itspuddingtime00

I had to replace the carb body on my trx 2.5, so I reset all the needles to factory settings. When I ran it today, my engine just wouldn't hold an idle or tune. It was constantly idling high, then it would drop down and eventually die out. Also after every time I restarted it, I would have to retune, and it would eventually lose that. I was getting temps around 250s and 260s. Its really frustrating becuase I've been just dishing out money the get my revo up and running, and when I finally do, it runs like complete crap. The weather outside just started to warm up a lot, and it went from 50s and 60s to 80s. Could this cause my tuning issues? One more thing, for those of you with MS airfilters on your revo, do you have any problems with the spur rubbing agianst the boot and ripping holes in it? This is my second MS airfilter and I'm running stock gearing. There seems to be no happy medium where they both won't touch.

scaryfast68

lots of people i race with have complained of replacement carbs causing probs. they dont seem to seal as well as the stock one. one thing i noticed with mine is that when you press the carb down on to the engine case push HARD and make sure it clicks down into place otherwise u will have a leak cus the little red o-ring isnt sealing enough. my two cents, hope it helps

itspuddingtime00

Alright, I'll try taking it out again and pushing down this time. Any info about the motor saver air filter rubbing?

mittimj

cant help you with the filter troble. but your engine troble sounds like a air leak somwhere. I would try seating the carb better against the case like scaryfast said. I take a little hammer and give it a tap to get it in.

itspuddingtime00

I tried pushing it in, and it helped a little, but my idle is still really high, then it will drop down and cut out. Also I have to run it really lean in order for it to shift and get up to top speed. If I run it the slightest bit rich it will go about 15 mph WOT and never shift. But I'll turn the HSN 1/8th of a turn and I'll see no smoke, but it will shift fine and reach top speed. Also, I took the temperature of my pipe and it was 260! It never gets that hot. It was hotter than the engine. I'm about to bring it down to my lhs and ask them to tune it for me, but I don't think its worth it, because it will be way off next time I fire it up.

stilllost

My Feedback: (3)

patience

don't give up and last throw that dam temp gun in the medicine cabinet. you said you check the exhaust temp and it's higher then the head hmmmmm wonder why? have you done the pinch test like the manualsays? look thru the manual and try to troubleshoot. i could give you my setting here on the coast and they would be way off. what you are looking for is blue smoke. the shift point might be set high, shifting late. try adjusting the shift point..

sorry for venting. had one of those days

itspuddingtime00

I have adjusted the shift point as oulined in the manual, and it didn't do much. I can pretty much tune it, but my biggest problem is the idle. I'll bring it to a stop, and the clutch will start engaging and the truck will move forward, then all of a sudden the idle speed will drop significantly and it will cut out. It will only run for about 7 seconds at idle before it cuts out. When I try and decrease the idle speed to stop it from jumping forward, it won't start. Also when I lean my lsn my idle speed goes up.

stilllost

My Feedback: (3)

ok try to richen the lsn. there are only 2 reason to mess with the lsn for racing, which is not going to be much, and as a last resort. try putting the lsn to stock setting which is flush and start over. get the hsn dialed in first dont worry about shifting right now. btw, i hope you turned the right screw for the shift point.

after you get the hsn dialed here's what you look for on the lsn side:

when gone it from the start is there alot of smoke then kind of tapper off? lsn TOO RICH
bog down when you nail it? TOO RICH

from you said in last post it sounds like your too lean.

me personally i never touch the lsn until the engine gets old and worn, too much of a head ache for the lack of gains. IMHO

Crazy Canuck

Hey, I had the same problem with my MS airlfilter, spur was tearing away at it. What I did was modify the MS airfilter to accept the stock Revo airfilter tube...works great and no rubbing. I just measured the stock airfilter hole and traced it onto the MS Airlfilter, cut out with hobby knife...fits like a charm and engine runs great.

Cheers

itspuddingtime00

Thanks a lot, I just did that and it works really good.

Crazy Canuck

Glad to be of assistance...Happy Bashin!

Cheers
[8D]

itspuddingtime00

haha yeah, only if I can get my engine tuned up and running smoothly.