ninjette.org - View Single Post - Pulling the carbs and doing a valve check.

Bob KellyIII · February 13th, 2023, 01:15 AM

Well, back to getting the 2012 250R Ninja running again....
over the last 4~5 days I put the bike back together....
(very carefully I might add) and finally got to the point of putting the carburators back in ( the ones I sent to Gordon..) I took them out of their bac and looked them over and I've never seen them look so good before !
so I started to stuff them in their hole and they would not fit at all.... I set the carbs on the shop rag and started looking to see if I can move the air box back MORE because I had to move it back to get the carbs out..... and I noticed that the air box was all the way forward again... i don't know HOW it got there
but it was.... so I managed to move it back as far as it would go AGAIN and what'da'ya' know the carbs went in there 1st try ! ....well after I took off the left cylinder carb boot for the intake.... then after they were in there and posisioned correctly, I put that boot back in (in the proper orentation) clamps and all.... so the carbs were on.... it was cold so I didn't work on it much more that night... and over the next 2 days I had everything all hooked up and air box back where it should be. and the throttle cables on and routed correctly as I had to move them 2 times to make sure they were not binding in any way.... so the throttle and choke levers work much better than they ever did before.... I put 50/50 radiator coolant in the bike and checked for leaks... and didn't find a single one. I then put on the gas tank and Hooked up the vacuum lines on the front and the gas line and vacuum line to the petcock and plugged in the fuel gauge. and then I could try starting it.
.... I turned the petcock selector to PRI and gas filled the fuel line filter and gas came running out from under the bike.... I turned it to on and then took a wrench and tapped the bowl of the carb on the left side that was stuck and it finally stopped leaking..... it set in that bag for a long time on my bench
so I guess that float valve decided to stick.... but it did stop leaking with a few good whacks ! so that's good...
I hooked up the battery turned on the choke and key and hit the starter button and it turned over about 12 times then tried to start ... at first it was barely able to idle so I added a little to the idle adjust knob and then it set there idling at about 400 RPM.... so I let it idle a bit.... no leaks anywhere
but the valves were clicking noticably .... but as it warmed up that went away
as it warmed up the RPM slowly gained which is usual.... I gave it some throttle and it reved right up to about 4000 rpm.... I held it there and did not notice anything amiss.... it was running on both cylinders nicely...
i let it drop to idle and recover and then gave it a handfull of throttle and it
jumped up in RPMs but at the top RPM's it sounded funny....
so I did that again and this time it went up to 8000 RPM and then fell to 4000RPM and held that... when I was holding it at the 8000 throttle position
I thought eeek that's not right at all.... !
so over the course of 2 days I have replayed that sinario dozens of times
and each time it will not take throttle to 9000RPM and hold it ...it drops doen to 4000~6000 RPM and it sounds bad when I try to take it to higher RPMS
like it is running very lean.... misfires and pops and in general running like sh*t..........
after talking to Gordon I thought he replaced the jets in the carbs with stock jets but he told me it had stock jets in it already... so he didn't change a thing.... and all this time I thought he changed them to smaller jets so I figured the jets were TOO small.... but that's not the case as their the same ones that were in it.... so that means "USER instillation".... or ..dare I say it ...valve timing !
.....
so what I know about motorcycles or engines in general I've came to this conclusion.... it's either got one heck of a big AIR leak or the valve timing is off..... ( probably only a tooth) because it runs and runs fairly good below 4000 rpm valves will do that..... I've seen that before on a VW engine
it would not take throttle at all.... ....there were 2 punch marks on the crank
I happened to guess and used the wrong one... luckly no valves were bent !
.....(Old 36hp VW)
so sense I spent all day playing with the Ninja trying to find a vacuum leak
I am thinking that it's not the vacuum at all... but the valve timing even though I double/tripple checked it before I put the valve cover back on it.....
perhaps it moved one tooth .......
the only way I'll know is to pull it apart again.....
.... and that is the LAST thing I want to do on the Ninja....but I have no choice as it won't run this way.
.....
AURGH !

....
Bob......

February 13th, 2023, 01:15 AM	#56
Bob KellyIII Retired motorcycle Mc. Name: Robert Location: Weed, California. Join Date: Jul 2021 Motorcycle(s): 2012 Kawasaki Ninja 250R, 2021 CSC TT250, 1977 Triumph Bonneville 750cc,2001 Honda XR650L. Posts: A lot.	Well, back to getting the 2012 250R Ninja running again.... over the last 4~5 days I put the bike back together.... (very carefully I might add) and finally got to the point of putting the carburators back in ( the ones I sent to Gordon..) I took them out of their bac and looked them over and I've never seen them look so good before ! so I started to stuff them in their hole and they would not fit at all.... I set the carbs on the shop rag and started looking to see if I can move the air box back MORE because I had to move it back to get the carbs out..... and I noticed that the air box was all the way forward again... i don't know HOW it got there but it was.... so I managed to move it back as far as it would go AGAIN and what'da'ya' know the carbs went in there 1st try ! ....well after I took off the left cylinder carb boot for the intake.... then after they were in there and posisioned correctly, I put that boot back in (in the proper orentation) clamps and all.... so the carbs were on.... it was cold so I didn't work on it much more that night... and over the next 2 days I had everything all hooked up and air box back where it should be. and the throttle cables on and routed correctly as I had to move them 2 times to make sure they were not binding in any way.... so the throttle and choke levers work much better than they ever did before.... I put 50/50 radiator coolant in the bike and checked for leaks... and didn't find a single one. I then put on the gas tank and Hooked up the vacuum lines on the front and the gas line and vacuum line to the petcock and plugged in the fuel gauge. and then I could try starting it. .... I turned the petcock selector to PRI and gas filled the fuel line filter and gas came running out from under the bike.... I turned it to on and then took a wrench and tapped the bowl of the carb on the left side that was stuck and it finally stopped leaking..... it set in that bag for a long time on my bench so I guess that float valve decided to stick.... but it did stop leaking with a few good whacks ! so that's good... I hooked up the battery turned on the choke and key and hit the starter button and it turned over about 12 times then tried to start ... at first it was barely able to idle so I added a little to the idle adjust knob and then it set there idling at about 400 RPM.... so I let it idle a bit.... no leaks anywhere but the valves were clicking noticably .... but as it warmed up that went away as it warmed up the RPM slowly gained which is usual.... I gave it some throttle and it reved right up to about 4000 rpm.... I held it there and did not notice anything amiss.... it was running on both cylinders nicely... i let it drop to idle and recover and then gave it a handfull of throttle and it jumped up in RPMs but at the top RPM's it sounded funny.... so I did that again and this time it went up to 8000 RPM and then fell to 4000RPM and held that... when I was holding it at the 8000 throttle position I thought eeek that's not right at all.... ! so over the course of 2 days I have replayed that sinario dozens of times and each time it will not take throttle to 9000RPM and hold it ...it drops doen to 4000~6000 RPM and it sounds bad when I try to take it to higher RPMS like it is running very lean.... misfires and pops and in general running like sh*t.......... after talking to Gordon I thought he replaced the jets in the carbs with stock jets but he told me it had stock jets in it already... so he didn't change a thing.... and all this time I thought he changed them to smaller jets so I figured the jets were TOO small.... but that's not the case as their the same ones that were in it.... so that means "USER instillation".... or ..dare I say it ...valve timing ! ..... so what I know about motorcycles or engines in general I've came to this conclusion.... it's either got one heck of a big AIR leak or the valve timing is off..... ( probably only a tooth) because it runs and runs fairly good below 4000 rpm valves will do that..... I've seen that before on a VW engine it would not take throttle at all.... ....there were 2 punch marks on the crank I happened to guess and used the wrong one... luckly no valves were bent ! .....(Old 36hp VW) so sense I spent all day playing with the Ninja trying to find a vacuum leak I am thinking that it's not the vacuum at all... but the valve timing even though I double/tripple checked it before I put the valve cover back on it..... perhaps it moved one tooth ....... the only way I'll know is to pull it apart again..... .... and that is the LAST thing I want to do on the Ninja....but I have no choice as it won't run this way. ..... AURGH ! .... Bob...... __________________________________________________ Its too late when you've gone too far !