Topic: Fork swap welding question

[szalkaiz]

Hi Everyone

I have been reading for quite a while and doing research on the subject, but I cant seem to find the answer to this one. I am just about to do a fork swap to a modern usd fork on a 92 honda nighthawk. Pushing stem out and switching seem straight forward enough, but while on pre 96 models lower triples were metal you could weld the new stem in (just like stock ones) but since new usd tirples are aluminium you cant do that (or it is extremely complicated welding alu to metal that is). Is there any way around this issue cause nobody seems to address this. Or steel stem should just be pushed in to the alu lower triple. I have seen people gluing them in and using jb weld even one guy put aluminium tape around it. But non of those solutions equal welding. I guess bottom line question is that is a non welded alu metal tripel combination safe enough for high speed riding.

thnx

Z

[Scott S]

 Hi Z... and welcome.
 Since the '92 Nighthawk is a later DOHC cam model, I'm moving this to Other Bikes forum.

[slikwilli420]

Not sure I understand the issue? Why is there any welding involved in a stem swap? I guess if you needed to you could weld the stem surface up larger to mate with the new lower tree, but that would be it. Unless this is a known swap and parts are out there already, you may need a custom tree and or stem for your swap.

[calj737]

You can not weld aluminum to steel or vice-versa. If you want to use an aluminum stem in a lower steel triple, press it in with an interference fit, and perhaps use a set screw drilled into the face of lower triple to pin the two pieces together. Or, press the stock steel stem back (out) and re-weld it. You can source conversion bearings at All Ballz bearings.

[szalkaiz]

HI Everybody

Thank you for the quick replies. It might be my lack of knowledge but, as I understand older models (like mine) had the stem pressed and welded in the lower tree (I guess to make ti safer) That is why first we have to grind of the weld before we press it out. Newer models w the alu lower end are only pressed, now if I want to press in my existing steal stem into the new lower yoke (ALU) I can not weld them together. I guess If I understand you guys correctly if I do an interference fit then that should be fine even tough it is not welded???

thnx

Z

[slikwilli420]

In this case, I have heard of taking the old stem out and welding a piece to the bottom that is larger in diameter than the press-fit portion. When the stem is pressed into the new tree, that new piece serves as a positive stop and adds a bit more insurance. If you think about the forces at work and where everything is bolted together, there is literally no way the stem would come out of the lower tree but people like to overbuild things like steering, understandably so.

[calj737]

An pressed fit is more than adequate. So feel free to mix and match your steel stem into the alloy lower, or vice-versa. Welded lowers seem to be more common where two similar metals are used.