New Forks Wont Fit, Please Advise!

[Spike_R]

Just bought a set of showa forks for my derbi senda, and suprisingly enough they dont fit! got one prob that the clocks dont mount on, but i can deal with that the main problem is that the steerer tube is to fat and the bearing nuts dont fit!

well, i think i need the tube out the old forks, will this work ? i can hit stuff with a hammer but got no welding gear handy! ... the old set of yokes wont fit as the new forks are USD and the legs are closer together coz of this!

thanks for your help
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Derbi supermoto with cr500 engine, niceee

[stinkwheel]

Steerer tube? Bearing nuts? tube out the old forks?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Spike_R]

steering stem needs to be changed over , ive got the one out that fits in the frame but getting the other one out is proving to be a bit harder, i cant find my sledge hammer
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Derbi supermoto with cr500 engine, niceee

[stinkwheel]

Having looked into doing this before, it is not an easy job. You are also working on the assumption that the steering stem from your old yoke will fit in the new bottom yoke. This is not a foregone conclusion, they are an interference fit and if the size is not exact, you could be in trouble.

They also sometimes weld it in as well

What is the exact problem with the one on your new yoke? Is it too short? Too wide? Bearings the wrong size or type?

Your problem may be better attacked from the direction of getting someone (professional) to modify the new steering stem to fit or ordering some different sized bearings.

Also, if the forks were sold to you as suitable for fitting to your bike, you might want to have a word with the seller.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Spike_R]

no i did the stupid thing and assumed they would fit, i do think they are the wrong ones now but i cant be sure, still had no luck getting the other stem out, im considering going to an engineering place and asking them to make a custom one that would fit the yoke, and frame, to save hassle! as also when i put this new tube on the top yoke's mounting hole is too thin. so its going to need alot of work! ....

the new tube wont fit so that will have to be welded, i think a new stem custom made will be the only viable solution!
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Derbi supermoto with cr500 engine, niceee

[stinkwheel]

If the bottom half of the new one fits, I have seen a bodge (you need a good engineer to do this mind!) that might work for you.

You cut the two steering stems in half and keep the top half of the old one and the bottom half of the new one. Next you machine the inside of the stems so they are the same diameter and sweat-in a solid slug of metal the same size. Now drill a hole horizontally through both the stem and slug above and below the join and fit pins in the hole to stop rotation. Grind it all flush and you are finished.

Remember, this is a precision job and should only be done by someone with a lathe who is good at using it.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Spike_R]

im going to try and get the correct bottom yoke first, else im going to try and get one custom made, which will cost a small fortune but be worth it
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Derbi supermoto with cr500 engine, niceee

[ZRX61]

[Spike_R]

well they aint got any more yokes, they said they would give me a refund if i send it back, however ive given the top threads a severe beating so would have to hide that i think! ..

would need the top yoke mount widened and the bottom of the stem widened too to make them fit, i dunno which route to take now, think im going to do all the rest of the planned work done to the bike today then consider my options of what i can do .

whats your suggestioons, im realllly confused!

and i didnt mean custom yoke, just a customized stem, which i reckon would cost about £100.
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Derbi supermoto with cr500 engine, niceee