Bad gas story

[Rich82GS750TZ]

Mat, on my quick glance through that multi-model 400 manual, I also did not see the valve adjustment procedure. I just assumed it was in there somewhere. I’ll do some digging and see what I can find. I don’t want to send you to the instructions for a 4 cylinder TSCC because I have to believe it will be misleading.

This manual for the 250T-300L Twins from BikeCliffs Website clearly shows the valve clearance procedure on a TSCC Twin. Starts on page 2-5 (pg. 30 of the pdf).

https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/GS250T-300LZ_manual-82.pdf

[Mat]

Thank you very much Rich I would not know where to look.

I have read and printed pages 30-31 and I better understand where to measure with the gauge but I'm not sure about how to position the camshaft for it.
Will make some tries when I'm back home tonight, and post pictures for help


On another note I'm curious about my motor design, is TSCC a better or less solid design in general?

[Rich82GS750TZ]

Suzuki thought it was “Better” I guess, but apparently not enough to use the design in their shaft-driven motorcycles of the time. There are a few pages about the TSCC design in that manual.

[Mat]

I read thoses pages but that's just Suzuki saying that... wonder what the test of time says


After the morning coffee I think i'll be okay with camshaft position

we'll see tonight

[Rich82GS750TZ]

I'll highlight some key points from the manual where the images are faint/hard to read and where the instructions aren't very thorough.

Pardon me if I write something that you think is obvious. I don't know what you don't know, and I was where you are 5 years ago.

You need to take the ignition cover off the right side of the engine. There's no oil behind it, and no gasket except maybe a paper dust gasket that you can re-use.

Removing Spark plugs will make turning the crank easier/smoother.

You need a 19mm wrench to turn the nut on this end of the crank shaft CLOCKWISE ONLY / the direction the motor turns, to get the mark by the "T" on the advance wheel to line up with the arrow you should see in the hole in the ignition plate. The cam shaft ends have a notch in them that is hard to see in the pics in the manual I've highlighted them as:
Red- Position A,
Blue-Position B

With the timing mark at "T", The cam shaft end notches should either be at position A, or position B

If at position A, you measure and adjust. Intake. and Exhaust of the Right Cylinder, and Intake of the Left Cylinder (Right is as you're sitting on the bike- this is always the case when manual refers to Right and Left).

or.

If at position B, you measure and adjust Exhaust of Left Cylinder.

After you complete measuring and adjusting at one position, you rotate the the crank shaft 360 deg. bringing it back to the "T" mark, but the notches will be now in the other position.

I think it's a good idea after measuring.at one position to turn the crank 2 full revolutions, and measure again, just to be sure. Probably not necessary, but couldn't hurt.

[Mat]

Thank you for that, it makes an excellent guide, very easy to get into action That very last image helped a lot with the colors.

My tool should show up in the next few hours, will report back how well it went after the job.

[Rich82GS750TZ]

The biggest job by far is cleaning off all the old gasket. It looked pretty bad in the pics on your other thread.

[Mat]

All went pretty good after all. Yeah, that gasket was a mess to pick up.

I have one question before I fire the engine, the left intake valves required a lot of adjustment. Most valves were tight and required a quarter turn but the left intake valves required a lot and you can see it top left, the adjusting nut is really high over the lock nut compared to the others (you can only see one on the pic but both are about the same. Should I be worried?

I noticed hand cranking is smoother after the valve adjustment

PXL_20230530_223814213.jpg

[rphillips]

Did you turn the eng' over a few revolutions then put the cams back in the correct positions and recheck?... Just to be sure.

[Rich82GS750TZ]

Yes, I would double/triple check your measurements before you close it up. Make sure the cam shaft end notches are in position A to measure L intake as I noted above.

[Mat]

Did you turn the eng' over a few revolutions then put the cams back in the correct positions and recheck?... Just to be sure.

Yes I did at least 3 revolutions before checking back the gap.
I did check twice but towards the end I was excited and tired at the same time so I decided to call it a day for now.


Also I had got my hands on the proper torque pattern (inside to outside) but forgot where I've seen this


The gasket I had ordered off ebay wasn't the correct one so I crafted a new one with some Felpro I had. Did I read somewhere some ppl spray it with WD40 to be able to reuse it next time they do valves? I'd be happy not to do paper construction too often, wish there were some real gaskets (silicone) available for my model.

[Mat]

Yes, I would double/triple check your measurements before you close it up. Make sure the cam shaft end notches are in position A to measure L intake as I noted above.

I wasn't doing it right, my brain was half-working yesterday night and I was doing the left intake valves at the wrong cam position. The bike idle well so I'm going for a test ride and see how it goes.

[Rich82GS750TZ]

You wouldn’t want to use a “Real Gasket”. They’ve been known to cause problems in this type of engine with the tach drive in the valve cover. The gasket squishes too much and causes problems where the tach drive meshes with the worm gear on the exhaust cam shaft. OEM is best. So I’ve read.

[Mat]

Good to know about Real Gasket.
When people say OEM, does it mean they can order from Suzuki direct or it's old stock on ebay only? I guess old stock only?

I'm a little better at doing my own gasket, still spent a couple hours on it but no leak at least.

BTW I'm happy to report I just did a good ride without any problem Could never gone trough it without your help all
My dad (PO) was quite impressed to see all that help I got

[rphillips]

Congrats Mat, learning curve, now that you've done it, pretty simple from now on.