T350 porting and maybe some squish band improvement
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- dyrberg123
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- Joined: Sat Jan 11, 2014 12:41 am
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- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
T350 porting and maybe some squish band improvement
Hi Guys, Due to the first signs of spring i decided to take the old T350 for a spin yesterday. That lead my though's back on doing some porting on the barrel. Is there anyone in here that have any experience with porting thise barrels, i just want something for street performance with as broad a delivery as possible. I am currently running Keihin PWK 28 flat slides and homebuild chambers.
Cheers.
Cheers.
If it's not broken - don't fix it. Why not?
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Re: T350 porting and maybe some squish band improvement
dryberg123.
I had a T350 and have T305 and just completed another T350.
I never found much actual examples of how to mod for street or race. I as you want street. I don't want to have to run high octane gas (I hate gas pumps that have one hose: most do here. if you select Hi-test you'll get over 1/2 gallon of low test first.)
There is a person on eBay selling t350 top end with H1 head
http://www.ebay.com/itm/Suzuki-T350-com ... 3cdd3c347a" onclick="window.open(this.href);return false;
I heard Rd heads can be made to fit.
So there is one way to get squish band using a hand drill without sending heads to a person who can reshape if you can not.
With that said I have never had any problems with the doomed /quiescent heads (pinging) for street. I use the later T350 head and it seams to cool better than early.
Proper set of Chambers is probably the best. Not sure what your design is but, I used D&G from Yam RD and worked well street. One other person has said the same and claims been dyno'd seams a little exaggerated, but does help and importantly power is still very broad. D&G calls these street pipes not race and I agree.
Next port mods. Check your port timing now and compare to what Bell's 2 stroke tuning book advices for the rpm range you want. Porting Software exist as well, can't help you here
The only port mods I have seen for is from
Joe Eastmure 6hr race from the period. He was really stock , but did shave 1mm of intake. As you can see it sure did not hurt
I went 2mm off intake via skirt. It did change bikes feel and enjoyment more power just above mid through to now a higher shift peek power up. Bike lugs well low end idles the same, no jetting changes
I came about this number somewhat carefully for I noted Suz data for the T20 and T305 had very similar timing accept intake. T350 is very similar to T305 Since all have same stroke I gave it a try. 2mm is much less than the difference between two bikes (forget now exactly but 4mm is what I recall - 5mm). Everything is rare for this bike pistons and jugs. I got spare pistons just in case I did not like mod.
I use the larger factor carbs (32mm). Your 28 may be even better, I suspect no worse if you want good low end too.
For the T350 I was going to raise exhaust port too. But was not sure how best to restore compression. I think if you went < 2mm you might be able to shave head say 1.5mm and still have safe clearance to piston as I think you cut into dome at that depth (forget now easy the check) But need to check that after heads were cut. If not you have to reshape head.
Based on how my T305 turned out that may have been too much for my taste and did not want too be to greedy. I am sure it would make a difference. The exhaust port I think was fairly wide street and the T350 has those extra little ports. I am sure you can a little wider again if not to greedy
I have no dyno to prove anything. It maybe all just be a placebo affect. Don't think so for I have done many other mods that did nothing or made thing very poor for street.
I just may rubber mount the engine. Now that's a mod you would like if you are expecting to run sustained higher rpms. Great little bikes
I had a T350 and have T305 and just completed another T350.
I never found much actual examples of how to mod for street or race. I as you want street. I don't want to have to run high octane gas (I hate gas pumps that have one hose: most do here. if you select Hi-test you'll get over 1/2 gallon of low test first.)
There is a person on eBay selling t350 top end with H1 head
http://www.ebay.com/itm/Suzuki-T350-com ... 3cdd3c347a" onclick="window.open(this.href);return false;
I heard Rd heads can be made to fit.
So there is one way to get squish band using a hand drill without sending heads to a person who can reshape if you can not.
With that said I have never had any problems with the doomed /quiescent heads (pinging) for street. I use the later T350 head and it seams to cool better than early.
Proper set of Chambers is probably the best. Not sure what your design is but, I used D&G from Yam RD and worked well street. One other person has said the same and claims been dyno'd seams a little exaggerated, but does help and importantly power is still very broad. D&G calls these street pipes not race and I agree.
Next port mods. Check your port timing now and compare to what Bell's 2 stroke tuning book advices for the rpm range you want. Porting Software exist as well, can't help you here
The only port mods I have seen for is from
Joe Eastmure 6hr race from the period. He was really stock , but did shave 1mm of intake. As you can see it sure did not hurt
I went 2mm off intake via skirt. It did change bikes feel and enjoyment more power just above mid through to now a higher shift peek power up. Bike lugs well low end idles the same, no jetting changes
I came about this number somewhat carefully for I noted Suz data for the T20 and T305 had very similar timing accept intake. T350 is very similar to T305 Since all have same stroke I gave it a try. 2mm is much less than the difference between two bikes (forget now exactly but 4mm is what I recall - 5mm). Everything is rare for this bike pistons and jugs. I got spare pistons just in case I did not like mod.
I use the larger factor carbs (32mm). Your 28 may be even better, I suspect no worse if you want good low end too.
For the T350 I was going to raise exhaust port too. But was not sure how best to restore compression. I think if you went < 2mm you might be able to shave head say 1.5mm and still have safe clearance to piston as I think you cut into dome at that depth (forget now easy the check) But need to check that after heads were cut. If not you have to reshape head.
Based on how my T305 turned out that may have been too much for my taste and did not want too be to greedy. I am sure it would make a difference. The exhaust port I think was fairly wide street and the T350 has those extra little ports. I am sure you can a little wider again if not to greedy
I have no dyno to prove anything. It maybe all just be a placebo affect. Don't think so for I have done many other mods that did nothing or made thing very poor for street.
I just may rubber mount the engine. Now that's a mod you would like if you are expecting to run sustained higher rpms. Great little bikes
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
- dyrberg123
- To the on ramp
- Posts: 218
- Joined: Sat Jan 11, 2014 12:41 am
- Country: Denmark
- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
Re: T350 porting and maybe some squish band improvement
Hi, Thanks for your answer, i will read again tomorrow night standing in the garage, so i understand it as intented.
Just to clearify Things, are you running DG's on your T350? And how do you identify the new vs the old heads? I have heaps of parts to this Little bike, so i could have what it takes. Cheers so far, and i will for sure get back. THANKS!
Just to clearify Things, are you running DG's on your T350? And how do you identify the new vs the old heads? I have heaps of parts to this Little bike, so i could have what it takes. Cheers so far, and i will for sure get back. THANKS!
If it's not broken - don't fix it. Why not?
- Coyote
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Re: T350 porting and maybe some squish band improvement
Zook-e, (Eric) the owner of this message board is an expert at hopping up these small twins. Visit his site! http://sundialmotosports.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
I was born with nothing and still have most of it left.
.
1978 GS1000C
1976 GT550 ongoing money pit.
.
1978 GS1000C
1976 GT550 ongoing money pit.
- dyrberg123
- To the on ramp
- Posts: 218
- Joined: Sat Jan 11, 2014 12:41 am
- Country: Denmark
- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
Re: T350 porting and maybe some squish band improvement
Thanks for your responce, i have send him a mail now.. 

If it's not broken - don't fix it. Why not?
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Re: T350 porting and maybe some squish band improvement
dryberg123,
Let me know if he has anything specific for the T350 streat mod
Or even your final plan. And, how it works out for you when you are done.
The later heads have angled fins. Some on eBay and see suzuki part fiche online
I personnaly like the looks of the older too. But, the later head is wider and taller and overall apears to have more area to cool so I swapped over. I did run the early style no problem but, that was before I made changes. Probally still OK, but just something to consider if you push it a little hard on a hot day
Yes I am running DGs on a T350 and T305. Other pipes for Yam RD have been made to fit with minimal effort(just like the beautiful green one you posted).
The DGs tuck under engine so you have to remove center stand unfortunately. I never corner that hard where it mattesr for me if they are under. Prefer center stand.
Let me know if he has anything specific for the T350 streat mod
Or even your final plan. And, how it works out for you when you are done.
The later heads have angled fins. Some on eBay and see suzuki part fiche online
I personnaly like the looks of the older too. But, the later head is wider and taller and overall apears to have more area to cool so I swapped over. I did run the early style no problem but, that was before I made changes. Probally still OK, but just something to consider if you push it a little hard on a hot day
Yes I am running DGs on a T350 and T305. Other pipes for Yam RD have been made to fit with minimal effort(just like the beautiful green one you posted).
The DGs tuck under engine so you have to remove center stand unfortunately. I never corner that hard where it mattesr for me if they are under. Prefer center stand.
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
- dyrberg123
- To the on ramp
- Posts: 218
- Joined: Sat Jan 11, 2014 12:41 am
- Country: Denmark
- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
Re: T350 porting and maybe some squish band improvement
Oh no, i pushed the buy it now button on that top end
Can't wait for the post man to come around. I did read Graham Bell's book two weeks ago, and i have decided to follow his step by step on the porting on my old barrel. and when i find something usefull i will post it. Next weekend iam out but there after. I also have a new set of DG on the shelf, maybe i will try them, great idear...

If it's not broken - don't fix it. Why not?
- tz375
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- Location: Illinois
Re: T350 porting and maybe some squish band improvement
Try EBOS http://www.ebos.se/2stroke.asp" onclick="window.open(this.href);return false; They are a little closer than the US and are experts with 2 strokes of all kinds.
In the UK there's Pete O'Dell who is a Suzuki 500 expert and also Mick Abbey, Pete Lindemere, Stan Stevens.
Porting a 2 stroke is not difficult, but knowing where to take metal out and how much to take is the key.
In the UK there's Pete O'Dell who is a Suzuki 500 expert and also Mick Abbey, Pete Lindemere, Stan Stevens.
Porting a 2 stroke is not difficult, but knowing where to take metal out and how much to take is the key.
- dyrberg123
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- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
Re: T350 porting and maybe some squish band improvement
Hi, Thanks TZ, just for info - Stan Stephens only do very Little now, and only RZ / RD 350 YPVS. Mick i actually know, might give him a call, i my mind he is a Yamaha guy, but yes he do all kind of work.. Eric from this forum havn't replied yet, any one know if he still is doing bikes?
If it's not broken - don't fix it. Why not?
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Re: T350 porting and maybe some squish band improvement
I am considered a T500 expert but I also race prep many bikes/makes from 50cc Itoms to hyabusa's and have done a lot of work on the smaller suzy twins, I was the first person to produce TR250 replica heads and barrels and other T20 race parts.
we currently have 2 T200 race bikes for my son and building a GT250 race bike, Kyle will be racing a TS250 based race bike which Stan Stevens tuned originally (for previous owner) and had to correct his poor work to stop it blowing up as it did previously.
we currently have 2 T200 race bikes for my son and building a GT250 race bike, Kyle will be racing a TS250 based race bike which Stan Stevens tuned originally (for previous owner) and had to correct his poor work to stop it blowing up as it did previously.
- Suzukidave
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Re: T350 porting and maybe some squish band improvement
Yikes !!! i sure hope you never look over any of my work PetePete O'Dell wrote: and had to correct his poor work to stop it blowing up .

the older i get the faster i was
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Re: T350 porting and maybe some squish band improvement
I would wager a bet your works far better than Stan the monkey Dave the man has a wholely unjustified reputation with pissed off customers probably the square of happy ones, and the happy ones are too thick to know any better 

- dyrberg123
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Re: T350 porting and maybe some squish band improvement
Not that i am a totally rookie, but is Stan must be able of something, besides branding. I mean on the RD sites there is a hole choir that praised his Work. Maybe he had some luck at some stagePete O'Dell wrote:I would wager a bet your works far better than Stan the monkey Dave the man has a wholely unjustified reputation with pissed off customers probably the square of happy ones, and the happy ones are too thick to know any better

If it's not broken - don't fix it. Why not?
- dyrberg123
- To the on ramp
- Posts: 218
- Joined: Sat Jan 11, 2014 12:41 am
- Country: Denmark
- Suzuki 2-Strokes: T350 GT750 T125 RG250 RD125lc RD350lc RD400
Re: T350 porting and maybe some squish band improvement
Any body in this forum having any experience with Mick Abbeý and Suzuki? Just curious...
If it's not broken - don't fix it. Why not?