so you know nothing slipped in the process. Done!! :)
OK, well I think I have it in the right position then. Took a break before I try to wrestle the rear tensioner back in. This job really is significantly worse on an ABS bike. There's hard brake lines in the way of getting the rear valve cover off, and the ABS module + some more brake lines and wires behind the rear tensioner make working with that even worse. Had to take the rear wheel off just to try to get more access. I've heard the rear tensioner is a huge pain, but honestly it looks like it would be pretty easy if I didn't have ABS.

So, maybe I'm just confusing myself, but I would expect a 2 cylinder 4-stroke to have an even firing order where both compression strokes would be 360 degrees apart. Wouldn't that make the most sense for vibration reduction? If the rear gets to TDC of the compression stroke 270 degrees after the front, then the next compression stroke would be 450 degrees away for the front cylinder, right? Two rotations of the crank is four rotations of the cams, or one complete cycle. Just seems odd in my feeble little mind.
 

·
Registered
Joined
·
6,732 Posts
The 90 degree 'L' Twin is an odd-firing motor. No way around it unless you'd create a split-journal crankshaft which would add width and defeat one of the advantages of this design...being narrow. The 'L' Twin is actually in perfect Primary balance so it needs no add-on balancing shafts like so many designs do or suffer from terrible vibration. The motor does have a Secondary imbalance but it's minor and mostly vertical and easily absorbed by the frame so the rider feels a nice smooth running most of the time.

If you look at the SV1K motor (similar design mostly) it uses chain drive from crankshaft to a gear mounted low in the head which then drives the cams via straight gear drive....so we can remove and reinstall cams without touching the chains. Very nice setup and a better one than the 650 IMHO...but you've got to work on what you have I guess. Sounds like you're on the road to success...:) Ride safely!
 

·
Registered
Joined
·
199 Posts
Discussion Starter #13
The 90 degree 'L' Twin is an odd-firing motor. No way around it unless you'd create a split-journal crankshaft which would add width and defeat one of the advantages of this design...being narrow. The 'L' Twin is actually in perfect Primary balance so it needs no add-on balancing shafts like so many designs do or suffer from terrible vibration. The motor does have a Secondary imbalance but it's minor and mostly vertical and easily absorbed by the frame so the rider feels a nice smooth running most of the time.

If you look at the SV1K motor (similar design mostly) it uses chain drive from crankshaft to a gear mounted low in the head which then drives the cams via straight gear drive....so we can remove and reinstall cams without touching the chains. Very nice setup and a better one than the 650 IMHO...but you've got to work on what you have I guess. Sounds like you're on the road to success...:) Ride safely!
Considering I just spent an hour trying to get the tensioner back in without getting a single bolt started, I'd say I'm not on the road to success. If I have to take the tensioner back out to shim again like I did on the front cylinder, it's going to be a very long week.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #14
Left the bike for a couple days and finished up today. Had to have help to get the rear tensioner in. Exhaust was only slightly in spec after adjusting, 0.008" and 0.009". Intake at 0.005" and 0.007". I really don't understand what's going on, they all should have been looser than they ended up being with the shims I used. Oh well, they're in spec. Replaced the oil and plugs, and cleaned and adjusted the chain. First start was fine, though I imagine I'll be smelling oil when it gets hot from the drips off the rear tensioner when I removed it. I hope the valve cover seals hold. I'll lube the chain in a few minutes and take a little neighborhood ride.
 

·
Registered
Joined
·
37 Posts
This may or may not have bearing on the inconsistency of clearance issues you've had, but I have seen in another manual, GSX-R600 I think, that you need to rotate the engine through several cycles to settle the shims and the oil they are coated with to get accurate clearance readings.
It does make some sense.
 

·
Registered
Joined
·
199 Posts
Discussion Starter #16
This may or may not have bearing on the inconsistency of clearance issues you've had, but I have seen in another manual, GSX-R600 I think, that you need to rotate the engine through several cycles to settle the shims and the oil they are coated with to get accurate clearance readings.
It does make some sense.
Yup, the SV manual says to rotate it once to squeeze the oil out. I did that.

My ride was fine, bike feels normal. I can hear valve tick when the motor is running now, which I never noticed before. I suppose that's due to all of them being loosened so I guess it's fine.
 

·
Registered
Joined
·
37 Posts
Hmm, can't say if this SV ticks or not while riding... it's the Missus' bike and she won't let me put miles on it.
 

·
Registered
Joined
·
6,732 Posts
"My ride was fine, bike feels normal. I can hear valve tick when the motor is running now, which I never noticed before. I suppose that's due to all of them being loosened so I guess it's fine."

You should be able to hear the valves...just a little at idle. This is something that gets people into trouble because they normally get quieter with wear as the clearances decrease and thinking that they'll get looser and louder (as many older pushrod type engines will) has a bunch running with very tight valves. If you've ever adjusted the valves on the old Corvette 'Duntov 30-30' factory racing cams (the 30-30 is the clearances in thousandths) the SV sounds like a sewing machine with just a mechanical busyness of mechanical things lightly hitting one another while running....which is how they're supposed to sound rather than being super quiet.

There is an old saying " A tappy valve is a happy valve" :)
 

·
Registered
Joined
·
199 Posts
Discussion Starter #19
"My ride was fine, bike feels normal. I can hear valve tick when the motor is running now, which I never noticed before. I suppose that's due to all of them being loosened so I guess it's fine."

You should be able to hear the valves...just a little at idle. This is something that gets people into trouble because they normally get quieter with wear as the clearances decrease and thinking that they'll get looser and louder (as many older pushrod type engines will) has a bunch running with very tight valves. If you've ever adjusted the valves on the old Corvette 'Duntov 30-30' factory racing cams (the 30-30 is the clearances in thousandths) the SV sounds like a sewing machine with just a mechanical busyness of mechanical things lightly hitting one another while running....which is how they're supposed to sound rather than being super quiet.

There is an old saying " A tappy valve is a happy valve" :)
Yup, I think it's all good. Nice to have this out of the way. I don't get to commute on the bike anymore so I shouldn't have to do it again for at least another 4 years.
 
1 - 19 of 19 Posts
Top