1986 GS400E Valve Clearance

[d0zer]

Greeting All,

Firstly I wanted to say that this site has been a huge help in my quest in knowing all there is to know about the GS twins...THANK YOU

50,000 ft. overview....

I recently purchased a 1986 GS400E and have been working feverishly to get the bike up and running to it's optimal performance. My first step in getting the bike on the road was too locate some service manuals which was the easy part thanks to this site

I located the Clymer GS400-450 '77-'87 manual for this bike as well as the Haynes GS 250, 400, 450 79-85 manual (two heads better than one?) and started down the path of performing a major service of the bike.

The first part of the service consisted of Changing the oil and break fluids, new battery, new air filter, cleaned out the tank, new inline fuel filter, rebuilt petcock, and of course paint ...this got her on the road..and a happy week it was..

The Problem....

I then noticed a small oil leak coming from the cylinder head cover just above one of the half moons at which point I decided to take the cover off and replace the gasket. Once I got the cover off and spent some time reviewing Basscliff's valve guide for 8/16v motors, then more time reading the manuals I figured I might as well clearance the valves while I had the cover off as the top end of the motor sounded a bit louder than expected.

popped the plugs out, turned the motor till the cam lobe was pointed straight up and started looking the clearances....by eye, it seemed that the clearances were excessively large for each(almost a quarter inch?). rather then measure each one (which I know I should have done) I decided to go about setting them to the factory .003-.005 range (my gauge set started @ 004 so I started there). reassembled and tried starting her... the motor would barley turn over, wouldnt idle, and the top end sounded like it was about to explode...shut her down...

readjusted the valves going to a larger .007...she started..top end still sounded way too loud but I decided to take her out for a boot. The quick boot went OK and I decided to do the 120K commute to work the next day.

got in OK...heading home stopped by a mechanic friends shop and he agreed that the top end seemed really loud and that the clearances would need to go bigger... left the shop...about 10 minutes away...throttle cable snapped right at the throttle...no biggie.. managed to make it another 30K by manually pulling on the throttle cable wrapped around my finger and driving slow. All of a sudden...the bike cuts out on me... while rolling I try starting it again and it started...got another K before it did it again...when it happened the third time..the bike totally died...no lights, no camera, no action.

My questions...

1. am I using the wrong values for clearance? should I be looking at X manual rather than Y (I believe one states 003 -008 another 003-005)
2. being I have a new battery that should have been fully charged (considering I drove 100K that day) does this indicate stator issues?
3. is it sheer luck that all of this happened after performing my valve clearance( I can see the throttle cable being random...but could I have fried something with the stator?)

I have yet to dig into the bike after getting it home last night. My plan would be to check the overall health of the starting/charging system per Basscliff's guide and then move on to the valve clearance issue. I was also thinking of posting a video of the bike when started in hope of someone listing to the top end to see if Im crazy or not...

Thanks in advance for the response!

[cowboyup3371]

Welcome.

Valve clearances should be done in metric not standard - .03mm to .08mm
Go through the stator papers that you can find on the main page of the GS Resources site itself. Click on In the Garage and navigate from there
I would say that as things started working more like they should. When were your carbs last cleaned properly? Checked all connections?

Basscliff will be along later with the official welcome that has more links than you can imagine.

[Steve]

Is your 400 one of the 4-valve per cylinder models that we didn't get?

If so, your clearances are larger, I seem to rremember something like 0.09 to 0.13 mm, but I could be wrong, I don't do much with 4-valve engines.

In INCH measurements, that would be about 0.0035 to 0.005".

.

[pete]

Firstly, welcome!

Secondly, if you don't know how long it's been sitting, I think you'll find Cowboy's mentioning carb cleaning is where your issues could lie... give those carbs a good clean to be sure they're in good running order.

Have you checked for rust in the tank? If there's any in there then small flakes could potentially block the fuel supply also.

As for correct clearances etc. there's a seller on eBay e-classic bike (I think) out of New Zealand who may have a factory reproduction manual for a very reasonable price.

There's a 450 carb rebuild guide on BassCliff's site (which it sounds like you found already) but it's for the '80 - '82 carbs which I believe are quite different to yours. It still may help though.

[d0zer]

Pete, Steve, and Cowboy...Thanks for the prompt responses...

Cowboy...thanks for the clarification on the inch/mm.

Clymers lists Clearance should be 0.03-0.08 mm (0.0012-0.0030 in.). Haynes lists 0.08 - 0.13 mm (0.003 -0.005 in.) Basscliff's 8/16 valve guide list S .003-.005" (.08-.13mm) so we know which of the three is wrong

I have yet to touch the bike since bringing it home however Carb cleaning/electrical checks are on the to-do list this weekend. As the bike was running better before the valve clearance.... I dont think the excessive noise from the top end is related to the carb.

Steve, yes this is one of the 4 valve jobs we only got up here in Canada as I managed to get it running with the .007 the 009 to 013 sounds like it would be in the ball park for these heads... Im gonna try a nice even 11 and go from there.

Pete, Carbs will be cleaned this weekend...after I get the valves properly clearanced..and check the timing...

do you guys think running the motor with the reduced valve clearances may have caused the motor to run hotter than normal thereby maybe frying the stator? I'm not too familiar with bike mechanics so just trying to wrap my head around this all.

I know I can check this with some simple electrical tests..just trying to wrap my head around the concurrency of the events....

If anyone on here can confirm the values for the 1986 GS400 w 4 valves it would be greatly appreciated.

[pete]

Hmmmm normally I would trust the Clymer over the Haynes, and I'm completely confused about the 8 valve 400's as going by the Haynes I have it appears to indicate 0.03 - 0.08mm which is the same as the 4 valve...

Running low clearances won't be good, but I don't know if it will make the engine run hotter, but I do know that lean fuel/air mixture will make the exhaust hotter...

I'd really suggest trying that eBay seller for the correct factory reproduction manual, then you'll know for sure... Mine was $US30 plus shipping, cheap!

[d0zer]

Pete,

I managed to find a GS400E/S supplementary manual on ebay at the following location...

http://cgi.ebay.com/ebaymotors/Suzuki-GS400E-S-Factory-Supp-Service-Manual-motorcycle-/270629804862?pt=Motors_Manuals_Literature&hash=item3f02cb1b3e#ht_657wt_939

waiting for the west coasters to wake up and will give the guy a call regarding the manual and hopefully he will be nice and provide me with the clearances over the phone.

Thanks again...I'll update after the weekend wrenching on my baby...

[pete]

Aaah nice find! I was about to say oh but it's an GS400E/S manual, thinking 4 valve head, then realised the seller's in Canada so it should be for the 8 valve head I would think...

It gets a bit confusing because here and in the UK we call them GSX's, whereas the US seems to have them all as GS'... makes it very confusing!

[d0zer]

Just wanted to update everyone on the progress..some success some new troublesome finds (maybe)

Firstly...I pulled the valve cover and checked the clearances again...They were really loose...I read through the different guides again and realized that I didnt set the ATU to T mark as I should have and just used the cam lobe/notches as my guide.

I set the clearances correctly and the motor came to life and sounded pretty decent although she died on me a couple of times with the idle below 1300.

I repaired my throttle cable using some fresh 1/16 steel aircraft cable, a block of wood, drill bits, flux and some rosin free solder. took me 4 or 5 tires to get the process correct but I managed to make a custom cable for under 5 bucks.. I tested the tensile strength of the solder end piece in a vise and couldnt pull it out so I think this cable will work just fine.

I went for a ride and everything went well but I could still hear a bit of noise coming from the upper end of the engine at different times throughout the rpm range.

I pulled the valve cover off again due to a small leak at one of the half moons (new ones being installed tonight) and while looking at them I noticed that my exhaust camshaft has some side to side (horizontal) play to it. The Intake cam is rock solid and has no movement so I am assuming this might be the problem.

Questions...

1. could this just be a loose cam bearing cap?
2. should there be any horizontal movement in the bearing?
3. what are common causes/fixes for this play?


Thanks again in advance.

[pete]

Good to hear you're getting somewhere!

I have seen along the way that these can develop some cam walk which I believe may be what you're seeing, although I'm pretty sure the noise from that is only heard at idle, so if you're hearing it on the move I suspect it may be something else, but not 100% sure on that.