Guzziboys gsx400F of death

[guzziboy]

Hi ladies and gents
I'm pretty new around here although I have been lurking around this lovely site
for quite some time researching,reading and learning!

Now to the death machine...aptly named because so far..well..she's dead


This is the 81 one model and quite hard to find much decent info on.



The eBay purchase of what seemed like an 800 buck steal on closer inspection might have been a little hasty. So I've started with the normal things, cleaned the carbs,



Bought a battery, rebuilt the starter, new starter relay and wammo! She turns over but no fire? So I go thru the normal stuff yep 4 spark plugs new and sparking, stripped the carb again properly and decided a valve gap was in order where I make my first amateur mistake



Don't force things on 20 year old bikes !!!!

So leaves me at my current predicament trying to work out what the hell is going on with my timing? Can't find a timing mark for the life of me ?



I'm no mechanic but something weird is going on with these cams, the marks don't line up ????



See the cam on the left is pointing straight up while the one on the right is flat ??? Wtf !

[Guest]

one more WTF, Why is there an EX (exhaust) mark on the intake cam?

Timing is way off unless someone has been messing with cam timing or installed another set of cam's from another bike.


I also notice that you have the # 2 on top. Its supposed to be #3.

I'd say Start there. Advance the intake cam until its notches are pointing towards eachother. There should be 18 or 20 pins between the #1 on the exhaust cam and the # 3 on the intake cam, Which ever makes the cam's point towards eatchother.

I wonder if you could treat this engine like the 550? Might be worth looking at and comparing.
On second thought it looks more like the 750's in terms of overall design.



Looking at the picture of the rotor It looks like timing mark is part of the hole on the left just above the oil pressure sensor.

[guzziboy]

Thanks mekanix... I know weird huh ! I thought that lug on the bottom of the ignition casting might be it but all the pics I can find show it where I have it?

Here's what my manual shows



I reckon the intake side is a full quarter turn out of whack ...should be a three on the top of the left cam but I got a two !!!



^ this ones the left side





^ this ones the right (exhaust side)

[BassCliff]

Greetings and Salutations!!

Hi Mr. guzziboy,

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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please Click Here For Your Mega-Welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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Thank you for your indulgence,

BassCliff

[john mc]

gsx400f of death

I agree 1/4 out of whack , who ever rebuilt the motor has got it a little bit wrong.

[guzziboy]

Cheers basscliff and by the way your site is awesome I've been studying it for weeks!!

Oh and for everyone's info I reckon I've already made 8 out of the ten newbie mistakes already!!!

There's a small notch in the front plate of my points maybe that's the timing mark? Regardless of where I turn it the end of the cams ( on the throttle side) never line up straight!!!

Cheers for the replies gents

[Guest]

I reckon Mekanix is onto it with the EX on the intake cam... I also see a IN on your exhaust cam...

Looks to me whoever put the cam's back in put the cams in back to front, so I'd be starting there, then doing the cam timing.

If it's that far out of whack, I'm wondering how much of a chance of a bent valve there is... I guess do the easy stuff first by swapping them around and timing them and then see what happens.

Just make sure to read through properly on how to take the cam chain tensioner out safely, and make sure that when you take the cams out you take note of which bearing cap belongs where (they're machined together) and make sure you tie the cam chain up so it doesn't fall down. Also try to keep a little tension on it so the links don't bunch up under the crankshaft in the bottom end.

[Agemax]

it could even be the sprockets swapped on the cams as well. i am sure they are marked. check the EX. sprocket is on the EX. cam, and same with the inlet.

[Guest]

I was wrong.


Looking at the cam sprockets they both have IN AND EX on them and are both identical

Depending on which cam you you put the sprocket on you either put the bolts in place to line up with the EX if its on the Exhaust cam or IN if its on the intake cam.


I'd say the crank and exhaust cam are lined up and the intake cam has to be rotated so that the notches are pointed towards eatchother and that there is 23 pins between the # 2 on the EX cam and #3 on the intake cam.

If your one tooth off you will have interference issues so rotate slowly the first time.

[Guest]

AAaaah yeah I see now, both definitely have IN and EX on the sprockets...

[guzziboy]

Yeah they do both have ex and in on the sprockets
Talk about confusing! I'm going to try line them up according to the manual and see if she fires up ... Fingers crossed

I don't suppose you guys would know what aftermarket signal generator would fit this thing ?? I've emailed a few places but no one seems to know?

Still can't work out where the so called "timing mark" is but I'm guessing through the little sight window in the front plate is a start

[Agemax]

i would say that is where the timing mark is. take the back plate off and clean up the area well behind the hole. i bet you will see a little "notch" there for the timing

[Guest]

Ok your signal generator looks exactly the same as mine, and yes there is definitely a timing mark through that cutout in the plate.

As for after market signal generators, the Dynatek DS3-3C is a good one for the 450 twins, but yours is a 4 cylinder... you would need to talk to them about dual firing coils I suspect but typically they sell the DS3-3C kit which includes two coils.

If you do go that path, make sure to email/call them as they are very helpful and are happy to try new models etc. You will likely also need a spacer that they use on other models as well.

The GS500 ignition setups are a bolt in for the 450's as well, but again they're twins so won't help too much with your setup.

[john mc]

signal generator

Mate i have the next couple of days off so i will try to take a picture of my signal generator , timing marks etc .this might help as my bike was running , ( not very well ) ( carb"s needed to be cleaned ) . .
john mc

[nikosg]

oh yay cant wait to pull my gsx400f apart too now.... lol
thats a mess mate. Goodluck