82' xj750 maxim repairs.

Correct!

 

Since I'm waiting on parts to arrive now for re assembly I figured the next step was to check valve shims. Realizing my set of feeler gauges wasn't accurate enough ( jumped from .10-.13 and from .15-.18.) and without a feeler gauge for every size I don't feel comfortable confirming any numbers, but I did go ahead and give checking them a "test run". Since I have never done this before. Seems alot scarier than it is. Also have to replace two of these rubber seals on the inner screws.


I added photo of what position I put the came lobe in just to be sure, because some of the numbers are way out of spec. I'm going to check them all again and compare results once I get a new set of feeler gauges.







I did have a small amount of blackish oil stuck to the magnet when I drained the oil. I know any amount of that is place for caution but how much should I be worried? I forgot to snap a pic before I wiped it off on my finger tips to feel it.


When I turned the motor over with the wrench, it acted totally normal and smooth

 

P.s is some surface rust on the sides of the cam shaft normal over time in a humid rainforest like environment, like mine haha?

 

Also got the insides and outsides of these nice and clean. Ran q tips in them until they came out clean.

 

You're on a roll! Valve position looks fine. Fuel pipes look great. It's not uncommon for valve clearances to be really small ("tight") if they haven't been done in quite some time (i.e. the previous owners ignored checking/adjusting them), as valve clearances DECREASE over time. Tight valves, especially exhaust valves, are a Very Bad Thing (it's much easier to burn an exhaust valve). Since the previous owner(s) neglected this basic task, they probably neglected everything else, too, so go over the bike with a fine-tooth comb (inspect/adjust steering head bearings, swingarm bearings, wheel bearings, , inspect all brakes, probably needs master cylinder and calipers rebuilt, change engine oil, fork oil, and final drive fluid).

 

Yea it definitely shows that neglect was had for sure with clearances that low. Poor bike couldnt exhale..!

Brake pads on the front are newish, fluid inside the master cylinder was crystal clear when I got it and still is.., someone had installed the stainless lines on it so I'm assuming that was all done at once. I picked up some EBC rear pads for it so that'll get done, got 10w fork oil with oil seals and dust seals.

I definitely do need to check wheel bearings, head tube bearings, final drive fluid flush ect.


Good thing she's off the road for awhile. The master list can get done while she sits in hibernation.

 

As for the .13 intake valves. Should you set the limits at the biggest gap, so you have the most time before having to do them again or should they be right in the middle of the tolerance?

 

As long as the valve clearance are anywhere within the specified range, you're okay; and besides, shims are only available in 0.05mm size increments (actually, older model BMW's also used the same size shim and they came in odd size increments, but they are only available used, and are hard to find and can be expensive...…..). Spec is spec, so for your intakes, you're going to have (after replacing shim #1), you'll have 0.15 - 0.13 - 0.13 - 0.13mm for the 4 intakes.....this is fine. In an ideal world, you'd want all of them the same (anywhere within the specified range), but in reality, it's not worth the effort and will not produce any useful or meaningful positive results.

 

I wouldn't feel too bad about it - some neglect yes but there have been quite a few members that have found valves with no clearance. I think sometimes PO's are afraid of the valve adjustment and worried that they will screw something up - especially if they had not joined xjbikes for the encouragement and advice to make the bike safe and reliable. Those stainless steel front lines are a real bonus and at least something positive as far as TLC for the bike.

 

you will have no choice as it is determined by the shim size.
your intake .10 will be set to .15
exhaust .15 will be .20 exhaust .09 and.07 will become .19 and .17

metal filings on drain plug is normal unless you find a lot every time you change oil better on plug than in motor

 

A lot is kind of subjective, maybe this would help. Do you consider this a lot or about normal? I'm not sure there is a right answer but it never hurts to ask.

 

okay awesome, i know some other threads ive read people have had very low readings also.. just couldn't remember if there was anything else you could do, besides change the shim. Yea the SS lines were a big motivator to buying this bike. Some things were shotty and unknown, but there was some good parts on it atleast, like the SS lines, newer tires and what not. I paid about 1000 bucks for it, took a gamble, and seems to be what i paid for so far haha.

Thank you for bringing this up, Im also interested if thats a little, or a lot. I had about that much on mine as well.

also interested in knowing what is normally wearing and causing this, or is it multiple parts that make contact just slowly wearing down over time.. USUALLY, that is?

 

drain plug would be from transmission gears, chains (internal) and the gears they connect to

shim clearances change as the valve beats itself into the valve seats

 

Bigfitz's AIRHEAD VALVE ADJUSTMENT with Pics - parts I & II
In-spec is in-spec. No micromanaging required.

GO ahead and dip the carb bodies while you're wating on parts (follow the reccomendations on the can). Spray cleaner never gets them as clean as a good dip will.

 

if you've never had the oil pan off and cleaned it out, there's no way to know if the iron on the magnet is new or was just hanging around in the back of the pan
that picture looks fine to me

 

Is this something I should do while I have the time to inspect? I know in cars / trucks you don't take the oil pans off for shits n giggles but since this one is so small and accessible might as well?

Or does the motor have to be removed from the frame to do so

 

I picked up some gunk brand hydro seal parts cleaner, and I'll soak them as per your advice!

 

i think it could be done in the frame, i don't think it would be easy. it's not that hard to pull the motor but it is a heavy s o b

 

It's a slippery slope, if you pull the motor you may as well go ahead and take care of the primary chain guide and rebuild the starter clutch. And, speaking of the chain guide, I guess I can imagine / speculate that some of the metal filings might be coming from the chain grinding away at the oil nozzle - I really prefer not to think about that.

 

I did pick up a new oil filter, gasket and washers today. Painted up the oil cover a golden yellow. I think I'll go black bike with the golden accessories , calipers and some other items. I had an anniversary edition Yamaha dirt bike ( an 06' 450 yzf ) and I loved the old black and yellow scheme. I'm currently hunting down a seca tank which will be all black with a yellow Yamaha decal of some sort.





Took the calipers apart today. Pads were good and all rubber seals seem good aswell. One kinda rusty bleeder valve so I cleaned up the hole and I'll get two new bleeders. Gave them a coat of paint and just waiting for them to dry before install.


Noticed the tci unit has been swapped with one from 83.. Hmm wonder what that's about.





I also have a box of parts and a maxim tank for sale if anyones interested in them. Just random odds and ends that will sit in a box for ever collecting dust if I don't pass them on to someone who'd use them.


Stock cluster. It all works. Some clips cut off on the back

750 maxim tank

Highway leg bar/engine protectors

Rear tail lamp plastic

Foot pegs

Stock bars.

And other odds and ends I'll look into more.





( These sideways photos are killing my ocd..) I don't know why they upload like that...

 

Also got these trim pieces laying around.

 

.

 

I assume you mean 83 and not 93 tci. the tci from any of the 81 to 83 650 and 750 will work properly in your bike. even the black box tci will work but has no connection for the sidestand safety circuit.

 

Went back and fixed that. Thank you

 

After receiving some parts from xj4ever, I took a couple hours and got the throttle shafts and butterfly's back in. Thankful I attended church more than usual lately, and took photos.






Carb #1 is showing some tiny bit of light through the one side so I'm going to have to adjust that butterfly a tad when I get some more time in the next few days.

Will be pulling the last two exhaust shims needed for measurements,and placing an order for those shortly.

 

Nice n fresh shaft seals.

 

Had some more time tonight as the gf is working night shifts at the hospital. Took another few hours and got the carbs racked back together. I still need to locktite all the main rack screws one by one now that it's all back together and looking square. I aligned them on my glass drafting table Im working on, and then slowly tightened the 16 screws in an alternating pattern, as you would a head or wheel lug.

Next up on the list in bench synch, and then double triple check everything is good up to this point then continue with needle valves, floats, bowls, diaphragms ect.. I have replacement needles for the diaphragms so those might aswell go on in reassembly also.

 

Also I can't say how much the church of clean has helped me with the advice it gives. Im mechanically inclined and usually take a few photos, and thought ahh I probably won't need this many, but I've looked back at them alot during this and some of the ones I didn't think would help were the ones that helped the most! So take lots and go to church people. I've avoided some timely mistakes plenty .

And might even have made some I don't see yet until I check it all over again... And again haha.

 

Today I bench synched the carbs with the method of setting the first one with the idle adjustment to the back of the hole, snapped the throttle a few time and then set the rest to the back of the hole. Went back and adjusted the idle screw to the middle of the hole and then set the others to match.

After that I went into trying to set the dry float levels. My reasoning for this is that Id much rather do it this way and double check after by a wet float level check to be sure, than to be filling and draining bowls of fuel indoors in my basement, and the carbs won't be back on the bike in a running manner for some time as I have way more on the list. I've been reading thread after thread, and many people are very confused by this method as I was for many hours, and the more I read the more I thought I got it, untiiill I realized I didn't haha.


What I came out with is when the tang is just about to pull up the needle valve ( simulating when the fuel would stop coming in, that the measurement from the gasket mounting surface to the "bottom" of the float should be 17.5 mm.

It was very hard to get the carbs on an angle that simulated this, and they kinda just hung down low from the tang on the needle valve, so I raised the float until the tang on the float and the tang on the needle valve made contact because that's the moment when the valve is closed and fuel should stop coming in, correct?

I couldn't get a photo of this exact process because I only have 2 hands but this is sorta what I was doing. I didn't adjust any float levels yet as I'm still not sure I'm correct in this method and Im not sure they are out of spec even.

Here's a photo to show what I mean.



I would set the calipers to 17.5mm. place on this surface and then raise the float until it juuuust touches the tang on the needle valve. I am getting very close readings to 17.5mm with this method so I'm hoping I'm on the right track.

When the carbs are on an angle I still have quite a gap between the two tangs. This is what I mean, and floats stay in the same position until they are almost now pulling on the needle valves which is not how I can measure them.

 

gravity sets the float level flip carbs on hats. the float should be springy measure and adjust , then wet set.
when you get your first float wet set you can use that height as the next starting point on the next float.

 

The carbs are on their hats in these photos. Having the carbs on a 30° angle or flat on the hats didn't make any difference in how the floats sat so I measured with them flat on their hats.

By springy you mean that the tang on the float should be touching the springy dowel on the needle valve when I measure the height?

 

From what I've read and watched my floats seem to sit low when they are touching the springy dowel.. I'm at a bit of a loss for what it's purpose is since there's a gap between making contact with the open tang that wraps around the float, and making contact with the springy dowel. I'll put the original needle valve back in and see if maybe it's an issue with the aftermarket ones I got with the kit?

 

After more research I know exactly what I have to do/ what you mean, as there are multiple types of needle valves which all have slightly different dimensions so who knows what height the floats should be for my aftermarket needle valves.

I'll find The height for one like you said, and then set the rest accordingly, since they are all the same. Now to find some tubing.

Thanks!

 

yes if its not touching it its not holding it in place.

 

Well the carbs are back together for now. Dry heights set and I'm currently in the process of waiting to buy some stuff for the leveling jig, aka PVC pipe or whatever else seems best to set wet fuel levels. Since that's been done my next task is fork dust/oil seals which I have, and fork oil which I have. What I don't have are the air seals at the top so an order from chacal will most likely be happening again soon! For now the disassembly begins.




Wheel bearings seem very okay which is good. Both forks have dark grey hunky crap coming out of them, one even ditched some water first... Glad to be draining them and going over them. I purchased 10w fork oil which I'm almost positive I read somewhere here that, that is what I needed.

The springs seem to very responsive still, and I don't think I'll upgrade/replace them since a fork swap may very well be in the future down the road, so oil, and seals will be good for now. Head tube bearings seem shot.. very stiff and not smooth. In a video I watched off this site he said the triple tree should be easy to move with a single finger. I don't have the wrench yet to loosen the two nuts holding the stem in yet but I doubt that it's just " too tight " . I'll be upgrading the bearings to the tapered ones if replacing is needed.

I'll be grabbing some parts tomorrow such as new bolt rubbers for the valve cover , valve cover gasket, and shims at the Yamaha shop tomorrow so I'll also grab a wrench and continue the tear down of the stem.


P.s the palm bay was free!

 

Check you steering them bearings people! Even if you don't think you need to.

 

you don't have to worry about loosing any of those bb's

 

Haha that's for sure. Into the trash they went and tapered roller bearing kit was ordered.

Got my new oil seals in the forks. Gonna paint them and then re install dust seals / new oil.



Mocked up the new to me tank I found and cleaned up some other parts as well.

 

put the lower triple tree in the freezer it will make installing the lower bearing easier

 

I haven't posted in awhile but I've been plugging along but made a bone head mistake. I didn't have much to do, at a stand still while the 750 seca tank is being prepped, and I put some air into my forks since the rebuild. I had a little pocket hand held bike pump and greatly mistook it's abilities haha. I put 4-5 strokes into the forks and then tested the pressure with a gauge at it was at 20 psi. I immediately drained them. I read the limit is 17.5 awhile back and now I have some minor oil residue on my forks after a good handful of full compressions. I removed the forks, and I was hoping maybe I could salvage the new oil seals by drying everything out, and creating a tight dry seal again? I ordered new oil seals in case it doesn't work out but they won't be here for a couple weeks. Has anyone ever done this. Can 3-4 psi really ruin the new oil seal and it's spring ?

Thanks in advance

 

oil does transfer to forks from seal. 17 psi is max if you did not ride bike like that probally no damage done

 

Thanks man! So a little fork oil on the tubes is normal? There's none collecting around the seals or anything, just oil residue that'll leave your finger tip wet around the fork tubes. I did not ride the bike at all, filled, tested with gauge, then drained. Maybe I'm just over reacting.. which can be normal haha