xj650 brat/tracker

my 10mm sockets mysteriously vanish. I am buy a new one on average twice a year

 

I want this shirt

 

to give an update to this the wheels are painted and look great. I tried two motogadget speed sensors a two wire and three. The two wire sensor worked but wasnt accurate, so I removed it. to test it I glued a magent to the chuck on my drill and placed it 1/8th of an inch from the sensor, and wired it to the bike. the drill spun at a consistent speed but the two wire sensor would jump from 25 to 80 mph. the koso speed sensor is 3 wires and was consistent. I am still looking at other options but might try a gps sensor koso sells. just don't know how reliable it will be driving through Manhattan. I found other 3 wire sensors but aren't worth the money or smaller than the koso sensor

 

To recap another thread, I was getting rf and emi interference on my mbutton, so I replaced my plug wires with supression spiro wires by taylor. seems ok but I still see the occasional random turn signal flash. less than before, going to try a copper wire mesh on the button to see if that helps.

I did run into a new issues this past weekend, for some reason my boot to head gaskets started to leak giving me a lean mixture, so after eating tacos for dinner I made new gasket seals using the taco box... I used permatx gasket dresser and sealant to make it a lil beefier. it works beautifully. Did a color tune to check the new coils, gaskets and wires and 3 and 4 were perfect, 1 and 2 great spark but would not fire unless I gave it throttle. I sprayed starter fluid into 1 and 2 at idle and with the color tune in and they came to life.

I suspect it to be a carb issue, but I am concerned it could be a piston ring problem. I rechecked the valve shims and they were in spec, going to double check after I warm up the engine. last time I checked the valves shims the engine was cold. not sure if that makes a difference.

I won't work on the bike for another 2 weeks but these are the steps I plan on doing to trouble shoot.

compression test
leak down test
check floats
inspect jets

is there anything else I should check?

 

Valve clearances are always to be checked with a cold (ambient air temperature) engine.

I'd check to see that the floats on 1 and 2 aren't stuck, preventing fuel from getting into the bowls. Sometimes they can get airlocked on the first fill too.
Rap on the bowls with a screwdriver handle, and crack the bowl drains to check for flow.
Might be worthwhile to inspect the vacuum port caps too while you're down that way.

 

i'd swap the plugs around first

 

it's not the plugs they are new and it's happening with the color tune in. I can see it arching with the color tune but no bueno unless i give her throttle.

caps are nice and tight. I coated the boots and carb with starter fluid while it ran looking for a leak and nothing.

I really hope it's the floats. I want it to be simple.

 

hi folks, hope everyone is playing it safe with covid. I finally have some time to work on the bike again wooohoo and I have a confusing problem.

I performed a compression test and I got 160 psi on 1 3 and 4. on cylinder 2 I got 150 psi, added a lil engine oil and it shot up to 200+ psi.

I rechecked valve shims, made some tweaks, did another test, same numbers. I performed a leak down test and... I am concerned. 3 and 4 are perfect, minimal psi drop. 1 and 2 is horrible, 2 doesn't hold anything sounds like its comes out the intake and exhaust. cylinder 1 100psi spins the motor, at 70 psi nothing spins but comes out the intake.

I am about to pull the head to look at it but could this be a shim issue or valve seals? I don't thinks its the rings but then why the increase on the compression test.

need advise and I can take video if necessary

 

update... pulled the yics blocking tool i use and replaced the orings. no issues. I did a leakdown at 100psi and it leaked. Thinking the values are moving a bit, did it again at 70 psi no leak. slowly increased the psi to 100 and equal pressure all the way through.

I hate yics. it there a better way to block it?

 

just completed another compression test... 190 psi. there is still oil in the cylinder. shoukd I pull the heads and check?

 

how did you do the leak down test? did you make sure the the valves were closed on the cylinder you tested?

comp test increasing with oil is normal it indicates rings.10 psi difference is in spec.

 

Prior to test i bring each cylinder to top dead center, then hook up the gauges and perform the test. #1 would move at 100psi so i would do 70psi and raise the pressure. I pulled the yics blocking rod that i normally keep inside to check it on a hunch and replaced the orings and i found some burnt gunk on the rod. cleaned and replaced the orings and redid the test and no leaking.

I thought when you add oil to the cylinder there shouldnt be any increase on a compression test. if you do, its a sign of a bad ring. When i redid the compression test on #2 with oil still in it, it shot up to 190 from 150. isnt that a sign of a bad ring or am i looking for a problem i dont have.

 

oil will seal rings it is whats done to find if its rings or something elas.

do you run your motor ride it with the yics blocking tool in place?

 

I do, I never take out the yics blocking tool

 

went for a ride today. couldn't resist. driving good, gotta tweak a few things but all is well.

might swap out my speedo for something different. the koso tnt is fussy.

I have a side project... i am attempting to convert a cbr300 rear wheel with disc break to fit the xj650 by cutting down a rear clutch hub from an xj900. Got most of it done... just need a mill to get everything round. The hub fits the rim with some modifications. I also need to make the bushings which isn't hard.

 

I also want to lower the front of the tank no rush and rather get the rear disc sorted.

 

What do you mean "rear clutch hub" Confused (not unusual for me)
I used a hub from an XJ1100 (has disc brake that I didn't use) and a front wheel (tri-spoke with rim) from a 2000 R1. I TIG welded it together and it's centered properly and true. I can't get pictures to load otherwise I'd have shown it a month ago, sorry about that. About the disc brake, I made an adaptor for a modern rear rotor from a moto-X bike to mate to the XJ hub. Now the front and rear wheels match and are both 17" for modern radials, Pirelli Diablo Rosso III 120/70/17" front and matching Pirelli 140/70/17" rear. Then I run a custom S/S brake line to the left handlebar and M/C for a "Thumb Brake"
Cheers, 50gary

 

on the xj900 rear wheel the drive clutch hub (gear) comes off on its own hub and uses bushings. I matted thus to a cbr300 rim by reducing the diameter and trimming the prongs that go into the hub/bushings. if I get this to work then I just need to buy a rear disc, caliper mc and bracket from the cbr300 or just go brembo.

 

would love to see photos

 

So you have r1 front wheel on the back, what do you have up front?
I'm contemplating using x900s wheels front and back, with brakes on my 900f frame project, any pitfalls you see? Sorry for the hijack...