suggestions Wont start

[moorhous]

Hello, Last winter I put a 406 bore Tc cam, ProComm box, HMF pipe11:1 comp piston ran grate all summer! I was out playing on the lakes the other day and seen a small leak at the silver gasket so I took it home. About a week later I went out changed the gasket. Now I can’t get it to start!! Wont fire it is kind of cold out 35degs it was jetted last spring. The battery I have sucks I need a new one bad! to get it out to the lake I had to jump my quad off some one else’s quad. its on the charger now but even when the charger says the battery is full only get about 9 cranks out of it before it starts to slow down but it don’t seem to be trying to start??

Thanks

[Rip_Tear]

Try all the regular stuff? Is it getting gas, could be frozen, a bit of water in the line could have iced up... You might need to rejet depending on the temp... How's the air box, any creatures build a home in there? All the electrical alright? Didn't break anything with it being all cold did you?

[slodsm]

When you jetted it in the spring, what pilot did you go with and what clip on the needle. Are you hitting the choke or leaving it off? Do you have a rev box?


Short of what I would do, pilot jet of 42, 3rd clip, no choke, 1.5 out on the airscrew. It won't be perfect but it's generic enough it should start and you can tune from there.

2, if you are anywhere near that right now, I would skip to spark plug, I have found that with a 42 pilot, if you miss the initial start with the choke on, it will kill the plug (drench it in fuel) and you need to pull and dry to get it to start, I use no choke on mine at all even down to the low 30's and it starts on the first hit.

Next, if you have an aftermarket rev box (this is from reading, no hands on experience since I use the stock one), if the battery is low whatsoever, it won't crank. Plug your stock box back in and make an attempt with that prior to buying a new battery just to see.

With that and rev's suggestions on living things in the airbox (it can happen if it's sat) and frozen water (condensation from temp changes can cause a lot of "ill" in a fuel line), it should fire up. If not, post back up.


I had the learning curve from hell with my 400 on cold/won't start and I have pretty much the no start steps burned into my head now.

[Tater049]

if nothing else work try cleaning out the carb. That turned out to be the problem one time on my yfz. There was sludge, dirt and what not in it. I took the carb apart, put it together and it started up like a champ. The lines were a little clogged too.

[moorhous]

yes I have a rev box spark is there and so is the gas. I might be crazy but I think I hear a rubing noise (strang) when the choke is on and im trying to start it. but I dont know if its just cuse its cranking a little slow. can I put the battrey charger on my starter and just run from that???

[GPracer2500]

Which gasket did you change?

[moorhous]

the gasket that is has 3 metal sheets

[GPracer2500]

So, the head gasket then.

Has it ever started since the head gasket was changed? If so, did it run normally once started?

If the answer is negative to either of those questions then the first thing I'd check is the cam timing. Make sure the hash marks on the cam sprocket line up with the top edge of the head with the piston at TDC.

[moorhous]

Thats what I thought so I checked that. its right. no it has not started since I changed the head gaskit. it sounds like no spark this is what I was thinking. When I checked for spark I took the sparkplug out put it on the head and there was spark! but mabe when I put the spark plug back in it cranks slower makeing it not fast enough to make spark because of the revbox?

[GPracer2500]

Originally posted by moorhous
...because of the revbox?

Some rev boxes ARE known for not properly sparking unless the battery is in excellent condition. The WB unit is known for this (although I never had an issue with mine)--don't know about the ProCom. Try your stock CDI and/or replace the battery.

Another thought: Does your TC cam use the stock auto-decompressor mechanism? If so, make sure the little spring and plunger that fits in that small hole in the head are still there. With the auto-decomp mech in use the engine will not start without those pieces.

[exrider2001red]

was the spark blue or yellow if it was yellow the spark may not be strong enough to light the fuel learned that in shop class

[moorhous]

Originally posted by GPracer2500
Some rev boxes ARE known for not properly sparking unless the battery is in excellent condition. The WB unit is known for this (although I never had an issue with mine)--don't know about the ProCom. Try your stock CDI and/or replace the battery.

Another thought: Does your TC cam use the stock auto-decompressor mechanism? If so, make sure the little spring and plunger that fits in that small hole in the head are still there. With the auto-decomp mech in use the engine will not start without those pieces.

Not sure. some hp cams dont use them right?

[GPracer2500]

Originally posted by moorhous
Not sure. some hp cams dont use them right?

Most aftermarket cams don't use them. You've got to press off the mechanism from the stock cam and press it onto the new cam to keep it.

[idro]

start simple, does it have gas? Adequate?

[Hillshooter]

Try hooking the battery up to a charger. Let it charge for 10-15 min. and then try it. If it dosen't start take your stock rev box and plug that in and then try it. That was my problem. Most aftermarket rev boxes for 400ex's are actually a stock rev box from one of their 4-stroke dirt bikes (either their 250 or 400). They're designed for a motor thats kickstart not electric. They definately make it run better but can cause starting problems especially with a low battery or cold weather.

[sandspanker]

:) make sure your batt. has a full charge. next put a little bar b q under the engine to warm up the engine and the oil. good fresh gas. new plug. give it a try. (cam in time?)

[moorhous]

OK I got a new battrey now its about 70 here. it would not fire up (want to start) so I pulled every thing back apart The cam chain tenchner will not stay tight so I took the head off to look at the valves they look fine not stuck open whats a good easy way to tell if there bent?? When I turned it over after the new battrey I could hear a slight knock or tapping thats why I stopped and took it apart. not sure if a pic would help. some good info would be cool! any one have a pic of a head with bent valves??