1981 gsx400l project/complete rebuild

[C_OUELLET]

Trying to get it runing

Thanks for that huge reply SoHum!
So a small update, I took your advice and put some oil in the cylinders and turned it over clockwise by hand a few dozen times, it seems to have a little resistance when turning over (feels like a normal amount) but then after I hit a certain point (maybe TDC) it will turn on its own for a bit (maybe till the piston is at the bottom) ??? does this sound normal? Ill try and get a video of that over the upcoming weekend.

Tried starting it with out the exhaust just to see if I could get it to run for 10 seconds, but no luck. What I did get however was a loud snap and some out the carbs
The next time I tried starting in I got a ball of fire out the left side exhaust valves. If I stick my finger in the left side exhaust hole (remember I don't have the exhaust on) it is fairly wet with gas, the right side is dry. The flame ball seems to be coming out the left side only.

I also got new NGK plugs, but I'm not sure if I've got the right coil going to the right cylinder, is there any way to figure that out?

After that I found a place fairly local to me that has OEM valve cover gasket, chain tensioner gasket, as well as the oil breather gasket at the to of the valve cover. SO off came the valve cover and I'll be checking the valve clearance shortly. I have not found a write up for my bike on the Basscliff site, however I did find this thread;

http://www.thegsresources.com/_forum/showthread.php?167473-how-to-check-valve-clearances&highlight=400ez

It appears I may just have to turn a screw to adjust my valves instead of getting new shims, does that sound right to anyone? Also does anyone have any suggestions on starting up this bike, ill be putting the exhaust pipes back on before trying again.







Don't mind the horrible quality, though my camera was broken. Turns out the settings were all wacked out.

[C_OUELLET]

Getting bummed out by the lack of replies I'm getting on this tread, maybe I'd have better luck in the GSTWINS section of this forum?
Anyways, I got myself a feeler gauge set and was going to have a go at adjusting the valves until I realized that my cams aren't lining up like they do for the 4cyl bikes. Here's a picture of the notches;


If this is correct, what valves do I check when the left (rear) cam is facing out, level with the cylinder head? and what valves do I check when the right (front) is facing outwards?
I tried checking all my valves when I had them turned either way, all them are too tight. I couldn't fit a .003 feeler gauge and specification shows .003-.005" (.08-.13mm) ON BOTH INTAKE AND EXHAUST.

Also took a picture looking into the exhaust ports, looks pretty dark! Should I be worried? Is there any need to go further than valve adjustment? should I be looking into taking off the cylinder head and cleaning the top of the pistons and the top of the combustion chamber? I've priced out a cylinder head gasket at around $90 :/ I'd like to avoid going deeper into the engine if at all possible. Any thoughts?

[Fjbj40]

Do you have the factory maintenance manual? It would answer lots of the question you are asking. Rust on the cam lobes is not good, however it is only very minor in those pictures.

Exhaust ports get dirty, that's their lifestyle!

If the plugs are in when you are turning it over and it is hard to turn then compression is building, when it gets easier it is when the piston begins to go down so it is no longer building pressure so it is easier to move.

http://www.mtsac.edu/%7Ecliff/storag...ete_Manual.PDF here is a manual.

Daryl

[C_OUELLET]

Just a small update, no good progress though tossed the carbs, exhaust and air box on, tried my luck cranking it over a few more times. Didn't fire up, pulled the plugs and the left one was dry, last time I worked on it, the left was getting TONS of fuel and even spitting gas out the exhaust port (didn't have pipes on). When I pulled the left plug and held it against the block I found it had a weaker spark than I remembered. I'll have to look into the "relay coil mod".

I'm hoping I can get the valves adjustment done soon, I'm still not sure how to go about it, I'm still not sure if my cams are positioned correctly. I'm also trying to get my hands on a compression tester to see if I need to dig any deeper into the engine. I just want the bike to run so I can start doing some cosmetic stuff to it!

[posplayr]

I just noticed this thread. Some of the first pictures were pretty scary, kudos for having the patience and drive to get this thing fired up.

If you have compression, it should fire. Pull all the plugs and put your finger(thumb) over each. The compression should blow your thumb off. Until the bike has run, there is no reason to actually try and measure pressure as it will probably only get better as the rings start to reseat.

If you have compression then all that is left is spark and fuel. Make sure that the bike is generating spark on all cylinders. You need an exhaust and airbox to get it to run. Trying without either exhaust or airbox is going to be very disappointing.

Try to avoid using too much starter fluid (you will be temped I'm sure).

To start with you can wire the coils right off the battery through a fuse to get full power to them. The coil relay mod can come later.

I assume you have oil in case you do get it running. I would crank it over for a while to make sure it is fully oiled before starting.

[2BRacing]

I am not a twin cylinder fundi, but the basic principles are similar to the 4 cylinder engines. Just from browsing through your photos and posts, I can make the following suggestions:

1) refer to page 9/139 of the manual linked to you in post #18 above for the cam timing picture. Make sure you turn the crank to the correct TDC mark (look in small round cover on right side) and then look for the arrows and numbers 1, 2 and 3 on the cams. Count the number of pins on the chain as shown. If not correct, get the cams set correctly first.

2) that manual does not describe how to set valve clearances. Refer to another manual for a 16 valve engine on BassCliff's site and read up how to do the adjustment. You have mentioned that your clearances are too small. Using the correct procedure, get your valves adjusted correctly. Too little clearance could result in some valves not sealing properly, resulting in low compression, which will make starting difficult. While you are in there, lubricate the cams with oil from an oil can to prevent undue wear on surfaces when starting up.

3) once you have the above two items sorted out, go ahead and try to start.

Good luck!

[Gorminrider]

....that manual does not describe how to set valve clearances.

yes it does. Page 88.

[2BRacing]

yes it does. Page 88.

I scrolled through all 139 pages of the manual linked in post #18, and did not see the valve adjustment procedure (which was odd to me at the time, as this is usually in the manual).

I have just looked again, and still cannot see that information on page 88 of that particular manual!

Can you provide a link to the manual from which you have copied the page?

[C_OUELLET]

I also have never seen that page before!
So 2 nights ago a gsx400 engine popped up on Craigslist, just the engine, no carbs or starter, he wanted $100 but said he'd take 60 if I picked it up fairly quickly. Needless to say, now I've got a parts engine. I'd like to think that was a good buy

now on to the one in the bike..... I pulled the chain tensioner out, adjusted the cams in the proper positions, now I'm counting 20 pins between point 2 and 3. Then I put my finger over the spark plug hole while cranking it. I felt suction, not pressure. Tried the other cylinder, same thing. Had a pressure gauge I borrowed from a friend, it's reading 0psi. Has anyone heard of this. Also, I was checking my valve clearance, and at TDC, one intake and one exhaust were up, then at the other tdc only 1 set was up. Are there 3 cam positions in order to check all my valve clearances?
Also noted my engine oil now smells like gas. I've been running a water bottle to the T fitting on the carbs. Does the mean my float needles are stuck and its flooding into the cylinder then into the oil?

Ive vey obviously got more research to do! But thanks for all the replies.

[Vmass]

Hey C, looks liKe a great project! I don't have any experience with twins, so I won't be much help.

The carbs look awesome..........you set the bar high for the rest of the bike! Good luck.

[Gorminrider]

I scrolled through all 139 pages of the manual linked in post #18, and did not see the valve adjustment procedure (which was odd to me at the time, as this is usually in the manual).

I have just looked again, and still cannot see that information on page 88 of that particular manual!

Can you provide a link to the manual from which you have copied the page?

My mistake. I think Bass Cliff has updated his manuals. But I was sure I got the Haynes I show from him.
He now seems to have the actual GSX shop manuals! good thing too because they disappeared from their original location online where I got them. "GS250T-GS300L '82 Service Manual (91MB)"
I am not going to download it all to be sure, but it matches the size of mine and I am assuming it's the case.


whatever.
The GSX400 manual is meant to be used in concert with the 250 shop manual . You will find valve adjustment in them but get the clearances from the 400 manual...dyou see? The 250-300's are the only 2 cylinder GSX (4valve per cylinder) sold in the states.


Bass Cliff's library

http://members.dslextreme.com/users/bikecliff/

anyways if it gets too difficult I'll have to post the pages (or somewhere, the whole manuals)


have a look here too but I don't see the Haynes here either.
http://www.pdfmotomanual.com/index.php?r=site/page&view=manuales&order=t&key=S&make=1809&lang=EN G

[C_OUELLET]

So I got fed up with not knowing what the deal was with no compression so I started pulling apart the new parts engine. The valve cover came off easily, then removed the cams, kept the chain from falling in the engine, removed the head and looked at the valves. I figured I couldn't mess it up by removing the one on the bike, so I pulled the head with the engine still in the bike. The valves on my bike look I little more beat up but they looked like they'd still be able to hold pressure. After inspecting both heads, I concluded they were the exact same and finished a head swap, put the cams in, counted the pins between the cams and put in the tensioner. I gave it a few spins by hand with no issues so I put my compression gauge in the sparkplug hole and cranked it over.
I was reading roughly 55psi in each cylinder with both sparkplugs out. Is this a good number? If I recall, I think it should be up at 120 ish? but I'm hoping that when I put the carbs on and 1 cylinder fires the compression will go up? Can anyone confirm this for me? Now I've got to try and get my carb boots off this new head (totally forgot to do that when I had the head out of the bike, and the screws are striped )

Unfortunately I didn't take any photos, I'll upload a few of my old valves in a while, you guys can let me know how bad they look!

[C_OUELLET]

Getting there!

So, starting from where I left off with my last post. I had an hour or so Friday, before grabbing a burger/beer after work, so I figured I should go putter on the bike, since it was on the way to my evening plans. Took out the small propane torch, heated up the intake boot screws and managed to get them off fairly easy. After that, when comparing all my intake boots, I noticed they were directional, who knows if I had them all backwards before! Picked the best looking two of the four, put in my new 34mm Viton O-rings (I have 2 spares in case someone reading this one day needs any) slapped the carbs on and cranked it over. Nothing. Took a good look at the carbs and tried to remember how exactly they worked, got fed up and thought to myself "do I need to completely deprive it of air to get gas in this thing". Grabbed the closest, driest rag I could find, held it up against the carbs. BOOM! Bike fired up instantly It died about 4 seconds later (I assume because I was completely covering the carbs, starving it of air. I started it up like that 2 more times before realised I was running late for my plans.
As I was packing up my tools I noticed a bunch of oil leaking from the head, that's right, when I did the head swap one gasket got all torn up, the other was in decent condition. I stacked them on top of each other because I figured "hey, I'm just checking for compression, I'll need a new gasket regardless and ill deal with it when I have compression"
So now looking back at it, if oil was spewing out, I could only imagine I was losing some compression there too. Il be picking up a new gasket this weekend, ripping it apart again and re assembling it. This time ill try and put the air box on as well. Can anyone tell me the best way to install it?

Anyways, now that ive heard it start, im seeing a light at the end of the tunnel. Now comes the fun part, spending all my money on new parts. I was quick to get rid of my old tires, sandblasted my rear wheel today, hopefully the front gets done tomorrow. One of the maintenance guys at work helped me pull my old wheel bearing out and told me to get new ones ( I planned on it anyways). He then proceeded to go through his catalog and find the bearing number that was stamped on my wheel bearing and showed it to me. $6USD, he assures me its the same exact thing, my concern is safety. Anyone know if this is ok to do?

ill upload another update of a parts I'm looking at getting.

How the bike sits right now, wheels off for sandblasting.


Small LED panel I'm working on. I plan on putting the oil, high beam, neutral and gear indicators lights on there.


Rear wheel sandblasted

[C_OUELLET]

Cosmetics and wheels

Today I managed to sneak away from my desk and get some sandblasting in. I've now got both wheels ready for powder coating but still need to sandblast the rear drum brake. A coworkers brother works for a powder coating company and got me some sample colours today. I think I've chosen 3 colours I want the bike to be. Wheels are going to be getting done next week with an "Iron Glimmer P7" colour. I don't plan on painting the whole bike at this point, just the wheels before I buy some new tires. I'm all ears if anyone has any tire recommendations! I went ahead and found the same bearings for my wheels, they aren't "Suzuki" wheel bearings but the are the exact same bearing number. 6302 and 6303 if I remember off the top of my head. These new bearings have a metal guard on both sides where as oem ones have only the outside covered. Should I remove a side from these new ones and pack a small amount of grease into them as well?

Tomorrow I should be picking up that new head gasket, ill know by the end of the weekend if the bike will run or if there's more issues once its all together.

enjoy some pictures Let me know what you guys think.

Both wheels sandblasted, ready to be powder coated. Still need to sandblast the brake drum.


New wheel bearings


Wheel colour options


Three colours I'd like to see the bike. Iron for the wheels and frame, sparkle silver for the engine and black for the exhaust and battery box and others.

[jbird7262]

Looks good!!, keep up the posts, and try the twin section of the forum for more tips from the 450 guys. Should be a nice little bar hopper when done.