1980 390 WR Engine Will Not Turn Over

[390wr Jon]

Good Afternoon,

I am in the procees of starting to restore my 1980 390 WR that I bought new in 1980 in hopes of doing some NETRA vintage rides. My brother had it for a while and I now have it back. However, the engine crank will not turn with the kickstarter (my brother does not recall why it does not turnover...he had not ridden it in many years). I got the cylinder off, so I know that is not the problem. The countershaft sprocket also turns freely in neutral. I took the kickstarter cover off and it looks spotless inside (see pics). It has about 1,400 light trail miles on it (not raced) and I would prefer not to split the cases unless I have to. Does anyone have any diagnostic suggestions before I go any further? Any help would be greatly appreciated. Thanks.

 

[justintendo]

would be surprised to think it has a crank bearing issue..
would the transmission shift in and out of neutral while it was together?

 

[troy deck]

well if the top ends off it should be clear pretty quick if the rods moving then its the crank bearing or the main shaft of the trans pull the clutch.....

 

[jimspac]

It may be an issue with the kickstarter assembly as it sits in the clutch case. If it does not swing properly off the engine, you will not be able to kick the engine through assembled. Also check any bearing support of the kickstart shaft ( clutch cover & centercase left) for out of roundness(egging). If everything else in the engine does not bind with the clutch case off, it is isolated to the kickstart shaft assembly. For what it is worth the needle bearing for the kickstart end in the centercase looked iffy to me.

Take the sparkplug out so you can check function without the kickstart mechanism influence. Turn engine over holding by the clutch or if the sprockets and chain are installed, put it in gear and use rear wheel by hand to drive and make sure you feel no binding or hear any clunking. You may be better off at this point to split the cases to check gear condition and install new viton rubber crank seals when you reassemble. Even though you state it has low and easy miles , rubber seals deteriorate because of age and low use.

 

[markt2]

Have you pulled the ignition cover? Not common but I have seen flywheels and stators rust up enough when sitting to stop the crank from turning.

 

[jimspac]

He implied that was not the problem when he had the cylinder although he did not state that the crank moved.

 

[390wr Jon]

Gents, Thank you for the quick responses. Answers to above questions as follows:

• Transmission shifts in and out of gear with no issues
• Piston rod moves freely on crank (piston is at, or near, bottom of stroke)
• Clutch pressure plate moves in and out easily with clutch lever
• Kickstarter turns freely in clutch outer case with clutch case off engine. Center case kickstarter bushing slightly egged, but not bad
• Flywheel and stator look fine

I tried turning the engine (with cylinder and outer clutch case off) using the flywheel nut, but it would not budge. I tend think it is bad crank bearings. There was no air filter in the bike when I got it back, and I am beginning to think a little furry visitor got into into the crank sump and did his business, but it seems hard to believe it would corrode the crank bearings. Does this seem plausible?

 

[justintendo]

Gents, Thank you for the quick responses. Answers to above questions as follows:

• Transmission shifts in and out of gear with no issues
• Piston rod moves freely on crank (piston is at, or near, bottom of stroke)
• Clutch pressure plate moves in and out easily with clutch lever
• Kickstarter turns freely in clutch outer case with clutch case off engine. Center case kickstarter bushing slightly egged, but not bad
• Flywheel and stator look fine

I tried turning the engine (with cylinder and outer clutch case off) using the flywheel nut, but it would not budge. I tend think it is bad crank bearings. There was no air filter in the bike when I got it back, and I am beginning to think a little furry visitor got into into the crank sump and did his business, but it seems hard to believe it would corrode the crank bearings. Does this seem plausible?

ive had a few engines ive torn down where the crank cheek was stuck to the case by corrosion..case rot..was on a nice set of cases too! might be best to split these anyway..easy to do anyhow..

 

[84scrambler]

I really don't see why most people are not wanting to split the cases. If you can do a piston and ring change you can split your cases, its really not that hard. You need new crank seals if you want to believe it or not, as soon as you get it running anyways they will most likely start leaking. Get you some pullers and clear off a good work bench to lay your parts out . I am sure there are a lot of guys here that will help you through it. I was nervous when I did my first but after you do it you will understand so much more and how easy it really is. Good luck, make a project and take some pics for us to see.

 

[Bill502]

I would remove clutch assembly and and eliminate anything on the drive end. All that's left then will be crank related,flywheel,bearings and ignition.

 

[justintendo]

I really don't see why most people are not wanting to split the cases. If you can do a piston and ring change you can split your cases, its really not that hard. You need new crank seals if you want to believe it or not, as soon as you get it running anyways they will most likely start leaking. Get you some pullers and clear off a good work bench to lay your parts out . I am sure there are a lot of guys here that will help you through it. I was nervous when I did my first but after you do it you will understand so much more and how easy it really is. Good luck, make a project and take some pics for us to see.

plus, no shops will touch these things...and if they would, the it be all jacked up when you got it back or be expensive.

 

[jimspac]

You live in New England and if you get the cases open or even just turn the bike upside down with the fuel tank and cylinder off you may find as much as a cup of water trickle out. Condensation will build up inside the engine from sitting in an unheated shed for many years or even worse in a tarp shelter or just outside in general. I have several set of cases all coming from the same PO that all have mild to moderate corrosion in the crank well. In which case you might as well just split the cases, make sure you are in fourth gear before splitting the centercases. If you need tools or help I am in Somers CT , You are welcome to come over with your engine and I can show you what you will need. 2 jaw puller to remove primary gear from left end of crank. I have a good set of universal case splitters and the Mangle as well. I just got my 390 torn down last year because when I got it I found it had a piston that was at least .020 under the bore size with a broken skirt. That much piston slap breaks the skirt off and perfed the rear of the crank well. I have fixed it with JB Weld as it is in a non stressed portion of the crankcase. You are welcome to pm me if you want to come over.

 

[Bigbill]

Remove the clutch basket this one has the rubber snubbers on the back side of the basket. Maybe one of the rubber discs turned out?

 

[jimspac]

Take the clutch off and the ignition(rotor and stator). Check to see if the crank will move now Doing that will give you a good look into the crank bearings and use a penlight or such to check for rusting. Work some WD-40 into the bearings and try to work the crank loose. If you could not move it without the application of WD-40, you need to replace the crank bearings and that is another item you can not afford to skimp on. Another thing to try is to derust the bearings one at a time using Evapo Rust . I actually saved an electric 3/4 motor by soaking the rusted bearing ends and rotor in Evapo Rust for about 2 days. The bearings spun free with no crunching and the rotor cleaned up nicely. If you do not have the engine out, you can lay the bike down flat on the right side. That will allow you to soak the left crank bearing. Keep solution on the bearing for 2 days. Stand bike up and rest on kickstand if you have one. You can use a garden hose to flush out the bearing with fresh water. Keep tipped over and dry with a hair dryer . Spray bearing with oil to keep from rusting. Lay bike flat down on left side. Remove the seal plate from over the bearing and apply the same process to the left bearing. You should replace the bearings even if they loosen up.

You can get a gallon of Evapo-Rust from Autozone for around $25

 

[390wr Jon]

Gents, Thank you all for your guidance and suggestions. I hope to tackle it this weekend. Jimspac, If I don't have any luck, I may reach out to you for a future trip to Somers. Thanks again. Jon

 

[390wr Jon]

Hi Guys, Here is the update....I went to take the flywheel off and the engine broke free. Looks like a little bit of corrosion/ gunk between the crank case and crank was enough to keep it from turning by hand. In any event, all the bearings look good and are rust free and the engine turns freely with no play. I am reluctant to replace the bearings because they look so good and everything I have read on the forum talks about inferior new bearings as compared to original Husky bearings. However, I do want to split the cases in order to clean up the crankcase compartment of any corrosion/ gunk. If everything looks good after splitting the cases, I was only planning on replacing seals. Forum discussions seem to favor Viton seals. Do you agree? If so, what is the best source members can recommend?

Also, does anyone have a workshop manual for a 1980 390WR in pdf format? I tried downloading the two similar workshop manuals (Vintage and MK & ML) in the Tech Section, but they would not download. If so, could you kindly PM me so we can exchange emails? Any help in this regard would be greatly appreciated.

Here are some bearing photos:

 

[justintendo]

ive had a few engines ive torn down where the crank cheek was stuck to the case by corrosion..case rot..was on a nice set of cases too! might be best to split these anyway..easy to do anyhow..

 

[jimspac]

Get a mechanic's stethoscope and turn the crank thru and listen for any crunching sounds before proclaiming them usable. Split the cases and flush the bearings out very well

 

[Bigbill]

You will see play in the bearings once the case is split. Replace the bearings anyway. The engine will go another 40+ years.
You can't beat the Swedish quality and craftsmanship.

 

[suprize]

would be well worth the effort to split and reseal. mate just redid his 85 kato and bypassed the "seal replacement section" even thought it was apart for gearbox issues. first ride he got about a km in and looked back to see a jet style smoke trail all the way from his place! its fixed now after another "engine on the bench" session.