Help Timing the bandit (GJ74A GSF250)

Are these "some people" Suzuki certified mechanics or mechanical engineers who work for Suzuki and/or able to read Japanese?

Not actually worked on a Bandit before but I'd use the timing mark after the T as per the picture. Service/workshop manuals have example pictures for a reason.

 

Just in case you haven't solved this yet (and for those playing at home) this how I would tackle it.

Firstly, put a screwdriver down plug hole of cylinder #1 and find top dead centre to confirm the T mark is indeed TDC. Leave it there and align the timing marks as per the manual, count out the 16 links of the chain. Install can chain tensioner, then SLOWLY turn the engine over by hand 2 full revolutions. If it stops anywhere, take all the bits out, re-time it as per the manual and repeat. If there is no piston to valve contact on either mark it should be safe to start the engine. Give it a gentle rev, it should be pretty obvious if the timing is out. I think timing it to TDC will win. I've been working off an Across manual & my GJ73a is exactly the same.

 

Yeah, the idea with the screwdriver down the plughole is you can find TDC when it stops rising or falling, but the marks are very close together so it might not be accurate enough to tell. The only more accurate way would be to use a positvie piston stop and a degree wheel, these can be home made from an old spark plug by drilling it out and threading a bolt through it and a cheap 360 degree protractor for the degree wheel. Google for a guide on how to do it.

That rotor is not easy to decipher alright, so timing it to TDC is the way to go. Even if it turns freely by hand I'd be careful about timing it to any marks in front of the T as if not correct this will advance the timing and the engine could detonate if it starts. Sounds like you have multiple issues, getting the right igniter box is going to be key. I had a bit of a look on Yahoo Japan, plenty of cheap-ish ones for the Bandits but without knowing part numbers for the 40hp box it would be a guessing game. When I get a chance I will test my two from the GJ73a and the Across with the ohmmeter and can give you the part numbers of each, but this will most likely just give you a couple of numbers to avoid! See how we go though...

 

Hey Stu
I'm trying to locate the disc for my 400 Bandit that Grey sent me, might have something we can work with ????...............it is in ENGLISH
What do we think is the right answer?

 

Here is the CDI in mine. Its the 45hp model.



Couple of things for you to check that the internet doesn't seem to outline clearly.

1. Left hand coil does 1 and 4, right hand 2 and 3. Mine was the other way around when I got it.
2. Make sure you have the positive and negative around the right way on the coil. The coil is labelled. The wires that are the same colour on both sides are the positives. Getting it wrong will produce a weak spark.

 

Ahh that's great news you have the timing sussed! I hope you checked the valve clearances before taking the head off, if they have closed right up that could be the source of the problem. But I'm guessing that's why the cams came out in the first place. I have now checked clearances on 3 of these engines (2 GSXR, 1 Across) and they have all had lots of tight intake clearances but mostly in spec on the exhaust side. Seems like more than a coincidence, maybe the seats are soft on the intake side for some reason... My mate's engine that I am servicing atm has one intake now down to the thinnest available shim which is a bit of a worry. It has 50,000ks on the clock, I will leakdown test it when it's back together.

 

is it an import ? most of them have the speedos wound back

 

Great thread! When I replaced the valve shims I also had to redo the timing and went off the line right after the 1.4T

 

hi i'm ajith.
i have a bendit gsf250 .
my cdi unit mcu is us. so i cant repair it.
but i can make a new unit using a mcu. but i have no idia about ignitioan timin and timing weel signal. can you explain how to start ignition using timin weel image. then i can try. thank you.