What should I look for on an RZ350 project bike?

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MDZ1Rider
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What should I look for on an RZ350 project bike?

#1 Post by MDZ1Rider » Fri Aug 26, 2016 12:43 pm

Greetings all. I didn't see an introduction section so I guess I'll post here. (Admins, please move if this belongs somewhere else)
I've been restoring Vintage Japanese bikes for about 25 years, mostly Kawasaki 900/1000 4 strokes, but I have done an H2 750 2 stroke. I'm comfortable with 2 stroke engines from years of MX racing rebuilds as well.
A Yellow/Black KR RZ-350 has always been on my "to do list". I don't have to tell you guys that they are hard to find. I recently stopped with one of my restored bikes on a trailer and a gentleman approached to look at it. During the conversation he mentioned that he had 60 bikes in a barn...mostly dirt bikes, but a few 2 stroke street bikes as well. "You wouldn't have an RZ-350 would you?"...Yes. Would you consider selling it?...Yes. Is it the Bumble Bee or Red, White & Blue paint?...Both! He said they have been sitting for years and need completely rebuilt. He also said he wanted them to go to someone who would restore them right and based on my bike he was looking at I may be the right guy. At this point it took everything I had to hide my shaking knees as I casually asked if I could stop by and see them.
I'm going to look at them when he returns from a trip. Since there's years of collective RZ knowledge on the forum, any advice on specific items to look for? Are there known weak areas in the engine or frame that tend to crack? Are there certain parts that if missing are impossible find? Any advice and education on checking out an RZ-350 as a project bike is appreciated. I hope to buy both and do one all original and one with some "resto-mod" upgrades.

RuZty
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Re: What should I look for on an RZ350 project bike?

#2 Post by RuZty » Fri Aug 26, 2016 6:33 pm

If they are all original and complete, especially low mileage, you shouldn't have much trouble. It is good practice to replace crank seals and check the crank and the top end while you are at it on a bike that has sat a long time, doesn't sound like that would give you any trouble. They are pretty simple and robust when properly maintained, the biggest challenges come from fixing crap work done by previous owners, but that might not apply in this case. Stick with OEM seals and gaskets, all are still available new.

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Questo vecchio rz
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Re: What should I look for on an RZ350 project bike?

#3 Post by Questo vecchio rz » Fri Aug 26, 2016 8:30 pm

1st off Welcome.

Im in Seattle working in my hotel room and just typed you a novel w photos..but it all disappered...UGggg!
So I'll redo this as short & simple as possible.


1.) FRAME:
Many are fatigue cracked @ the kickstand area, many people dont even realize it either, its often results from sitting on bike while on its sidestand. Check the entire perimiter of the weld and take a inspection mirror for viewing the inside frame area. Generally a easy welding fix.
Check the frame for cracked paint around any welds or gussets, especially around the steering head area, cracked paint often shows a bent frame. Also check steering stops for damage and finally view the subframe head in from the back for any visible twisting. NOTE* These frames bend really easy, but are almost always a easy fix for any feame shop.

2.) FUEL TANK:IMPORTANT!
This is probably the worst area if concern on a RZ. Inspect it alongside each side for any rust spots or discoloration, gas bubbles under the paint. Check the entire tank along all lower areas and all seams, remove the tank and look underneath and @ petcock area. Hopefully the tanks were DRY! If fuel was left in them there likley rusting badly. If possible take a illuminated inspection tool with you and look inside tank. Minor rusting is completley common, but anything mid level to major rusting on the very thin metal can result in a $1000.00 repair/paint bill.

3.) BODYWORK:
Inspect all bodywork for cracks & fatigue at all faseners and plastic grommets & tabs on sidecovers. They can be repaired but often repairs(plastic welding) of push/pull gromnet tabs just dont hold up well. Perfect crack free body work is golden!, check all fasenting points on 1/4 fairing, chin fairing and seat cowls. Note* in future lubricate all push tabs & grommets for easy install & removal.

4.) ENGINE:
The usual 2 stroke storage issues, Only you can determine the conditions it was stored in, hopefully a dry non humid enviorment with no fuel and dry carbs.
Keep in mind that one cylinder is always open to the atmosphere, and if exposed to moisture could potentially lead to rust & pitting on the crank & bearings, necessitating a rebuild/ replacement.
Check to see if oil injection systems appear intact, A functioning oil injector is ideal and prefered over premix, its better for the bike and performance under most operating conditions. Rebuilds are fairly straight forward, unless the entire system has been removed.
Check all the cables, brakes etc..
Check all the radiator & overflow for rust or any evidence of leaking around hoses or cylinder head.
**If possible take a freshly charged battery with you , Turn the ignition on and ( listen ) if the power valve cycles through its startup routine. Its the servo motor doing its cleaning cycle. Functioning YPVS powervalve system is paramount to all the performance the RZ has to offer.

Other than this its the usual pretty basic regimine of bringing a bike out of storage and back onto the road.
Buy the best condition lowest mileage bike you can get, buy both if possible!
Other notes are, Original undamaged catayized pipes are desired for a original bike.
For your hot rod RZ with just basic modifications like gearing, pipes, porting you will discover your little 350 will meet or exceed your H2 in performance in every category. Unless if course your H2 was substantially modified...lol.
These RZ350s are great lil performers and when cared for are quite robust ,indestructible lil machines.

Good luck & have fun.
Banshee (Baja) race bike,+ 2 A Arms,L.E.Ds, Toomey, +4 stroker IMS tank, run flats.
96 GSXR SRAD, Future Yoshimura rep.
85 custom Tri-Z
RZ/YZR bike(project)
86 VFR750 RC24 Merkel replica (project)
Royal Enfield Bullet 500

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Zedixe13
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Re: What should I look for on an RZ350 project bike?

#4 Post by Zedixe13 » Fri Aug 26, 2016 9:04 pm

You can still buy from the dealer the rear fender , turn signals lens , the oil and expansion tanks but that's about it for the plastic parts .

http://www.yamahapartshouse.com/oempart ... 350l-parts" onclick="window.open(this.href);return false;

evan_calgary
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Re: What should I look for on an RZ350 project bike?

#5 Post by evan_calgary » Sun Aug 28, 2016 12:22 pm

As mentioned the gas tanks are super hard to find and rot out in the areas close to the fuel petcock. Haven't seen any frame issues before here but we live in very dry climate. Engine parts available from Banshee so really a cheap rebuild if you are used to getting 2-stroke cranks rebuilt. Wheels are typically straight. Fork tubes rust but pretty obvious.

RZ was really the best of the (available) 2-strokes and better than the usual air cooled bikes.

MDZ1Rider
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Re: What should I look for on an RZ350 project bike?

#6 Post by MDZ1Rider » Tue Aug 30, 2016 11:52 am

Thanks for all the input. It sounds like the RZ's don't really have any significant weak points to watch out for other than abuse and neglect by a previous owner.
Since one of the bikes will be an original restoration, besides the Factory Service Manual, are there any good reference books I should pick-up? Coming from Kawasaki Z1 projects, there are some incredibly detailed restorer's guides outlining all the differences. A different year part may fit and work just fine, but some small detail makes it incorrect for that bike.

evan_calgary
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Re: What should I look for on an RZ350 project bike?

#7 Post by evan_calgary » Tue Aug 30, 2016 2:48 pm

Not to that extent. Some of the Aussie guys have done some very good original restorations. Sounds almost like BMW rider mania on those Z1s. You only had one model that made it to the USA. If looking for parts recognize rest of the world also got the 86-90 F2 bikes and 85 was a different model from Canada to the USA (1-year only bike in Canada which was a mix of early and late parts).

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