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Discussion Starter #1
I bought a 1985 VN 700 from a friend. It's in nice shape but it won't run. It will start up but won't continue to run. The local dealer told him the rear cylinder cam has jumped time possibly due to a cam chain issue. He also said the engine had to be removed to fix the problem. The bike only has 18,000 miles. Is there a way to check the cams before removing the engine? The dealer he took the bike to isn't always on the up and up so I'd like to double check his diagnosis. This is my first Vulcan (and V-Twin) so I have no previous knowledge of this engine configuration. Thanks in advance, Snapper
 

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Will it continue to run if you rev it, or does it just start and die no matter what?

While running, does the engine sound "healthy", or is it making clacking noises? From both cylinders?
 

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Is is unlikely the cam chain jumped a cog. Several people have done the "Grambo trick" while their bike is running at idle and have not jumped a cog.

Unless your friend (or the dealer) was reving the bike up while messing with the Automatic Cam Chain Tensioner (ACCT), I don't think the cam chain jumped a cog (but it is possible).

Do you have a clymer manual? It shows how to make a tool (with tinsnips) to keep the ACCT wound up so it can be re-installed after you remove it from the bike. That way you could take it apart and rewind it a little tighter.

Does it have a maintenance free battery? Make sure the battery is charged up!!! How old is the gas in the tank? If is has been setting for more than 6 months, maybe the carbs are the problem. Check the sparkplugs to see if they are wet/dry and black/brown/white.

More of the bikes history is needed to give/get better answers
 

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Discussion Starter #4
Thanks for the replies

I thoroughly cleaned and refilled the tank with fresh fuel, cleaned and checked the carbs and installed a new battery. The bike will fire but won't continue to run on either cylinder. I was wondering how the dealer came up with the cam diagnosis. My friend said he (the dealer) didn't disassemble the engine, just tried to get it to run. I do have a Clymer book but it says (unless I'm missing something) the engine has to be removed to check the timing. If the cam(s) were out of time, is it possible for the valves to hit the top of the piston or is there enough clearance for the valves even if the timing is off. Thanks for the replies, Snapper
 

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I am going to go with a fuel problem. If it sat around a while with gas in it, its likely it is gummed up.

May have to remove the carbs, dissassemble them, fully clean them, and put it back together.

May also try some Seafoam in it first before tearing it apart. If the gas will flow through the restricted areas, the Seafoam may clean it out.

Thats why I asked if it will rev freely and just not idle.
 

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ry soaking in seafoam without removing them first. Get a hand bleeder bottle (with clear hose) kit for a few dollars. Turn of the fuel. Hook up the hose/bottle to the float bowl drain and drain the gas (due one carb) and note how much fuel was drained. Dump out the fuel into the gas tank and put the same (maybe a LITTLE more) amount of seafoam into the bottle holding it up higher than the carbs so the seafoam goes into the float bowl - repeat for the second carb. Hook up battery tender/charger, let set for a day or more, then drain and fill with gas.

Before attempting to start remove a plug from each cylinder and turn it over a little (make sure the spark plugs are not hooked up) to make sure gas didn’t fill the cylinders.

It doesn’t take much to drain the battery and a running bike does not keep a charge unless running at about 3000 rpm or above. So while you are working on the bike keep the battery charged.

If you can get it to fire afterward but still doesn’t run right, try to get it running for a little while, let it die, and pull the plugs to see how they look (wet/dry/grey/black).
 

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If you cleaned the carbs by taking them apart and soaking them, they they shouldn't be a problem. Check how the plugs look after getting it to run a short time. If you have a timing light you might be able to hook it up to see if the problem is electrical. I know you are right about cam timing on the rear cylinder needing an engine pull.
 

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Discussion Starter #8
Thanks for all of the help. I'm going to try the seafoam method and be sure to keep the battery charged up. It just doesn't have enough miles for the cam chain to jump unless something unusual occurred. I'll go with the fuel problem first and check the timing and electrical system before tearing into it any further. I'll keep you updated as i progress. Thanks again for all the help, Snapper
 

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You'd definately know if the cams were out of time. There is very little clearance between the piston and an open valve. You'd hear the valves hitting the pistons if the timing was off.
I too vote for a fuel problem. One other thing to check is to see if the carbs are truly seated in their intake clamps and hoses. After my rebuild, they got disconnected and I didn't catch it. I ended up taking it in to a shop (not Kawi) and they caught it to the tune of $174!! I had some other things wrong as well so it's not fair to blame the full cost on the carbs but just shows how easy it is to overlook some things.
 
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