Ton up SR250 - a cafe racer by the numbers: 100mph, 100kg, 30hp

der_nanno

Faster!
teazer said:
That's interesting to hear. Do you know what thread size they are?
M6x1.00 so should be the same pitch. (I definitely swapped them round with SR500 adjusters.) The length varies a bit between the various models.

teazer said:
One trick that people seem to underestimate is getting the squish right - or at least making the squish band work. That usually requires the head and piston and barrel to be machined which will raise compression a touch. The result of getting it to work should be more power everywhere in the range. Good squish allows higher compression before detonation sets in.
Or do as I did on my XV1000/TR1 engine and omit the base gasket and use liquid gasket instead. Got the piston 0.5mm closer to the squishband, all of a sudden making it run a lot more efficient as it got close(r) to the magic 1.00mm mark.
 

doc_rot

Oh the usual... I bowl, I drive around...
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Psychopasta said:
Remember that BikeExif never state whether the bike is a runner or not...
I worked at custom shop briefly when I was in college. We took in a bike that was featured on Bike exif to get it road worthy. Dude paid 20k for the bike and then had to bring it to us to make it ride-able. I literally had to go through every component because nothing worked. the GSXR fork swap was so poorly planned that the front wheel would contact the header under braking among many other stupid things.
 

Pete12

Been Around the Block
That's not really bikeexif's fault though, it's the dickhead that built the bike. I had a bike featured on there and no one had to touch it when I was finished...
 

JadusMotorcycleParts

Over 1,000 Posts
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All show and no go! Yepp, plenty of show bikes and plenty of posers as well. Thankfully there are also a lot of very talented and honest builders that get featured there often as well. The way the article is written usually gives away how genuine or not the bike/builder is.

I wish Paul from The Kneeslider was still active writing about cool bikes and engineering feats, that was my favorite blog for years :)
 

JadusMotorcycleParts

Over 1,000 Posts
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I keep checking in to see if there's an update here, it's been a while! You alright, man?
Thanks for asking man! Yeah, still around and still really wanting to move ahead with the project!

Like so many other projects/stories I have read on here, life has gotten in the way :p Moved the Jadus workshop, got engaged, bought an apartment, been to Australia, quit my day job and got a new one! Aaaaand, unfortunately, both Jadus and myself personally have run out of finances (with the move, ring, holiday and apartment haha)... Which means it's going to be a bit slower on the development/purchasing of custom parts for this and other projects. Unless Jadus all of a sudden gets a huge flood of orders or I win the lottery haha. BUT, the passion and will is still there! It'll just be a bit slower than the already slow pace.

Hope everyone's having a good weekend.
Cheers.
 

sav0r

Coast to Coast
Glad to hear you are doing well! Congrats on the nuptials, new shop, etc.!

When I got married, I also bought a house, and that meant moving my shop. It took me two years to recover. Being flat out broke and the overwhelming time requirements of moving my family and shop while working a full time job, the shop ultimately took the back seat. So I understand how that can be! Keep on it! I can say that now I have a better shop, a better home, and things are all around much better here at the three year mark. Sometimes it's healthy and productive to take a step back from passion projects anyways, it clears the mind and allows for better focus when you return.
 

crazypj

Split personality, I fake being smart
Interesting little bike in link but probably only lost around 30lbs (13Kg?) off original weight. You can save a LOT of weight by fitting lighter tyres, rear wheel on my CB'360' went from around 50+ lbs to around 30lbs (forget exact numbers and I ain't searching thread for them) Alloy rims save around 2lbs each compared to steel. USD forks arelarger diameter and much thinner wall so are lighter but only by 3~4 lbs (more on bigger bikes where original fork tubes may be 1/4" thick steel and only 35~38mm dia)
 

JadusMotorcycleParts

Over 1,000 Posts
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Very little action this year from my part here. But there have been bits and pieces happening in the background - both related and non-related to this project.

The related things have been clearing a space and preparing table room for the project. I have booked the frame and swingarm in to be blasted and have received and tested the first aluminium prototype for the magnetic oil/sump plug. It works really well, just a couple tweaks and I'll be able to order a production batch.

Non-related things have been finalising the performance intake kit for the XV535. After many, many prototypes and a whole day of dyno testing, we ended up getting a 10% power increase over nearly the entire rpm range. Am now planning how to bring it to market because it is a real sweet kit - the power is felt a lot - a 5hp increase at 4500rpm. I made a video about the testing of it here:

And one more non-related thing has been finalising the carbon seal kit for the . I just sent a prototype to a guy in the UK building a turbo SR150 for him to test. If you're interested I can give more info about it and you can also check out his instagram account: shed_built_customs
 

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JadusMotorcycleParts

Over 1,000 Posts
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Finally got the frame blasted and welded up some things that needed patching. Hadn't welded for well over a year and to say that I am not proud of these welds would be a gross understatement. If they were going to be cosmetic welds I would have got a professional to do it but they are just patch jobs, non-structural as well.

Perhaps it's also time to fork out for either a MIG or TIG. The old gas welder has its benefits for sure but I can't seem to master it (maybe that means I couldn't master a TIG either?!). As with most things I guess practice makes perfect!

Now to prep the frame for paint! I bought the Rust-Oleum Combicolor that was suggested here :)
 

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Chanyote66

New Member
Nice! Iv been off the forums for a while... Glad to see there is still progress.

Every time I have had my bike down to the frame, I think of making a custom titanium or aluminum frame. I have a solidworks model of the frame to do stress analysis so changing to aluminum would be quick.

On a side note, anyone know the part # or connector series used for the CDI box? I working on an entire new wiring harness and that thing is my last connector to get.
 

JadusMotorcycleParts

Over 1,000 Posts
DTT SUPPORTER
Nice! Iv been off the forums for a while... Glad to see there is still progress.

Every time I have had my bike down to the frame, I think of making a custom titanium or aluminum frame. I have a solidworks model of the frame to do stress analysis so changing to aluminum would be quick.

On a side note, anyone know the part # or connector series used for the CDI box? I working on an entire new wiring harness and that thing is my last connector to get.
Yepp, still chugging away, piece by piece. A lot of time has gone into the XV535 projects we started working on as well. But hopefully will be riding this one summer 2021 (have said that 3 years in a row now :p)

You should build a custom frame if you get time! That would be the ultimate. Plenty of excellent inspiration on this forum too :)

Not sure about the electrical contact to the TCI box unfortunately... Could you buy a cheap second hand wire harness and harvest the connection from that?
 

remotorcycled

New Member
Hey dude! We speak on instagram, just wanted to drop a note saying hello and enjoyed reading this. The xv535 upgrade is cool, they seem quite popular over here so good to see an upgrade for them!
 

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