Crankshaft wobble - freshly rebuilt engine

[CanadianSteve]

Hey all, I recently rebuilt the top end of my (new to me) 78 XS650 SE. The following was done:

New camchain
New front and back tensioner
New Wiseco Pistons and rings (second oversize)
Machined out the jugs to fit
New Boyer Bransden Ignition setup
Cylinder head ported (intake/exhaust)
Cleaned carbs, timing set, chain tensioned, etc
Case was split and all gears cleaned and checked for wear

The bike was running well for a very short period of time, in fact it was running awesome. Super responsive, smooth, started easily, I was happy. Got about 4-5 hours riding time on it and started to hear a high pitched squeal that increased with RPM. Looks like I have crankshaft issues as per the attached video.

I'm pulling the engine again and will likely have the crank rebuilt, but I'm wondering what your thoughts/opinions are. Most of my questions will likely be answered when I tear it down, but:

1) Do you think that the crankshaft was failing and the extra compression/power caused the failure?

2) Do you think it was possibly a problem I created during reassembly?

3) Do I scrap the engine and look for a used one with decent compression and cut my losses, or keep going to try and fix the current one?

I welcome all thoughts and feedback on this one, sooooo frustrated!

 

[Downeaster]

I'm pretty sure the stock crank is just pressed together, so yeah, the extra compression and power may well have tweaked the crank, especially if it was a little tired to begin with.

Hopefully, somebody that actually KNOWS will be along directly with a definitive answer.

 

[Paul Sutton]

You may be able to keep your project going. After stripping down you could get the crank trued up again and have it spot welded to prevent future distortion. You may only need to replace that large ball bearing.

I hope it is fixable.

 

[gggGary]

Yeah these cranks can do that, not frequently but sometimes, sorry it happened to you. I had one go in a couple minutes, after years of riding. I did an engine swap and never have pulled down that engine. But I did get some cranks welded up for when I get a round tuit engine build(s). Since it's the off season wouldn't hurt to snoop around see if you can find a good engine. Even if you elect to rebuild, might be better to start with a crank/bearings that haven't scissored.

 

[CanadianSteve]

Hey guys thanks for the kind words, it helps me get motivated for the rebuild. I’ve got feelers out for a used 78 engine but might just get the crank rebuilt on this one. Won’t know for sure until I tear it down but this way my new pistons and porting efforts won’t be wasted.

Paul, if I get this crank rebuilt and buy new bearings, do I do all three bearings (I think OEM# 93390-00003-00) or just one?

thx guys, you’ve definitely lifted my spirits today.

 

[Paul Sutton]

Sorry to admit but I am an amateur. Regarding the bearing replacement it will depend on whether or not the crank has twisted in more than one place. Whoever you get to true-up/weld the crank will be best to advise following their initial examination. If I were to get the job done I would replace all 4 bearings. Out of interest, did you observe any wobble on the alternator end?

 

[Paul Sutton]

Here is a nice thread regarding wobble and welding:

http://www.xs650.com/threads/why-to-weld-your-xs650-crank-for-all-engines.6878/#post-71390

 

[OHRider]

Talk to Hughs Hand Built about rebuilding your crank.

 

[CanadianSteve]

Talk to Hughs Hand Built about rebuilding your crank.

I definitely would but I’m in Canada which complicates things a bit with shipping/duties etc. Will definitely keep the option open depending how the tear down goes.

..... engine coming out of the bike Wednesday night, then it’s tear down time.

Steve

 

[lakeview]

Hi Steve. Where abouts in Ontario are you?There are more XS650 fans around than you might guess.

 

[CanadianSteve]

Hi Steve. Where abouts in Ontario are you?There are more XS650 fans around than you might guess.

Burlington

 

[MaxPete]

I definitely would but I’m in Canada which complicates things a bit with shipping/duties etc. Will definitely keep the option open depending how the tear down goes.

..... engine coming out of the bike Wednesday night, then it’s tear down time.

Steve

Steve:
I don't know where you are in Canada (its a big place) but from my experience, the one shop I would take that to is WolfeWorx in London, ON.

EDIT: ahhhh - our messages must have crossed in the ether. You are in Burlington, so you are about 90-120 minutes from London on the slab.

Terry Wolfe has worked on numerous XS650s (including mine and those of forum members the late RobinC, TotalFool and Lakeview) and he knows them inside-out. He is a licensed motorcycle mechanic and a journeyman machinist and is fully equipped to assess and fix the issue plus he has good access to parts suppliers.

1040 Hargrieve Rd.
Unit 1
London, ON
N6E 1P5​

• ph: (519) 680-1122
• EML: wolfeworx@rogers.com

Highly recommended.

Pete

 

[CanadianSteve]

Thanks Pete that’s definitely not too far, I will shoot him an email and see what he says, thank you so much for the info.

 

[xjwmx]

I definitely would but I’m in Canada which complicates things a bit with shipping/duties etc. Will definitely keep the option open depending how the tear down goes.

..... engine coming out of the bike Wednesday night, then it’s tear down time.

Steve

If you can afford his prices you can afford the shipping! By private courier in a suit and tie. I had the same problem with my crank after about 60,000 mi. One day the starter caught funny and whomp. You heard it happening, Now I make sure I keep the button down until after the engine is running and the relay turns the button off. I read a story somewhere where back in the day a guy laid an xs650 crank on the counter at the parts department at a dealer and the guy there knew immediately what had happened. I'd ask on here in the classifieds for a new crank. One person was offering a great deal once, or on ebay, should be well less that $100 incl shipping (if you were in the states)

 

[CanadianSteve]

If you can afford his prices you can afford the shipping! By private courier in a suit and tie. I had the same problem with my crank after about 60,000 mi. One day the starter caught funny and whomp. You heard it happening, Now I make sure I keep the button down until after the engine is running and the relay turns the button off. I read a story somewhere where back in the day a guy laid an xs650 crank on the counter at the parts department at a dealer and the guy there knew immediately what had happened. I'd ask on here in the classifieds for a new crank. One person was offering a great deal once, or on ebay, should be well less that $100 incl shipping (if you were in the states)

Ok I didn’t know how much the HHB crank was going to cost, unfortunately that’s not something I can afford

Well I was able to take the engine apart pretty easily since it had barely run. Some bearings on the crank look absolutely shredded. I’m told it might have been starved for oil so I guess next steps would be to investigate potential causes of this.

Thanks again everyone for your help.

 

[CanadianSteve]

Ok so a few things discovered. I can’t really make sense of it and would welcome your advice.
On the middle crankshaft bearing that failed, three of the rollers are all scored but the rest seem fine. Also it looks like the other bearings are ok.

The crank seems to have a bit of rust on the side closest to the failed bearing (picture attached). Also there are 2 chips in the case closest to the failed bearing.

I would like to get the crankshaft rebuilt but I’m afraid if I can’t identify the cause of failure I’m going to just ruin another bearing when it’s back together.

Any thing I should check or be looking for? Thanks again everyone for all of your help.

-Steve

 

[MaxPete]

Ok so a few things discovered. I can’t really make sense of it and would welcome your advice.
On the middle crankshaft bearing that failed, three of the rollers are all scored but the rest seem fine. Also it looks like the other bearings are ok.

The crank seems to have a bit of rust on the side closest to the failed bearing (picture attached). Also there are 2 chips in the case closest to the failed bearing.

I would like to get the crankshaft rebuilt but I’m afraid if I can’t identify the cause of failure I’m going to just ruin another bearing when it’s back together.

Any thing I should check or be looking for? Thanks again everyone for all of your help.

-Steve

I would simply take the entire mess to Terry Wolfe. You haven't got anything that he has never seen before and he will give you and frank, honest and correct assessment of the prospects for rebuilding that crank.

If he says its a no-go - then just come back to the forum and I'll betcha dollars to doughnuts that someone on here can help you out - fast and cheap. The only potential downside is the cost of shipping a heavy assembly like an XS650 crank - but there are lots of folks within driving distance who may have spares and a roadtrip to meet a motorcycle buddy in the cold mid-winter is always fun.

Just my $0.02.

Pete

 

[MaxPete]

Agreed. The later pics and descriptions make it seem like it's worst than I first thought. One bad inner main bearing will require a virtual total disassemble.

Yes - and that is a non-trivial task requiring some pretty serious machinery and if one bearing is toasted, I'll bet the others have damage too which renders the entire whole ball of wax -> scrap. Trying to cheap-out on a crank repair is a path that leads down into the depths of despair IMO.

I could be all wet here, but my perception is that the XS650 crank seems to fail rarely. In fact, while I am fairly well calibrated on most other parts, I have no clue as the cost and availability of replacement bearings - but I'll bet they are not cheap or easily found.

Pete

 

[MaxPete]

OK - I was intrigued so I looked the parts up on XS650 Direct (the CDN counterpart of MikesXS) and here is the verdict:

• two big-end bearings = $90 (sounds like the line from the sub's chief engineer in Das Boot)
• one drive-end ball bearing = $80.00
• three crank roller bearings = $375.00

TOTAL $545.00
HST $ 71.00 (this is the 13% sales tax or Human Sexuality Tax as we sometimes call it up here)
GRAND TOTAL $616.00

Plus another other parts needed such crank pins etc., labour and the use of huge press to install the parts etc. etc. etc. I'd be surprised if you got away for under one large Canadian, if not two.

Big End Bearing/Thrust Washer Set

Big End Bearing/Thrust Washer Set - Each Kit Contains: 1Pc. #93310-62660
Standard Needle Bearing + 2pc. of # 90209-26014 Thrust Washers, Made in Japan.
Fits: All XS/TX 650's (1970-84) right or left side - (256 or 447 engines)
Part #05-0011 $44.95 CAD Set (each bike has two of these)

Crank Main Bearing

Crank Main Bearing - Drive End - RH (Ball Type) - B6306C3 - Special. 1 Pc.
used per engine. Made in Japan. OEM# 93306-30604-00-00.
Fits: 1970-84 650's
Replaces the Discontinued and long unavailable Koyo brand original Bearing.
Part #05-0008 $79.95 CAD Ea (one required per bike)

Crank Main Bearing

Crank Main Bearing (Special Roller Type) - 3 used per engine. - Located center (2)
and Left hand side of crankshaft (1). OEM# 93390-00003-00 - Made in Japan.
Fits: All 1970-84 650's
Part #05-0009 $124.95 CAD Ea (three required per bike)

 

[grizld1]

Ouch! Yep, those bearings are expensive, but at least they're genuine Koyo and still available. A few years ago the only XS650 bottom end bearings offered anywhere were Chinese repops, and my guess is that if those were very good Mike's XS would still be selling them. The bearings are costly because the outer race has to be drilled for pins and oil passages, so they're small batch items. Rod pins and big end bearings are included in the rod kits from Mike's and XS Direct, and if the coating isn't intact in the small ends you might consider new rods. They're excellent quality, Japanese made, with harder material than OE rods so they don't require the copper alloy coating that Yamaha used.

Edit: Never let it be said that I don't give Mike's XS credit where credit is due. Good on 'em for making those Koyo bearings available again and offering better-than-OE rods!