Barnyard Find 82 maxim 650 - Brakes question

Hi everyone,

Today I acquired an 82 maxim 650 with 9000km on the clock! EXCITED!!
All indications so far are that it is in fact unmolested after 40 years. Stock, even has the original toolkit. Garaged,covered and babied its whole life.

It sat for most of the last 10 years and not started for at least two. Initial assessment is new battery and carb overhaul, and new tires.
I noted that while petcock was in res position, it was dumping fuel from a hose I believe the airbox - a bad float valve seat I believe.

I can take care of the items above, but I would like some opinions on the front brakes. The front brake is very soft and fluid is discolored. Brake lines and caliper look good.

Question is: can the m/c be flushed and restored to service, or is it best to replace the assembly? I place a high value in being able to stop!

Any other "resurrection" tips are welcome!
Bob

 

That is a beautiful bike, can't be too many around like that.
Suggest you replace the hoses, they look original & will be well overdue for replacement. It would be a good idea to remove the caliper & check the pistons move freely, there's a chance the piston seals may have hardened. New fluid will probably transform the brakes. The master cylinder may not need any work however seals and rebuild kits are available if necessary.

 

Man, that’s a nice bike. I restored one and it is a great bike to ride.

You cannot just flush the MC, get a quality rebuild kit from Len and do it right. If the lines are original you really should change those out and rebuild the caliper too. The factory brake setup is more than adequate for the stock bike but it’s really important to make sure it’s up to the task.

Do not replace it with some $17.96 Chinese master cylinder.

Welcome to the best place for XJ knowledge and parts.

 

Nice looking bike!

This is a good video that someone else posted on another thread, and it shows why you should (as Yamaha and other mfgs. recommend) rebuild your calipers and m/c every 4 years. Rubber seals under stressful conditions (brake fluid, heat, pressure) will deteriorate, losing their flexibility and rebound characteristics, and a whole lot of what makes your brakes perform well and safely is...........rubber "springiness":

www.youtube.com/watch?v=kZTFS9TYf4I

 

Except the corrosion he points out is NOT on the piston. It’s in the upper corners of the seal. In the small corner gap that is there. No I’m not advocating leaving the corrosion there..... just pointing out that it’s not holding up the piston.

 

That's a really nice looking example!

I need to do the same thing to my XJ650J front brakes.

 

True. I wonder if he did the same with an old seal if the piston wouldn't retract?

 

I agree you should rebuild the whole braking system - every 4 years? Maybe if I was selling parts...
I don't agree about the original brakes being adequate - they may have been for the rubber that was available on the road back then, but modern tyres have come a long way. And if it was adequate why did they fit twin discs to the seca?
The flat bars on mine meant I needed a new m/c, I went with an RD half inch bore one - much better.
That bike is remarkable in that it looks not to have been messed with - treat it well

 

I fitted a Honda Pan European master cylinder. Works well. I saw a 900 Diversion with Yamaha's blue spot calipers on it. It's a pity they don't fit the XJ's.

 

Ok so here is my order of battle

Parts are ordered (some I have on hand) to completely refresh the front brake system. I am going with rebuilt Mc and caliper from chacal.
Also coming are clutch kit, petcock rebuild kit and tires. New battery on the charger already.

While parts are in transit I am going to pull the carbs, rebuild them and get the bike running. I have a carb kit from chacal, ultrasonic cleaner carb dip and all the good guidance here.
I will post my results!

 

Very nice machine, you were lucky to find it!
last summer I picked up an 82 seca it had 41000km on it but just two owners stored for 11 years. Put on 600km last fall and today turned.another 800.
Burns no oil. Increased pilot jets turns that took the bog out of excelleration. Stainless.brake.lines. Have done 3 oil changes last one this spring. Also valves adjusted and carb balance with vacuum bottles. New tires shinko put those on another bike liked them
these are fun machines to ride, enjoy and keep it between the ditches!

 

One thing to note with these long lay-up bikes - we all (well I did before I stripped one) that wet clutches are allways in oil - well of course they aren't, the oil is in the sump. So there is a good chance the plates are squeezed dry, and maybe a clutch rebuild is allways a good idea? Anyone have thoughts on this?
My seca hadn't moved for 10 years plus, and even after breaking the clutch free it didn't sound or feel happy. A strip and clean was all it took to change this - with the caveat that the basket and centre was refitted well worn, but it still works.
And no I didn't replace bolts or springs either. Note that I'm not recommending this, but I do feel capable of assessing the state of these bits.

 

Hi everyone,
I'm draining fluids and have quickly come to the dreaded frozen float bowl screw x4 scenario.
Based on past experience, I feel these will strip if I try to turn them. What is the general consensus on how best to proceed?
Also, if forced to what's the best way to get gas out of float bowls when the screws are seized that doesn't involve getting gas all over myself.

Thanks in advance

Bob

 

bigfitz52 Has often reccomended a new clutch for a bike that has sat for a good while.
I've been on the fence about that.
It seems to me that if the clutch is of modern friction material (not cork) that it can be salvaged by turning it 180º and letting it soak for a few days in the sump oil (oil does wick into porous componenets, and the friction material is porous).
My Seca is on the same clutch that I bought it with, and the PO had let it sit for three years with the clutch that he bought it with. The mileage is low enough that it could very well be the original clutch from '82.

 

I don't see why you would need to replace the plates - a clean and maybe a soak for them would be fine I think.

 

If it isn't broke don't fix it. My sec a after sitting for 11 years clutch just fine. Put 1400km on it since layup. Shifts smooth no slip finds neutral easy. Of course in the first 600km changed oil three times. Rotela 15/40.

 

Can't argue with that...

 

Regarding bowl drain screws. My XJ550 had similar looking screws that hadn't been removed in years, and look semi stripped like yours. I used penetrating oil, let it soak for a few days, then was able to coax them out with flat head screwdriver and light tapping to break loose without further damage to the screw heads. I then replaced with hex versions from xj4ever.

 

If you get the bowl drain screws out get a set of stainless allen head screws from len. I got them and very happy with them

 

Hello all,

Carbs are out, and I am getting organized to disassemble. Remarkably clean for 40 years old. Screws all appear to be original I am first one in. The story seems to have unfolded a bit... the float needle on carb 2 failed and caused gas to dump out. The PO put the bike aside and forgot about it.

I inverted the carb body over a drain pan to get the gas out, about 150ml, without getting it all over me (a first).

Slides move, slide one is a bit gummy and slow to return.

 

Not too dirty but still need cleaning. Get those bowls off ans see what is going on inside (don't forget to get new gaskets if the old tear). Work on getting the drain screws out. Get JIS screwdrivers. Find the float valve issue. Clean all jets. Check the diaphragms and correct the failed clunk test slide. Follow the church of clean and don't forget the jet in the bowls.
http://www.xjbikes.com/forums/index.php?threads/in-the-church-of-clean.14692/

 

Three drain bowl screws are out with a tap from a 1/4 manual impact driver. The gummed up bowl hasn't given up yet, it's soaking - try tomorrow
Bob

 

Success! A soak in carb dip, rinse, heat, and a smack from my 1/4 manual impact driver did the trick. So satisfying to win the battle!

 

Disassembly is completed and first body is in the carb dip. Pilot screws had the rubber plugs and turned freely. I have one last float pin to remove, it's seized with all the crap. Pb blaster overnight

Question, can the floats go in the dip, or how would you go about cleaning this one up.

Bob

 

Wow, this looks CLEAN!

 

Careful not to break the supports the float pin goes through. Not sure about the carb dip, I think I would use carb cleaner in a spray can and a cloth to clean the float.

 

Cleaning complete! I was able to get that float pin out using the spin then pull technique I learned about in another thread here. The float I showed earlier cleaned up perfectly in the ultrasonic. All the float posts survived!

For these carbs, the floats had so much gunk that either the floats were seized onto the pins or the pins were seized to the posts. Either way the float arms were frozen in place, causing the gas leaking I mentioned in the first post. Something as simple as this caused the early retirement of the bike by the po.

Parts from chacal arrived today, petcock kit clutch kit and new master Cylinder. Already have the carb kit. I hope to get the bike on the road this weekend.

Bob

 

Good work I need to get one of those ultrasonic cleaners.

 

I had thought about skipping the valve clearance inspection based on the low mileage. I read the periodic maintenance intervals chart and it said at 9k, it's due for its second inspection lol. SO better to do it and know for sure.

Intake I have 2 at .004, 2 at .005.
Exhaust is .006 for all four.

I did pull the plugs and pour in a bit of oil before turning the motor over for the valve clearance check. Had no problem turning it over by hand.

I have reassembled one carb, three to go.
Should be able to try starting it tomorrow.

Bob

 

Can anyone confirm order of assembly on #3 throttleshaft, with respect to the shim placement. My Haynes book doesn't even show the shims. I am thinking the shim on the side isn't required.

 

You don’t put one on the left side by the thick white collar. You are also missing the big spring, the linkage, and the two butterfly screws. It also looks like you butterfly is upside down.
Dfox

 

Thanks for the reply Dave. You are correct in the picture the butterfly is laying upside down from how it is actually installed. For clarity I've attached pictures for final assembly.

So to confirm, you need 7 shims for the carb rebuild. chacal's kit has 8, one is extra. Is that right?
Bob

 

Thanks Dave for your timely update and info!

I did assemble it with the shim, and the immediate result was that the throttle shaft began binding as I tightened the nut. When I loosened it, the binding went away.

It seems this was the likely root cause of my slow return to idle issue reported in another project at the link below. I believe I used all the shims when I did that rack.
https://xjbikes.com/forums/threads/slow-return-to-idle.129003/

I assembled this carb without the shim on the left side, it seems right as rain.

Bob

 

Correct— if you install a shim where it is not supposed to be, the shaft will bind up. Remove the shim from the left side of the shaft on #3

 

An update... when I got to carb 2, I had two shims in my parts bag from the teardown. I'm certain the rack has never been apart before, so I believe that from the factory carb two had shims left and right.

I put both shims on, no binding of the throttle shaft was noted.

Rack is reassembled and benchsynced. Tomorrow back into the bike it goes

Bob

 

Even the factory can make mistakes. As long as there is no binding then there's no need to remove the extra shims.

 

I used my sheet metal brake to align the carb bodies for final tightening, and then as support for the wet set. I had to adjust tangs on two of the carbs to bring the level down to spec.
Bob

 

I have one carb bowl where, when the screw is opened enough to all flow out the drain hole, a fair amount of gas weeps past the screw. The other bowls are fine. Is there a way to correct for this, or is a repayment bowl needed? Fyi new drain screw with antiseize.

Bob

 

You should have gas come out all four drain screws when you open them. If gas isn’t coming out the drain screw—
1. Your bowl doesn’t have any gas in it
2. Your bowl drain is clogged.

 

Let me be more clear. Gas will flow out the drain outlet where I put my hose to catch it. It will also weep past the threads of the carb drain screw. Makes a bit of mess.

When I tighten, it doesn't leak, so I can live with it as is, but I was wondering if anyone ran across thus and what they may have done to correct it.

Bob

 

Oh now I understand. Sounds like threads are a little worn.

 

This above set-up is correct for HSC32 series carbs:

On the HSC32, carbs #1, #2, and #4 use 2 shims per carb, and the #3 carb uses only 1 shim. Thus, on HSC32 model carbs, there are a total of 7 shims used per entire carb rack.


HSC33 models carbs (XJ700 air, 1984 XJ750RL, some Policia models, perhaps others) use the following set-up:

On HSC33 models, carbs #1 and #4 used 2 shims per carb, the #2 carb uses only 1 shim, and the #3 carb uses none of these shims. Thus on HSC33 model carbs, there are a total of 5 shims used per entire carb rack.

 

IT RUNS!

LOL

A bit rich but it runs! Even still, it sounds sweet and even before the first round of tuning. Very excited!

I did get it last night to a crank no start state. Checked compression, results below:
1 150psi
2 150psi
3 150psi
4 140psi

Electrical checks, found a cap on #3 had much corrosion where it grabs the top of the sparkplug. Had a spare, threw that on.

Now onto running sync and colortune...
Then front brakes, petcock investigation, etc

 

I completed the running sync, nice and even with a steady idle at 1100 rpm.
Starts instantly without choke. I am 2.25 turns out on my pilot screws, before the colortune.
Went for supplies and did the final gear oil change.
Tomorrow is front brakes installation, colortune and final sync.

 

You are an animal!

 

This is correct. The midnight rack I’m on had a broken shim, that is visible in the pre-pic, but pieces had fallen out when the linkage was loosened.

 

Check the o ring on drain screw.

 

I did replace all the small o rings for the pilot screws, even though the old ones looked fine.

Front brakes are done, with new lines and rebuilt caliper and Mc from chacal. Thanks for the awesome parts, it makes the job super easy!

The petcock is leaking badly in normal pos, but no leaks in prime pos. So I decided to take the bike out for evaluation before I rebuild the petcock.

Took it on a 30km shakedown ride lol.

After warming up, it's idling at 2000rpm. No problem just turn it down

The clutch (still the original) at first was causing some roughness when applying the power but it smoothed out nicely by the end.

I have a laundry list of small items to do aka petcock
Colotune
Final sync
Idle adjustment
Then I will take it out for a longer ride. Can't wait because the bike is a blast to ride. I'm used to riding my Honda ST1300, this is such difference. Lighter, good power... great bike in town.
Bob

 

The o ring around the petcock "handle" was broken and brittle. Easy fix.
Colortune and final sync complete. Idle when warm is just over 1000rpm, perfect.

Still have what seems like a stutter or shudder as I am pulling in 1st gear, other gears too but less so.

I am thinking clutch so that's next up for me unless some has other ideas.
Bob

 

The hitachi carbs don’t have that on the 650/700/750’s. That’s a mikuni thing—-