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Messages - James P

Pages: [1] 2 3 ... 6
1
General Discussion / Re: DT 200R Piston question
« on: October 03, 2020, 02:43:20 PM »
The engine is back together with the blaster piston and all works.  :)

Good to know its working OK. For background info; The DT200R had cylinder reed intake from 1984 to 1987, then crankcase reed intake from 1988 onwards.

Regards,
James

2
The best known ones and they have all the gear is Johnston’s at Smithfield. A mate used them with no dramas but they were not cheap.

Thanks - I had that firm on the list already, but more positive reports will make the choice easier!

Regards,
James

3
General Discussion / Any recommendations for machinery movers in Sydney?
« on: September 26, 2020, 02:51:24 PM »
In the near future, I need to move some workshop machinery (400kg lathe, 1000kg milling machine, pedestal drill, tool & cutter grinder, band saw, power hacksaw, hydraulic press and some sundry items) from one place in Sydney's inner west to another - a distance of about 10km as the crow flies.

With the smaller items, I would be reasonably confident just hiring a small to medium flatbed/dropside truck (equipped with a basic crane) myself and roping in a friend to help. However, mistakes due to my inexperience with transporting machinery may be costly where the larger items are concerned! I would therefore be glad to know whether anyone can offer any testimonials in favour of transport firms or individuals who are particularly experienced in moving this sort of machinery.

This should not be a big job for someone with the right gear and could likely be completed in three trips...or less if the truck is big enough. I'd prefer recommendations based on personal experience, but any leads may be useful.

Thanks & regards,
James

4
Yamaha / YZ125 cylinder head O-ring groove
« on: September 21, 2020, 08:56:18 PM »
Anyone got a YZ125 cylinder (1986 or later) lying about from which they could take some measurements?

I'm looking for the dimensions of the O-ring groove for the combustion chamber (ID, OD, depth).

There are/were different O-rings used for sealing the combustion chamber, depending on the year of manufacture:

93210-65721 - YZ125 1986-1993
93210-63442 - YZ125 1994 onwards

If anyone is in a position to supply measurements, please let me know the year and/or model code of the cylinder you have measured.

Thanks in advance & regards,
James

5
Suzuki / Re: PE250B Vintage Supermotard
« on: January 28, 2020, 09:37:11 PM »
maybe this type of pipe could have the outlet aimed at the chain to keep it lubed

;D Now there's an idea!

To answer your questions; I've not ridden it much so far in this configuration, as there is still a small amount of work left to do before registering. However, the silencer exit is angled slightly away from the bike and is below the level of the foot rest, so no smoke in the face and I don't expect any unburnt fuel-oil mixture on the left boot or rear tyre. Still, these are aspects I will be watching out for when the bike gets on the road. Whether it blows any dust remains to be seen - if it does, I might be able to use the bike for clearing the footpath outside the house as well ;) .

Regards,
James

6
Suzuki / Re: PE250B Vintage Supermotard
« on: January 22, 2020, 08:35:37 PM »
Have you got any more photos or details of that TM pipe Leith? I'm struggling slightly to comprehend which bit is which :o !

Regards,
James

7
Suzuki / Re: PE250B Vintage Supermotard
« on: January 04, 2020, 01:12:49 PM »
Why did you do it then ?

Sorry, maybe I didn't make it very clear. The prime objective for modifying the exhaust was to reduce the noise. If the performance remains unchanged, I'll consider it a bonus!


the whole point of the centre bleed is to have a complete pointy cone end to the pipe which sends a complete reverse wave back to the exhaust port therefore giving better performance by holding more charge in the cyl instead of loosing a tad through the stinger hole in the wave. a block should have some effect i guess but who knows. a dyno before and after is the only real answer and its probably a gnats difference anyway..looks way cool!

Thanks :) . I can't argue with the theory, but am hoping (as you suggest) that the short length missing from the reverse cone will make little difference to the performance compared to the previous set-up, where the cone was also 'incomplete'. The reverse cone is still the same length as before and it remains to be seen whether my 'seat-of-the-pants dyno' will detect any difference - hopefully not!


Regards,
James

8
Suzuki / Re: PE250B Vintage Supermotard
« on: December 30, 2019, 09:40:35 PM »
...is an okay youtube video that explains it not bad. https://www.youtube.com/watch?v=n5AvG-hDvY8

I thought I should have another look at that video (I'm pretty sure I saw it while researching the internal stinger concept previously). I don't necessarily disagree with anything the narrator says, but stingers arranged as per the second or third drawings will lead to lower performance if Gordon Jennings' findings are to be accepted (and if I have understood them correctly :-\ ) - he found that stinger exits which start anywhere in the reverse cone caused a drop in performance compared to the standard set-up (the first drawing in the video). Jennings stated that an internal stinger should start about an inch ahead of the reverse cone, which I take to mean 'in the parallel-wall belly section'. In the absence of contradictory evidence, I have assumed that an outlet anywhere within the boundaries of the parallel-wall belly section will perform in similar fashion (i.e. same performance characteristics as standard set-up, but with less noise).

Two-stroke pipes are a minefield and I have so far avoided designing my own in preference to buying (or sometimes building and/or modifying in accordance with) known/proven designs. I just don't have the time to experiment by continually chopping and changing pipes...only to end up with something which may be the same as (or more likely inferior to) an existing product.

However, all of this does not mean that I'm not interested in the design aspects...but I know enough about them to realise that I don't know enough about them!

Regards,
James

9
Suzuki / Re: PE250B Vintage Supermotard
« on: December 30, 2019, 08:57:36 PM »
interesting, can you explain the concept of the pipe and if you noticed the diference in power delivery ?

There is a brief description of the concept in the Diffrent Strokers write-up (http://diffrentstrokers.com/phpBB2/viewtopic.php?t=2511). Since modifying the exhaust, I have only ridden the PE around a concrete car park for about 15 minutes. It felt pretty much as I remember from a 'response' point of view, but I'll have to wait until it is officially 'back on the road' for a proper evaluation. In theory, there should be no difference in performance compared to the previous set-up. However, dyno runs before and after would be the only way to be sure if the theory is good in practice.
The first (and only previous) time I tried out the 'side-bleed' stinger concept on another project bike did not provide any info on performance difference - I made that first exhaust up from a pair of pressings and fabricated the header pipe and stinger from standard bends - I didn't have any previous experience of that particular pipe in the form for which it was originally designed. Having said that, the characteristics of the finished product were very agreeable...not valid for a comparison though.


did you end the pipe cone to a point?

No - I just blocked it at the end of the reverse cone (i.e. at the start of the existing stinger) with a plug, which also served as a sleeve for joining the original stinger/tailpipe back together. I did it the same way on my only previous side-bleed attempt. I'm not sure if this is the 'correct' approach, but I couldn't think of a better way to do it which would satisfy both technical and practical considerations. With the standard stinger arrangement the 'true' end of the reverse cone is an imaginary point...and trying to manufacture a small cone extension/plug/sleeve would have been a bit fiddly. I don't recall seeing the reverse cone of any expansion chamber end in a closed-off sharp point, although I'm not claiming this as technical justification of my method! If anyone has any input on this particular aspect, please let me/us know!


Regards,
James

10
Suzuki / Re: PE250B Vintage Supermotard
« on: December 28, 2019, 01:30:33 PM »
Thanks Leith. Is that 'proboards' forum new? I wasn't aware of it until now.

Regards,
James

11
General Discussion / Re: ‘70’s trials bike rego
« on: December 28, 2019, 01:16:32 PM »
So yes means bikes like 75 and 76 RM's, CR's, YZ's even though they do not have compliance plates, can all be registered once you mod them to meet ADR requirements of lighting/mirrors/horn etc.

Yes, that is my experience too...but check to see if your state has any additional requirements (i.e. in addition to the minimum ADR requirements).

Regards,
James

12
Suzuki / PE250B Vintage Supermotard
« on: December 28, 2019, 01:05:07 PM »
This isn't quite finished, but there isn't much left to do.

It isn't an 'off-road' bike any more, so may not be to everyone's taste!




More photos and info here: http://diffrentstrokers.com/phpBB2/viewtopic.php?t=2511


Regards,
James

13
Suzuki / RH67 for sale in Japan...
« on: October 19, 2019, 06:38:20 PM »
I came across this by chance:

https://page.auctions.yahoo.co.jp/jp/auction/p719518079

I don't know a great deal about these bikes, so can't tell whether this one is genuine or original. Still, I know they are rare so thought it may be of interest to forum members.

Regards,
James

14
Yamaha / Re: IT 175J intake manifold
« on: August 16, 2019, 02:13:16 PM »
If you want to avoid welding, an alternative would be to use a flat plate with a 34mm hole in it (best done on a milling machine, but can be done by hand), four M6 holes to secure it to the cylinder reed housing and two more (tapped) holes to mount a rubber adaptor flange like this:



These adaptor flanges are available from many sources in many sizes (you can start by searching for "Mikuni rubber flange"...). As you suggested, you may be able to utilise part of your original (or remade) inlet manifold to obtain the reed block 'stuffer' portion - just see how it looks once you've removed the outer portion of rubber. It may be difficult to obtain a nice smooth passage into the reed block, so you could possibly make your own stuffer (from Araldite or Devcon or something similar) which will give a uniform intake passage and fill any 'dead space'.

Regards,
James. 


15
Yamaha / Re: IT 175J intake manifold
« on: August 12, 2019, 03:50:22 PM »
If you are handy with welding and machining (or know someone who is), you could make an inlet manifold from aluminium plate and tube, welded together.

The tube can be machined to suit the internal ribs of a proper carb-mounting rubber, e.g. https://vintagetriumphparts.com/Carburetor_Mounting_Rubber_Spigot_MK2_Genuine_AMAL/p710.

If you have the standard VM34 carb, the Amal Mk2 (30-34mm) rubber should fit...or you can use car radiator hose as a bodge!
You can seal the joint (between the new manifold and the reed block) by making a gasket to suit, or lap the manifold surface flat after manufacture and use sealant. If the original rubber manifold has a reed block 'stuffer', you could make this as a separate part...or adapt one from another bike.

Regards,
James

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