I drove it very little last summer. It would die unless I ran it on prime and it made a terrible tapping noise. As soon as I found this site and figured out the problems I parked it. It sat for about 4 months but still would crank while it was parked. About a month ago I got a verslavy and a raptor petcock. I started with the tensioner. Drained the oil. Tied the bike off and loosened the plates that hold the foot pegs took small muffler guard off on the right side. Removed entire exhaust in one piece. Oil filter cover off then clutch cover off. Replaced tensioner and gasket. Clutch cover back on. New oil filter in and cover on. Broke a bolt on clutch cover from using a torque wrench too big so I waited until I got some replacement bolts and a smaller wrench then put the last bolt in. Exhaust and guard back on then tightened those bolts for the kickstand/foot pegs. Next I did the raptor mod. The gas was already drained so I just took those two bolts out of the tank and put the new petcock in with the white filters in the ends of the tubes inside the tank. Tightened that back down. Cut the vacuum hose shorter and put a small bolt in it with a hose clamp to seal it. Filled the tank with gas and the engine with oil. I followed the post about filling the oil on the stand until you can barely see it in the window. took my battery off the charger and hooked that up. Tried to crankit and found the battery to be completely dead. Bought a new battery and charged it. Put it on and tried to crank it. Engine turned over but I notice I had an oil leak around the front of the engine in the seam of the clutch cover. I tightened the bolts close to it but it still seeped out. So I pulled the exhaust again after draining the oil. Took the cover off and put a little sealant on both sides of the gasket. Replaced the cover and torqued the bolts (I marked the ones with rubber washers and the longers ones) to 60, then all to 80 then to 95. Put the exhaust back and tightened everything back down. While waiting on this to set, I changed the handle bars. Went from z bars with 6" rise and all stock cables to plain drag bars. Also I made sure the gas was off the entire time so it didn't flood the engine.  About 36 hours after putting the sealant on I put the battery back on and tried cranking it. Hate to be so simple but I want to cover all my bases. Key is on, bike is in neutral, clutch pulled, run switch on, gas to on position, choke all the way out. Hit the start switch and the starter turns the engine over and it turns over fast. This is where my problem is. The only way I know how to describe it is the bike sounds like its just about to run, but it just keeps turning over and won't actually run. Plug is sparking too.

Now I'm not a "mechanic" but I do have a general knowledge of mechanics. I can turn a wrench and make things fit. But I don't know much about compression valves or carb floats or anything like that. That's why I'm here. If somebody can point me in the right direction I can find and hopefully fix it.

EDIT- sorry I took so long on this post, Versy got a post in ahead of me.   Try his decomp check first...

Okay..
Battery is good.. it is powering the starter... and the engine is turning over at adequate speed...
It sounds like the petcock is good... it's a Raptor, it's set to ON, and the vac line is plugged...the carb is getting fuel...
The engine is turning, so nothing is obstructing rotation in the clutch case... (I'm guessing at the torque... those are inch pounds ?... but, nothing stripped out, and nothing is leaking)...

We're down to basics...
I'd recommend that you double check every connection you can find under the seat and tank...
Then,.. it's spark, fuel, air, compression,

You said you are getting fuel, and spark... air hasn't changed...
That leaves compression...  rings. valves, decomp,...
Rings haven't changed...
check that there is some slack in the decomp cable...
If you haven't removed the head cover, or taken off the camchain entirely, the valves should be okay...

Okay, no problem,... it should start... ...
You've missed something...

On the off chance that you've been cranking a lot,... a whole lot... without starting...
There is a thing called gas wash,.. that can happen when fuel is entering the cylinder, but never gets burned...
This washes the oil seal off the cylinder walls, and can bring compression down to almost zero...
Try a squirt of oil into the sparkplug hole... give 2 seconds of crank with the sparkplug still out,.. then put the plug in and try to start again...

If that ain't it... I just don't know where to go from there...
Start over,.. and check everything again...
Battery, cranking speed, fuel, spark, etc...

Best luck... keep us informed...
You know, as do we,... that this is a fixable problem...
... and it's likely nothing too serious...

We've all been there... ...

Sorry, but how do you know the carb gets gas, and delivers gas mixture to the cylinder? Wet spark plug? If thatīs the fact, it might be simple.

Plugs that have been soaked while cranking for a long time seem to fire properly outside the engine, and may refuse to fire when reinstalled. The spark just canīt develop properly under compression. I have seen this on NGK plugs on my old Triumph chopper - and even on new ones. Cleaning them / burning off the oil/gas/dirt may help, but is not guaranteed.

So..change the plug to a known good one/new one and see if it fires.

(Yes, I learned this the hard way on the chop...I even tore down my ignition, realigned it TWICE, swapped the coils, cables and lots of other stuff. Finally, I put two old 1980:s plugs into it...and it fired on first kick - after a month of kickstarting efforts. Turned out both plugs had been fouled up, they refused to fire under compression. )

Get a can of either (quick starting fluid) from any auto parts store or Walmart.

A 2 second blast of either down the carb throat followed by a quick hit on the starter will answer the fuel related questions very quickly as if it runs revs up some on either even for a second or three you know the problem is really fuel delivery.

mhart731 wrote on 04/05/14 at 14:08:57:


Try shooting some starter fluid in the air filter. Also, are you pulling the choke out? I had some starting issues when I changed my petcock and did the Versy mod too for some reason. No clue why, but starter fluid got me going.

OK:

You are sure:
Bike ran before you worked on it.
Battery is good - fully charged
Getting fuel - either gas or starting fluid
Plug is good. Plug is firing

You mentioned a tapping noise when the bike was running. Was the original cam chain adjuster apart when you took the clutch cover off, or was it just extended close to the limit?

I'm thinking valve/valve timing problem. I can't imagine what you could have goofed up putting the modified adjuster in, but that's where I'd be looking next.

If the tensioner was all the way out would replacing it throw off the valve timing somehow?

mhart731 wrote on 04/06/14 at 18:39:47:


I'm not sure. But if the adjuster was completely apart - plunger out of the housing, spring falling (or fell)out - I think it's possible for the chain to have jumped a tooth on one of the sprockets. If it did, the valves are now out of time. Just putting the modified adjuster in won't fix that.

I haven't been deep enough into one of these motors to know for certain if the cam chain can jump even with no tension on it - it may not. But the symptoms you are having point in that direction.

Hopefully someone who's done an overhaul or two will chime in.

Quote:


I thought we already did that.