Quantcast
Jump to content

  • Do you own an ATV, UTV or SxS? Join our Community Forum!

    QUADCRAZY ATV Community and Forum are FREE to join! We keep our ATV, UTV, and SxS forums clean and user friendly. All first time posters in our forums will have to wait to have their content reviewed and approved. Once your first ten posts are approved, you will no longer need to go through a forum post approval process. To bypass the approval process with immediate access and a NO ADS experience in our ATV, SxS, and UTV forums, consider subsribing to a Premium Membership

YFM250 Moto 4 - Breathing new life.....help?


pokolbinguy

Recommended Posts

Hi All,

Following on from the brief interlude in the "introducing myself" thread....

 

In a nutshell, I acquired a YFM250 Moto 4 (1991) for cheap recently with the previous owner citing "no spark, needs a new magneto coil and I don't have time to fix it"... anyway I am dubious that the magneto/generator is the issue and thinking more along the line of ignition coil as after a clean up of the magneto I was able to get a rather decent voltage reading off the magneto with pull start and resistence readings seem to check out that the magneto is all ok (all 3 x phases = 1.2 ohms and no run to ground)

None the less I ordered a new Ignition coil and Magneto/generator coil and am waiting for them to arrive.

 

In the mean time I cleaned up the current Magneto, popped in a new battery and sparkplug, checked out all the wiring harness, all seemed good except I came across the "neutral switch" wire was broken.

 

After wiring up a new neutral switch wire, the neutral light now comes on  (small win) and the starter relay (attached to rectifier) now clicks. If I hit the starter switch on handle bar the starter motor spins and if I  pull the cord starter I get a spark on pull....YAY!! I'll try and attach a video below if possible.

 

So onto the starter motor. Starter solenoid seems to work A-ok, even if it looks crappy and starter motor spins as it should when I hit the start switch....but here is my issue.

 

When the starter motor runs it turns Cog #1 and Cog #2 (see photo below)....but the chain in the back of the starter which I assume is the timing chain, does not move and there is no apparent movement of the piston in the cylinder.

 

If I turn it by hand (per photo) or with the pull starter however the chain moves and the engine turns. However cog #2 rotates but not fluidly with the "Crank" (part I turn by hand) for the lack of a better word to use if that makes sense?

 

 

Is there a grub screw or similar on Cog #2 that fixes it to the center shaft to make it all turn when the starter motor is run? Could there be a part missing? Previous owner had the starter apart so could be possible?

 

The outer/front part seems to be on a key-way so not sure how to remove this easily to check how Cog #2 is attached.

 

What am I missing here?

 

 

 

 

 

Starter_marked.jpg

no_plastics.jpg

Quad.jpg

Edited by pokolbinguy
Link to comment
Share on other sites

You need a starter clutch.  It bolts to the back of the flywheel.  It's a one way clutch that locks up cog 2 when cranking.  You'll need a flywheel puller if you don't have one already.  Be sure to loctite the screws that hold the starter clutch to the flywheel.

Edited by wanrep
Link to comment
Share on other sites

Looking at these links;

 

https://www.partzilla.com/catalog/yamaha/atv/1991/moto-4-yfm250b/generator

 

https://www.partzilla.com/catalog/yamaha/atv/1991/moto-4-yfm250b/starter-clutch

 

I assume the 'starter clutch' sits behind the generator rotor assembly?

 

Surely the original clutch is still in position and just needs freeing up?

 

 

  • Like 1
Link to comment
Share on other sites

Yes, the starter clutch bolts to the back of the rotor/flywheel.  It has 3 rollers in it that grab the big gear when turned in one direction but freewheels in the other direction.  Usually the rollers and/or springs go bad, allowing it to slip instead of grabbing that big gear.

  • Like 1
Link to comment
Share on other sites

1 hour ago, wanrep said:

Usually the rollers and/or springs go bad, allowing it to slip instead of grabbing that big gear.

 

 

Thanks for the point in the right direction. Sounds like I need to the rotor/flywheel off. Any tips?

Surely the rollers / springs can be cleaned up instead of replacing the whole clutch?

  • Like 1
Link to comment
Share on other sites

Rightio so I got the fly wheel off behind the generator and removed the starter clutch......

 

Ummmm....See photo.

 

Where at the internals of the clutch? Springs etc?

 

Seems someone must have had issues with the clutch in the past so has removed the workings of it. Damn...Now I have to replace them / it.

 

In the mean time, is anyone able to explain in layman's terms how this clutch works? there doesn't seem to be anything to physically engage the cog (aka Cog #2 in previous post) when the starter motor runs?

 

How does the magic happen?

 

Cheers, Pok

starter_clutch_2.jpg

  • Like 1
Link to comment
Share on other sites

So I had a partial win after a dig around in the 'bucket of parts' (mainly bolts etc) that came with the Quad.

 

I found most of the parts for the starter clutch, well I think so anyway, (photo below)....but missing one part (Grrrr!!!) - 1 x 'CAP, STARTER CLUTCH SPRING' (part 1J7-15583-01-00). Hopefully I can get my hand on this. Partzilla shows it as available so hopefully available in Australia as I am sure it will be cheaper than replacing the whole clutch assembly if I can get away from it.

 

What I didn't come across, and not sure if I need them or not are the unknown parts that are shown on the exploded parts diagram (see below as "What is this?) - When I have looked at photos of the Starter clutch on line, replacement parts etc there doesn't seem to be any other parts?

 

Also, am I correct that the dowel pins are out of scale in the exploded view? I assume they are the the parts I have marked in my photo below and not another part that I require???

 

Cheers, Pok

 

Link to Partzilla with parts diagram as per below - https://www.partzilla.com/catalog/yamaha/atv/1991/moto-4-yfm250b/starter-clutch

 

 

starter_clutch_parts_marked.jpg

Starter_diagram_marked.jpg

Link to comment
Share on other sites

I think the mystery part in the diagram is still inside the clutch.  If it came out easily, there'd be a part # for it.  The dowel pin, in the diagram, is the big roller that you have.  They didn't draw it to scale.  Looks like all you need is one of those spring caps.

Link to comment
Share on other sites

  • 2 weeks later...

So I got a new Starter cap today (part #9 on diagram), but still waiting on the new springs (part 8), I have the original three springs but figured they were the weak link in the chain so worth replacing....BUT they are coming from Japan and I won't have them until next week at least and I was hoping I might be able to get the old girl running sooner than that, so I thought I would put the starter clutch back together using the old springs. 

For the sake of it some photos attached to show the Starter clutch fitted back to the fly wheel to show it all ready to roll.

However, when I attempt to install the fly wheel  / starter clutch on the bike one of the little dowels keeps falling out.  VERY frustrating.

Am I right to think the springs need replacing and they are "lazy" ? Therefore they don't apply enough pressure on the dowel pin within the clutch plate to hold it into position as the flywheel/clutch is installed? Or am I just not doing it right...is there a trick?

Any suggestions?

 

Cheers, Pok

 

 

 

Clutch_installed_1.jpg

Clutch_installed_2.jpg

Edited by pokolbinguy
grammar
Link to comment
Share on other sites

If the springs are too weak to hold the rollers in, it's good you ordered new ones.  They are probably too weak for the clutch to work properly even if you got everything together.  I'd wait until you get the new springs.

When you're ready to install it, put the gear into the starter clutch first.  Then slide it on the crank as a unit.  Before you slide it all the way on, you'll have to fit that small gear (cog #1 in your picture) into place. 

  • Like 2
Link to comment
Share on other sites

  • 1 month later...

Alright so I have finally had all the parts delivered that I was waiting to come in.

For interest sake, new parts include battery, starter clutch springs, case bolts, ignition coil (didn't end up needing it) , regulator/generator (didn't end up needing it either), spark plug, oil filter, air filter, engine oil.  I think thats all of it...not all yet installed.

 

First port of call was to put the starter clutch back together with the new springs (x 3) and a new gasket for the starter assembly cover. Assembled, connected all the wires and hit the starter button....still have spark...nice start, that means the starter clutch is doing it's job now.

Put the spark plug into the head, hit the switch....sounds like she wants to run.

Pulled the carby apart, cleaned it out, found a bit of crap it in. Fuel flow now all good. Put back together. Hit the button, still wants to run but just not getting there...a bit of "start ya bastard" (aka aero start).....and ...well see video.

***See post below for video***

 

......watching video....seeing awesomeness....Yeee Haa !!

So now that I have had that side of things sorted it looks like I am heading in the right direction....so now to check the drive side of things....damn, for the life of me I can't get the oil drain plug off. All that is happening is rounding the head off the bolt/cover.  So removed the oil filter cover to find the lovely contents within....seems this bike has, as suspected, been very wet at some stage in its previous life, possibly a flood.

Off with the oil filter cover, and out with the oil filter....

 

Oil_filter_cover.thumb.jpg.0613b2ed1b41b9d5855d62b0917b9a81.jpg

Oil_filter_housing.thumb.jpg.72c2e1ea9e7ba8839174a0803f75a14d.jpg

 

Mmmm yum. Took the other cover off the side of engine....not sure what this cover is called;

 

cover.thumb.jpg.4a18e84f88b9fbf86504cc6019e7f0b8.jpg

 

under_cover.thumb.jpg.05fdf384bb4826dd957e5a6b6c1c89a1.jpg

 

That junk under the cover screams flood to me !

 

Any hoo, seems things are going the right direction at this stage in regards to getting the engine running but I have one question that I was hoping for some feedback on.

 

If the previous oil had water / other crap in it and I can't get the drain plug off, I was thinking of filling the engine with basic cheap engine oil (read cheapest available - Gulf Western Hi Tech Premium Engine Oil - 20W-50, 5 Litre  e.g https://www.supercheapauto.com.au/p/gulf-western-gulf-western-hi-tech-premium-engine-oil---20w-50-5-litre/105586.html?cgid=SCA010704#prefn1=size&srule=Price+Ascending&prefv1=5+Litre&start=1), possibly without oil filter, run engine for a very short period, to loosen any crap in the engine, drain contents at oil filter housing. Put in new filter, again cheap oil. Run, drain. New oil filter, new good oil (Castrol Activ 4T 15W-50 ...already have 4L of this on hand) ..happy days??

Thoughts?

Cheers, Pok

 

Video of awesomeness.

Edited by pokolbinguy
Link to comment
Share on other sites

Nice work on the progress.  I would not run the engine without a filter.   The filter will catch any junk that’s in the engine as your running it clean.    So unfortunately it sucks to have to waste a few filters but I would do it at this point based on what you have into the bike already.  

Use a cheap oil at first for a flush, put a fresh filter in.  Run the bike leave the filter in drain the oil. Put fresh oil in run it again and drain once more changing the filter and oil this time and you should be good to go. Maybe put a few hours on the bike and change it one more time.  

As for the oil plug that’s a bummer but there is an alternative to get the oil out.   Take a look at this. It’s a small pump with a tube that gets down in the engine.

They have electric ones as well but this one works good. My buddy uses it on his boat engine and the price is right.

Made in USA -GasTapper () Power Equipment Model w/filter - Gas, Oil, Water, Fluid Changer Pump for Lawnmowers, ATV's, Quads, 4 Wheelers, Power Equipment, Motorcycles, UTV, Generators, Tractors - Search "by Gentap" to see other versions https://www.amazon.com/dp/B00TA5ECJQ/ref=cm_sw_r_cp_api_i_bOLFCb26VZSZC

  • Like 1
Link to comment
Share on other sites

21 minutes ago, Frank Angerano said:

I would not run the engine without a filter.   The filter will catch any junk that’s in the engine as your running it clean. 

 

Yeh fair point. My gut says don't run it without a filter....my tight arse wallet says do it just to loosen everything up and then dump the oil....but I guess there is little benefit to doing that.

 

21 minutes ago, Frank Angerano said:

 

Made in USA -GasTapper () Power Equipment Model w/filter - Gas, Oil, Water, Fluid Changer Pump for Lawnmowers, ATV's, Quads, 4 Wheelers, Power Equipment, Motorcycles, UTV, Generators, Tractors - Search "by Gentap" to see other versions https://www.amazon.com/dp/B00TA5ECJQ/ref=cm_sw_r_cp_api_i_bOLFCb26VZSZC

 

 

They don't ship to Australia :( Shall keep any eye out for this sort of gear though. good idea. Otherwise could just use the big syringe type.

 

Edited by pokolbinguy
Link to comment
Share on other sites

7 hours ago, Frank Angerano said:

Any boat marina service location should have something like that since it’s really a device for boat engines.  Try a local auto parts place.   You will find one.  It’s not that hard to find.  

 

But that wont get all the crap out of the bottom of the engine will it??

Link to comment
Share on other sites

There shouldn’t really be any crap in there it was just water in the oil.  Most of the stuff will get pushed through the filter as the bike is ridden over time and removed by doing oil changes.  Whatever crap was in there should flush through the system and get trapped in the filter I would think.   If the drain plug gets destroyed while trying to remove it then it’s party over ! We all seen that with the plug on that post a few weeks back by one of our members.  So I would think if that’s going to be it and not touching the plug as to not destroy it then go with the pump.  

Link to comment
Share on other sites

Update - The old girls seems to want to run quite well.

I need to adjust the H-L-R adjustment as getting into reverse is not working properly and need to replace carburetor gasket...but at the moment  all sounds and seems to function normal in forward gears......well as much as up and down the driveway. Need to get the H-L-R sorted and get his old girl on the farm to see how she reallly runs.

 

So far....winning !!!

 

Edited by pokolbinguy
Link to comment
Share on other sites

  • 1 month later...

Hi All,

I am hoping someone may be able to help me with how I go about adjusting the H-L-R lever.

Currently I have the shaft (marked below as A) installed but have the catch/locator (for the lack of a better term) that engages "B" off.

Bike is running well, and I assume it is in High range.

When the shaft is connected to the H-L-R lever I can not get it to move from H all the way through to R. I assume due to being out of adjustment however when I move the shaft (A) back and forth when disconnected  from the H-L-R lever it seems to click back and forth into two different positions.

Now this is where I am confused? If there is High,Low and Reverse, should there  be 3 positions, not two?  OR is the lug marked as "B" on the below image involved in engaging Low?

 

Any tips on how to adjust the H-L-R lever would be great as it would be handy to be able to use reverse.

 

Cheers, Pok

 

 

 

spacer.png

Link to comment
Share on other sites

  • 1 year later...

Did you get the H-L-R lever fixed?  I have a 91 YFM250 and it will not go in Reverse unless it is in first gear and then it seams to be finicky, I have to shift to to Low then roll/rock back and forth a little then it will go into Reverse.  Hope you got it fixed long ago but maybe this info would help someone else.

Michael

Link to comment
Share on other sites

Good work with the excellent pictures and descriptions pokolbinguy. It helps a lot if people describe things really well and not expect people to guess..

 

 To get the drain bung out, were you using a six sided socket ? If not, grab one and try that. The other standard way mechanics get things like that out is to use a small not too sharp cold-chisel, or nice sharp good condition regular round pin punch,  and tap it around out on it's outer circumference.

Link to comment
Share on other sites

  • 2 weeks later...
On 12/30/2020 at 11:39 AM, mnmsmith7304 said:

Did you get the H-L-R lever fixed?  I have a 91 YFM250 and it will not go in Reverse unless it is in first gear and then it seams to be finicky, I have to shift to to Low then roll/rock back and forth a little then it will go into Reverse.  Hope you got it fixed long ago but maybe this info would help someone else.

Michael

G'day Michael,

It has been a while since I posted about my quad, but from memory I think the main thing I came across was the need to be in 1st gear to then be able to engage reverse. As you have mentioned. Once I knew that, it was happy days. originally I was trying to get things working manually without the engine running which of course didn't work.

For records sake, quad is still going well. Doesn't get a huge amount of use but I rode it today after having to drain some old fuel and connecting a jump starter direct to the starter motor as the start solenoid is playing up. None the less still life left in the old girl yet.

On 12/30/2020 at 12:30 PM, Mech said:

Good work with the excellent pictures and descriptions pokolbinguy. It helps a lot if people describe things really well and not expect people to guess..

 

Thanks. As they say, a picture tells a thousand words !!

 

On 12/30/2020 at 12:30 PM, Mech said:

To get the drain bung out, were you using a six sided socket ? If not, grab one and try that. The other standard way mechanics get things like that out is to use a small not too sharp cold-chisel, or nice sharp good condition regular round pin punch,  and tap it around out on it's outer circumference.

 

I just tried a standard socket and spanner. I ended up just draining the oil out via the oil filter cover. I figured even if a small amount of old oil was left behind it was better than destroying the bung.

On 12/30/2020 at 12:39 PM, Mech said:

And would the lack of travel from the change cable be because there's an interlock button to stop it going into reverse.. perhaps you need to press some button or something to get full travel.

You have to put the transmission into 1st gear first ... then you can engage reverse. it's odd, but it works.

Link to comment
Share on other sites

  • 7 months later...

Hi All,

 

So I am now having an issue with my Quad not wanting to start.

When I hit the start button the stater solenoid (located next to the battery) clicks very loudly but the starter motor doesn't spin.

If I put power direct to the starter motor (with a jump pack) the starter motor spins. From memory, when I was fiddling with it about a month or so ago, I was able to get it to start and run by using the jump pack on the starter and spraying some aero start into the air box. From there I was able to get it to start via the pull starter. But I need to try that again as I can't bloody remember.

I also haven't had a chance to take the panels off and grab my multi-meter so in the mean time I thought i would check in here to see if anyone has a suggestion of what could be up?

I had a look at the wiring diagram and the only thing I can think of is the starting circuit relay or CDI but to be honest I'm not sure as the diagram doesn't show the starter solenoid itself so possible the diagram is not the correct one.  ( I have attached for reference)

 

Any tips?

 

Cheers, Pok

Wiring diagram.jpg

Link to comment
Share on other sites

  • 2 months later...

You need to use a volt meter to look for voltage across places, and at times, where there shouldn't be any.. So from one side of the solenoid to the other should show battery voltage when you aren't trying to crank it over, but that voltage should drop to near zero when you operate the starter. If it shows more than about a half volt as it's cranking then there's a dirty connection in there somewhere, possibly inside the solenoid or in one of the battery lead terminals. Then check for voltage across(from one end to the other) of each battery lead while cranking, there should be no voltage shown.. if there is a voltage shown it's because there's a dirty connector or near broken lead. To speed things up you could check for voltage while cranking right from the battery to the starter terminal, if there's no voltage shown then those leads and connections are clean and tight and working. If there is more than about a half volt then there's a bad connection in that power feed somewhere so you start checking one lead and the solenoid at a time to find which one. Then do the same process with the earth.. from the battery earth terminal to the starter body should show no voltage while cranking. If there is a voltage then there's a bad earth connection somewhere, so check one lead to earth, then earth to engine, then engine to starter body.

When checking the starter leads, make sure you are checking from terminal to terminal, they can get bad connections where they crimp to the wires..

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Forum Topics

    • By CaptJim
      Hello guys, I hope I am not invading your space, but as you can see the current state of my project here it's not but about 50% ATV. I am hoping that some one here can point me to a wiring schematic that I can reference since the "Complete wiring harness" i purchased from Amazon did not include a diagram of any kind.

      The ones that I am finding on line vary greatly but none show the connections for the separate 5 wire connector coming from the motor.

      Can someone tell me where these wires go?
       
      Thanks in advance for all help!
    • By DrtyGrlKristin
      Just thought I'd start a new thread for newbies to the site!
      If you're new here, tell us who you are, where you're from and what you ride!!!
      Lets get to know each other a little better shall we?
      I'm not new to the site, obviously, but...
      I'm Kristin from Denver!!! I ride a 2008 Yamaha Rhino. She's my muddy baby!!!!!! Several aftermarket parts on her. She's good to me! We try and ride every weekend. This weekend we're off to MOAB! :woot:
    • By Ajmboy
      Starting a new topic for the 2024 Presidential Elections. Please be respectable with open discussion 🙂.
      Wikipedia (See who has entered the race):
      2024 United States presidential election
      2024 Presidential Polls: 
      RealClearPoltics
      FiveThirtyEight
      270toWin Interactive Map

       
      Previous topics (now closed):
      2020 Presidential Election Discussion Thread
      2016 Presidential Election Discussion Thread
       
    • By BuckBilly
      Good morning to all !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      Let's see if we can make this a daily event.
    • By Suzukiquad
      Hi, I have been around everything with a motor since I was little, and finally purchased more to get my husband, and kids involved. I have 4 quads I will be searching around for information on. I have two 2002 Suzuki LT80K quads, a 1997 Yamaha Timberwolf 250, and a 1996 Kawasaki Bayou 220. I have had different ones throughout the years, and plan on buying another Yamaha Banshee. I plan on trying to learn more about all of them, so I can customize some of them. I know nothing about them besides how to race them, my dad always took care of the rest, but figured it was time for me to learn. 
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...