Yes the rings should be staggered. ...brewsters rite, check valves clearance before putting cover on and also pour some oil in the top end on cams and all the parts. anyone else notice it was " dry " going back together? before you crank it kick it over several times..slowly .. alot... before you start it. it would be nice to have oil in all the places it needs to be...its called priming an engine....as for break in.. just dont run it hard rite out of gate. I know what works for me and I explained it.

brewster, on 10 February 2012 - 08:50 PM, said:

yep - I didnt personally, buyt the guy who recond the head and put the new valves etc in did that for me before he sent it up to me.

thanks Bikerman - I smothered the whole lot with a good doseage of oil as I put it together, put oil on the cam journals etc - then before oputting the cam cap on I poured oil through there aswell.

I was on my way to get the replacement water fitting on saturday and I was involved in a road rage incident where i was attacked and dragged from my car. Yep thats right folks, NZ is not the safe little haven people think it is.

needless to say I wasnt in the mood to ride yesterday - nor could i get the broken water housing on the weekend, so the grand moment of startup will be tomorrow night hopefully.

...and still I wait for a small yet vital part to turn up so I can complete this mission. the suspense is killing me !

Berthany the beloved KLX lives again !!

took about 30 kicks, but she fired into life nicely.

I've run her for about 20 mins - varying the throttle accelerating up & down for the first 10 mins, then riding up and down some easy hills and making her work a bit - after she'd well and truely warmed up I started to open her up a bit - and...NOTHING....theres no power there - anything above 4 - 5000 rpm and it just tries to rev but can't pull - she seems to be running smoothly - a little lumpy when idling but generally sounding and running pretty nicely - any ideas ? is it because i havent run the engine in enough yet perhaps....

Are you saying it feels normal until you start into the upper range ? If so did you go thru the carb while you had it off ? I would think that if it was carb related the main is way to lean or the needle is placed down too far. Have you run it enough to get a good plug reading ? I know that this will sound stupid but I had a friend who forgot to remove a rag from his air box and it acted the same way.

have only run it for 25 mins max . yeah it does feel normal - off the bottom it felt pretty good - once you open her up it flattens out completely. I did take the carby off 2 months ago whenn this problem fist happened as i thought it was a dirty bowl - its been sitting on the shelf ever since then wrapped in a rag to stop the dust etc. have checked for rags too - its definately not it....

by plug reading you mean compression ? I don't actually have a compression gauge but i can get it tested easily enough. I'm just concerned that its something to do with the run-in - i wasn't as 'hard' on it as some run-in procedures suggest....although Im not finished running it in yet so its hard to tell.

morgansamuelnz, on 16 February 2012 - 11:03 AM, said:

The main reason for a proper break-in is to seat the rings. What you are experiencing doesn't sound break-in related.
Carb and cam timing would be the most likely suspects. Is there a difference between under load, like in a higher gear or uphill, and just smoothly rolling on the throttle?

Ride on
Brewster

phew ok, thats good - I really was just concerned I'd undone all the money/work I've just done.

no there doesn't seem to be a difference between those two scenarios you mentioned Brewster - while she was running - up the hills (gentle slope on a road) she seemed fine and gently rolling on the throttle on the flat it seemed normal - I did have to change down a gear or two up the hill parts as I didn't want to load it too much at this point. the main difference is on what i would call "grabbing a handful" - theres just no pull at all. I'm going to take her out for another warm up/gentle ride and see if it improves at all or if I can find some more consistency with it.

was just chatting with a bike mechanic - he mentioned with the vacuum carbs there is a vacuum hose that if not connected it won't ruin properly as the slider won't lift up when you open the throttle. I'm at work but I'm going home now to see if this is the case. any ideas where the hose it goes onto the engine ?

The stock Kehien carb uses a hole in the slide to pass the vacuum to the diaphram, no hose. And tha'ts something you might check.......the plastic cage that goes above the needle has "feet" on it. Make sure none of the "feet" are blocking the hole in the slide that the vacuum goes through.

The reason I mentioned under load is that the high voltage side of the ignition system can miss fire under a load if there is a problem in that part of the ignition.........bad plug or plug wire or ignition coil.

Ride on
Brewster

yep - I thought wrong, no vacuum hose. the manual shows one on the KLX250E which i think may have been the diagram i was looking at in the manual.

The only thing in terms of electrics that was questionable was a lead that looked like an earth - with a bolt hole electric fitting. Ive attached this to the nearest bolt that goes into the frame which happens to be the top radiator mounting bolt. could that be it >?

anyway....I went home to give it another whirl, and still no avail after draining the carby and going for a blat with the throttle wide open - she just won't rev or pull the skin off a rice pudding . I noticed she is running a little rough at low revs but not backfiring or pinking...
for now I've admitted defeat with success and taken it down to the bike shop . she starts first kick from cold, so i don't think its anything serious but i just don't have the skills to pin point what it is. . as i said Im quite stoked just to have gotten this far - fingers crossed I can make a ride on sunday…if not…theres always next weekend keep you posted.

I've been thinking - Brewster - could a bad earth terminal be causing this ? when you say mis-fire - would that cause the engine to splutter ? the earth lead I'm talking about was in the same mini-loom that had a wire which plugged into the thermostat sensor on the left radiator - was this supposed to be put on the engine itself - or earthed to the frame ? heres the cable that i think it is in the manual (circled on the picture below) only on my bike theres only one of them, not two as pictured. currently its attached to the radiator mounting bolt.

i should add - the engine is not "spluttering" under the hard acceleration, it sounds smooth but is reluctant to rev - it feels starved - it just doesn't rip into life like it used to....

......and the award for diagnosing mechanical faults over the internet goes to.....BREWSTER

my KLX rebuild mission ended last night at about 6.30 pm. The bike shop was no help - they checked the air screw and that was it. I almost left the bike there for them to just fix next week somtime, but something kept pulling me to go and get her and have one last stab...
So i simply took out the carb, and stripped it down carefully - and Brewster - thanks mate - thats exactly what it was - the small plastic cage was blocking the vacuum hole at the bottom of the slider chamber - it was also sitting crooked as well so even if the slider wanted to come up, it couldnt, as the spring was fouling on the top edge of the cage.....carefully put it back together, and installed it on the bike - not expecting much difference when starting her up.... (you learn to not get ur hopes up after a while) ...BUT...she ripped into life and barked at me - i could tell just by sitting there that she was normal again...took her for a quick spin down the road to check....

"HOLY SH*T" came the muffled cry of enthusiasm from inside my helmet.

what a difference ! I havent properly opened her up yet - but from what I can feel its at least another 3rd of the power, maybe even twice what I had before this whole rebuild - it feels so peppy and responsive, she just wants to rip into life. absolutely stoked I am. (thats kiwi for very happy)

So people of Thumpertalk, it is with a very satisfying feeling in my mechanical soul that I write this final message, and say one last THANKS to anyone who's commented, given advice, or even just followed the story from a far.

I hope someone will get something out of this - if not just a few chuckles at my mechanical 'muppetness' then at least a good story of an old bike returned to former glory by someone who ...lets face it - really didn't know what he was doing.

Moral of the story is - don't trust bike shops - AND - if you think you can fix it, you probably should - just don't expect it to happen fast.

now....first things first.....lets RIDE !!!

over and out

Morgan
NZ

sorry been out of pocket. glad u got it running good. enjoy!

just thought i'd post back to say....went on a big trail ride yesterday did 3 35 km loops - spent the first two taking it easy then opened her up a bit more on the last one - and the bike is awesome. it now has more power then I know what to do with - very surprised at how much better and responsive she is. absolutely stoked ....now to sort out the suspension....

CONGRATULATIONS!!!!
The combined knowledge and experience of this site has to be much greater than any mechanic. Thank you for posting your progress through the rebuild and trouble shooting. Now YOU can post up potential solutions to the next rounds of "What's wrong wilth my engine?" Hopefully this will inspire others to dig in and at least try to fix their bikes...........You cannot succeed if you do not try.
Now, get going on the suspension improvements, a new learning curve.

Ride on
Brewster

You are the real winner here. I am glad it is running like you want it too. When I mentioned plug readings I was talking about making sure your bike is properly jetted so you do not create other issues down the road. What I do is mark my throttle grip with index marks at fully closed, fully open, a halfway point, and then two marks so my throttle is measured in quarters. A mark needs to be placed on the throttle housing that alligns to the fully closed mark when the throttlle is fully closed. There are three fuel circuits to be concerned with. Although they work together each one has more control of the engine at different throttle ranges. It all starts with the proper main jet which has the most influence in the last quarter of the throttle. The position of the needle controls the flow from about an eight turn to about three quarters of the throttle position. The fuel screw adjusts the idle and provides a clean transition as the needle takes control. The purpose of the marks is to figure out where in the throttle range you do most of your riding. In determining proper jetting you will have to pull the plug after a ride and look at the insulator. What you want to see is a nice chocolate tan color. This will indicate a good air fuel mixture giving you the best performance. A black sooty insulator indicates to rich and when it starts looking white you are too lean. A too lean condition can cause the bike to run hot and burn up all your hard work. This process allows you to know where to make adjustments if needed. I am sure there are many processes that people use to get the same results. Any way it has been fun following your progress and the reason Brewster was the first to identify your problem is because he knows his stuff.

Happy Trails