gear box

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gear box

Postby irish1 » Thu Jun 09, 2011 5:36 am

Hi all, been quite a while since I've been on this site. Put away my wanta be tr500 for awhile but I'm ready for another round of fun, headaches and wasted money. Has anyone had any luck finding a different trans to fit, or perhaps gears that will interchange for a closer gear box. Anyone tried a gs500, looks to have a very similar style trans. I haven't ported the cylinders yet nor built my expansion chambers till I see if I have to make it a wide power band or go for the Big HP numbers. I know about the Nova gear boxes but so does the wife $$$$$ so I'm shopping e-bay. Thanks for any and all input.
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Re: gear box

Postby diamondj » Fri Jun 10, 2011 1:10 am

Hey,

Someone speculated on if a GS550 six speed would fit (I think on the Sundial board) as it only uses one shift fork shaft similar to the T500 gearbox. I don't think anyone has tested it out yet. I do know the 550 gear boxes are pretty cheap on ebay.

This might serve as inspiration or as a warning:

http://www.suzuki2strokes.com/forum/vie ... ilit=gs750

It's the tale of installing a GS750 gearbox into a GT750....

Jim
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Re: gear box

Postby irish1 » Wed Jun 15, 2011 9:29 pm

Hi Diamondj, thanks for the info, I saw that bit on the gs750 trans to gt750 and that looked like more fun than I could handle. I think I'll keep a look out on ebay for a gs550 and if I find one cheap enough I'll give it a try. If it works I'll post it, if it doesn't I guess I'll have another trans alongside rd 350, gt350 and gs750.
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Re: gear box

Postby dinoGT » Thu Jun 16, 2011 3:50 pm

You think put rd350 box in a T500 ?
You want to do expension chamber... do you speak about exaust or head cylinder ?
I can tell you what doing for squish (head cylinder).
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Re: gear box

Postby irish1 » Sat Jun 18, 2011 11:26 pm

Hi Dino, yes the rd350 trans was a bit of wishfull thinking, in fact it fit better in the box it came in, so that was a waste of $10.00. I did have higher hopes of the suzuki gt350 trans, and the gs750 was perhaps from to much Guinness. They do however fit very good under the work bench. As regards to the cylinder porting and expansion chambers, I didn't want to make it to peaky for the stock trans. What ideas do you have in regards to cylinder heads? Now that could be another ebay search, do you suppose there's a nice head from some moto cross bike that could be made to work? I have a lathe that I use to destroy stuff but that off set spark plug would be nice to get rid of. I think I'll go make some more room under the bench for some useless heads I am sure to acquire.
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Re: gear box

Postby dinoGT » Mon Jun 20, 2011 8:12 pm

Shakespeare language is very difficult to understand to me.
My web site is not yet all in english
http://www.dinogt.fr/refabrications/cul ... en-soudure
Try to understand and I could tell you how to do if you think you can do it
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Re: gear box

Postby irish1 » Tue Jun 21, 2011 9:00 pm

Thanks again for your replies Dino, saw your pictures of the head mods, I can do the turning but would need some help with the welding. Would it be an improvement over stock head if I left spark plug where it is and removed 1 to 1 1/2mm from face and cut narrow squish in head? Also, in my quest on the transmission search, if you look at the pictures of Ron Grant he has a picture of gears that he changed but unfortunately no info as to whether he had them made or perhaps found something that interchanged. Is there anyone out there that might shed some light on this? By the way Dino your English is not so bad and your pictures in French are perfect.
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Re: gear box

Postby dinoGT » Wed Jun 22, 2011 1:59 pm

I don't know who is RON GRANT neither what he do.
I know only 2 links
http://www.mpe07.co.uk/.
http://www.novaracing.co.uk/suzuki-gt500.htm
But don't know what they do and at what price, no time to ask them,if you have any time or others links... let's go
For squish, put the spark plug at the middle (long thread is a little better)
External diameter...from 71 to 71.5 mm
Angle squish about 0.1mm (from 0.1 to 0.2) more than the piston, measure where is more thinner
Surface squish 1/2 total surface
Small radius(1/2 diameter) squish 2 or 3mm
Chamber volume, if you have good exaust > 190° from 21to 21.5 cm3
Squish from 0.8 to 1mm... from 0.8 to 0.9 is better for race
Those cylinders top I have made are running on a french championship since 2 years
When the cylinders top are doing, do'nt used 1 of them to have equal squish at both, you must used the cylinder and not the cylinder top
some mistakes, edit in red
Last edited by dinoGT on Wed Jun 22, 2011 6:40 pm, edited 1 time in total.
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Re: gear box

Postby irish1 » Wed Jun 22, 2011 5:59 pm

Thanks Dino, thats a lot of very useful information and hopefully I can put it to good use. As for the Late Ron Grant, he was an Englishman who raced with success in the U.S. and under race preparation on this site you can see his race tuning technique used in the late 60's early 70's. Unfortunatley killed in a boating accident in Ireland.
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