I've had enough... blown engine

[ripzay]

Hi guys...

so... i've blown my engine up. (1994 Suzuki GSX-R 400 GK76A)

The bike dropped out of gear at speed and jumped up past 16000rpm before i had time to react.

cue horrible snap noise and then tapping coming from the engine.

no smoke from the exhaust so i dont think it is bottom end.

It's deffinitely on cyl 3 (when i cranked the engine over this cylinder remained cold, so the fuel isnt being burnt, or isnt being burnt properly.

So i need some advice.. i'll be taking the bike apart tonight - just wondering if there's anything i need to know about removing my engine, anything that i am likely to forget about and will have to do..

i'm hoping i've just killed or spat a spark plug, but i don't think that this is the case.
next i'm hoping its just a snapped valve that hasnt been mashed into the piston too much..

but worst case scenario.... i need to buy:

piston
valves
valve springs
etc.

now, my question is, where will i buy these from if i do need them ?
and how much should i expect to spend.

also.. does anyone have a head off a running bike for sale ?

Thanks.

Ben
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[Kickstart]

Hi

Not being a UK model spares might be a bit hard to get hold of.

Personal guess would be that you are in the right area thinking of a valve issue. I would say take the rocker cover off and check the valve clearances. Also check none of the rockers have snapped. It is possible that a valve has clipped the piston, bent and now isn't closing properly, or that it has just spat a shim out (leaving you with a massive clearance on that cylinder), or even snapped a rocker arm (neighbour managed that in their car trying to change from 2nd to 3rd gear at high revs and instead getting 1st). If you are lucky it will be an easy fix (eg, shim is there undamaged and can be put back in).

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Barry_M2]

If it's still turning over, it could just be a cam follower thats snapped.

Or, worst case is that you've lost a valve and it's mashed into the piston and the head.


____________________
ZXR750R (M2) - For the road.
CBR1000 RR4 - For the track.
https://www.bikechatforums.com/profile.php?mode=viewprofile&u=4332

[ripzay]

still turns over and runs (fires on 3 cylinders - started it to diagnose, was running for like 5 secs before i hit the kill switch), but has a tapping from the top end and a bit of white smoke from the exhaust (unburnt fuel)

the bike wasnt shaking violently while it was running for those 5 seconds, just making a loud tapping, like as if the valve clearance was way out.

i'm thinking snapped rocker (or threaded adjuster on rocker) - i'm not sure if this bike is shims.. i've never had the head off or even seen inside one, earlier models didnt have shims afaik, they had screw adjustment on the end of the rockers.

we'll see tonight when i get the rocker covers / head off
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[Blau Zedong]

How the hell have you broken one of these I used to treat mine in a half_luke manner and it laughed at me then came back for more!!!!

Anyway - the GK76 models have shims but I think they use finger type rockers like the 750M, so if it runs it's possible you've just snapped one of these. Possible you could get a head off ebay to rob for parts. If it's dropped a valve I'd buy another engine and keep the old one for spares - by the time you've bought the gaskets, never mind any of the whirly bits, you'll be skint!
____________________
18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Barry_M2]

I snapped a rocker on an old ZXR400 I had (about 12 years ago now) and it still ran on 3 ok. I even rode it home about a mile or so as I didn't want to push it!

Fingers crossed thats all it is.


____________________
ZXR750R (M2) - For the road.
CBR1000 RR4 - For the track.
https://www.bikechatforums.com/profile.php?mode=viewprofile&u=4332

[Pete.]

If it's dropped a valve head and battered the piston crown you're going to need to pull the big-end cap off and check the rod bearings for signs of contact with the crank journal.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[ripzay]

Well, i got the engine out last night... and it's bad.

the cause of the destruction was a snapped cam follower, which has then fallen down the valve into the engine and bounced around a bit atop the piston.

the results are:
1) Snapped Cam Follower
2) Bent Valve
3) Mashed spark plug
4) Mashed piston (i guess, havent taken the head off yet)
5) Lots of bits of ground metal in the intake, and probably in the cylinder.
6) Scratched / pitted cylinder bore.

I've managed to find a guy with an engine i can have for £350, which has done 10000km, (25000 less than my engine) and i'm going to pick that up tomorrow.

The dead engine, i'm going to keep and build a race engine out of it, there are kits available to make this engine 440cc, so as money allows, i will be doing this as a little spare-time project.

Gutted.

Some pictures:

https://www.binary-pulse.co.uk/Random/Bike/Pics/Damage_Remains.jpg
Bits of metal...

https://www.binary-pulse.co.uk/Random/Bike/Pics/Damage_SparkPlug.jpg
Remains of Spark Plug

https://www.binary-pulse.co.uk/Random/Bike/Pics/Damage_Garage.jpg
No Comment - my landlord would kill me
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[The Shaggy D.A.]

Nice wellies.
____________________
Chances are quite high you are not in my Monkeysphere, and I don't care about you. Don't take it personally.
Currently : Royal Enfield 350 Meteor
Previously : CB100N > CB250RS > XJ900F > GT550 > GPZ750R/1000RX > AJS M16 > R100RT > Bullet 500 > CB500 > LS650P > Bullet Electra X & YBR125 > Bullet 350 "Superstar" & YBR125 Custom > Royal Enfield Classic 500 Despatch Limited Edition (28 of 200) & CB Two-Fifty Nighthawk > ER5

[ripzay]

[Kickstart]

[Barry_M2]

Quite right Keith, cant believe I didnt' spot that either!!

What's likely is that the follower snapped, got jamed between the cam lobe and top of the valve, which held the valve open while the piston came up and smashed into it. The only thing that can fall into the cylinder is the head of the valves and spart plug tip.
____________________
ZXR750R (M2) - For the road.
CBR1000 RR4 - For the track.
https://www.bikechatforums.com/profile.php?mode=viewprofile&u=4332

[chris-red]

Funny but both of those wellies look like they could hold the old oil from the engine. I always have trouble find stuff to put used oil into...
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[ripzay]

good point r.e. the cam follower.. but yeah, i didnt find it in the head so i guess its in the sump..

i found the valve retainer, spring and the shim in the head.

I'll take more pictures after i've got my new engine in.

the old one is being put on the table in the kitchen, drained and stripped.
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[Barry_M2]

[ripzay]

split up with gf on monday, she moved out.. so nobody to complain..

i paid the rent when she lived here anyway.. ripzay rules the roost
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[Kickstart]

Hi

By the way, as you blew this engine from over revving it, was the rev limiter mod in your sig a good idea? .

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Finglonga]

[ripzay]

well.. i found these little presents in my exhaust manifold:

https://www.binary-pulse.co.uk/Random/Bike/Pics/Damage_%20Remains%201.jpg

https://www.binary-pulse.co.uk/Random/Bike/Pics/Damage_Remains%203.jpg

2/3rds of the end of a valve.

1/3rd of a valve seat, and various other chunks of chewed up metal..

still not got the head off the old engine but i've got my new engine in, so that's the next job!

r.e. the rev limit mod.. that appeared to have failed.. it was only supposed to raise it, not remove it :p
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[ripzay]

Please excuse my ugly lino and ugly wallpaper, i cant be bothered to decorate yet....

but...

Cams out...
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2328.JPG

Cams...
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2329.JPG

Head & Barrels Off....
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2330.JPG

MUNCHED PISTON!
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2332.JPG

MUNCHED PISTON.. from another angle...
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2333.JPG

Down The barrel & valves.
https://www.binary-pulse.co.uk/Random/Bike/Pics/FubardEngine/IMG_2335.JPG

I think its fair to say that that head and piston is now worth nothing more than its weight in... cast aluminium ;p
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

[Barry_M2]

I have a piston just like that from when I brought my ZXR. It now sits on a shelf in my room as decoration!

https://i7.photobucket.com/albums/y269/Barry_mc21/ZXR750M%202006/DSC00052.jpg

https://i7.photobucket.com/albums/y269/Barry_mc21/ZXR750M%202006/DSC00049.jpg
____________________
ZXR750R (M2) - For the road.
CBR1000 RR4 - For the track.
https://www.bikechatforums.com/profile.php?mode=viewprofile&u=4332

[stevo as b4]

That explains the reason why it was smoking alot and running on 3cyls!

Definately put a std cdi box back on for your next engine!

[ripzay]