Operation: RZ350N REVIVAL - Florida 1985 48H Project

[TwoStrokeNut]

Thank you sir for the input and thanks for stopping in. It's good to have options!!

[TwoStrokeNut]

Service M02 - Replace air filter element...

While I wait for that penetrating oil to do its job on the cylinders, there are plenty of other tasks to do (and my list keeps growing!!).

After 18 years, the old oil-soaked filter turned to dust. Just rubbing it collapsed it. I’m glad I didn’t start the bike without first checking it, as it would have disintegrated and wound up in the carbs and cylinders. I went with the same UNI brand because of cost but will keep its lifespan in mind.

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It looks like UNI changed the design of the NU-2291 since I bought it last time since now it is a 2-stage design.

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After literally vacuuming out the old one (LOL), here is the new filter installed. I will oil it later when the bike is ready to be started. For now, it will serve to keep the dirt and critters out of the clean side of the airbox, and we all know Florida has plenty of those!

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M02 Total Cost: US$14.00 (Air filter element)

[silverstrom]

There is no need to oil it unless you plan on riding off road. You'll have much better airflow with a dry filter.

[Whymee]

There is no need to oil it unless you plan on riding off road. You'll have much better airflow with a dry filter.

The problem with this is that there is nothing to trap the microscopic particle that will go through the filter. At least with filter oil, dirt particles get trapped on the tacky oil, and will not find its way into your engine. YMMV


Just a FYI, One thing I do is use grease on the sealing lips that touch the airbox. This is a carry over from my MX days. In my mind this makes a better seal. I also use either Twin Air or Bel Ray filter oil (non aerosol).

Carry on sir...

[waltmil]

I don't think anyone intentionally rides in dusty conditions but the occasional dust storm, construction site is why we use filters. as whymee said, carry on

[TwoStrokeNut]

silverstrom/Whymee/waltmil – Thanks for your thoughts and tips guys. Unfortunately (but fortunately from a seclusion standpoint!), there is a sand entrance road leading to the big shop where this bike will be stored, so the bike will inevitably will see a small amount of dust on every ride. I normally put a light spray of oil on my filters just to give it some protection. Hey who knows, as a bonus, maybe the oil will deter any critters from going where they shouldn’t be. LOL

[TwoStrokeNut]

Service M03 - Carb cleaning and rebuild...

CARB DISASSEMBLY

Before even beginning this section, just let me say what a big difference proper-fitting JIS screwdriver bits make in working on the carbs. Try one and you will be amazed at the increased torque you will be able to apply without having the bit strip the screw. I bought these 2-packs because I wanted to keep a set at each of my shops. I added a red stripe to them for quick identification.

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The bike was fitted with a pair of TM carbs and pod filters when I bought it, but I sourced an OEM airbox and 26mm carb set in an effort to bring it somewhat back to stock. I still have those big carbs and I’m tempted to toss them on there just to note the performance gain. But first, I intend to get it running again with the stock carbs, just the way I had it when it got stored away. It was running fine back then with the setup, so if I keep everything the same, it should run fine again after cleanup. I’m praying I don’t have ignition issues, but at this point, I can’t even kick it over to check for spark.

Here is what I started with after taking the bike out of storage.

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Here is the carb set before disassembly. I took a bunch of pictures from all different angles in case there are questions during reassembly.

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And here are the right and left carbs disassembled and bagged up, awaiting ultrasonic cleaning.

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M03 Total Cost: US$0.00 (Labor only)

[TwoStrokeNut]

Service M03 - Carb cleaning and rebuild...

CARB JETTING
Now that I have the carbs apart, I can document what jetting was in there. I remember it running okay with the set-up, so this jetting will become my new baseline moving forward.

The right side carb contained the following:

Needle Jet (Mikuni 0-8, 357)

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Needle (Unidentified, Groove position 2)
I doubt this is the original needle since there are no markings. If you recognize it, speak up!

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Main Jet (Mikuni 240)

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Pilot Jet (Mikuni 20)

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The left side carb was identical.

I also noted the air screw position on each:
Right side carb = 1.75 turns out
Left side carb = 1.25 turns out
These will definitely be adjusted as needed once she is running again.

I like to document jetting in a spreadsheet to keep track of everything. Its way too much for this old mind to remember! If I’m lucky like with the RZ500, I won’t need any re-jetting to have it running properly. I’m no expert, so the hunt would be primarily trial and error until I stumble on the sweet setup.

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M03 Total Cost: US$0.00 (Documentation only)

[JonW]

I just got goose bumps! I didnt know you had a 350 as well... and now there is a thread on it, wahooo! Hit me up if you need any help mate.

[TwoStrokeNut]

I just got goose bumps! I didnt know you had a 350 as well... and now there is a thread on it, wahooo! Hit me up if you need any help mate.

Yep, here I am! Truth is, I had the 350 long before the 500. In fact, I didn't know the 500 model even existed until about a year before I purchased it after stumbling upon the RZRD500 website.

I appreciate you taking time from your busy day to stop in and give some encouraging words. Help?... I got a feeling I'm going to need plenty of help on this bike after all my neglect! I'm still trying to figure out how to break that engine free, without actually breaking anything. LOL. Time is on my side, luckily.

[JonW]

I just got goose bumps! I didnt know you had a 350 as well... and now there is a thread on it, wahooo! Hit me up if you need any help mate.

Yep, here I am! Truth is, I had the 350 long before the 500. In fact, I didn't know the 500 model even existed until about a year before I purchased it after stumbling upon the RZRD500 website.

I appreciate you taking time from your busy day to stop in and give some encouraging words. Help?... I got a feeling I'm going to need plenty of help on this bike after all my neglect! I'm still trying to figure out how to break that engine free, without actually breaking anything. LOL. Time is on my side, luckily.

Haha, its been cold and rainy here and hanging out in the garage with the 251LC project hasnt appealed much today to be honest, hence i was reading the forums instead

Lots of patience, heat and penetrating oil will work. just take your time. I had some stuck rings in a newish wiseco piston I wanted to save. The stuff that gummed em up was much like your build up and it took a lot of effort and time, but I did get them free... they broke of course, but I was replacing them anyway after the ordeal.

Excited to see how you progress with this, your 500 thread is one of my all time faves. You set the bar high with that one... 'a rod fer yer own back' as old folk used to say haha.

[RuZty]

Once you have the engine out of the bike you might find only one cylinder is stuck by unbolting them and seeing which one you can lift. At that point if you can get the cylinder high enough to rotate it slightly it might come loose quite easily.

[TwoStrokeNut]

Haha, its been cold and rainy here and hanging out in the garage with the 251LC project hasnt appealed much today to be honest, hence i was reading the forums instead

Cold and rainy actually sounds like a nice alternative to hot and humid at the end of this loooong summer! Sometimes it nice to live vicariously for a moment through others on the forum while sitting in the comfort of your home. We all do it, including me! Now, get back out there and get to work... that bike isn't going to build itself!! LOL

Lots of patience, heat and penetrating oil will work. just take your time. I had some stuck rings in a newish wiseco piston I wanted to save. The stuff that gummed em up was much like your build up and it took a lot of effort and time, but I did get them free... they broke of course, but I was replacing them anyway after the ordeal.

I was born with abundant patience, so I have that on my side too! It's amazing how this gas (petrol) residue can stick better than glue sometimes.

Excited to see how you progress with this, your 500 thread is one of my all time faves. You set the bar high with that one... 'a rod fer yer own back' as old folk used to say haha.

Thanks! I'll keep everyone updated with the good, the bad, and the ugly. Had to look that saying up... I guess I did do it to myself. LOL. As far as the thread goes, the 500 thread is kept in a MS-Word document, so it was fairly easy to copy it and fill in my new 350 story and get it ready to post. As far as the project goes, my plans are to have this bike happily cruising down the road before the end of the year, rather than being a 6 year on-and-off-again project. Major engine work will kill that schedule, however.

[TwoStrokeNut]

Once you have the engine out of the bike you might find only one cylinder is stuck by unbolting them and seeing which one you can lift. At that point if you can get the cylinder high enough to rotate it slightly it might come loose quite easily.

I'm glad you chimed in RuZty. I hadn't really considered the possibility that ONLY ONE piston is stuck. That would make it a lot easier with the fact that the crank will be allowed to spin in at least one direction as it pushes the stuck piston and cylinder up off the mounting studs. With assuming both are stuck, the crank would be guaranteed locked from rotating too because the piston on its downstroke couldn't move, even if both cylinders were unbolted. Even if both are stuck, it likely that one is not stuck as bad at as the other, and that may offer some opportunities as well.

Right! Everyone knows it is easier to rotate a stuck pin in a bore to break it loose, rather trying to drive it axially out. Should hold true for pistons too! I just need to not overload the conn rod needle bearing if torqueing that cylinder.

Thanks for the tips!

[TwoStrokeNut]

Service M03 - Carb cleaning and rebuild...

CARB RE-ASSEMBLY

What a difference a little cleaning can make! Far from perfect, but the carbs should actually perform their function again. These are much heavier than my all-aluminum RZ500 carbs with what appears to be diecast zinc (???) bodies.

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An internet tip led me to a cheap rebuild kit for the RZ350. It is intended for a Banshee ATV with different jetting, but I re-installed the existing jets as a baseline after the ultrasonic cleaning, so I only needed the seals, float valves, and drain screws from the kit. The extra parts may come in handy for other projects in the future. And who knows, maybe those shiny brass needles will still work on this RZ. If this bike needs some re-jetting once all back together, I will buy new jets then in the specific sizes needed. I might even pop in those shiny new main jet washers at that time just for some bling.

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I decided to buy a float adjustment tool and try it for the first time on these carbs. In all honesty, I prefer using the tail end of a set of calipers for the job instead. Maybe this tool would work better with a couple modifications, I don’t know. I just found them too bulky and I kept bumping the float after I had it properly pressing on the needle without compressing the spring plunger.

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Here’s an image looking down into the slide area.

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If you were wondering where they mark the carbs, here it is, and I was glad to see the proper “48H00” ID on this ebay pair.

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Here are the carbs all back together.

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I’m debating whether to re-coat that un-plated the spot on the bottom support where rust had formed. I think I remember seeing some type of black rubber or plastic band in the center section and maybe that’s what caused the corrosion in the first place.

After I do a quick bench test to verify float height (and that the budget-minded float valves shut off all the way), they will be ready to go back on the bike.

M03 Total Cost: US$18.50 (Banshee carb kit)