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Discussion Starter · #1 ·
I was given a number of RDs the best 2 76/77 are of the 400 variety. One of which would be considered good to excellent condition with a title the second fair to poor has no title.

The 350 in my evaluation is trash and i am turning that over to another party to hold onto for parts.

The good/excellent condition bike, almost excellent has acid stains on nice solid chrome stock pipes.

Should I re chrome them to keep the bike completely stock? Or should I go the performance route and do chambers? Chambers might be actually be cheaper than the re-chroming. I will have to check. I would think stock would hold more value on resale of this vehicle.

I honestly cant say I want to keep the bike and will probably just repair the nice bike and sell the set.

The crank is suspect for rebuild, it holds pressure on a crank case pressure test up until push up or down on the end of the crank at the magneto taper than promptly leaks. At minimum seals and outer bearings will be needed. I have ordered a full gasket and seal kit. I have considered doing the crank myself, but am concerned about getting this correct on my first attempt without onsite guidance? I have a press but no experience + would need to have spacers and blocking made up for the process.

Who actually rebuilds these things now and if you send them out are they true when you get them back through the mail? No shop around me does anything of this sort.

Yes I have bike 2 but this was clearly not maintained and the crank would not initially turn in the bearings until it sat in wd40.

In spares i received 2 fresh cylinders "in need of paint" and a set of unused wiseco pistons which are noted to be fit to the cylinders. Other than the pistons everything looks stock.

This thing even has a period utility rack and crash bars with alternative foot pegs.

NADA pricing looks a bit crazy. Are those prices for real? Nada is usually good for the 90s and 2000s bikes I have been playing around with.

OK, Who pays 10g for this stuff? 1976 Yamaha RD400C 400 Standard Equipment, Prices & Specs

I have to consider actual value. I don't want to throw away money on a bike I cant say i will keep but don't want to be a wezel dick "see 1974 Honda CB200".
 

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ed toomey in carolina for crank rebuild, he will use the proper yam parts. dont be tempted to buy the rebuild parts from cruzin on ebay. there ok for piston kits but the bearing/seal kits are junk. ive heard that the seals dont even cover the whole of the bearing? and leak from the get go. ed did my suzuki 500 with new rods for about 800. i had a triple done by a guy in maryland but forget his name. i would have thought 4-5 for the rd in verygood cond. but hell if there fetching 7. rechrome those pipes and get 7. giddy up, i havent heard the term wezel dick in eons. boy that brings back some memories
 

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Lyn Garland used to do cranks but I heard over on twostrokeworld.com that he is taking a break. I recently found a guy in WI that does cranks and bores and he did a good job on a GT750 bore and hone for me recently. I saw some RD crank parts in his shop so I know he does them. Rods are available form various sources and Yamaha still sold OEM seals last time I needed some. If all the crank needs are outer bearings and seals, the crank doesn't have to be split. Just pull the bearings with a bearing puller and press the new ones on. Rick Merhar in Ohio used to be a great source of TZ and RD parts and built cranks but haven't heard from him in a while.

Suzuki 500 cranks are a different kettle of fish with very unusual and unobtainium bearings.

For a 350 crank a Vito's is cheaper and perfectly acceptable quality but last time I checked they didn't list a 62mm crank for the 400. Last time I checked for a 10mm over banshee crank as a possible replacement, the best price was $2,500 so I let that pass.

As for values, I never pay more that a few hundred dollars for a bike in bits - the old dollar per cc rule. :)
They have gone up in value but when they say Excellent condition, that translates to better than it came from the factory. It's easy, but not cheap any more, to get fenders and such chrome plated but most platers hate doing old two stroke pipes. Try to polish them with aluminum foil and mothers metal polish and see how they look after that.
 

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Coo, I haven't done RD cranks for 30+ years.
The acid on exhaust is completely 'normal' on them, Yamaha did some strange things to save 0.0001cent back then (it lead to broken drive chains and engines when chain snapped due to battery breather being too short and discharging acid vapor directly onto chain) plus, your unlikely find anywhere willing to destroy their various chemical vats with a used two stroke exhaust (it isn't possible to get internals completely clean and the risk of contaminating several thousands of dollars worth of chrome salts isn't worth it)
Crank building and truing is a pretty simple job which doesn't need a lot of expensive equipment or space for more than a press and truing stand (even if I could get hold of a decent priced cylinder boring machine I have no where to put it)
 

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Discussion Starter · #7 · (Edited)
Looking at the stock exhaust I don't think there is any way to remove the stains. I started looking at retro chambers and from what I see there is Higgspeed and JL. I like the way the JL set looks. Anyone with real-world experience with either of these?

 

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Looking at the stock exhaust I don't think there is any way to remove the stains. I started looking at retro chambers and from what I see there is Higgspeed and JL. I like the way the JL set looks. Anyone with real-world experience with either of these?

on the h1 i had a set of the higgspeed, not fancy looking pipes but they seemed to work well, also check ebay. once on a while you can find a decent set. dg etc looking at the link the ones i had looked like chambers not stock pipes. webike might have repo of stock ones.
 

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DG used to be really cheap and were better than stock and lighter but definitely the budget end of the spectrum.

JL pipes are great. They look stunning and work well but you have to remove the center stand and move the side stand or add an extender and heat and bend it.

Spec2 used to make great pipes and probably still do.

Higgs pipes are OK but sound like a popcorn machine at idle which some people like and some of us not so much. Someone was making Micron or Allspeed pipes in the UK. Not sure if that's still the case. There are others such as Mick Abbey who make custom pipes.

Best pipes on an RD400 IMHO are a set of mild steel Swarbricks made by Dave Swarbrick in the UK.
 

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Spec2 used to make great pipes and probably still do.
i seem to remember a company , and looking at a catolog that made yamaha 4 stroke performance stuff along with the 2 stroke. 1982-84? big bore kits etc.for the seca 750/4 . spec2 also?
 

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whos the guy that posts on the ahrma site? hes up in mich, minn or something, he makes pipes, big al knows who he is. gary at dyna something or other
 

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DG used to be really cheap and were better than stock and lighter but definitely the budget end of the spectrum.

JL pipes are great. They look stunning and work well but you have to remove the center stand and move the side stand or add an extender and heat and bend it.

Spec2 used to make great pipes and probably still do.

Higgs pipes are OK but sound like a popcorn machine at idle which some people like and some of us not so much. Someone was making Micron or Allspeed pipes in the UK. Not sure if that's still the case. There are others such as Mick Abbey who make custom pipes.

Best pipes on an RD400 IMHO are a set of mild steel Swarbricks made by Dave Swarbrick in the UK.
Think I'm right in saying Gibson in Romford still make Allspeeds, https://gibsonexhausts.co.uk/
 

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Discussion Starter · #14 · (Edited)
i seem to remember a company , and looking at a catolog that made yamaha 4 stroke performance stuff along with the 2 stroke. 1982-84? big bore kits etc.for the seca 750/4 . spec2 also?
Nice pipes that sound great.
SpecII looks to be historic at least the site.

LOL I used to live 20min from this address in La Canada.
 

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For sure, Gary's web site is a bit out of date - like a decade or two out of date. His pipes are great though. I have a set that a PO fitted to my RZ350. They look the part, sound great, not noisy and work well. Swarbrick's pipes look even better but I sold that project as a basket case and the other swarbricks I have are on road race bikes, so I can't comment on their streetability. They sound awesome on a TZ though :)
 

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Discussion Starter · #16 ·
Did a bit of digging through boxes today. Found a Y-Boot Kit with K&N, clean carbs look stock, new sprockets and chain, and some old car style coils + new points and plugs and an 2t oil pump rebuild kit . Looks like I can get going with some reed blocks, exhaust, I still need to inspect that pesky crank more closly. LOL and some hoses no hoses here so far. Effing skinny Avon tires also.

The B motor spins and seems to have compression. I will have to test it.
 

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Discussion Starter · #17 ·
Not sure there is actually 2 bikes here looks like 1 and some parts. This could have come off either bike. The second engine tests out at 120psi in both cylinders. I need to find a manual what is acceptable compression on these things?
Azure Rectangle Font Aqua Electric blue
 

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If it's in the service manual I could not find it, they did make reference to compression test in the trouble-shooting section, but no spec throughout the rest of the service manual. carl salter site has the RD250/400 manual free

... if that's the best photo of what you have so far I hate to imagine the rest of it.
 
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