Sp 400

[sleepy]

What wheelbase did it end up at, looks a bit short. Should be good for wheelies 
Look good though but when your not looking I will steel the tank to make my little old TM125 look a bit better.

[cloggy]

What carb did you use?

[Nipper]

Nice work that's a credit to you stew.
Where did you get your tm 125 tank stickers from?

[cloggy]

You mentioned recently on another topic that you have gearbox problems.
Vic Eastwood campaigned a Hagon framed stroked Suzuki and found the gearboxes to be extremely fragile.White Bros only went to 420 on their DR400 due to the poor durability of the 370 when tuned.
I thought the 400 box was beefed up, however early 400 engines used 370 cases which were known to break on kick back. The engines can jump out of second or third[I think it's third] and the best way to fix this is simply to change the worn dogs for a new part. An english road racer  posted that. He also said the inlet valve was a couple of mm too small for peak power and that whilst he went to a bigger valve he also filled in part of the inlet port as it was too big . He dynoed his stroked motor at 52 bhp.

[mick25]

Yep small gear dogs on third gear  , dr500 , dr400 are the same part numbers , I had a dr500 and broke the third gear dog , after I put a new one in it because it was broke when I got it .
I also got a spare bottom end for parts and third gear was broke in that to .
So it's a common prob .
The tt500 gear dogs are twice the size and I have had these bikes for 25 years and never had gear box woes .
Even the Xl500 , xr500 have better gear dog sizes than the sp , dr suzukis 

[Oldfart]

cloggy , the trans may not be up to the extra Hp, and yes it seems to tear the dogs off 3rd gear of which I have experienced. Since then I have done a few mods to allow for extra oil flow
thru the driven shaft . There  is an idler gear that has a bronze bush ... attention needs to be taken here that it is  has not worn badly thru lack of lubrication. The gear will not run true and only pick up on one of the 4 dogs when under power.   Plus you need to make sure the idler bearing has a seal on trans side and note you have a cavity on the sprocket shaft at seals to allow for  oil to pass up shaft.
To me if there is a lack of oil the gears they will wear rapidly - get side movement -  and not mesh as one.

Strange as it may be I have the same motor same trans  DR 400 that is just under 500cc and I have flogged the hell out it for 6 years without one issue with the trans.
Main difference is the DR was built as a rever with revs its rs off.  Were as the 511 has a lot more torque.
 
        I will report back after I have been for a ride. fingers crossed I have it sorted   

[Oldfart]

mick .. its a real bad design on Suzuki behalf, as a good 75% of the dogs are on a shoulder between the gear and selector groove  about 6mm wide.