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sweet!
 

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Hello Fang, I would Like to say thank you for using our product. (pistons) Rember if you have any questions or need any other help, You or anyone elce, can Drop me a line [email protected], If needed i will give you my phone number and we can discuss how we can help you.
 

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Hello Fang, I would Like to say thank you for using our product. (pistons) Rember if you have any questions or need any other help, You or anyone elce, can Drop me a line [email protected], If needed i will give you my phone number and we can discuss how we can help you.
 

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Discussion Starter #45
A couple quick updates. Yesterday my machinist came by the workshop and picked up my pistons, promising that the cylinders will be ready by Friday (tomorrow). How long has this been drawn out?

Also in similarly related news. The 6mm (4th overbore) pistons I got from Turbo1Racing this time around (my third set) are really of disappointingly poor quality. I edited my first post to mention this too. I believe that these most recent pistons are from a fresh batch, and the forging is sloppy, the ports are full of slag, leaving them misshaped, they weigh about 3.7 grams difference between the two, and the factory machining is unnecessarily sloppy. It took a lot of time to 'dress' (machine) the pistons just so they could be used. I think they will work, and if they last few sets had not performed so well, I would have thrown them away when they arrived. I can't recommend them until this gets sorted out, that is unless you are looking for a piston upon which you intend to do some machining to make it fit.

I emailed my contact at Turbo1Racing this morning to share this stuff also.

Peace and grease,
fang
 

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Why wouldn't you contact them first before doing any work on them? That way they can see issues with them. Pictures are one thing but I wouldn't of touched them and sent them right back and let them deal with it.
 

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I used to always use Pro-X pistons, and then discovered that Wiseco pistons work just fine and come in more sizes. I've never had a problem with Wiseco in my race engines.
 

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Discussion Starter #48
I guess I am (1) a lazy bastard, (2) just don't care enough to send them back, and (3) probably don't expect that anything would have happened even if I did. Plus these pistons cost me about $70 less than the set of PRO- X I almost bought.

Either way, if the alloy is otherwise the same, they should end up being fine pistons for me. I thought I was buying plug and play pistons, but these required some extra work. Oh well. Besides, I have been waiting for MONTHS now on this BS cylinder bore job, and I am sick of it. It should have taken one day. Two days tops. I'm ready to move on with what I've got and chuck it up as a learning opportunity.

I'm sure I'll feel differently if a month from now my pistons have blown up and ruined the bottom end. Then again if a year from now things are still ticking along nice and tight, then we'll know it was no big deal. There is no way to know right now, so I might as go with what I've got.

peace and grease.
-fang
 

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Discussion Starter #49
Cha-Ching! I came home from the Monastery last night around midnight, and voila! My machinist finally came through -- he actually delivered the parts back to the workshop, clean and ready to go. Kudos to him! I will come back, edit this post and fly a few pics a little later. but right now it is time to down some Saturday morning coffee and hit the wrenches.

peace and grease,
fang
 

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RD350 help and information desperately needed

I have a RD400 that I'm trying to decide what to do with. Fix up and sell, or fix up really nice and flog. Been racing RD350s for years. Post any questions you have.


Hey, I have just gotten a rd350a that I want to do a little work to but cannot find much info on the port timing etc. - any help regarding this would be well appreciated (degrees open duration, opening degrees for ex, in, tx closing etc etc.
This is the second one of these I have owned and wanna make this one epic - I have some pipe design software and wanna try building my own expansion chambers, I have already started to graft an USD front end onto the frame and have a box section swing-arm and wheel for the rear end (with decent hydraulic brakes!)

If you have ANY info you could share it is very welcome.


cheers - Keith
 

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I have a RD400 that I'm trying to decide what to do with. Fix up and sell, or fix up really nice and flog. Been racing RD350s for years. Post any questions you have.


Hey, I have just gotten a rd350a that I want to do a little work to but cannot find much info on the port timing etc. - any help regarding this would be well appreciated (degrees open duration, opening degrees for ex, in, tx closing etc etc.
This is the second one of these I have owned and wanna make this one epic - I have some pipe design software and wanna try building my own expansion chambers, I have already started to graft an USD front end onto the frame and have a box section swing-arm and wheel for the rear end (with decent hydraulic brakes!)

If you have ANY info you could share it is very welcome.


cheers - Keith
TZ was the race version of the RD if you want to make a faster RD you should copy what Yamaha did to make the TZ.

USD front end onto the stock frame :/ she's still going to wiggle like a bitch when you set that front wheel down after a high speed wheelie.
 

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I have a RD400 that I'm trying to decide what to do with. Fix up and sell, or fix up really nice and flog. Been racing RD350s for years. Post any questions you have.


Hey, I have just gotten a rd350a that I want to do a little work to but cannot find much info on the port timing etc. - any help regarding this would be well appreciated (degrees open duration, opening degrees for ex, in, tx closing etc etc.
This is the second one of these I have owned and wanna make this one epic - I have some pipe design software and wanna try building my own expansion chambers, I have already started to graft an USD front end onto the frame and have a box section swing-arm and wheel for the rear end (with decent hydraulic brakes!)

If you have ANY info you could share it is very welcome.


cheers - Keith

RD350 needs a lot of work to make more power.. There are port diagrams all over the web starting with the maps posted by Ed Erlenbach. Timing is not so much the problem as the transfers which take a lot of time to get the ducts right. Then the intakes have to be opened up to take YZ85 reeds..... But for a mild build, keep teh stock reed cages and modify them and fit YZ125 reed petals.

Cheap pipe software sucks. Better to buy a cheap set of DG pipes and if the budget allows it go to a set of Spec11 pipes or even a set of stainless Jim Lomas pipes. Then you will need at least a Y intake and better ignition.

But before you do any of the above, do a leakdown test and then rebuild the crank with new seals because it will leak. Have you at least checked compression?

I just finished an early RD350 that had seized on one side and it leaked from the intake manifold joints as well as the crank seals. Jets were blocked in the carbs and timing was way off where it should have been.
By the time we finished, that bike cost a small fortune to get right. But for cheaper thrills, just get it back to stock condition without air leaks.
 

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teazer isright on
back in 75 i had my rd crank rebuilt and put some bassani pipes on it and it really woke the bike up more power in the band and higher revs without flattening out
i dont think the torqy mid was hurt at all
i think optimizing the squish and pipes will suprise you along with careful accurate setting of the ign timing
just ride it
if you want fast and street ridability i think ypvs is the only choice ,that is an rz
can you say banshee
a friend of mine has 2 kenny robert rz350 ypvs
one with full kit specc2 i think
the other closer to stock with toomey pipes
they really rip tons of fun !
 

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A TZ is at the same time, the same as an RD and completely different. :confused: Leaving aside gearing differences and teh dry clutch - neither of which are good on a street bike, the basic design is the same but they are very different when it comes down to intended use and porting to produce different outcomes. A TZ is designed to make a lot of top end power and who cares about low end or midrange? Not really needed on a race track. On the street, lack of low end can really make a bike a PIA to ride and attracts way too much LEO attention. On the street we need low end so we can ride on a whiff of throttle and we need a bike to run cleanly from low revs and small throttle opening to flat out WOT.

In the real world, bikes spend most of their time at 1/2 throttle or less. So we need porting and pipes that support that and we need as much compression as we can use without hurting top end too much. So we need reasonably modest exhaust port timing and pipes like XB33's Bassanis which were reputed to be some of the best street pipes in their day. Chuck (supertune) Quenzler is a big fan of them and he makes his money working on two strokes of all kinds.

The most cost effective pipe is DG which gets a bad rap compared to other pipes but it has a wide powerband and is perfectly streetable. Producing your own pipe is not easy. I have designed a couple and have built and modified more, but it's not something I'd recommend unless you are a first class welder and you can roll cones.

DG pipe: https://www.ebay.com/p/DG-Performance-14-4315-Exhaust-System/171152061?iid=312248667786&chn=ps

Lomas pipe: https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/engine-related/exhaust-chambers/expansion-chambers/jl-jim-lomas-expansion-chambers-yamaha-r5rd350rd400/

Highwayman: Complex stainless GP style pipes with 54 cones total! | Highwayman Bikes

But as I said earlier, the place to start is with a sound motor, properly tuned. It will make more power , be more reliable and is easier to ride than a bike with pipes and poorly set timing and leaks.
 

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As I remember TZ's they came with a real nice expansion chamber and I just assume the pistons might be different, I thought they had trick pistons, no?
heck even my ancient Montesa had a single ring piston. I never owned a TZ I just drooled all over them in the showroom :/ too busy riding dirt and street bikes at that time.
There was a huge number of versions over the years I'm sure.

I rode an RD350 that was part time race bike and it was scary fun,
narrow power band came on violently and really late in the curve only, then it dropped down to like a regular RD, very hard to ride fast and not wheelie, I distinctly remember it wiggling a lot.
Bikes owner was head mechanic at Markham Yamaha shop so it was pretty pumped, had modified stock exhausts which is probably why the power curve was crippled :|
still very very fast for a mid 1970's 350 :cool: sooooo easy to lose your license on one, soooo hard not to leave 2 con trails.
 

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Once you start seeing pistons with holes in the skirt, you know you are in experimental territory and trial and error is an expensive way to figure out where and what shape to drill holes in a piston skirt. Scavenging ports can be cleaned and polished to reveal a few more horses, but once you start changing the shape and dimension of those ports significantly you better have a stack of spare barrels on the shelf.

Case in point:
Hi guys. I dropped the cylinders and pistons off at a new machinist almost two months ago, and he botched up one of my jugs.
I've been in a holding pattern since he told me things were screwed up -- about two weeks.
Otherwise, things are buttoned up and ready to go.
Needless to say, I'm pissed.
-fang
 
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