Motor probs

[slosh13]

I went riding yesterday and my motor took a dive on me. Im having trouble with the tranny.I shift into 1st gear...no problem, shift from 1st to 2nd....no problem, shift from 2nd to 3rd....it sounds like i hit neutral, kickin into gear and out of gear, shift into 4th and 5th....no problem.. My sponsor who does my motorwork was down there and he said he thought it might be a shifting fork bent or broke..... Has this happened to any of you and if so howd you fix it? If it matters my bike is a 2001 400ex ported polished shaved head bored .80mm over to a 406. thanks







Sponsors: JP Cycle, Line-X, B-Town Boyz Racing, SHI Racing, Mom and Dad

[mxracer111]

yeah man....ive gone thru 3 different transmissions that way.... same thing every time.... youll need to replace all 3 shift forks and 2nd and 3rd gear when your down in there.....2nd gets torn up from 3rd jumping in and out...... i have torn up 4th too at the same time if you beat it hard enough before fixing the prob. i replaced all of the gears and shafts and everything in my race motor jsut to be safe..... cost about 1200 or so in just trans parts then blew it out again the last race of the season......i couldnt find any stronger gears or anything..... good luck.... i gave up with that trans ans switched to a yz motor.....hopefully that will handel my abuse

[slosh13]

I already put about $1500 worth of motorwork into my bike. Ported and polished shaved head bored .80mm over new hardened rockers new cam new oil pump. A local bike shop did all my motorwork and was nice enough to sponsor me as well. How much were 2nd 3rd gears? if its too much $ to repair motor, how much did you payfor your YZ motor and where did you get it from? appreciate all your help.






Sponsors:JP Cycle, Line-X, B-Town Boyz Racing, SHI Racing, Mom and Dad

[mxracer111]

i was in the same boat as you.... alot of money into my motor and making a lot of power....too much for the trans to hold. i dont remember how much just 2nd and 3rd cost..... i figured i was in there....i put all new bearings in and all new gears and shafts to keep everything fresh and i thoguht it would hold up for a year or 2. well i got through another 6 months and it happened again....jsut from beating the crap out of it..... thats when i decided that i could buy a yz motor and get more reliability and power out of it for about what it would cost to rebuild my engine to all new again. i paid $1500 for my yz motor.....complete with everything....now they seem to go for 1000-1500. takes some work to puyt it in the 400ex....but it is worth it to take the time and do it right.... im still in the process of building mine....but being reallly picky...so it will be a while

[slosh13]

How much work was it to put the YZ motor into the 400ex frame? What kind of mods would I have to do to make it fit.... Do you know where I might possibly find a good YZ motor for a decent price? Im kind of on a tight budget and I dont got alot of $ to spend so finding a good cheap,but reliable YZ motor would help my problem I think instead of shelling out who knows how much more money to try to fix the stock motor. Thanks for your help.






Sponsors: JP Cycle, Line-X, B-Town Boyz Racing, SHI Racing, Mom and Dad.

[dhines]

If you're on a tight budget you can forget about the YZ conversion. The cost of doing one goes way beyond the price of a motor (and they're not cheap).

I'm in the middle of changing out the transmissions on two different 400EX engines right now. On our cross country engines we always blow out 2nd gear before 3rd since we probably spend much more time in that gear than people who race MX. However, 3rd has been pitted on every engine I've torn apart so far so I'm going ahead and replacing it too.

On our engines, I'm replacing both the counter and main shaft 2nd gears, but only the main 3rd - the counter seems to be in fine shape.

Below are the main parts you'll likely need - although if you've been trying to ride it as is you may have damaged a lot more. Needless to say, don't even try to start it up again until you've torn into it.

Main 2nd Gear (16T) 23421-HN1-000
Main 3rd Gear (19T) 23441-HN1-000
Counter 2nd Gear (31T) 23431-HN1-000

You can get all three from someone like Service Honda for less than $125. Add on gaskets and what not and you're up to a total of maybe $175 in parts. That's really not too bad. If you don't feel like doing it yourself you'll likely have to add on another $300-$400 for someone to handle the labor (still thousands less than a YZ conversion!).

Good luck!

p.s.

I'd love to hear the experience of any others who have done this work. Did you replace anything else? Any other gotchas?

[mxracer111]

there is a guy on ebay right now..... quad customs i think they are..... selling the whole YZ motor....with everything. $1000.00 thats a good price for everything..... then you will need an oil tank, radiator, and some welding skills..... if not i think quad customs said they cousl instal it in your frame for 550 and powder coat your frame..... so.... under $2000 and you have a complete yz conversion