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Discussion Starter #1
I am working on a 97 Suzuki marauder. A little about why I need to know, The bike just started making a loud rapping noise on the front cylinder and then shut down. It sounded like the timing chain and the tensioner I beleave let go and it jumped timing. What struck me odd at first but makes sense now is it doesn't want to turn over BUT if I remove the plug wires it cranks right over so I think its firing on the up stroke stopping it from turning over thus my guess at the chain jumping. With the stator cover off I can turn it over by hand and the valves are moving so the chain is intact.

Well my question is is the VZ800 a non interference engine or is it a interference and may have to replace valves.

Dauntae
 

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Leg Humps The Snap On Tool Man
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If the valve were bent a quick compression test ought to let you know.

NMc
 

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Discussion Starter #3
Unfortunately for a compression test I would need the timing right and have the valves closed at the right time, I unfortunately have no good place or all the right tools to work on this. In the middle of trying to buy a house and this happened. This bike used to be mine but sold it and became friends with the buyer so I'm helping him get it fixed. He hasn't had it that long and since I sold it to him I want to help get it going again. But for now I'm just trying to figure out what is wrong and how bad it could be. Hoping the valves survived but with the plugs out it turns over pretty easily without any feel of the valves hitting the piston so I'm hopeful.

Dauntae
 

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Leg Humps The Snap On Tool Man
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Going to again go with a compression test. Its quick to do. If you have no compression, the valves are bent and not sealing. If the numbers are low you may have skipped timing. Beyond that you will need to pull the valve covers off and do like a normal adjustment but you will find that there is excessive slack when there shouldn't be meaning a bent valve is not returning to it's rested position against the valve seat. Equally alarming would be if there was never slack when there should be meaning the head of the valve had broken off allowing the stem to travel further up than it's natural rest position. How does it sound when cranked with the spark plug wires disconnected? How is the cranking speed? Faster than normal with a nominal charge?

If the timing chain had jumped and there is no damage then you should not have slack at any of the appropriate valves at TDC *BUT* as you slowly rotate the motor over you should be able to view the valves go through normal operation just at an inappropriate time. Likely, several degrees after TDC. Your machine has two timing chains and two tensioners so it is possible and likely for one head to work appropriately and one to be misbehaving and will make it easier to see the difference.

I suspect there is a chance the magneto pick up or bracket could have come loose and is giving a false signal. Also, don't over look it, drain the oil and strain it. Dissect the filter.

NMc
 

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i am working on a 98 VZ800 does anyone have the timing marks for this engine, i have a repair manual the cams are differant as far as showing the timing marks i set the timing the way it shows in the book but it acts like it's 180o out of time it backfires pops and cracks when i put my hane over the front cylinder carb it draws in like it is in time but will not start at all.
any idea's ?
 

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Discussion Starter #6
Wow this thread brings back a few memories, been quit some time since I had mine. One question on your bike, Do you have the carbs hooked up to the air box, if not it could be just really lean from drawing way too much air in, The filters actually restrict the air intake and the jets are set to run with the amount of air coming in, That's why when people change air intakes to after market and exhaust they need to reject, if too lean you'll get massive popping and some backfiring if excessive. Try putting on the air filters and see if it improves, if there already on then I'm not sure what to tell you on the issue. Can't really remember much on that engine, The one I had ended up having a crank go bed and got a 98 parts bike with the new owner that had a good engine and transplanted it, turned out much cheaper than fixing the old one.

Dauntae
 

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everything is factory the only thing i done was installed new rings, a moron fresh out of bike school tore it down and refused to put it back together saying it needs this and that who wants to spend $1500 on parts for an old bike i can get another engine for a 3rd that price
 

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i am working on a 98 VZ800 does anyone have the timing marks for this engine, i have a repair manual the cams are differant as far as showing the timing marks i set the timing the way it shows in the book but it acts like it's 180o out of time it backfires pops and cracks when i put my hane over the front cylinder carb it draws in like it is in time but will not start at all.
any idea's ?
If I were you I would try to set the valves again. It sounds like you didn't get it right the first time.:bluethum:
 

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On the bright side... it seems like a great opportunity to buy new tools :) New shiny tools :)
 
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