Hello all,

finaly got the 400 bolted back together. she started up righ5t away and everything looked and sounded fine.
took her a few hundred feet down the road and it just died. like it didnt have fuel almost. Well, i cant figure out whats wrong with it now. tried checking the carb etc, it has spark but compression seems kinda low although i havent done a test with extra oil in the cylinder. Any ideas what could be wrong and why i might not be getting fuel? I have the 400 trail ported cylinder, billet head, v force reeds and the 39 pwk carb.

anyway, if you guys have any ideas let me know
and Rick, if you see this please give me a call
thanks everyone
Matt

 

It sounds like it siezed up. Was the 39 prejetted for the trail mod setup? If you werent fat enough on the pilot it would have siezed. Better pull the exhaust pipe off the head and take a look inside. That will tell you pretty quick if it has to come back apart.

 

jammer42 I dropped you a couple of personal messages....if you get a chance reply and let me know what you think.

 

check your fuel tank switch,,maybe it is on "off" position so it can't
deliver the gas trough the hose til the carb...

 

Dont over think it.....If it still turns over and has comp,it could be just a plugged tnak breather...did ya have the tank off

 

i took it all apart
something bad happened cause the piston and the wall were messed up
i sent everythin back to rick and hes gonna try to figure out what happened cause i havent a clue
hes been very helpfull with my questions though. very easy to do business with.
thanks rick

 

Did the piston skirt look like it went molten? Were the rings stuck in the lands? I recently went through a problem like this on my scrammy. It would burn it down in the midrange, it would onlytake a couple hundred feet at a decent cruising speed. I ended up switching to race fuel to cure the problem, this happened after putting a 12;1 comp cool-head on it. Was it pinging at all? Hate to say it but it sounds like it seized. Remember: LEAN IS MEAN but also expensive.

 

yup
the rings were stuck in the lands, the piston material kinda mushed over them
i wasnt going very fast at all and the thing went maybe 800 ft
we put in the biggest jet i got, the 170 to keep it safe.
well, i should know more tommorow

 

Did you say 170? I have a 300 main in my 38 TMX and it is just about perfect you sound way too lean, maybe the 39 PWK is different. What compression ratio is your head? What octane are you running? 92 octane was not enough for mine, it would burn it down no matter how big the needles and jets were. I had it so rich that it would blubber all the way up, but it would still burn it down in the midrange.

 

Sounds like to lean to me. I had the very same problem when I put a 34mm carb on our TB . Your description of your piston looks just like mine did. Mid range was too lean and it melted. After changing the needle and jet needle everything is ok now.