Can a DR 250 become 350?

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Hi everybody!

I am the happy owner of the Suzuki Dr 250 in the picture above! I bought it two years ago, 1000 €, that is less than 1500$, for off road & trail riding mostly. I also own a BMW F650GS 08 Twin, for the everyday use. I do not know the exact year and model because the bike was imported to Greece in 2000, so before that it’s a mystery! The bike’s frame number is SJ44A-105067 anyone has a clue?

When I first bought it, it had serious carb problems. It was hell to make it start, and when you did, it stopped any time.. Reading this forum and speaking with my mechanic, made me buy the Mikuni Tm-33 pumper carb (I ordered it from the states) that resolved the problem at once!

Now that the winter season is over (I only use it in winter, summer is too hot for off road riding here in Crete), I am planning to do some major maintenance at this poor old bike that has offered my so many hours of pure pleasure! I want to make her pieces, inspect every part, change some things that are broken or very used, paint the frame and the tank, and whatever else will pop up during maintenance. Anyone can tell if where can I find these plastic fork guards that are half broken? I have been searching EBay two years now without luck..

But the major modification I would like to do is to increase the cylinder’s capacity. You see, my dream would be a Dr 350, but I cannot find a used one very easily.. I live in an island, that even though is big enough, the market of used bikes is not so big.. So I am thinking, can I increase the cylinder’s capacity somehow? I have heard other people here doing this in various bikes, but many have discouraged me telling me that it will only bring problems..

Is there a kit like the one for the dr350, the big bore kit, that makes it 441cc?

If I find a used engine of a DR350, can it be fitted on a 250?

Can anyone tell me how could I increase the power of this bike, without producing too many problems?

Well, that’s enough for beginning, I will keep you informed how the maintenance project evolves!

Yes, the DR250 can certainly be punched out to a 350 for about $350-$400 US

http://www.kientech.com/

This requires sending your cylinder to Kientech (I'm sure you can find a local shop to bore it for you) along with a new piston, rings, gaskets ect:

Kientech sells all the parts to make it a 350cc, just email Jesse. jesse@rvi.net

Can you PLEASE tell me all you know or all you can find out about the jetting and needle setting to get the TM33 to run properly on the DR250. Any air box mods, Exhaust mods, etc: ?

You are the only person I know of that has managed to make a TM33 work with the DR250.

I've been playing around with trying to get a TM33 to run right on my DR250 for a while with poor results.

I would really appreciate ANY information that you can provide.

Thanks.... I REALLY need this information badly. :thumbsup:

Edited by Bob Onit
Anyone can tell if where can I find these plastic fork guards that are half broken? I have been searching EBay two years now without luck..

Your DR250 looks like the European model with the inverted (upside down forks) and the height control.

You can leave the broken plastics on and buy the longest pair of Shock Sox. No need to disassemble anything as they mount with Velcro.

They will protect most of your fork tubes.

I have them on on one of my bikes and they work great!

http://bermmotorsports.com/shocksox.php

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Edited by Bob Onit

Hi Bob and thanks for the quick response!

You are the only person I know of that has managed to make a TM33 work with the DR250.

Well, my mechanic is probably that person...I like to do the maintenance in the DR, but for some things, like carb and valve adjustments, I don't feel very comfortable yet, so I leave it for the pros.

But I promise that when I will take this baby to pieces, I will open the carb and have a look for the information you are seeking.Hoping to be able to close it again properly.

I have already checked the kientech site, but they don't sell something for the DR250(You don't have lots of them in the States, right?). Only for the 350.. Perhaps I have to mail directly this legend called Jesse! Hoping that he can send things to Europe, without paying a fortune on shipping..

Bob you own a Dr250 right?Have you thought punching it out to a 350? If not, why? Do you know anyone that has done it and did he have any problems after?

Hi Bob and thanks for the quick response!

Well, my mechanic is probably that person...I like to do the maintenance in the DR, but for some things, like carb and valve adjustments, I don't feel very comfortable yet, so I leave it for the pros.

But I promise that when I will take this baby to pieces, I will open the carb and have a look for the information you are seeking.Hoping to be able to close it again properly.

I have already checked the kientech site, but they don't sell something for the DR250(You don't have lots of them in the States, right?). Only for the 350.. Perhaps I have to mail directly this legend called Jesse! Hoping that he can send things to Europe, without paying a fortune on shipping..

Bob you own a Dr250 right?Have you thought punching it out to a 350? If not, why? Do you know anyone that has done it and did he have any problems after?

Yes I do own a DR250, I was thinking about boring it to a 350 and Jesse is the one that told me he had the parts and he could bore the cylinder as well or I could have it done local.

Jesse does sell the parts, he just doesn't have them listed on his web site for some reason.

Any information on the TM33 jetting/needle position would be very much appreciated.

Perhaps your mechanic knows what he did to the TM33 for the DR250?

Thanks

Bob

Hi again Bob!

Yes my mechanic will surely know what he did, but I am not sure if he remembers without opening the carb, because it was fitted more than 20 months ago..

If you can wait a bit, when I start the maintenance program I will definitely let you know. Try to Pm me after a couple of weeks if you don't have any news from me.

What made you stop from boring it to 350?Apart the cost?

Are there any serious problems that may come up from these type of procedures?

The 250 and the 350 models are almost like twin models, that's why I am thinking that it will not be such a radical change for the bike. I don't know about the engine though. If this will take the engine to it's limits..

Can anyone who has done it please tell me he's impressions?

Thanks!

What made you stop from boring it to 350?Apart the cost?

Are there any serious problems that may come up from these type of procedures?

The 250 and the 350 models are almost like twin models, that's why I am thinking that it will not be such a radical change for the bike. I don't know about the engine though. If this will take the engine to it's limits..

Can anyone who has done it please tell me he's impressions?

Thanks!

I already owned a '91 DR350S and I wanted more out of the DR250S. I was about to pull the top end off and order the parts when I found a '93 DR350 in nice shape for a very good price so I decided to bore the 350 to a 441 and sell the 250.

So right now I have two 350's and a 250, three Honda XR/XL's and two very old Harley Davidson's. One complete and running, the other is in pieces :confused:

Just waiting until I can find some spare time to tear the 350 down.

According to Jesse the 250 cylinder is plenty thick enough so there's no problem boring it to a 350.

The 250 bottom ends are just as tough as the 350 so that's not an issue either. :thumbsup:

Do you remember the mechanic that put the TM33 on your 250 saying that he had any problems getting it to run right?

I'm wondering if he may have somehow found and installed a TM31 which is the stock size pumper for the 250.

The TM31 is almost impossible to find in the states, the TM33's are easy to find.

Bob

So right now I have two 350's and a 250, three Honda XR/XL's and two very old Harley Davidson's. One complete and running, the other is in pieces :thumbsup:

WOW! that's a nice collection of bikes! I wish I could find a DR350 with electric start! It would make my off road riding so easier...

Do you remember the mechanic that put the TM33 on your 250 saying that he had any problems getting it to run right?

I'm wondering if he may have somehow found and installed a TM31 which is the stock size pumper for the 250.

Well I remember telling me that he did some tests until he found the best combination.He also did some tricks mounting it in order to fit right.Tomorrow in the daylight I will take some close up photos and I will post them. The carb is a TM33, ordered from an Ebay-Motors store from the states.And for sure my mechanic would never get into trouble searching something else to install than the one I gave him.

In a couple of days I will pass and ask about boring the cylinder, so I will also ask him what he did about the carb. But I doubt he remembers without opening it because a long time has passed. Soon I'll make her pieces and I will let you know the info you need. The carb runs almost perfectly, except a small gap/loss of power that has every now and then when accelerating full throttle. But it's so unbothering that I haven't taken the bike back to fix it.

WOW! that's a nice collection of bikes! I wish I could find a DR350 with electric start! It would make my off road riding so easier...

Well I remember telling me that he did some tests until he found the best combination.He also did some tricks mounting it in order to fit right.Tomorrow in the daylight I will take some close up photos and I will post them. The carb is a TM33, ordered from an Ebay-Motors store from the states.And for sure my mechanic would never get into trouble searching something else to install than the one I gave him.

In a couple of days I will pass and ask about boring the cylinder, so I will also ask him what he did about the carb. But I doubt he remembers without opening it because a long time has passed. Soon I'll make her pieces and I will let you know the info you need. The carb runs almost perfectly, except a small gap/loss of power that has every now and then when accelerating full throttle. But it's so unbothering that I haven't taken the bike back to fix it.

Thanks, the problem that I'm having is that it bogs (wants to quit for a second) when I first give it some throttle when I'm starting off in first gear. It runs well after that point.

Maybe the billing receipt from your mechanic has detailed information?

Good luck with the 350 kit. Since the 250 revs 1,000 RPM higher than the 350 it should run very strong! :thumbsup:

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