1986-2007 carbs

[Motofool]

Originally Posted by juliusmichaelhonrada

btw when i opened my cam chain tensioner , there was no spring inside , and its all rusty and dirty, there is just 1 bolt , and 1 round like bearing .. but still when i put the cap on , it still give some tension on the cam chain to the point that teeths dont jump

A spring is essential for that tensioner to work.
There is no tension on the chain with no spring.

We have too many variables now and need to take a break and start from the beginning of the combustion process.

First, you need to clean, service and install a spring in that cam tensioner:
http://faq.ninja250.org/wiki/Cam_cha...sioner_removal

After that is OK, insert a pencil in the spark plug holes and slowly turn the crancksahft.
Mark the top dead center for each cylinder on the flywheel.
If those marks coincide with the factory marks, the flywheel is in the correct angular position respect to the shaft.

Next, you need to determine what the valves do near the four TDC's.
For one cylinder, all valves should be completely closed (there is a gap between cams and rocker arm's points of contact) near one TDC and all should be at least partially open for the second TDC (timing overlap).
Same for the other cylinder, but in a different phase.
Adjust the timing as needed.

Check the compression of each cylinder; roughly by hand if you don't have a proper tester.

Only then, you adjust the proper gap of all the valves.

Link to original page on YouTube.

[RacinNinja]

Is it possible he has a MANUAL cam chain tensioner? From his description, that seems to be the case. Pictures are worth a thousand words.

[juliusmichaelhonrada]

Originally Posted by RacinNinja

Is it possible he has a MANUAL cam chain tensioner? From his description, that seems to be the case. Pictures are worth a thousand words.

Yes i think my ninja is older than me , its a 1988 GPX250-RII japan only domestic market version of the ninja 250 with the dual front disc brake

Yes it think , by the way guys everything seems to be perfect . The timing was perfect , the Flywheel didnt slip i can confirm 2T is indeed 2TDC and 1T is 1TDC i had inserted a screwdriver in the plug hole , and i can see it rise and fall. I confirmed it rise on exhaust stroke and compression stroke and goes down on intake and power stroke both cylinders.

Im going to check the spark plug next because the tension wires does not look stock its like been taped by an electric tape , the spark plug is not U24FSR its a U22FS denso... for 125cc mopeds damn good thing the previous owner did not put a longer plug than 12.7mm threadreach or he destroyed the whole engine.

As for the chain tensioner , it doesnt have a spring , and i can see inside the cap there is a Nut and bolt system that i had never seen in the pregen ninja with spring , i guess mine is a manual one

[FrugalNinja250]

That looks like a standard tensioner assembly. The way it works is a spring pushes the rod downward through the ring with the ball bearings in it. The ring and balls are called a sprag clutch, they allow the rod to only travel downwards but not back up again. You're missing the spring. The screw up top in the housing is only for assembly. You loosen the screw almost all the way out, push the rod up into the housing until it bottoms, and tighten the screw so that it engages the groove at the top of the rod to hold everything in place. You tighten the housing down on the engine casing then loosen the screw to release the rod. The spring pushes the rod downward to engage the cam chain follower, then you tighten the screw to keep it from falling out. Once the rod plunges downward the screw does nothing when it's tightened.

[juliusmichaelhonrada]

Originally Posted by FrugalNinja250

That looks like a standard tensioner assembly. The way it works is a spring pushes the rod downward through the ring with the ball bearings in it. The ring and balls are called a sprag clutch, they allow the rod to only travel downwards but not back up again. You're missing the spring. The screw up top in the housing is only for assembly. You loosen the screw almost all the way out, push the rod up into the housing until it bottoms, and tighten the screw so that it engages the groove at the top of the rod to hold everything in place. You tighten the housing down on the engine casing then loosen the screw to release the rod. The spring pushes the rod downward to engage the cam chain follower, then you tighten the screw to keep it from falling out. Once the rod plunges downward the screw does nothing when it's tightened.

The bolt in my tensioner is not stock right? i think the previous owner , slipped some bolt and a nut and tightened it with the screw so that it permanently pushes down the rod without the spring?

What i did to diagnose the tensioner is , while at 2T mark in the sightglass , the tensioner is not bolted down tightly in the engine but still has some tread sticking , when i turn the crankshaft the tensioner bolt wants to go up and down and the chain was not tight and the cam skipped a tooth or two so i had to remove everything again and retime it .. but when i boltdown the tensioner assembly fully tightened the chain cant skip a tooth no matter how hard i crank it and how fast , how do i know if it tensions good enough


update :
the bolt and nut inside the housing was like a manual tensioner , when i rotate the nut counterclockwise the housing goes up pushing teh bolt more down and tightening the tensioner more and vice versa... lol

[juliusmichaelhonrada]

Originally Posted by Motofool

A spring is essential for that tensioner to work.
There is no tension on the chain with no spring.

We have too many variables now and need to take a break and start from the beginning of the combustion process.

First, you need to clean, service and install a spring in that cam tensioner:
http://faq.ninja250.org/wiki/Cam_cha...sioner_removal

After that is OK, insert a pencil in the spark plug holes and slowly turn the crancksahft.
Mark the top dead center for each cylinder on the flywheel.
If those marks coincide with the factory marks, the flywheel is in the correct angular position respect to the shaft.

Next, you need to determine what the valves do near the four TDC's.
For one cylinder, all valves should be completely closed (there is a gap between cams and rocker arm's points of contact) near one TDC and all should be at least partially open for the second TDC (timing overlap).
Same for the other cylinder, but in a different phase.
Adjust the timing as needed.

Check the compression of each cylinder; roughly by hand if you don't have a proper tester.

Only then, you adjust the proper gap of all the valves.

Link to original page on YouTube.

yes sir , i opened it up again today everything was fine , i remember now what the previous owner did , He switched the intake cam , and put it into the exhaust cam and the exhaust cam goes to the intake cam , then he aligned the marks via the 1T mark in the sightglass, thats why when i put it in 2t ,the mark on the cam point upwards , i tested it now and it should never point upward in any 2T no matter what stroke it is , it should only point sideways opposite side and pointing against eachother horizontally no matter how many turn on the crankshaft and the 2t mark in the sightglass shows

[juliusmichaelhonrada]

I tested the spark plug , it wont spark unless i push the starter button, is it normal?

I mean im cranking it in the flywheel by hand , when i see 1T or 2T in the peephole i should see a spark or it doesnt work that way ? this was done with the battery connected , the engine kill switch is set to on .

I can only see sparks when i push the starter button but thats happening so fast i cant actually see my spark timing relative to the crank, and oil squirted on the peephole and almost covered my face lol

[juliusmichaelhonrada]

Ok guys i have some update , the bike fired up on the first 3 second of cranking with full choke on , i found out the spark plug wire was mutilated and as i remove the electric tape it just fell off... what i did was cut the high tension wire rubber to expose some 1 inch of wire , then intertwined them together with a longnose and bombarded it with electric tape...


But still the bike would die without the choke..

It started idling high at about 4000-5000 rpm when i play the choke knob on and off , it respond instantly , when i turn off the choke the rpm would go down and die slowly , when i turn on the choke it goes back up to 4000-5000.

How would i rectify this issue , where should i start

[juliusmichaelhonrada]

Lol guys after i posted that one , 1 minute later i went down and started it again , i can simulate the action of the choke by covering the carburetor , when i cover half of the carburetor it would IDLE so good like it was in choke and it wont die ..

I WILL BUY AIRFILTER TOMORROW ! OH IM SO HAPPY NOW ! I LOVE YOU ALL GUYS THANKS FOR STICKING UP TO ME

[juliusmichaelhonrada]

after i corrected that timing guys , NOT EVEN A SINGLE BACKFIRE was given that day , and i even havent adjusted the valve clearance and spark plug gap because i dont have a feeler gauge right now , OH BUT IM HALFWAY THERE

[juliusmichaelhonrada]

I tried it again and covered almost 3/4 of the carb WITH THE CHOKE OFF ,and it still can idle up to 1500 rpm low at its operating temperature i can see smoke coming from the exhaust manifold from the engine oil that i put in there to avoid corrosion so it is hot .

so my pilot jet was too small and the mixture was too lean, how can this be possible i saw a #38 pilot jet and my pilot jet hole is like 2x bigger .

my pilot jet is #48 it should be very big , well but i have no idea about Open carburetors with no filter the mixture was so lean at this setup , i even only have the air screw out for about 1 turn and a half

my main jet is #138