VX800 Symptons and Cause

Well, settle in with a cuppa, or a glass, this is likely to be a longish post. 
Bought my first Suzuki a coupla weeks ago. 1990 VX800 89k km. The vendor said suspected gearbox  transmission, or clutch fault. It was about 400km away from me, but only a few km from a good mate of mine. so, asking a favour he agreed to go see it for me. On inspection seemed in quite reasonable external condition,  engine started ok with no smoke or noises, so took a punt, made an offer, and deal done.  My mate, (I`ll call him "Jim", because that`s his name), started to investigate  the problem with it. 
Engine starts OK. No smoke no nasty noises. Oil and coolant seemed clean. On centre stand went thro the gears but seemed "lumpy". Took a chance and went for a gentle ride up the road. Transmission seems smoother now, but engine was flat. Bit of head scratching going on now. Jim got his compression tester out. Hmm, no 12mm adaptor. Few days later La Poste arrive, and compression test done. Rear pot shows 130psi. Quite acceptable for a cold engine. Front pot shows 0psi. Yep, zero. Not something Jim`s come across before. As he said, even a holed piston will show some thing as the engine spins over even if it`s only a little twitch on the needles. More head scratching, but now accompanied with 2 furrowed brows. Bike loaded into Transit van and arrived here Friday night. 
 Sat morning, and spanner time is here. First idea is to take off front cyl head to have a look see what`s happening. As most of you already know the engine has to come out for this. Tank off, side plastics off, carbs and air boxes off. coolant hoses, wiring, clutch cable, etc. All pretty ordinary so far. Next is one of the VX800 quirks, front right frame section, (which doubles as a coolant pipe comes out. A jack takes weight of engine and she`s ready to be slipped out front and right. We put a sturdy storage box of a suitable height with a strong board across it next to the engine. bit of gentle heaving and engine slips onto board and box dragged away from frame. No skinned knuckles, so that`s a result! 
 We put a couple of wooden blocks under the engine, and put a ratchet strap over the rear pot to secure engine to board. Well, another VX800 quirk: the heads only come off with the pots. This is because the heads are not only secured with 4 long bolts into the crankcase, accessible from under the tappet casing, but also with some shorter ones threadedinto the cylinder head casting, with the bolt heads appearing between the "V" of the cylinders with, (seems to be), to possible access while in situ. The books we were working with seemed to be saying to remove both pots simultaneously.  Probably because of awkwardness of the coolant pipes between the pots?  Not what we planned so with a bit of fiddling around the front pot/head assembly came off. The reason for the zero reading on compression gauge now became ... well...obvious. 
 I`ll post this bit up now, before I loose it,  and try and get a coupla piccies..

Righto, no images going up from me at the moment, so you`ll have to put up with a few more words instead. 
 When the front pot/head came off the crankcase, the piston came off with it too! Con rod broken. 
Time for a cuppa.
 The part of the con rod left in the engine was twisted and wedged into the crank, so it was throwing itself around and didn`t split the engine totally. The piston and short part of the rod were resting in the bore high enough not to touch the crank, and low enough not to be touched by the valves.  The cylinder bottom was cracked and some bits chipped off. Took cylinder head off, and piston came out the top. Piston skirt cracked/chipped. Head appears ok. Looking from the front of the engine appears that the back pot has been hit on it`s bottom edge too, but as I`ve already said it was running on that one pot ok. 
Well, where are we now? Pointless stripping owt else. The crank is now suspect because of the rod wedged between the throws. Gearbox maybe ok or may have been damage by metal debris? Clutch maybe ok or not? Stripping out the rest, examining it, replacing bits etc is likely to be more expensive than a complete replacement engine. 
 Now looking on eBay ,and some sites over nearer here, for an engine, or maybe complete bike to donate an engine. If no luck I`m confident the bike sitting in my garage can be parted out if necessary to recoup my outlay. 
 One good side effect is that I do have a garage again.... Following some odd jobs around the house, and garden equipment etc my garage was only accessible if one breathed in and tiptoed, but in a fit of energy and enthusiasm I did clear it up to receive the bike. So, every cloud...! 
 Anyway that`s my ownership of VX800s to date. Any offers of good engines/sympathy gratefully received!

Sounds like you have a 400cc single then

Good luck with the search for an engine, when I had my GS650GT I managed to pick up a engine and gearbox for about £40 and made one good one out of the two.

Aye ! Thanks for the wishes of good luck.
 With summat as drastic as it turned out to be, was amazed the thing was actually turning over, let alone running. Still with patience we`ll get a result yet.

What a nightmare, best of luck mate. I am sure you get there.

Interesting read Brian   unfortunate outcome though   I hope you source the parts you require at minimal cost, eBay and patience is your friend when looking for used parts, have you tried the european  ebay sites? 

That's jap engines for you ,pretty tough compared to a lot of euro units like ducati etc.... Andrew I also had a Suzi Gs650gti with the fastback tail end .engine ran shells on the crank ,I bought it with 78k on clock and abused it for a further 46k ,sold it cheap as it was smoky ,guy rebuilt it and was still using it up to a couple years ago.
Back to original post , sell it for parts ,you will never be 100% sure if you rebuild it won't eat itself again ..

Yes to that Sim. Trying eBay  UK, France, USA, Germany and some other French sites too. The guarantees on eBay are helpful, but buying 2nd hand parts are, we all know, always a bit of a lottery. There are several breakers advertising here, but on different sites without guarantees, so it`s obviously best if they`re nearer, so the parts can be examined. Even then buying a complete engine that`s been already removed from the donor bike is not easy to check. Dealers have a reputation to uphold, but if one travels to collect something, strips for examination, and then discovers some undisclosed faults, the time and hassle are a problem. Money refunded won`t cover all. Still, that`s the name of this game. Check what`s possible, and hope for a little luck to top it out!

Ross, hi. Guess that applies to any 2nd hand vehicle tho? I`d say a correctly rebuilt engine is a known quantity whereas a newly bought used bike is pretty much unknown. Mind you,  a properly rebuilt engine is gonna rack up the cost too much for me. So as you say either keep this `un for my own stock of spares or sell spares off it. We`ll see what else is out there before getting out my angle grinder! 
 I would like to know what the underlying cause of the failure was though. As I said oil and coolant all seemed good & clean. No sign of gasket failure. The piston slipped nicely out the top of the bore when the head came off. No damage to valves. Crank spins over nicely, and rear cyl still running fine before dismantling. But that`s to satisfy curiosity, and maybe avoid summat in the future with a different engine, as this `un seems likely to be boxed up rather than stripped and rebuilt. Costs of separate parts to repair this `un are prob more than a complete lump. 
 Have seen a bottom end for sale, buts that`s a 600km round trip and would still need to source at least the front pot n piston too. Guess I`ll sit on it for a bit. 
 Watch this space. but I may not be very quick with news.

Hi Brian,
Sorry to hear of your findings - quite a mess inside that engine, and as you say, not really worth re-building.
I suppose the sensible (cheapest) option is to break the bike for spares to see if you can recoup your outlay, and look for a running 'VX' that you can test ride.
Next best thing being buying a full engine to build back into your bike - but as mentioned - you will not know how good the engine is, unless you are buying an engine that has yet to be removed from a bike - in which case that bike might be the better 'starting point' & make one good one out of two. Keeping spares you might need & off-loading the rest.
It is always difficult when buying a 'non-runner' - as you don't know what you are actually getting for your money (So I would only ever give a low price for a non runner - or runner described as having problems). Hope you has a similar strategy with your purchase, & hope you can either find a suitable engine, or recoup your financial outlay by breaking for spares ...... as is so often in these cases - your time & effort in working on it rarely gets 'recovered'.
Best of luck mate
Yam

They are generally good robust engines if somewhat quirkily designed for a jap unit.... I know the frame etc was designed in America but I wonder if engine was designed there too ...
I think even a rebuild with good parts might prove too expensive and risky, at least until you know the initial cause of the failure...
Have heard a few instances of race bikes snapping a rod when a coil pack fails at high revs causing a hydraulic effect with the unburn fuel and the imbalance of the other cylinders or cylinder carrying on at full chat.

If you got it cheap, and you like to muck about with engines just for fun you could turn it into a single with a little thought ,mind you it would need to loose a bit of weight from the body too...

Well Ross are you saying I need to diet before a 400cc bike will haul my lard ass?

Nah, I know what you mean!

gtland wrote:

Well Ross are you saying I need to diet before a 400cc bike will haul my lard ass?

Given a long cold winter I may take the engine apart further to see if the underlying cause becomes apparent, but that`s not a priority obviously. 
 One aside that is a bit annoying is that a engine in that state was such a bl@@dy liar! Being broken like that it didn`t even have the decency to make an honest noise. Should have sounded like a half brick being shook up in a tin bucket of nails, but no. And the con rod just hid inside the crank instead of showing itself in the open air. Didn`t have the honesty to show itself outside the crankcase! 
 Fortunately I didn`t have to remortgage my house to buy it, and it`s not needed as a daily commuter or owt, so I`m not crying too loudly. I may part it out later, but if buying another I`ll hold on that until I see which parts may be useful to me.

How`d  Simbo get that spy camera get into my BBQ area??

Hmm I've never seen a vx800 bobber before or if you did it s X400 bobber ...ha..

I think I`ve found a replacement lump to slot in. Coupla issues involved tho. 
#1 It`s a VS51A. So it`s of USA origin. As I understand it it`ll have different crank throws. The US spec engine has different firing intervals. Seems this was to give a more acceptable cadence to the engine note for the USA market. (more H-D I guess). May give more vibration too, but we`ll see. 
   I can`t find any reference to different compression ratios, or different cam profiles or gear ratios. (apart from final drive). So I`m assuming all the former are the same? I`d appreciate any correction or confirmation of that tho. As I intend putting the complete lump in & not doing a "mix n match" with the internals of Euro/US engines I don`t anticipate any issues if there are differences, but would like to have any info in advance. 
#2 The engine is with a dealer/breaker about 800km away from me. Although he`s asking a reasonable price for the engine, it`s no surprise that delivery is quoted at 130euros. (about 100 quids). Fortunately my employer was in a good mood t`other day so I`m able to swing down there next week to collect it personally. Time will be an issue tho, so the seller is going to have to take it out of the frame before I arrive. So I`ll not see it fired up before taking it away. I know this is a risk, but the guy has some positive feedback on various forums here so I`m gonna chance it.  
 Any info on US/Euro/UK engine differences most welcome.

Hi Brian, I've no idea on the differences between US models and Euro? would it show in the Schematics?
http://www.cmsnl.com/suzuki-vx800_model14274/

A bit risky buying without trying, I hope it turns out to be ok for you.

Hi Brian,

VS51A - is the designation given to the 'VX' ..... have a look at your chassis number & it will begin with VS51A.
If it helps - My engine number begins with S501-      (But that might change as to the build year)
The 'VX' is a Suzuki USA design - so they all technically originate from there.
There are small specification changes for various markets - but these tend to be minor.
As far as I know & understand it - all VX motors have the same crank-pin spacing (Degrees of separation of crank pins relative to centre of main journals of crank - NOT the actual throw or stroke of the crank), but that is different to that of the 'VS' or 'VL' (750cc motor) from which the 'VX' was derived. The revised crank-pin spacing on the 'VX' was intended to smooth it out a bit ...... but as you may read elsewhere in other VX forums, there can be a difference in how smooth (or vibration free) the VXes are. One member of this forum has had at least 3 & they all felt a little different (from rougher - smoother). 
After the introduction of the VX800, the cruiser derivatives saw an increase in capacity to '800' (Or 805cc if being precise).

The difference in final drive ratio will be to address the fact that the cruisers run a smaller diameter rear wheel. I'm not sure if this is 'addressed' in the diff assembly, or on the final drive of the gearbox output shaft ...... but if the donor bike is a VX800, & it is the original engine, then there should be no major issues with using that motor.

Obviously it is a snag that you cannot see/hear it running - could you ask him to start it up & film it running - so he can post you a clip or send you a live feed ?

Would be nice if there is some implied guarantee that it is a 'runner' .... but if it turns out a 'dud' it is at your 'expense' to return the unit, & extract your hard earned back from the seller. If it is a breaker, they usually offer a limited warranty.

Hope that might help. ........ & that you do get your 'VX' sorted

Thanks for the replies. 
I stand corrected about my misuse of "throw". As OldManYam says I was talking about the crank pin spacing. Not about throw or stroke. 
Seems I`m probably wrong about it being a US version too! So 2 helpings of humble pie. 
I`ve gone back to my original source....wikipedia....(yes it should be treated with caution). Anyway wiki says the US had a 45deg offset, other markets a 75deg offset. Secondary reduction US: 1.133 and others 1.096. 
Quoting wiki
 "Model VS51A, 45-degree crank pin offset, model VS51B, 75-degree crank pin offset"
Seems to me those should be the t`other way around?? 
My frame no starts VS51A, and current engine is S501-xxxxxx so same as yours. (reg as new in France 1990). 
Looks like I`m flapping about nowt? Saw summat, & jumped to some wrong conclusions. 
The seller is a dealer. Email describing it in good condition. Payment via PayPal. 100% feedback thro his eBay shop, but only low numbers as he`s new to eBay. Likes on Facebook. And not risking a fortune. I`m prepared to take a chance on it. But if you see me selling an engine in a few months do yourselves a favour and don`t buy it! 

Woops only partial post. Updating.

Are those numbers and specs reversed on wiki?
Anyways the seller is a dealer who has recently gone onto eBay France. Still a newcomer there but with 100% feedback. He has been dealing on other sites and has "likes" on Facebook... I`ve an email describing the engine as in good condition. Paid thro PayPal. Still taking a chance, but I can live with that. But do yourselves a favour and if you see me offering an engine for sale in the next coupla weeks don`t buy it!

Hi Brian,
Just read through the Wikipedia stuff - I stand corrected - it sounds as if the 'American' version might run a 'VS 750' crank then - which has a narrower pin offset ..... & the secondary drive reduction is in the gearbox - but the ratio difference is relatively small & I personally would not worry about the difference.
On the face of it, it seems likely that you will get a Euro/Rest of the World spec motor, as the US version is probably less likely to be found over here.
Sounds like you are buying from a reputable source - so fingers crossed this will provide you with a cost effective solution.
Hope all goes well for you                 Yam

Engine picked up on Tuesday afternoon, with the air temp touching 40deg c. Now back home with it. Picked up a rear disc from same guy for 20euros. That seems in good nick, only a coupla more weeks will tell if same is true for the engine! Fingers crossed. 
I`ll pull off tappet covers and check cold clearances before installing engine into frame. Will also spin it up on the starter without the plugs in, but not sure what else to do on the bench? My garage doesn`t stretch to a testbed. And will have to get a better trolley jack too, to line up engine into frame as my current one sinks slowly under load.

I hope everything turns out well with the engine and it turns out to be a good one 

Fingers crossed.

  to that Brian - hope it is a good engine & your 'VX' is soon back in running order.

Thanks for the thoughts. Will update you all as and when things progress. Household chores, gardening duties and earning my wage will have to get in the way a little, but won`t stop anything outright.

Nightmare mate - hope it all works out.  Keep us updated

Engine slotted into frame coupla weeks ago. Work and social commitments have intervened. Some issues with carbs and cooling system.  I`m going to do a bit of fettling today, but will put up a longer account of problems, and hopefully solutions, later on today, or tomorrow. Fingers crossed...again...

As previous post says we slotted the lump into it`s new home a couple of weeks ago. Fired up and seems ok. Had a quick bash around the block and seems like I now have a bike! 
 Few issues that may be of interest to others, and may help anyone else doing a similar job: 
I`m not happy with front carb and am going to investigate further, more on this later. As the original engine had a catastrophic failure of the front cylinder and the underlying cause is unknown I don`t want a re-run so am going to take things slowly for a bit.
 When putting in the coolant I did it by the book, and cracked off the bleed screw at the top of the left hand frame member. Well for "cracked off" read "snapped off". Effing thing was corroded and broke in half. My mate did the honours of carefully drilling out the old thread with Dremel type tool, while I searched my garage for a suitable tap set. ( garage resembles Steptoes yard). Hole tapped and now blocked off with flat head screw. Did firstly consider welding a nut over the hole and using that. But my welding skills would probably have blown hole in the frame! Anyway seems ok so far.
 The petcock (vacuum type) has a leak. Took it off the tank, stripped and examined it. Peculiar design, it seems to me: I can see it`ll only pass fuel when a vacuum is applied to diaphram, but seems that there is no "hard" off position? Even with the lever in the "off" position the vacuum will valve will allow fuel to flow. I`m assuming the original type is fitted, but with an older bike I can`t be sure. With no vacuum applied there is a slow drip from the tap, with vacuum applied there is a free flow. Reckon I`ll get a fully manual tap as a replacement. No need for over complications surely. 
 I don`t have any vacuum gauges, to set up carbs, so eBay will get a visit from me this afternoon. Any advice from any of you about good/bad choices you`ve made? 
 Right, I`m off for a ride to the Bakers for a fresh baguette and croissant. If it makes it ?!

Baker run went well. And so did the 55km following morning coffee break. Oil & coolant levels all good. Left it on fast tickover after a run, watching the temp light closely I saw the fan kick in. Put it back on slow running. waited until fan cut out and then shut it off. Seems all OK so far. 
 Handling feels a bit strange to me. But after a few years sitting inside tin boxes, maybe that`s just me?
 It feels as though the steering head bearings are tight; i.e. it seems choppy or weavey or wandering in the bends?? Difficult to describe. Steering head nice `n` smooth when on centre stand and front wheel in the air. Put a little extra air in the tyres, which made no real difference, apart from making me feel as if I`m doing summat. No noticable play in the swinging arm. Front tyre is new with moulding nobbles on it. Rear has a bit if wear, which is off centred. (Guess that`s due to being ridden on heavily cambered country roads). Anyway seems to be equally wrong on both left and right curves, so don`t think it`s due to wear. 
 I`ll put a few more kliks on it, within a small radius of chez moi, before doing owt serious I think. Maybe a bit more confidence in it will stop me being overly concerned.

Glad to see you are getting some fun out of your new project,always nice to get a reward from the work you do.You may be holding the bars to tight when in bends,which will throw you out,hope all goes well for you before summer ends.

Fair point Alfie. I`ve still got a little worm whispering in my ear that the engine`s gonna seize and throw me up the road! Few more miles under the wheels and see how it goes. At least we`ve got the weather to enjoy it.

Glad you've got it back on the road ,as for the handling it sounds about right for the VX ,I've only owned one but have ridden a hand full of others and they all seemed vague and unresponsive on the front... Its probably because of the kicked out geometry , some love it ,some don't ...they're still a great bike on the right road ..
You mentioned the front carb , mine had a dodgy/weak fuel pump that caused fuel starvation ,especially to the front carb which also had a reducer in the inlet rubber ...didn't keep it long enough to resolve the issue...

Thanks for the comment. Haven`t run it long enough yet to properly assess colour of plugs etc, but given original engine had a problem with front pot I`m gonna have to check for overheating due to weak mixture etc... Fitting a proper fuel tap soon so will be able (confidently) to fill tank above reserve level and get a few more miles on it. 
 Regards handling, maybe that`s why I haven`t seen any with scratched out foot-pegs?! Tis a lot different than my last bike. (VFR750). I`ll give a while yet I reckon.