Resistance...

[dna9656]

I got a friend who tells me my starter is no good. What does this mean? I know what resistance is; he says the field coils are no good, I disagree; the starter started the bike just fine. I asked him to remove the troublesome bearing in the snout. Any help would be appreciated, the starter is a 2 brush for a 84 XZV12DKC2

Here's what he found:

 

http://i280.photobucket.com/albums/kk195/dna9656/20140418_170304.jpg

[bongobobny]

Well, from what I see he is reading 3,000,000 ohms (3.xxx M) The reading can't be right if the starter worked. Notice the term worked as in possibly past tense. For the life of me I can't see why it is reading what it is!

 

Now, here is my suggestion. Replace that 2 brush starter with a 4 brush starter from a 2nd gen. They start sooo much better with a 4 brush. You can find a good used one on ebay for around $60...

[bkuhr]

I don't have a starter apart to verify your reading. The shunt field should have a high resistance, but 3.4 million ohms seems to me to be excessive, almost an open. Test the bus bars of each winding (coil/pole) of the stator and see if the resistance is about 850 K ohms, (apx 1/4 of the total 3.4 M ohms of the 4 poles wired in series). If this comes out correct, then I would confirm your 3.4 M ohms to be correct.

 

The only other issue could be a break down of the windings insulation, really need to be tested on a growler. Try to find a motor rebuild shop to due this test.

[dna9656]

Well I don't see the multiplier on the VOM, BUT the book for my bike (XVZ12DKC2) in the Appendices "Specifications" Chapter on page 32 says the resistance should be 3.5 ohms =/- 10% at 68 F. To me in the pic it looks like he's measuring the resistance of the field coil. BUT with the picture he says the magnetic field plates aren't any good. Now I'm no motor expert, but I never heard of "magnetic field coil plates" I typed it into the search engine and what came up was stuff about permanent magnet starters. Well I know a field coil is a electromagnet, it provides lines of magnetism. In the case of a generator you got to cut 1,000,000 magnetics lines to create 1 volt. Well I think that's what the instructor said in 1976-77? Starters are just motors, motors and generators are pretty much the same animal except you apply a voltage to a motor to make it spin and you spin a generator to draw a voltage and amps. I'm sure that's an over-simplification.

The starter started the bike JUST FINE. I needed the nose bearing removed is all and now we're doing this.

I have a 4 brush model on the way.

[dna9656]

I don't have a starter apart to verify your reading. The shunt field should have a high resistance, but 3.4 million ohms seems to me to be excessive, almost an open. Test the bus bars of each winding (coil/pole) of the stator and see if the resistance is about 850 K ohms, (apx 1/4 of the total 3.4 M ohms of the 4 poles wired in series). If this comes out correct, then I would confirm your 3.4 M ohms to be correct.

 

The only other issue could be a break down of the windings insulation, really need to be tested on a growler. Try to find a motor rebuild shop to due this test.

 

 

The starter works fine; it's apart to do the ground mod and while I had it apart I found the rear bearing was bad so I thought I should change the bearings, I bought the overhaul kit on ebay to overhaul it while the starter was out of the engine.

There were no performance issues with the starter.

 

 

All this testing is un-nessesary.

Edited April 19, 2014 by dna9656

[dna9656]

Just got done checking the number of brushes on the starter that just arrived via the USPS.

Using the excellent information provided by the membership of this and the Venturers forum I have learned that the 2 brush starters are easily ID'd from the 4 brush models from the outside.

They each have different numbers on the end cap(s) but the easiest way to tell what starter is for what engine is the 4 large Phillips screw heads in the center section of the starter. This is easy to see if the starter is somewhat clean, even when looking at pictures on EBay.

I have also (maybe in vain) explained to 3 or 4 vendors on EBay that just because they see other vendors showing that the starter on the 1200cc and the 1300cc motors fit either motor that doesn't mean that's what Yamaha intended. I explain that the 1300cc requires more starter than the 1200cc. So that means what they are saying is a legit fit really isn't and they are leaving themselves open to bad feedback and returned stuff at their expense.

I noticed that Mitsubishi just couldn't use common bearings or other innerds in the starters either so beware.

ALSO: Yamaha (in it's infinite wisdom) uses a generic exploded view of the starter throughout all it's parts and service manual (so far as I can tell) regardless of the actual model bike you're looking at. On every bike I checked a 2 brush model is shown. You might see something in the parts description saying some thing about 4 brushes per assembly.

So be prepared to explain this (as well) to a vendor on EBAY.

Edited April 19, 2014 by dna9656

[Neil86]

Maybe this will clarify things.

 

The Yamaha Venture used a 2 brush starter from 1983-1990......so it used them on 1300's for 86-90 (my 86 has one).

In 1991 the Venture went to a 4 brush starter to alleviate the hot cranking issues with the 2 brush unit. Eventually they

exhausted the complete 2 brush starters stock so they changed the starter part number so if you ordered a new starter for any 83-93

you received the same 4 brush unit.

 

The reason the parts diagrams show a 2 brush starter on the 83-90 listings is so folks with the original 2 brush units can still get the correct parts to repair them.

The 91-93 parts show different internals for a 4 brush unit.

Edited April 19, 2014 by Neil86

[Prairiehammer]

Maybe this will clarify things.

 

The Yamaha Venture used a 2 brush starter from 1983-1990......so it used them on 1300's for 86-90 (my 86 has one).

In 1991 the Venture went to a 4 brush starter to alleviate the hot cranking issues with the 2 brush unit. Eventually they

exhausted the complete 2 brush starters stock so they changed the starter part number so if you ordered a new starter for any 83-93

you received the same 4 brush unit.

 

The reason the parts diagrams show a 2 brush starter on the 83-90 listings is so folks with the original 2 brush units can still get the correct parts to repair them.

The 91-93 parts show different internals for a 4 brush unit.

 

I think Doug's complaint about the fiche pictures is valid. ALL the Venture (1983-2011) starter motor micro fiche IMAGES are the same. All show just two brushes, although the parts list does reflect four brushes, but the pics show just two brushes.

[Neil86]

They show the back view of the brush plate....thats why you can't count them.

 

Also note you could buy brushes separate....on the 2 brush...the 4 brush you buy the complete plate and brush assembly.

 

heres a front view...

http://www.oldbikebarn.com/core/media/media.nl?id=2045&c=669440&h=4985e06efa2f221b22ed&resizeid=-2&resizeh=400&resizew=250

Edited April 19, 2014 by Neil86

[dna9656]

I can only go by what I see in Yamaha's diagrams. Shame on them for not spending the money for a better picture...So far as I can see they all look the same, (I mean EVERY MODEL I looked at Venture and non-Venture... so far as the brush plate goes) I figured that the early diagrams (the 1200 CCs) would show the 2 brushes, later on when the 4 brush came along they'd show that but the diagrams all look the same; but there were differences in the descriptions...indicating the 2 VS. 4 brush issue.

Thanks you guys for everything!

Edited April 20, 2014 by dna9656

[Neil86]

I go more by the part numbers than the diagrams to tell things had changed...but yes guys, I concede they could be better.

[uncledj]

I'm a little surprised that that meter would read mega-ohms.

If it does, a 3.4 million ohm reading may well be the resistance through the insulation to ground. Better than I'd expect on a 12 volt system.

When I test 460 v motors, 5 million ohms is a barely acceptable minimum to ground.

I think a reading of 3.4 M is, in this application, for all intents and purposes an open circuit.

I'm just sayin'

[dna9656]

My good buddy, Lyle (even though he rides a NON-metric bike (read ROAD KING) got the 2 brush starter back together! He got that stubborn snout bearing out and installed all the overhaul parts for me! I'd really like to get him involved in our forums. He's a different kind of guy, he's deaf so he experiences the world a little differently than those of us who are not deaf. He has the in-plants and he does just (he is a co-worker) fine at work too.

 

Hooray for my good friend Lylw!

Edited April 20, 2014 by dna9656

[dna9656]

They show the back view of the brush plate....thats why you can't count them.

 

Also note you could buy brushes separate....on the 2 brush...the 4 brush you buy the complete plate and brush assembly.

 

heres a front view...

http://www.oldbikebarn.com/core/media/media.nl?id=2045&c=669440&h=4985e06efa2f221b22ed&resizeid=-2&resizeh=400&resizew=250

 

Also note that the 4 brush starter takes different overhaul parts!

[winston66]

I do not know about all of the preceding stuff as I did not bother to read it all.

I noticed that the Volt Ohm meter in the first pic was set to the lowest scale that means to me that the resistance of the field coil to the earthed case was 3.4 ohms , which according to a subsequent post was the factory specification , so I do not really know what every one is talking about , if that reading is what it should be

 

Cheers , winston66, Northampton , Western Australia:fingers-crossed-emo:backinmyday:

[uncledj]

The little "M" on the right side of the display typically means Mega- ohms, a "K" would mean Kilo-ohms, and no symbol would be simple Ohms.

That appears to be an auto ranging meter. Even looks to be True RMS.

 

[bongobobny]

I do not know about all of the preceding stuff as I did not bother to read it all.

I noticed that the Volt Ohm meter in the first pic was set to the lowest scale that means to me that the resistance of the field coil to the earthed case was 3.4 ohms , which according to a subsequent post was the factory specification , so I do not really know what every one is talking about , if that reading is what it should be

 

Cheers , winston66, Northampton , Western Australia:fingers-crossed-emo:backinmyday:

As DJ said, it is an auto range meter. Look again, there is no range selection on the function switch, just ohms...

[winston66]

OOPS

 

I missed that.

Cheers , winston66

 

[greg_in_london]

I'm going from memory here, though I could pull a starter apart to check, but surely the live connection (which the black probe is touching) is only connected to the carbon brushes. It only earths through the body when the central commutator is there and then eaths through the primary commutator coils, the brush plate and then through the body to the chassis.

The magnetic field that it works against is generated by strong permanent magnets bonded to the starter body.

3.4 Mega-Ohms means some continuity - maybe from the brush touching the body or else the fibre washer that insulates the live m6 bolt that goes through the starter body is getting old/contaminated. That's not going to be because of the coil's insulation because the commutator isn't there. Easiest thing is to rebuild it and see if it works - no point talking more about it