Operation: TRIPLE THREAT - 1985 NS400R Rothmans Project

[TwoStrokeNut]

Service T1.01 Test - Get Engine running (Part 2)...

With carbs preliminarily checked out, air box cleaned, oil injection inspected, battery installed, and tank cleaned and ready to supply straight gasoline (geez that sounds like a lot of work), I was ready to kick this old girl over again.

On went the fuel valve and fuel was witnessed trickling down the supply hose for a little while as the bowls filled and finally stopped. Ignition switch on and lights illuminated. Choke on. A soft kick or two to be sure cylinders are clear. A couple kicks and she fired up… on all 3 cylinders, no doubt. SUCCESS!!! (Or so it seemed)

After running for a minute, it developed that same misfire on the left-most cylinder. Weird. What happened? So I shut it down again to walk away from it for a while to let my subconscious work on the problem. I had plenty of other non-bike related chores to take care of anyway.

I got back to the bike in about 1.5 hours and decided to give it another go. As I’m reaching to turn the fuel valve back on, I noticed I had forgotten to turn it off last time… geez, I’m getting forgetful in my old age!!

With one kick the bike was fired up again. Right from the start, it was only running on 2 cylinders. Nice 2T smoke rumbling from those 2 cylinders too, so that was a nice verification the oil injection was doing it’s thing. There was not even I hint of fire on the left-most cylinder. But yet, there was still SOMETHING coming out of its exhaust. So of course, I hold my hand past the silencer and what do I see?... raw gas soaking my hand!!! Ok, that’s not good. Time to shut her down.

When I pulled the chamber off, it was filled with gas. I mean, COMPLETELY filled!!! Okay, I know what happened now… the cause of the misfire was due to a leaky float valve. Initially, the bike would run good. Then as the fuel level continued to rise up and beyond the set float level, it was flooding the cylinder and a misfire started. As fuel continued to flood in, spark completely died out. The cylinder was basically a fuel pump at that point with no ignition happening at all by the wet plug.

So I drained the chamber by letting it hang for a while. I figured there might be a little fuel still in the crankcase and with the chamber still off and also fuel valve off, I fired her up again to run on just what was left in the bowls. It ran and in just a few seconds, I hear a POP from the left-most cylinder. Then a POP-POP, then POP-POP----POP. I was feeling good again. Just as it was about to start firing on every crank rotation, I realized the wide open exhaust port was pointing straight down at a drain pan half filled with raw fuel… not a good thing!! I got her shut down before any fire ensued and thanked whoever is watching over me.

Needless to say, Float Valves are now on the shopping list. During all this, I also noticed my pull cable was frayed up near the throttle, so that will go on the list as well. I realized I had a golden opportunity to check those valves back when I had the carbs on the bench and I didn’t even think of it. Oh well, it’s not the first time my lack of intelligence has caused me extra work! LOL

T1.01 Total Cost: US$0.00 [None]

[TwoStrokeNut]

Service C5.01 - Tighten Kickstand and Lube...

While waiting on float valves to come in, I had plenty of other stuff to keep me busy.

I noticed the kickstand was loose enough on its pivot when up to hit the expansion chamber, so I decided to take care of that while bike was still up on the rear stand. I just did this on the RZ500 a few months ago with success, so it was time to try it again.

This shows it touching the chamber.

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It just takes a little pinch in the shop press to do it.

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It’s still fairly loose, but at least it doesn’t hit now. It doesn’t look too bad in this picture, but both parts could also use a re-paint and that is on the list.

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The true fix for these parts would be to build back up the worn material with a little welding and then grind it smooth, so I might try that if I have a free moment when the bike is up on the stand again. Of course, that would be the perfect time to paint it too.

One curious thing I discovered as I was looking at this stand was remnants of some little pegs welded on it, like they were meant for some type of hoop to assist kicking the stand down.

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A little research indeed shows there is a part broken off. This photo snagged from Ebay explains all. The hoop should be easy enough to make and weld on, so that is being added to the list. Once in the weld booth, it should be a good time to build the pivot material back up too.

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C5.01 Total Cost: US$0.00 [None, but the list grew!]

[TwoStrokeNut]

Service C2.01 - Replace Front Brake Lever...

Before I even started taking inventory of all the spare parts a while back, I spied the extra brake lever on a spare master cylinder in the bin. With the one on the bike looking so nasty, I stopped what I was doing and installed the spare one.

This whole area looks nasty (grip, lever, master cylinder reservoir), but these are very easy things to fix.

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The lever I found even is the adjustable type. Okay, so maybe the NS400R didn’t come with that adjustment originally, but small upgrades like this are fine to me.

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Here it is, mounted in place.

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It was the very first improvement I made on the bike and it was one of those instant gratification moments. It may not be ideal, but it’s a step up!

C2.01 Total Cost: US$0.00 [From spares inventory]

[TwoStrokeNut]

Service C4.04 - Fork - Replace Clip-Ons and Relocate above Triple Clamp...

The seller that had the front wheel also had a set of OEM clip-ons, so I worked out a deal to toss them in the box for free shipping.

Here are the auction pictures.

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Bar and weights were removed and prep started for painting of the straight 7/8” steel portion. That larger socket screw is fairly unique with that large head… don’t want to lose those!

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There was some work to do on the aluminum part too.

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After the aluminum was polished and the steel sanded, I masked off the aluminum and sprayed the tubes with a metallic silver. Not much of that tube is even seen, so I didn’t worry about researching that correct paint.

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Once that had dried, I shot the whole thing with a clear coat to seal off the raw aluminum.

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It’s still not perfect, but it’s not my intention to get this bike perfect anyway

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The bolts seemed to be in good shape, so I gave them a light rub with a brass brush to shine them up a bit.

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That looks better. I still need a second weight.

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Just for position comparison, I slid the OEMs on before taking the others off. Note the aftermarket slip-ons are below the triple clamp.

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The extra height should be more comfortable for this aging body! Note also that the OEM bars are quite a bit shorter.

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Here is the result. The refreshed clip-ons make the triple clamp look really bad now. I need to start finding a match for that gold.

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I’ll end this story with a couple shots of the old clip-ons. Perhaps someone that wants to tweak their riding position to perfection might want these.

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Those Telefix bars are sort of pricy when new… makes my $100 OEM versions look like a bargain now! There’s actually quite a bit of adjust on these. Who knows, maybe I will end up putting them back on someday after a good cleaning.

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C4.04 Total Cost: US$100.00 [Clip-ons with free shipping]

[TwoStrokeNut]

Service E4.02 - Replace Indicator Light Module...

Going back to this early picture, you can see the indicator light module just hanging on by cable ties. That’s because both mount tabs on the housing were broken off. I don’t even feel safe riding the bike with this piece in a spot that could jamb the fork from turning, so something needed to be done before any test rides would happen.

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Spare parts bin to the rescue!

As with many things on this bike, you can tell one of the previous owners wanted to repair this bike and spare parts were being gathered. Luckily, an indicator light module was in the stash. Unfortunately, it did not have the same exact light positions (and also pinout positions on the 9-pin connector was different), so I had to get a little creative and at the same time, accept a slightly non-factory rendition.

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Here is a comparison of the old and replacement versions. Even the replacement module has one mount broken, but it ended up supporting the module fine. Note the differences in the light positions…. “SPEED” is present, with the following 3 moved to the right one spot from the original version.

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Unfortunately the lettering is part of the housing, and this forced me to slide the light bulbs down. Here is the original light bulb housing still attached to this bike showing a blanking plug in that empty spot (the left side in this picture is actually the right side of the housing on the bike)

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So I popped the plug out and slid the middle 3 bulbs to the left one spot and moved the plug to the newly formed hole.

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With it back on the bike and colors showing, it’s easy to know what’s what, even with the lettering barely visible. It’s not perfect, but as always, I focus on improvement, not necessarily perfection, and this is a whole lot better.

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E4.02 Total Cost: US$0.00 [Spares Inventory]

[tacky1]

Coming together nicely

[TwoStrokeNut]

Coming together nicely

Thanks! There's about 10 more completed items I have yet to report on too. Some of these take longer to document than to actually do! LOL

[TwoStrokeNut]

Service E2.01 - Ignition - Shorten Switch (make flush with triple Clamp...

The current ignition switch is a replacement part installed after the bike theft in 2001. I don’t know if its aftermarket or a Honda part from another bike, but I know the key doesn’t match the other two locks and the switch sticks up too high in the top triple clamp.

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Since the key blank was a mirror image of the other two locks (fuel cap and seat lock), I figured the switch was aftermarket, and decided to purchase this $12 switch on Ebay in hopes of having an ignition switch that the original key blank would insert into, possibly allowing re-keying to the other two locks and resulting in having one key code overall. This came from a 1984 VF500F and was a cheap gamble at $12. It looked a fair amount shorter in the auction pictures than the installed switch, but it turned out it still wasn’t short enough. The other problem is, the key blank is still opposite that of the other 2 locks. A third problem is that the NS400R has an extra wire besides the 6-pin connector, but I think some internal parts swapping could have taken care of that. So it seems the NS400R switch is somewhat unique.

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With all these obstacles, I abandoned the switch swap idea (for now), but still wanted to make the existing tall switch look better somehow. A little black touchup paint helped, but it still looked out of place.

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But the vast piles of junk cluttering my shop usually offers up something to work with. This time, however, a suitable part didn’t come from a bin. I found what I needed in my cleaning supply drawer. A black cap from a carb cleaner spray can turned out to work nicely once a hole was drilled in it.

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Before:

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After:

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Again, not perfect, but better. It’s a fairly snug fit on there, so I don’t think it’s coming off. And while riding, the key head will keep it from getting lost if it does decide to work loose.

I’ll make another attempt at replacing the ignition switch at some point after a bit more research is done.

E2.01 Total Cost: US$12.78 [Trial Switch and shipping/Free Cap]

[TwoStrokeNut]

Service M2.01/M2.02/C4.05 - Replace Throttle Tube/Cable/Grips...

I noticed something not quite feeling right when twisting the throttle and upon further inspection, I found a frayed pull cable. That just won’t do and it will need to be replaced.

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The float valves were ordered from Webike, so I also ordered a new cable from them too.

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I needed a new throttle tube as well and since this same part is used on many vintage Honda’s, I found one that also included usable grips for nearly nothing delivered.

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Here is the cable and tube, installed.

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Although these grips are the closed end style, I believe they match the pattern the OEM NS400R had. I will just need to cut out the rubber centers when I add the bar end weights.

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<< Won't insert >>

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<< Won't insert >>

M2.01/M2.02/C4.05 Total Cost: US$56.82 [Cable 48.42 + Tube/Grips 8.40]

[TwoStrokeNut]

Service C4.06 - Refinish Top Triple Clamp (Temporary)...

I didn’t realize there are so many shades of gold color, LOL.

I’m not planning to tear the fork apart yet for a full clamp repaint, but I wanting to see if I could match that gold paint with the few rattle cans of gold on hand and none of them came close.

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But then I remembered the silver paint pen I bought for some touchup work came with a gold one as well… worth a try, right? Well it turned out to match really well and I would recommend it to anyone that has a scratch or nick to touchup on their clamp. I decided something was better than nothing, and coated the whole top surface. LOL.

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Here’s an overall shot with all the area updates showing, including a quick wipe on the left switch housing with 303 Aerospace protectant (which worked nicely).

I still have a dilemma, however. For the final refinishing, I still need match gold paint in a spray form, so I still need to hunt some down.

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And before you pick this apart too much in your head, just remember what it looked like when I bought it. LOL

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C4.06 Total Cost: US$0.00 [Just Touchup Paint from inventory]

[TwoStrokeNut]

Service M5.01 - Replace carb float valves...

The float valves took a little time to come in from Japan, but not too bad.

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The day after I ordered the valves, I realized the same place sold valves and seats as a kit for only $13 more and that would have been a no-brainer for me. Oh well.

The carbs came off a second time (won’t be the last time) and here was the typical condition of the seats.

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A wipe with a cotton swab and carb cleaner yielded this… not great but it will get much better when I get around to the ultrasonic bath.

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This close-up of the float valves shows the wear on the old.

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With the carb all back together, it’s time for what I should have done the first time these were apart… a proper float test!! I propped the carbs up close to how they are angled in the bike. Fuel feed line is positioned high with a piece of stiff wire. Bowl drain screws were opened and drain hoses were elevated to witness fuel level.

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Then just fill the funnel until fuel stops flowing into bowls (hopefully it stops anyway). A better test would provide maximum pressure head from a full tank of fuel, but you can’t have everything! LOL

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I let it sit for a while and checked whether there were any drips on the outlets of the carbs. None is good!

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Now is a good time to check float level. Even though I was pretty consistent from carb to carb when setting it, this shows it can still be off. I got two right anyway.

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This is just approximate, but I tried to hold the stick reasonably level to show where the fuel level is in the carbs. Fuel ports in the venturi are behind that hose somewhere, so level is below.

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I still didn’t have them perfectly matched, but I called it good enough (especially knowing I will be back in these carbs for a full ultrasonic cleaning soon).

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M5.01 Total Cost: US$44.90 [Float valves and shipping]

[TwoStrokeNut]

Service M5.05 - Fuel - Replace petcock...

As I mentioned earlier, the internals of the aftermarket petcock supplied with the bike were looking pretty sad, and although there is a rebuild kit for it, I found a completely new vacuum actuated valve as a suitable replacement.

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Here is a comparison of the old and new aftermarket petcocks, both with M22 nut. On the new one, the reserve suction port does not have any riser tube on it, so it will drain the tank dry I suppose. The new one has an outlet barb matching the large size of the carb inlet so I’ll be running 5/16” hose for the supply.

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Here it is, mounted on the tank. This is the first petcock I’ve had that had detents on the 3 positions. It’s actually very nice because it takes the guesswork out of it.

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With vacuum applied, I checked that all knob positions where doing what they were supposed to.

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On the bike, it looks reasonably well and nearly fills the body cutout. A larger faceplate would look even better. And knowing the factory fuel decal will identify the different positions, no worries about the existing labels going away. I will just need to index the knob 90 degrees CCW from where it’s at to match the OEM decal.

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It worked out well enough that I ordered a second one as a spare.

M5.05 Total Cost: US$14.47 [Petcock]

[TwoStrokeNut]

Service M5.04 - Fuel - Add redundant shutoff valve/filter...

One last item before starting this bike up again was finalizing the supply line from tank to carb. Since petcocks start leaking without any notice, I’ve gotten into the habit of adding a redundant fuel shutoff valve in the supply line. This valve, along with translucent fuel hoses can let you identify when one has failed… Turn on the tank valve and watch the fuel trickle down to the second valve and stop. Turn on the second valve and watch the fuel continue on to the carb.

This procedure works if the tank valve has a way to turn it on with the engine not running. These vacuum actuated valves many times have a “Prime” position that allows fuel to flow even without engine vacuum. From what the Owner Manual states, the middle position on the OEM valve is labeled “OFF” and it sounds like it functions as such. This new aftermarket valve functions the same way, center OFF.

That’s all fine until you run out of fuel and the float bowls are emptied. I don’t see a way to fill the carbs back up again for re-starting unless you apply some vacuum to the valve with a brake bleeder tool or similar. If anyone can shed some light on how to get fuel flowing again before the engine is started, I would be thankful.

On to the matter at hand… adding the supply hose.

I chose 5/16 lines because my flowrate experiment on the RZ500 proved it can handle the amount of fuel this engine drinks (and old reviews say mileage is down in the low 30’s… thirsty girl!)

Here is the filter and shutoff valve I bought.

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This task was so easy on this bike with its single carb inlet. Another benefit to adding the second valve in there is very little fuel is lost if removing the tank… shut off both valves and you only have fuel in that 5” length of hose between to catch. I found the hose tended to sag with the extra parts in it, so I added a little strap to the fairing bracket to hold it up.

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When installing all this, the only suitable sized hose I could find was this clear vinyl stuff and this picture shows where the barb is on the number 1 carb. It will get replaced with a proper black vacuum hose after I locate some (probably in my city garage).

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M5.04 Total Cost: US$20.53 [Filter and Valve]

[podman]

Very nice work as always mate, the fuel petcock was a particularity good find, neat and quality looking solution.

[TwoStrokeNut]

Very nice work as always mate, the fuel petcock was a particularity good find, neat and quality looking solution.

Thanks!