Author Topic: DOT 3 or DOT 4 and Spark Plug Questions  (Read 2187 times)

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Offline wingman

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DOT 3 or DOT 4 and Spark Plug Questions
« on: April 06, 2010, 08:38:05 AM »
hey guys (and gals) -

I am in the middle of rebuilding my 350f  from the ground up .  I replaced the original master cylinder with a cylinder off of a CBR600.  The new master calls for DOT4 fluid whereas the old system called for DOT3.  I am running a goodridge line from the master dirctly to the caliper.  Which should I use?  I don't want to damage the seals in the new master.  I have completely rebuilt the caliper - new seals, crush washers, etc.  The piston was fine so I left cleaned it up and put it back.

Also - I am thinking of switching the wires off of the coils as my are old and getting corroded.  And lets face it, new wires would look pretty cool too.  Is this a bad idea?  My electrical system has had a total make over with a Hondaman ignition, Oregon Electronics regulator/rectifier and a complete switch from regular bulbs to LEDS (inidcator lights, stop light, turn signals, etc.)  I found the FAQ post on switch cables but can't seem to locate the part that I will need to splice in the new wires.  Not to sound dumb, but can I do it with a soldering iron, silicon and some head shrink tubing?
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Offline lrutt

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #1 on: April 06, 2010, 08:42:26 AM »
thoroughly clean out all the brake system and switch to Dot 5. Less problems with moisture absorption. Best thing to do to keep brake maintenance to a minimum.
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline JBMorse

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #2 on: April 06, 2010, 09:04:59 AM »
Z1 has the wire splicers you need.  I haven't checked around but I bet they've got the best price.  They did on the plug caps.  http://www.z1enterprises.com/detail.aspx?ID=1890
I don't know about soldering, I've never seen it done. 
BTW, mind sharing what LED bulbs you bought to replace yours?
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Offline Gordon

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #3 on: April 06, 2010, 09:35:17 AM »
You've gone through the effort of upgrading most of the rest of the electronics, so why not go ahead and put on some new coils, too? 

Offline Duke McDukiedook

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #4 on: April 06, 2010, 09:43:36 AM »
+1, makes sense if you dropped that much money already.
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Offline wingman

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #5 on: April 06, 2010, 09:46:56 AM »
Any suggestions on new coils?  I am working against a deadline here to get this bike done so something I could get my hands on in the next two weeks would be great.
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Offline TwoTired

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #6 on: April 06, 2010, 09:48:21 AM »
thoroughly clean out all the brake system and switch to Dot 5. Less problems with moisture absorption. Best thing to do to keep brake maintenance to a minimum.
Completely disagree.
Dot 5 is silicone, once you switch, it is a one way decision, silicone can't be dissolved with anything, is very tenacious, and can never be completely removed from a system once contaminated with it.

No, silicone doesn't absorb moisture.  But, the system still gets moisture inside it through permeable seals, and collects in low areas.  Unless you have a low point system drain, the only way to remove it is to overhaul the system at the same frequency regular DOT3, 4, or 5.1 fluid changes are preformed. With the DOT3,4, and 5.1 fluid absorbed moisture is removed during the fluid change.  So, you only change the fluid, not overhaul the system.
DOT 5 does NOT minimize brake maintenance, it only changes what has to done.  It still has to be changed periodically, and requires a system overhaul when this is done.  If you keep the machine in a temperature and humidity controlled environment, then you can extend the brake fluid change and overhaul intervals.

Dot 5 is more compressible than the other DOTs, which results in a slightly spongier brake lever. (some do not notice this, though)

The biggest benefit of DOT5 is, if you are sloppy with the fluid and splash it on paint, it won't dissolve the paint.

For wingman:
DOT4 has a higher temperature tolerance than DOT3.  The heat tolerance is normally a requirement at the caliper where most of the heat is generated.  So, the master cylinder transplant was labeled primarily for the needs of the caliper, not necessarily the needs of the master.
Still, I believe the SOHC4 caliper seal is compatible with DOT4.    And, to be consistent with labeling on the master and to avoid confusion at future top ups, use the DOT4.

NGK makes ignition wire splicers (NGK J-1), so you can add new wires onto the stubs of the old wires near the coil.  There have been prior threads about this.

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline lrutt

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #7 on: April 06, 2010, 09:57:37 AM »
Well, in Florida where it's pretty humid, I used to have to do a lot of brake workon all my old bikes and old car. But since I've converted I've just not had any problems. Yes you still need to do a flush now and then, but the stuff just won't crystalize like the Dot 3 does.

don't matter to me what some one does. I can only say that dot 5 conversion is extrememly popular with old vehicle rebuilds, both cars and bikes.
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline wingman

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #8 on: April 06, 2010, 10:01:09 AM »
thoroughly clean out all the brake system and switch to Dot 5. Less problems with moisture absorption. Best thing to do to keep brake maintenance to a minimum.
Completely disagree.
Dot 5 is silicone, once you switch, it is a one way decision, silicone can't be dissolved with anything, is very tenacious, and can never be completely removed from a system once contaminated with it.

No, silicone doesn't absorb moisture.  But, the system still gets moisture inside it through permeable seals, and collects in low areas.  Unless you have a low point system drain, the only way to remove it is to overhaul the system at the same frequency regular DOT3, 4, or 5.1 fluid changes are preformed. With the DOT3,4, and 5.1 fluid absorbed moisture is removed during the fluid change.  So, you only change the fluid, not overhaul the system.
DOT 5 does NOT minimize brake maintenance, it only changes what has to done.  It still has to be changed periodically, and requires a system overhaul when this is done.  If you keep the machine in a temperature and humidity controlled environment, then you can extend the brake fluid change and overhaul intervals.

Dot 5 is more compressible than the other DOTs, which results in a slightly spongier brake lever. (some do not notice this, though)

The biggest benefit of DOT5 is, if you are sloppy with the fluid and splash it on paint, it won't dissolve the paint.

For wingman:
DOT4 has a higher temperature tolerance than DOT3.  The heat tolerance is normally a requirement at the caliper where most of the heat is generated.  So, the master cylinder transplant was labeled primarily for the needs of the caliper, not necessarily the needs of the master.
Still, I believe the SOHC4 caliper seal is compatible with DOT4.    And, to be consistent with labeling on the master and to avoid confusion at future top ups, use the DOT4.

NGK makes ignition wire splicers (NGK J-1), so you can add new wires onto the stubs of the old wires near the coil.  There have been prior threads about this.



Thanks TwoTired - I will stick with DOT4.  My main concern was compatiblity with the seal inside of the caliper.  The last thing I want is brake fliuid leaking onto my pads.

My coils worked great before.  I feel like I am finishing up some loose ends at this point and in the process of getting it running had to cut a length of wire at the plug boot to get to clean wire - they are a little short now and I would really like a set of red wires to go with my build.  I figured that the coils could use some new wire and it would be best to replace it.  What size are the stock wires on a 350f?

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Offline TwoTired

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #9 on: April 06, 2010, 02:25:54 PM »
Stock wires are 7mm, I believe.

That is the outer insulation diameter.  FYI, it is unlikely that the wire core is bad.  It's just the outer insulation that's hardened with age.

lrutt,
I wasn't trying to beat you up.  But, the US army switched to silicone brake fluid way back.  It was supposed to reduce maintenance issues as well as provide the operational temperature extremes desired.  They found out later there was no cost saving from maintenance.  And when DOT5.1 became available (wider temperature tolerance) the Army investigated using that and found that flushing the old systems completely was near impossible.  So, they muddle on with using silicone, as now there is little economic choice.

Yes you still need to do a flush now and then, but the stuff just won't crystalize like the Dot 3 does.
If you change it every 2 years as is recommended, crystalization isn't an issue.

I can only say that dot 5 conversion is extrememly popular with old vehicle rebuilds, both cars and bikes.

OK.  But isn't popularity based more on a belief system than science?  Further, many "old vehicles" are stored more than maintained and operated.

The point is, Silicone DOT 5 fluid was the right thing to use at one time.  But the "right time" has passed (unless you are in the army).
IMO
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline dusterdude

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #10 on: April 06, 2010, 04:26:35 PM »
dot 5
mark
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Offline cb350twin

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #11 on: April 06, 2010, 05:08:31 PM »
I use Dot 4. Noticed a slight performance gain, isn't quite as spongy.
« Last Edit: April 07, 2010, 04:10:28 PM by cb350twin »
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Offline wingman

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Re: DOT 3 or DOT 4 and Spark Plug Questions
« Reply #12 on: April 07, 2010, 07:02:54 AM »
thanks for everyone's input.  While I am not going for super high performance, I am trying to make the front brake more effective than it was originally.  I am going to run DOT4 with the stainless line and a drilled rotor.  I think I should experience better lever feel over the super spongy rubber lines that were originally in place.

Thanks again!
1972 CB350F - Who needs TV?  I have a motorcycle in my living room! http://forums.sohc4.net/index.php?topic=67528.0