Yamaha rd350 Road Racer Liquid Cooled!!

Re: Yamaha rd350 road racer



teazer said:
Nice work. I may have to send a set of heads for you to machine for me... :)

Should be zero. If not, it won't seal properly.
I'd be happy to machine some for you once I make sure I don't scrap these ones.

And yeah I meant before assembly as far as the o ring sitting up to high to allow it to register before torqued. I still have the tz groove dimensions you sent me, that's what I'm planning on using.

jpmobius said:
Indeed! to clarify, I was meaning the distance the ring sits proud of the groove with the head off. I guess easy enough to know by subtracting the groove depth from the ring dia.
Exactly lol ill measure today.
irk miller said:
I need that test indicator. You and your fancy measuring devices. 8)
That one is actually just the fairly cheap spi. I've used to to build several progressive stamping dies. If it's good enough for that is good enough for use on the old south bend lol.
Shoeman said:
Fantastic discussion gentlemen. All I'll add is that I worked on a set of the India made cylinders back in 2010 for a customer and one of the sleeves was offset to the port castings by several mm. I can't recall just how much, and the porting requested took care of the issue anyways. QC may have improved since then though. Oh, and they shipped two left cylinders initially. Oops.
Any possible way you could contact that customer and see if he still has the bike and how they are holding up?
 
Re: Yamaha rd350 road racer

Shoeman said:
Fantastic discussion gentlemen. All I'll add is that I worked on a set of the India made cylinders back in 2010 for a customer and one of the sleeves was offset to the port castings by several mm. I can't recall just how much, and the porting requested took care of the issue anyways. QC may have improved since then though. Oh, and they shipped two left cylinders initially. Oops.

This set is rather like that too. One liner is almost 2mm lower than the other and some voids between liner and ports to take care of. Porting will lean up most of that plus maybe some devcon in the intake to smooth flow around the step.
 
Re: Yamaha rd350 road racer

Tune-A-Fish© said:
Izarah Rosetta Stone for this language :-\

its not a language as much as it is a side effect to the disease known as twostrokefluenza.
 
Re: Yamaha rd350 road racer

hurco550 said:
its not a language as much as it is a side effect to the disease known as twostrokefluenza.

I heard somebody say that a 20cc injection of straight Yamalube will cure it, but that's just propaganda. Instead of curing the twostrokefluenza it creates an addiction and you are hooked for life. Too bad, too, because many of them use to be responsible citizens and now they are addicted hooligans. A real shame...
 
Re: Yamaha rd350 road racer

I just emailed the gent for his experience with them. I reread my old correspondences with him and they were actually Chinese manufacture. I also had noted that one intake port floor was a very rough casting that had a large void where it should have met the liner. If I had not been lowering that port, it would have left a gross enough mis-match to impeded the intake flow. Of the three cylinders I saw, only one was acceptable as is in my opinion at the time. I'll let you know what I hear.
 
Re: Yamaha rd350 road racer

Thanks shoeman! Still considering them. Here is what I have to work with at the moment, and trying to decide whether to use them. The two usable cylinders I have are the left one I pulled off the bike which is stock bore of 64.02mm needing a rebore. I already surfaced the head removing the original gasket groove and added the o ring grove. The second barrel I picked up has already had 4 over bores and is sitting at 65.04mm. If I use this pair, I'll have to surface the second head the same and add dowel pins which is no big deal, I'm just more worried about the lack of liner left, and the fact that they will be miss matched bore sizes. That is unless I take the other bore out to the same size, which seems wasteful as far as using up so many over bores just to make a matching set.

Thoughts from the gurus?

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Re: Yamaha rd350 road racer

I have bought used RD400 motors with 1mm over on one side and stock on the other side. I know it sounds all wrong, but in the real world on a street motor it makes less difference than you might imagine.

It's not the "right way", but we live in the real world and funds and time are not infinite resources.
 
Re: Yamaha rd350 road racer

Teazer hit the nail on the head. I would not mis-match bores on a race bike that lives at 10k most of the time, but you're not building that bike. I think I still have some 350 cylinders under my bench. I'll look and if there is right side closer to your left in bore size I'll give you a good deal on it if you like.
Might take me a couple of days, it's 5deg outside and maybe 20deg in the shop currently. I don't do much out there this time of year anymore. I used to do porting in the basement this time of year when I had clients prepping for Daytona or the NHIS season opener. Those days are long gone though.
 
Re: Yamaha rd350 road racer

I'd really appreciate that shoeman! I'd really feel better about it if I had one with a few more bores left in it and a sleeve that wasn't as thin as this one. If you happened to have a descent set you'd want to part with let me know as well! I hear ya on the cold shop too. I'm burning through the propane making my little shop as workable as possible. Darned thing is even when the shop gets warm, all the tools are still almost to cold to handle still. First world problems I know lol

I don't have the article handy, but I remember dad telling me about one he read where an old privateer snowmobile racer back in the day put a mod podge motor together to be able to run in a certain class. I don't remember the exact details, but it was among the lines of a twin engine motor that he ran one jug from a 340cc motor and the other jug from a 440cc motor to fall within total cc requirements. I didn't figure it would be a huge issue on a miniscule cc miss match, but I figured I'd check with you guys first. Thanks again for all your help so far!!
 
Re: Yamaha rd350 road racer

Check the porting also to ensure that they are both stock or the same at least. I also have an extra cylinder that I'd hook you up with if needed.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app
 
Re: Yamaha rd350 road racer

clem said:
Check the porting also to ensure that they are both stock or the same at least. I also have an extra cylinder that I'd hook you up with if needed.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app
Good call man, didn't think of that, though I'll have to look to make sure, I don't think any of the posts have any tool marks and are still factory cast.
Thanks!
 
Re: Yamaha rd350 road racer

I heard back from the fellow with the Chinese cylinders and he reports no problems, he piped it, added an electronic ignition, and ran the bike for a couple years then sold it. Used it to teach his then 13 year old son to ride too. Now that's a dad!
 
Re: Yamaha rd350 road racer

Shoeman said:
I heard back from the fellow with the Chinese cylinders and he reports no problems, he piped it, added an electronic ignition, and ran the bike for a couple years then sold it. Used it to teach his then 13 year old son to ride too. Now that's a dad!
Thanks for following up with him for me! If something doesn't work out with one of you having a barrel, I'll feel better about going that route now!
 
Re: Yamaha rd350 road racer

hurco550 said:
its not a language as much as it is a side effect to the disease known as twostrokefluenza.

Ah an STD... Simplified Twostroke Disorder... Nevr made the connection Mr. Obvious ;D
 
Re: Yamaha rd350 road racer

I wouldn't hesitate to run miss matched cylinder bores. Maybe a good topic for discussion elsewhere, but I don't see any downside. So what if the output on each cylinder matches or not? Even with one cylinder with zero output - even on a twin - the consequences might be annoying, but there isn't any sort of dreadful imbalance or stress added to anything. Of course in the extreme example of losing one cylinder entirely you lose half the power plus the power robbed by pulling along the dead cylinder, but as long as lubrication is maintained mechanically I don't see an issue. I have to think that you would commonly see a greater difference in output per cylinder for any number of reasons than the small difference due to the slight bore difference. After all, on most bike engines, each cylinder is basically a complete stand alone engine with separate carb, intake exhaust and ignition coil. Build two 175cc motors as carefully as you can and you would be hard pressed to get outputs that match exactly.
 
Re: Yamaha rd350 road racer

Got some more reading material =) thanks for the recommendation teazer!
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Re: Yamaha rd350 road racer

Golly, you guys sure are ringing in the technology...

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Re: Yamaha rd350 road racer

Redbird said:
Done yet?
Man I wish. I got put back on 13 hour days, so when I roll in the drive at 9:15 p.m. The wind is pretty well gone out of my sails. Also, the interceptor is up on the rack and I want it squared away by spring..... Oh and money, Im waiting on more of that too lol
 
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