1981 gsx400l project/complete rebuild

[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=ENG

 

[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!

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 :clap: 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

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.

 

[C_OUELLET]

Took a few pictures today while installing the head gasket. I wasn't sure what way the head gasket went so I put the "H" mark up. Got the bike running after the new gaskets were installed, so that's a plus!

spent an hour or so scraping the old gasket off


This is a photo of the new head I swapped in.
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[URL=http://s1374.photobucket.com/user/C_ouellet/media/1981%20400L/DSC_0447_zpsjzlun7xs.jpg.html]

 

[C_OUELLET]

Alright I'm back, been away for the last two months on vacation. I just started getting back into fixing this thing. A few updates; got the wheels powder coated, now I'm looking for tires. Open to suggestions!
Also bought all new wheel bearings and rear brake shoes.
Also bought an upswept rear hoop, I think it should look good.

 

[C_OUELLET]

Alright so its been a while since I've posted, been busy with work and also got a cb250 that was road worthy so I'm out enjoying that every chance I get.
wheels have now been powder coated, got bearings in them and also bought some IRC Durotour 310 tires from American motorcycle tires. I went with the 100/90/19 (front) and 120/90/16 (rear). Those are the factory sizes as far as I know, and one of the few options for matching both tires together. Tires shipped fast, would recommend the site. Side note; I've got to get some finishing paint so I can hide the wheel weights!
I had a bit of rust on my rotor so I put it on the lathe and took some sand paper to it. I figured if I tried machining it I'd end up taking too much off. Now my rotor is rust free sitting at 4.85mm (replace at 4.4mm). I also painted it black.
I also finished my LED display, I've bought a Suzuki clip so I can plug it directly into the exiting harness, that way everything is reversible.

link to my new tires: http://www.americanmototire.com/catalog/index.php?cPath=33_145_151

 

[Gorminrider]

oh,man. Lookit all that nice stuff!! and hard work too! Carry on!

 

[mambo]

Those wheels look great! Where did you get them powder coated? Would love to have my wheels refinished over the winter. Awesome work on your bike!

 

[C_OUELLET]

I got them done from a coworkers brother, he works for a company that powder coats railings and window frames. I've heard if you get a company that does railings to powder coat your automotive stuff it will be much cheaper then somewhere that specializes in automotive powder coating. I did all the prep work myself and in the end it only cost me $60 for both wheels I couldn't say no to that price!

 

[Chris]

Chris, great work and steady progress. I'm always glad to see a bike bike brought back from the dead and yours is shaping up nicely. thanks for taking the time to post all of this so we can share.

 

[C_OUELLET]

SMALL PROGRESS (pictures included)

SMALL PROGRESS (pictures included)

A few small updates; got the wheels back on, they aren't on for good as I still want to clean up the bracket that holds down the disk and clean up or buy new bolts. I also need 1 rear wheel tensioner. (PO removed it to take the chain off to roll the bike into his truck. He probably tossed it out as the odds of this thing ever running again were slim to none!)
I went ahead and tucked all the wiring harness back where it belongs, I regret taking all that time to remove it and do nothing to it! I've got my LED board in working order but still need to solder and head shrink all the connections once I make sure the high beam indicator light works. I also bought a new headlight that has built in turn signals, I think it will make the bike look pretty slick.
Also went ahead and got some slugs for the rear hoop, that should make welding it in a lot easier and stronger.
I wanted to do a 2-1 exhaust but at the price of $300+ for a really long megaphone style that I don't particularly like I think ill just stick with my stock header pipes and just add some 18'' shorty pipes available on ebay for $100 for the pair. Does anybody know if these will have a much different flow rate than the stock pipes? I don't really want to be pulling my hair out rejetting the carbs once I get it running. Some imput would be great.


Enjoy some photos of my slow progress :lol:

 

[C_OUELLET]

Looks like ill be doing some cyber Monday shopping and buying some 17" reverse style megaphones. I'm hoping if I buy them on dimecitycycles that the quality will be better than the ebay cheapos. The reviews sound good, the overall complaint is that they are not packed enough with fiberglass material, leaving them really loud. You can however open the cone up and repack them. I will most likely sandblast and paint the header with black heat resistant paint, despite everyone telling me how cool exhaust wrap looks.


link to mufflers
http://www.dimecitycycles.com/chrome-17-inch-shorty-reverse-cone-megaphone-muffler.html

 

[C_OUELLET]

brake rebuild help

brake rebuild help

Hopefully ill be working on the bike this weekend. I'm hoping to rebuild the caliper and master cylinder and order a steel braided brake line. Does anybody have any helpful tips to offer up? I've already got the piston out of the caliper, should I do a light sanding of sorts before putting the new piston in?