whats my tunning issue?(w/tuning vid)

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kryptonite5b

kryptonite5b

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so ya. ive come to realize my tt may have a tuning issue. its easer to just show a vid, then going back and forth. i always thought this was a symptom of being over geared, but today, for giggles i swapt back to stock gearing just to see. and it does the same thing. i thought it might be too rich and loading up, so i leaned it out, but it did nothing. maybe becouse it was? i don't really know why, but now i want to fix it. my mt on-road is over geared and it is consistantly the same for the whole tank. also take note to the difrence in the pipe sound. in the beginning it crackles, then it gets muffled and soft. i normally run 31/29 gears, but today went back to stock 29/31. the motor is an o'bros ported 26.9 with a stock carb and 8k spring. it did this before the motor job as well.
http://www.hobbyzip.com/videos/947/my-tuning-issue.html
 
first thought is its getting a bit lean as it gets hot. maybe the beggining stages of heat soaking.

i to have noticed sometimes motors will run better when cold then when warm. I am going out on a limb here and thinking it has to do with the ring becomming to worn.

as the ring wears, it gets less compresssion, so when cold its tighter than it is once its wamred up and things are expanded, therefore the compression drops a bit.

just a thearological thought.
 
the engine is worn and needs a rebuild.

its the tell tale sign great power cold, but drops off once warm, this meant shes worn out, also can be tune its its to lean, and runnignt o lean will cause the need for rebuilding soon then later

time for a new ring atlest, if the engines not that old mabe a a tune rethink after you rebuld it
 
thanx for the help guys. as far as the motor. it only has a gallon on it, maybe a little more. it did the same thing even before the motor job. again, it has always been overgeared so i just assumed that was the issue. last night i checked it for leaks and its just fine. it runs good, but just reall slugish before the pipe kicks on. the plug is a good color, maybe a little on the lean side(color), i run 32:1. my other rigs show no signes of this. my street rig is also over geared, but set rich and my mt is running a little lean. none of them do this tho. they all run ok.. could it be a ring at a gallon? i did 1 break in tank at 25:1 and haven't stopped beeting this pig.. i just want it to be consistant now that i know its not a gearing problem..
 
I have had a ring good bad after 1 gallon of fuel....A ring is cheap insurance....
I like to sat with 25:1 mix....I have used both 32:1 & 40:1 mix.....I feel 25:1 you need the
little extra oil for the lubing engine bearings...Just my opinion..Slawhammer
 
so i just got back.. its a mess. i started tuning it on the dirt road. had it tuned in about 15 minutes. took it on the grass and in a few laps it started bogging down. pulled it over and let it sit at idle for about 8 minutes.(got mt started for wifey).. put it back on the grass and it was an animal.. 5 minutes later its back to square one.. bogging down, so i did some speed runs(still dragging ass) on the dirt road to check the plug and its fine. light brown.. so i leaned it out. went a little better, but a few laps in she wont go till the pipe kicks on. checked plug, its white(i leaned it out). so i swapt gears. back to the 29/31. cleaned plug and retuned really quick, again, animal off the line, but coming out of the turn it sounded like the clutch slipping. hard to tell couse my tires arent that good(but its 4wd). within a few minutes it started again. bogging and dragging ass till the pipe kicked on. most of the time its still drivable, but now it cant even get out of its own way. i sprayed the whole thing down with wd-40 and the motor didnt spike. its hard to get to the main seals. but i really don't think an air leak couses this. its not running lean and keeps an idle.
could it be the clutch?. its the only thing that has stayed the same. it doesn't feel like anything is dragging like brakes or drive line. i would think if the spring gets hot and lose that the motor will still pick up. i didnt think to rev the motor to see where its grabbing. i keep looking at the tune becouse of how the pipe sounds muffled when it gets warmed up. when i pulled the head it all looked good. nice and clean and the ring looked fresh, but im still going to order a new ring, or simply blow this motor up and start over. i just really want to figure this out first. when i pulled the motor, the head looked brand new(it is!). it did the same thing ever since i put the pipe on it with the first motor, but now its really bad.

on the lighter side. still had enough fun to break a drive cup,drive shaft, stearing servo, and a stearing mount, and the wifey ran a full tank thru the MT. she said that is now hers and she loves it. she giggled like a school girl when she realized that if she runs over my truggy it makes a cool jump. she was way too cute out there with here manicured nails and a mini skirt..

clutch?
ring?
carb?
air leak?
please watch the vid again. im at a loss on this one
 
if the inside of the cylinder looks new & the same for the piston ring...seal up a new base gasket on the cylinder...I like to use copper gasket..What carb you using?...no air leaks...my next bet would be clutch...what are you using stock shoe's and red spring?
you know the tune ..color for the spark plug....
great to hear your wife had a grand time.......Slawhammer
 
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