1985 Maxim-X 750 Recommission - Putting it back together

I recently picked up an 85 Maxim-X 750 and am in the process of going through the checklist to get it back on the road. I was hoping I'd get further along in the list before I had to come looking for help, but here I am.

The first thing I did was check the valve clearance and 10/12 intake valves were out. I got new valve adjusting pads and just put them in. After re-installing the camshafts I can't turn the crank.

I followed the instructions in a post here as well as the service manual.

Any ideas as to why it won't turn now? Did the chain come off the crankshaft maybe? I really hope not... I don't want to have to dig that deep into the engine.

A little back ground on the bike. It was not running when I bought it. It was not running when the previous owner bought it, but he did not get around to doing much to figure it out. The handle bars, fuel tank, and seats were already removed when I got it. My plan was to get the valve clearance back into spec, clean the carbs and fuel tank and see if I could get the engine to run. After that I would go on to doing the brakes, brake lines, sort out any electrical gremlins (lights and whatnot...), petcock, all that stuff, to get it roadworthy. I've been working on old cars with my dad for a few years but this is my first bike.

Any insight as to what I might have done while adjusting the valve clearance that is now preventing it from turning? It was turning fine before I took out the camshafts to adjust the valves.

Edit: I checked to make sure it wasn't in gear for some reason and it is not. Is it possible to get the chain back on the crank without ripping it all apart? Like can I take the camshafts out and fiddle with the chain from the top and try to get it back on? It feels like it wants to turn, but is binding on something. (Don't worry, I'm not cranking on it very hard, I know how easy it was to turn it before and don't want to wreck anything by forcing it.)

 

Re: Maxim-X 750 Recommision

If it was turning over before the valve clearance adjustment, you have to determine what is currently binding it up.

Did you tighten and torque all 4 cam sprocket bolts? Are your spark plugs in so you can be sure you didn't inadvertently drop something in one of the cylinders?

At this point, I would go back through the dissasembly steps outlined in the manual and start over. Remove the sprocket bolts, then loosen and remove all the cam bearing caps, then extract the cams after supporting the sprocket and chain. Remove the tensioner and be sure to note if anything was keeping the engine from turning.

Hopefully, at this point, you can rotate the crank and set it up at top dead center for the #1 cylinder, and then start over with the step by step reassembly.

Let us know what you find.

Tony

 

Re: Maxim-X 750 Recommision - Looking for help

Possibly the chain guide is not in the correct position. But yes, you can get the chain back onto the sprockets at the bottom by figuring with it. I have a couple x engines apart right now and the chain is slack but I can get it back on the bottom really easily......

I'd look to see if a valve is stuck down, or a shim slipped off and is jammed or something.

Yep, you're gonna hafta go back in as far as needed to find the problem----

 

Re: Maxim-X 750 Recommision - Looking for help

I wasn't able to get both the cog bolts in as I couldn't turn it to get at the other holes. The spark plugs are out, but I could turn it up until I had the cam shafts and cogs back in.

I will have to pull the camshafts and cogs again and make sure no pads are jamming up the works, and fiddle with the chain to make sure it's on at the bottom and try it all again.

Thanks guys!

 

Re: Maxim-X 750 Recommision - Looking for help

Loosen up the bolts on the cam caps until they are just more than finger tight. If the crank turns then, but tightens up when the bolts are torqued to spec, look for scoring on the journals.
Since the bike hasn't run for a long time, have a good look at the journals anyway and lubricate well as you reassemble.

 

Re: Maxim-X 750 Recommision - Looking for help

Should have also said, if you loosen the cam caps and it still binds, then most likely one of the pads has slipped out of position and is sitting cross-ways under its bucket. This is very easy to happen on the X since the pads are tiny and live under the buckets (where you can't see them) rather than on top of the buckets like all the other XJ's.

 

Re: Maxim-X 750 Recommision - Looking for help

I had the cam caps too tight. I loosened them off and it turned just fine. (at least as well as it did before...) I retorqued to spec and it still turned.

Glad it was a simple solution, thanks for all the advice. Valve clearances are now all in spec as well so I guess it's time to button it back up and move on to carbs and fuel tank and see if it runs.

So far this has been a great learning experience and I am really excited to keep going. I only hope I can get it back on the road before winter, heh...

 

Re: Maxim-X 750 Recommision

Carbs are all apart and soaking. They were gummed up pretty good. Might have been anti freeze or something, or some kind of additive because it's all green. Comes off fine tho.

 

Re: 1985 Maxim-X 750 Recommision

Glad to see that you got it figured out.

Make sure you change the throttle shaft seals while you're at, especially if you're soaking the carb bodies. And, while you've got the carbs off, swap in a new set of o-ring seals for the intakes. Rubber that's nearly 30 years old needs to be replaced so you can eliminate any potential source of a vacuum leak.

Tony

 

Re: 1985 Maxim-X 750 Recommision

That's a good point. I'll see if I can get those parts ordered tomorrow. Is there a way to check if the current ones are still fine? Nothing is brittle or even weathered at all.

 

Re: 1985 Maxim-X 750 Recommision

As far as the throttle shaft seals go, you'd be doing yourself a favor just putting in new ones while you have it torn down. They may still be good, but you don't want to be chasing a vacuum leak after you get it all back together.

There's a good chance the intake o-rings will still provide a seal. But on the same note, no telling when the old rubber is gonna shrink and dry-rot to the point of creating a vacuum leak.

Most of the time it seems like you can get away with re-using old parts, but I'm sure you'd rather have a safe and reliable ride, and not constantly have to tear back into it replacing parts that should have been replaced previously.

I know the pics below may be an extreme example, but these are what mine looked like a couple of years back when I refreshed the 750X that I imported from Canada:

 

Re: 1985 Maxim-X 750 Recommision

if you have the carbs apart, do all the seals and o-rings NOW. Otherwise, you'll end up right back here again soon......saying to yourself "doh--I shoulda done these when I had the carbs off before...."

Green stuff in the carbs----nope, not anti-freeze.....that's waaaay old fuel. get that out quick, cuz once it hits the open air, it'll harden up quick. It is also quite acidic and can really do some damage if left in there, too.

In the snowmobile world we call it "Green Disease"......LOL

Dave Fox

 

Re: 1985 Maxim-X 750 Recommision

How do I get the diaphragm of the pistons? I don't want to rip them...

 

Re: 1985 Maxim-X 750 Recommision

Well if it's not one thing it's another... I took the carb bodies out of the soak after a few hours last night, wiped them down, blew out all the passages and they looked great. This morning after they dried out, they are now covered in a white residue of oxidation... I thought the solvent I used was fine but I guess not.

I just tried some vinegar to neutralize it but I'm not sure it worked. I'll find out once they dry again. Any advice on what I can do about it? They were looking so good last night... ugh. Didn't have this issue when I did the carbs on an old Triumph car.

 

Re: 1985 Maxim-X 750 Recommision

Yeah, the vinegar did not work...

What's weird is, they were all soaking for the same time, yet they are not oxidizing the same. 1 looks fine, 2 is a little worse, 3 a little worse yet, and 4 is the worst of all...

If I clean them off and then coat them in something like WD40 or a light oil of some kind? I really don't want to watch these rot before my eyes... They looked so good after getting all the gunk and varnish off them.

 

Re: 1985 Maxim-X 750 Recommision - Carbs oxidizing post cleaning

Just brush the white powder off with a toothbrush and wipe them flea with a rag. You can also rinse them off wi hot water and dry them quick with a hair dryerif it makes you feel better

 

Re: 1985 Maxim-X 750 Recommision - Carbs oxidizing post cleaning

Or simply give them a once-over with Scotchbrite, and then a good rub-down with WD40 (one of the few things it's actually good for.)

 

Re: 1985 Maxim-X 750 Recommision - Carbs oxidizing post cleaning

I wasn't getting very far brushing them off, so i scrubbed them down with wd40 and a toothbrush. So far they look pretty good. I'll see if the white comes back in a few hours and if not it's time to reassemble.

 

Re: 1985 Maxim-X 750 Recommision - carb assembly

I've got the carbs all clean and free of oxidation, just wondering if there is any torque specs or certain number of turns to use for the jets and needles and stuff. I haven't seen any in the shop manual or any of the guides, so do I just tighten them until they're snug?

Edit: nevermind I found it... 2 1/2 turns +/- 1/2 turn for the pilot, the rest just snug I guess.

 

Re: 1985 Maxim-X 750 Recommision - carb assembly

The diaphragms are not meant to be removed from the slides. Although, if they are torn, there are ways to fix it.

If I remember correctly, the Maxim uses a similar carb slide as the Venture, Virago, and V-Max. You'll have to remove the metal retention lip to get the plastic retainer washer removed.

Here's a video I found. Be careful not to destroy the washer as you'll want to reuse it. Also, go slow as the metal can heat up quickly.
https://www.youtube.com/watch?v=84DRVc9J5GQ

I've also used RTV, let it cure, and that has worked for quite a while. It is a surprisingly easy and stable temp fix.

If you want to replace the slide diaphragms, check out: http://jbmindustries.com/
http://jbmindustries.com/Dimensions.html
They have some very tough products that are less expensive than OEM.