Resurrecting a 78 xs 400 thats been sitting for five years

[gazampa]

This is the first bike that ive owned. I have a little experience riding smaller and later RD and DT models ( 2 strokes ) . I came by this bike when a friend gave up on owning it after having his second baby. Its been sitting in a garage for the last five years but did start back in the day. Overall it looks in decent condition.

So Far, I've

1 ) Unsieized the engine ( was likely a vacum seize )

2 ) Put in New Battery and Sparks. Checked both plugs were sparking and observed sparks.

3 ) Changed oil and filter.

4 ) Tank is clean, free of rust.

5 ) I havent taken out the carbs yet as i figure it should at least fire badly badly first.

6 ) I have observed fuel flowing into the airfilter when the petcock is left on prime with the engine off and also when the bike is left on the side stand. Is the carb functioning normally here for this bike ? Doesnt seem like a great feature.

Currently it wont kick or jump, have tried maybe thirty jumps. Felt like it nearly caught on one jump. Ive got the Haynes Manual but it doesnt really trouble shoot that well, just shows the different systems. I've read this model is a hard starter.

At this point im getting into cleaning the carbs. I am also begining to wonder wtf, thirty jumps and next to zilch. Im going to give it a go each night i get home for a week, see how that goes. But is anything else up here that anyone can think of, I havent worked on a lot of bikes so dont know what my expecatations of this bike should be.

All help greatly appreciated.

[JimR]

This is the first bike that ive owned. I have a little experience riding smaller and later RD and DT models ( 2 strokes ) . I came by this bike when a friend gave up on owning it after having his second baby. Its been sitting in a garage for the last five years but did start back in the day. Overall it looks in decent condition.

So Far, I've

1 ) Unsieized the engine ( was likely a vacum seize )

2 ) Put in New Battery and Sparks. Checked both plugs were sparking and observed sparks.

3 ) Changed oil and filter.

4 ) Tank is clean, free of rust.

5 ) I havent taken out the carbs yet as i figure it should at least fire badly badly first.

6 ) I have observed fuel flowing into the airfilter when the petcock is left on prime with the engine off and also when the bike is left on the side stand. Is the carb functioning normally here for this bike ? Doesnt seem like a great feature.

Currently it wont kick or jump, have tried maybe thirty jumps. Felt like it nearly caught on one jump. Ive got the Haynes Manual but it doesnt really trouble shoot that well, just shows the different systems. I've read this model is a hard starter.

At this point im getting into cleaning the carbs. I am also begining to wonder wtf, thirty jumps and next to zilch. Im going to give it a go each night i get home for a week, see how that goes. But is anything else up here that anyone can think of, I havent worked on a lot of bikes so dont know what my expecatations of this bike should be.

All help greatly appreciated.

Hi,

time to get the carbs to bits in the last 5 years of no running there is a big chance that the internals of the carbs will need some tlc. This is backed up from the carb floods you mention ... Take um off and spend a lot of time inspecting & cleaning them you may find the bike will start (in some form) when the engine is not flooded !

Regards Jim

[gazampa]

Thanks for the input Jim, I pulled the carbs tonight and will commence with the tlc. Its a first time job for me so will go slow and probably spend a good bit of time on it.

[JimR]

Thanks for the input Jim, I pulled the carbs tonight and will commence with the tlc. Its a first time job for me so will go slow and probably spend a good bit of time on it.

Hi,

let us know how you get on

Regards Jim

[gazampa]

Started on first kick ( only lasted about 60 seconds - all glory is fleeting )

Kicked it and it caught, revved it up to about 6 thousand revs pretty smoothly, lots of smoke, vroooooom, excellent. Good Idle, got in first and drove up alley pretty slowly on half clutch, let clutch out all the way and it coughed and died. Hopefully its my rusty driving skills that killed it. Im letting it sit before trying again, only left it on prime for about a minute after the earler incident so perhaps the carbs have not fully filled.

The Carbs.

1 ) One of the main jets was completetly blocked.

2 ) The other was partially but open.

3 ) Nethier of the pilot jets being removable, they looked a bit blocked, so carb cleaner soaked it and compressed air cleaned with aerosol can air. Best I can do for now, did get air through them before reinstall.

4 ) Both floats were stuck, unstuck and cleaned the filter screens on the needle valve assemblys, both of which were caked over in stuff.

5 ) Cleaned piston and needle until smooth, gave the diaphragm a bit of silicon spray ( dont know if this is completely kosher but hope it keeps the rubber supple.

Assembly and Reinstall was straight forward. Reinstall greatly helped by being able to dissassemble the air inlets and get them into position. Unthreading and Rethreading the throttle cable was the biggest pain, which wasnt really all that bad either.

After Reinstall :

Turned tank to prime and left for only about a minute, was a little sheepish after the earlier incident. Ive read it overflows the gas into the air filter rather than the cyclinder by design, thus avoiding any possible internal damage trying to compress a cyclinder full of liquid. That being the case, turns out to be a good feature though its far from a perfect to have gasoline belching out of air filters.

So, cant imagine it wont start again, but will have a better idea latter about how well it runs, but since it started, i figured that was worth a post.

[drewpy]

Assembly and Reinstall was straight forward. Reinstall greatly helped by being able to dissassemble the air inlets and get them into position. Unthreading and Rethreading the throttle cable was the biggest pain, which wasnt really all that bad either.

TIP;

take off the throttle cable with the lifted carbs out of the frame to the right of the bike, reverse to reinstall cable.

[gazampa]

TIP;

take off the throttle cable with the lifted carbs out of the frame to the right of the bike, reverse to reinstall cable.

Thanks for the tip Drewpy, I'll use that the next time.

[gazampa]

Ahhhhhhhh. ...

Cant get it started again, noticed the neutral and oil lights were dimmed so took a reading of the battery, 9.4 V. Its a new battery, purchased on 2/7 . Maybe its a dead cell, how would this affect the ability of the bike to start from kicking, and jumping isnt giving any better result ? I retested the sparks and wasnt getting anything from the right plug.

Im recharging to try and get it back around 12.6.

Im heartened by the fact that it did spring to life but its possible that there might be some electrical work ahead. Back into the Haynes, Whats the best place to start with this work.

Could it be that I didnt clean the carbs thoroughly enough ?

[drewpy]

Ahhhhhhhh. ...

Cant get it started again, noticed the neutral and oil lights were dimmed so took a reading of the battery, 9.4 V. Its a new battery, purchased on 2/7 . Maybe its a dead cell, how would this affect the ability of the bike to start from kicking, and jumping isnt giving any better result ? I retested the sparks and wasnt getting anything from the right plug.

Im recharging to try and get it back around 12.6.

Im heartened by the fact that it did spring to life but its possible that there might be some electrical work ahead. Back into the Haynes, Whats the best place to start with this work.

Could it be that I didnt clean the carbs thoroughly enough ?

get the battery charged forst and you may be ok!, my newish battery lasted 2 months and gave up. This made the bike run crap!!

So now I always buy a decent named battery.

drewps

[DirtyDT]

Once the battery is charged, take the plugs out and pour a little fuel into the bores. It gives it a head start.

[gazampa]

get the battery charged forst and you may be ok!, my newish battery lasted 2 months and gave up. This made the bike run crap!!

So now I always buy a decent named battery.

Ok, battery charged up and it started, however this time on one cylinder only, the left. The right fires intermittantly, makes a crack and puffs out some smoke every couple of seconds or so. Yesterday, there was smoke coming out both so I will get into the haynes and start error testing along the right circuit.

If the battery drained down to 9.4, is it likely there is an underlying problem in the electrical.

Once the battery is charged, take the plugs out and pour a little fuel into the bores. It gives it a head start.

Thanks DT, will keep that handy.

All in all, after putting a bit of work in, the bike is showing some signs of life, If I can get the right cylinder firing reliably I can start to get a bit more feedback off the bike as to what needs to be done.

[Follyworks]

All in all, after putting a bit of work in, the bike is showing some signs of life, If I can get the right cylinder firing reliably I can start to get a bit more feedback off the bike as to what needs to be done.

sounds like it's already giving you feedback as to what it needs - it needs that right cylinder firing!

If it's firing intermittantly, and when you tested you got no spark on that side, it's likely an electrical issue with the ignition system giving you an issue now. Check the coils and the points - a '78 is old enough it's still using points instead of electronic ignition, and they can be a bit fiddly at best.

[JimR]

Ok, battery charged up and it started, however this time on one cylinder only, the left. The right fires intermittantly, makes a crack and puffs out some smoke every couple of seconds or so. Yesterday, there was smoke coming out both so I will get into the haynes and start error testing along the right circuit.

If the battery drained down to 9.4, is it likely there is an underlying problem in the electrical.

Thanks DT, will keep that handy.

All in all, after putting a bit of work in, the bike is showing some signs of life, If I can get the right cylinder firing reliably I can start to get a bit more feedback off the bike as to what needs to be done.

Just set the Dwell & insure the plug is ok

Regards Jim

[gazampa]

sounds like it's already giving you feedback....Check the coils and the points.

Just set the Dwell & insure the plug is ok

Regards Jim

In the immortal words of manuel from Fawlty Towers...Que ! ( Fawlty Towers = Old British Sit Com )

Im sensing that im a bit out of my depth here being new to the electrical system, even after reading up on it in the Haynes and online, Im a bit sheepish about getting crazy with the cheese whiz. Is this type of testing that someone with a good hold on basic phyiscs from school and a multimeter could approach. Is it the kind of thing that a decent electrical guy in a shop could do pretty fast ? id like to get the learnin from doin it but dont want to stretch too far.

[JimR]

In the immortal words of manuel from Fawlty Towers...Que ! ( Fawlty Towers = Old British Sit Com )

Im sensing that im a bit out of my depth here being new to the electrical system, even after reading up on it in the Haynes and online, Im a bit sheepish about getting crazy with the cheese whiz. Is this type of testing that someone with a good hold on basic phyiscs from school and a multimeter could approach. Is it the kind of thing that a decent electrical guy in a shop could do pretty fast ? id like to get the learnin from doin it but dont want to stretch too far.

Hi

Dwell is measured as an angle: with contact ignition, the points gap determines the dwell angle. The definition of contact ignition dwell is: ‘the number of degrees of points cam rotation with the contacts in the closed position’. As an example, a 4 cylinder engine will have a dwell of approximately 45 degrees, which is 50% of one cylinders complete primary cycle. Therefore a twin will have a dwell angle of 22½ degrees. after some hunting on the net I would guess this one will do the trick ! http://www.amazon.co.uk/dp/B000RA2MLS/ref=...mp;linkCode=asn.

to find more about dwell angle, google 'motorcycle dwell angle' and you will find some good technical docs that explain it & you can make your mind up from there but tbh the difference between a bike with the points gapped and set with dwell is quite amazing

Regards Jim

[gazampa]

to find more about dwell angle, google 'motorcycle dwell angle' and you will find some good technical docs that explain it & you can make your mind up from there

(

came across this conceptual explanation video of the ignition system on youtube, its for an old four cylinder vw car but its seems fairly transferable, particularly in concept, there are also related videos on valve clearances, and some other stuff, plus dig the groovey music )

ok, so ive half and halfed it.

I read and read and read, removed the cover plate, then looked and looked and looked, referencing what I could see to what I had read up on but the condition of the right cylinder wasnt improving on reading and looking alone, So, I poked at it with a screwdriver !

The guy I know who has a garage and an oil pan is not around this weekend so I did a bit of a hack, I got a feeler gauge, picked it up for $1.99, and turned the engine over incrementally with the kick starter until the gaps looked all the way open and measured the gap. sure enough, there was a big gap on the right cylinder's contacts so i loosened up the breaker assembly, just a bit, and then nudged it over, just a bit, until it seemed about right with the feeler gauges.( .3mm-.4mm gap )

Presto. Well, Progress at least, and ill take that. Still a bit huffy, certainly still barking on the right especially when throttling down, but its firing significantly better. After going for a spin around the block, I had two warm pipes and a few suspicious neighbours. So, still backfiring but its changed for the better after the poke with a stick. I took it around the block a couple more times. Its rough, but one thing is that it is starting significantly better and that especially feels like progress to me.

Such is the progress in fact that I've dropped it in to a shop, HaHa ! To get it done properly, dynamically, at least I hope it will be. I also want to get an overall safety done for peace of mind as much as anything as well as a little stock taking done of things that need attention as Im begining to think in the back of my mind of getting the paperwork done on it with the great state of illinois and the no less humble city of chicago. Cant hurt to use this trip to the shop to gauge how close ( or indeed perhaps far ) it is to being on the road.

My sense is that to do the whole ignition timing properly, well statically anyway : alternator plate off, cranking till correct firing position, setting the gap is doable for a relative novice particularly if you have had the chance to see it done a couple of times.

If I had set the dwell completely myself, Id be saving a bit of money that I could put towards stuff thats really worth paying for, it bites a little to have to spend but hopefully im not very far off having it on the road. And after all, no man is an island however pennisular at times I at least may be.

So, I was able to drive it to the shop. And after talking about the problems and history was able to start it up on the first kick and demonstrate. Very Nice, it was seized up and covered in rust and dust not four weeks ago. Indeed, they waived the $200 they demand on older bikes, that was nice of them, maybe i looked just needy enough. In fact, After driving it to the shop, talking about it, seeing that it is in pretty good condition, i did think, Gahh, It probably just needs to be ridden in, but as its a first time project, I like the idea of having someone go over it at this point as fingers crossed it might not be too far from getting it out on the road. My goal is to be able to get it out for the Chicago Air and Water Show in mid August.

One big thing about this project to date is that I wish had taken photographs from the very begining to document everything.

So, im quietly confident in getting out on the road soon, its not until mid week that I hear back from the shop. Plus, im pretty sure that I have electrical work looming as the battery charges down over time. Also, the fuses are pretty loose and I noticed today that they have a tendancy to come loose and stop everything, but at least the fuse fix should be pretty straightforward. The shop is not a megastore but it doesnt feel entirely like a local mechanic either. If anyone has any local mechanics they can recommend on Chicagos North West side, please let me know, it may be that these guys are ok too, you know, but you can never know or have too many contacts.

Big Thanks for all the help from the Forum so far, particularly, JimR and Drewpy, folly and DT. I may not be on the main roads yet but I graduated out of the alleyways today and onto the back streets. Fingers Crossed, I can make it out for the Air and Water Show.

[drewpy]

glad your making progress.

I think its a matter of ensuring you can brake ( new fluid every 2 years!!) and that the engine has good oil and is tuned up.

start collecting tools as you can afford them ( even second hand)

strobes are good for timing and vaccum gauges for occassional carb balancing ( go halves with someone)

drewps

[jrhendryx]

glad your making progress.

I think its a matter of ensuring you can brake ( new fluid every 2 years!!) and that the engine has good oil and is tuned up.

start collecting tools as you can afford them ( even second hand)

strobes are good for timing and vaccum gauges for occassional carb balancing ( go halves with someone)

drewps

Second the picking up tools as you can afford them.... Definitely take the time to go over the brakes. On the kz305 I recently rebuilt, I had the front brake bleed dry and the back brake shatter on me. CHECK THESE SYSTEMS.

Bleed the front brake until you feel comfortable. Personally, I like mine to respond quick, and be pretty hard.... no jokes please

[drewpy]

Personally, I like mine to respond quick, and be pretty hard.... no jokes please

why? coz you always leave late, as you come too quick

[gazampa]

The Face of Progress.

Back from the mechanic - statically timed ignitinon.

Overall, the bike is starting and stays running with the choke fully in. The throttle is a little heavier than before and ive got the revs drifting up issue.

I took a movie. start is on full choke, put the choke in, ghost revs up to to about 4000+, falls back to idle around 1300-1400, then gave it some higher revs, a little unevenly perhaps, looking for responsiveness, of course.

start and throttle

Havent goten out for a run yet as the right air box started leaking fuel again, not like before though, its a drip now, not a flow, I had noticed a little gas in the floats previously, tried a solder job but i guess it didnt take and there's also a lot of solder already on them... So Ive got some plastics on order and will try them out. Before, the floats were jammed, now i guess its punctures causing them to lose buoyancy and fail to close the flow causing overflow into the air filters.

I think i will post another thread about changing over from brass to plastic for the mikuni bs34, could be useful.