2003 Honda 400ex NOT firing???

[DanOnWD40]

Hi guys, so Im i cam across this pretty nice quad. Its a 2003 400ex. Its priced at a little over $1,000. The seller states that it was previously rebuilt and has a hot cam in it. However, it is not firing. He says that it turns over and has spark. He also redid the wiring harness and still couldnt get it to run. I have some experience with quads from previously owning one.

My thoughts are its either something witht he wiring harness(cdi, kill switch...) or it isnt getting the right amount of fuel(needs carb rebuilt) or it's the valves. Or could it be timing? What do you guys think? Let me know!

 

 

I have attached a video so you guys can see how it sounds like. I feel like it wants to start but is missing something...

[Gwbarm]

It sounds like it tried to start a couple of times so it should be firing you could check the timing and make sure its getting enough fuel.

[Mech]

Has it run since the engine work and the hot cam ?

If it has run, when did they discover it wouldn't run, like, did it break down on a ride, or was it turned off and then not start after an hour, or did it get parked at home and then wouldn't start again the next day, or was it parked up for two years and now won't go ?

If you want to get it going, you should make sure it has compression, fresh gas, a new sparkplug, and then try starting it. If it doesn't start you pull the spark plug and see whether it's wet or dry, and you go from there..

Edited October 18, 2024 by Mech

[Mech]

I'd be a bit worried about this " redid the wiring harness". I doubt that's the problem since it has spark, but I'd want to know what he'd done, and why he did that and whether it had actually fixed any problem. He might have made more problems that he cured. These wiring looms, like everything on the bike, are designed to the umpteenth degree. Every tiny detail and aspect of the wiring loom is critical to it's operation and the reliability of the bike.

[DanOnWD40]

Yes compression would probably be the first thing I would check if I were to go and see it.

I wish I had information to all those questions... According to the current seller he bought it off someone who did the top end and hot cam. I asked the current seller if it ran after the rebuild/hotcam and he said he isnt sure. He told me that the last owner told him that he had it running, but never got the issue figured out. He bought it not that long ago without hearing it run. I did get a picture of the receipt of the top end rebuild which was a while back. The current seller said that he changed all the wires, it has spark and everything but it does not want to start. 

I don't have the quad but I want to see what people say about this issue, so if I do get it(which im considering) then I would know what to target. 

[Mech]

For that matter, the engines are designed to the umpteenth degree, and they are perfectly set up for the bikes design, it's intended use, and it's inherent limitations. People that try to improve on the design, mostly just compromise the machine.

I think, that unless you are competent as a mechanic, it might be best to stay away from this bike. Just buy yourself a nice reliable quad, and if you think you need one that goes well, buy a sport quad, not a workhorse, they're too heavy to ever perform like a sport model, their transmissions aren't suited to sport use.

[DanOnWD40]

Yeah true I'm currently 50/50 on buying it. It's a hit or miss. I have owned an atv before and it had wiring problems and I got it figured out but yeah. I just got interested in this one because it's listed for cheap and i'm not really afraid to fixing things. I also just want something simple and something reliable I'm not crazy on speed or performance just casual riding through forest

[Mech]

Well this bike, it sounds to me, has been owned by two "tutu" fellahs. Tutu is an indigenous word meaning "play around". I don't think either of them knew what they were doing, but did stuff anyway. Bikes like that can turn into a long run of frustration.

[DanOnWD40]

LOL yeah definetely tutu fellahs... I guess I will pass on this one than. Who know's what kind of "top end" work they did on it...lol

[Mech]

Yeah, I'd rather buy an original bike that was running bad and needed an overhaul, than buy something with a history of people modifying things and doing bad repairs. It's just a can of worms.

[DanOnWD40]

By the way what is your opinion on Yamaha Warrior 350? Found one... it starts and runs but bogs under load. Probably just needs a carb clean and a spark plug. Its a 1988 in blue. It looks to be in really good shape for the price and year(listed under $1000). 

Edited October 18, 2024 by DanOnWD40

[tater]

let me know if you need a manual for the Honda

[Mech]

I don't know much about yamaha, they aren't real popular around here, not because there is anything wrong with them, but because farmers like suzuki on the hills, and honda on the dairy farms and beaches. I think yamaha are pretty good though. Their two wheelers are good. The only jap bike I wouldn't buy would be a kawasaki, based on their two wheelers, which are made far too cheap and disposable.

I wouldn't know much about prices over there either, but a warrior sounds like a bit of fun for recreational riding. Gw probably has more experience with yamaha I think..

[DanOnWD40]

That makes sense yeah. Well I appreciate your help and advice!

[Mech]

Overall good condition is what you want. On quads the engines mostly go for years, but the suspension, brakes, wheel bearings and drive shafts get worn out and abused in water and mud, and if you start doing all that stuff up it can cost more than doing an engine up. Frames rust too some times and that can pretty much write the bike off.

 

Advice is free..  If you get a bike Gw and I can probably talk you through repairs. There are service manuals in here for free download.

[Gwbarm]

I  agree with what others have told you. I also wouldnt want to start with an engine that someone else had modified and never got running.

Yamahas are great bikes, the engines are very strong and long lasting. The Warrior is more of a sporrt model  very fast and, the Big Bear is a very strong utility Quad it has lower gearing and more pulling power, full time 4 wheel drive and foot shift only. The Kodiak is also a great bike it is like the automatic version of the Big Bear not quite as low geared but very good it has a 2 wheel drive 4 wheel drive button and belt drive also water cooled.. There is also the Wolverine a smaller version light for ATV very capable and fun to ride. Then there the Grizzly . The only negative thing i might say about the manual shift version is as they age the shift linkage get kind of worn and do not shift as smoothly and is usually caused by worn shift linkages. 

[Mech]

If you want sporty, don't buy anything with a belt drive. They don't have the wide gear ratio range the manual five speeds have, and the centrifugal clutches are set up for flat land. If you get on a decent slope they struggle to get going.

With the manual foot shifts, you can hold the shift lever up or down with your toe, rev the engine, then use the shift lever as a clutch lever to pop you over a log or get moving on a big hill.

[Gwbarm]

I agree totally, the foot shift is more robust, but if you  want something just to ease throught the woods with no challenging obstacles and no shifting automatic works OK for that. It works great for unexpierienced riders just give it gas and go nothing else to think about. I myself prefer manual shift but its probably because thats what im used too.

A lot depends on what is for sale and at what price point. I would get an automatic if the price was right. I was in negotiations for a Kodiak was kind of looking forward to getting an automatic but another came up with manual and i liked it better so went with that.