need help with forks

hi everyone, newbie here from uk,
I need some help with fork stansion diameteres.
I have bought some forks off ebay advertised as xj750 but they look to be xj900 as they have vented discs and the fork diameter is 37 mill , they will not fit in my yokes as mine are 36 mill, I have looked on net and they do fit these forks to xj750 here
http://www.denavalium.nl/george/Yamaha% ... 984%29.jpg

what model of xj750 yokes will fit 37mil forks ?
or will xj900 yokes fit ,(what model)?
does anyone have infos on fork diameters for the different xj750 models?.
cheers simon

 

HERE is a chart with the fork sizes of various Japanese bikes of varying vintages. I would just bore out my triple clamps the extra millimeter and be done with it, if it were my bike.

 

thanks for your help cooter but cannot find any reference on any lists of 37mill forks being fitted to xj750 only the photo here www.denavalium.nl/geor...984%29.jpg showing the forks I have bought.
Boring out triple clamps would cost me £50 uk pounds and would be cheaper to buy some second hand triple clamps if I could find the correct xj model, seems like the may have fitted these 37mills to xj650 seca ? cheers simon

 

I just double-checked, and the 650 Seca (USA-market anyway) has 36mm forks. Sorry. However:

From the list Cooter posted the link to:

37 Yamaha XJ-650 LK “Seca Turbo” (83)
37 Yamaha XJ-900 RK “Seca” (83)

Looks like your answer.

 

Nope, they weren't fitted to the 750, according to the list. The 650 Seca you mention is actually the turbo model. Pretty common here in the states, at least compared to the one year only XJ650R (Which was sold for several years over the pond- lucky blokes)

It is a fairly easy process to machine them; can't you just find a pub by a machine shop and strike up a friendly conversation over a pint? I know a couple people over here that have the equipment to handle the job, as it always helps to be able to barter skills.

 

thanks for your continued help guys, I bought a 750 seca to convert to a bobber ,the front forks and brakes were missing , only top yokes were there so I bought these forks off ebay item=220719044501 hoping they would fit the yokes,the guy said they are definatly xj750 but I think not,,

so I will also need air fittings for top of forks and poss xj900 yokes ? ,
my questions are
If I can find xj 36mill forks will the xj900 calipers, vented discs fit to xj750 forks and wheel ? or any ideas ?

or will xj900 yokes fit xj750 frame (I will fab up headlamp speedo etc)

 

The image you linked to is of a XJ750RL (1984) model, which is really an XJ900 frame/suspension with the smaller 750cc engine. As such, it used the 37mm front forks, same as on the XJ900 models.

Although you could bore out your clamps by 1mm to get them to fit, be aware that the XJ750RL/XJ900 fork tubes are also shorter (24" overall length) than the XJ750 "Seca" (26-7/8") or XJ750 Maxim fork tubes (26-1/4"). You need to consider the differences that using a 2-3" shorter fork tube may present in handling, braking, etc.

You didn't mention which model 750 you have, I would assume it's the 11M XJ750 Euro/UK model (which is what is called the "Seca" model in North American), and it uses a rather unique front fork system and brake system (cable-operated master cylinder mounted to the steering clamp bracket, anti-dive front suspension, etc.). They also have rather unique-shaped and configured upper and lower fork clamps (brackets).


I would suggest you try to obtain the proper fork tubes for your bike (we carry them), and look to sell the XJ750RL fork system that you have (it's a rare bike).......in fact, if the same fellow has any more of the specialty parts from that XJ750RL, I would consider buying them just for re-sale purpose!

 

Yes, now seeing the auction, those are the XJ750RL (XJ900) style forks.

Also note that those forks have the wheel axle mounted directly under the forks, whereas the XJ750 "Seca" front forks has the axle/wheel mounted FORWARD of the fork tubes........this is due to the rake angle of the steering head, and is an integral part of the entire bike handling and performance characteristics. Again, swapping systems like this can cause many changes----and some not for the better----in the handling, turning radius, and braking performance of the bike.

 

thanks for you replies
my bike is xj750 seca 2000 model

the image of the forks I bought is here uk ebay item=220719044501
and the image of the bike from the guy I bought forks off that he sent me stating they are 750 forks is here
http://www.denavalium.nl/george/Yamaha% ... 984%29.jpg
would you say that the forks off ebay are xj900 for sure ?
will the xj900 calipers and vented discs I have fit to xj750 seca forks and wheel ? or will I need new brakes ?

 

The XJ750RL/XJ900 brake rotors are a different style, size, and "type" than the stock XJ750 rotors. Their OD is different, their thickness is different, and most importantly, their "offset" from the wheel hub is different (750 Seca models used an offset, "dished" rotor, while the 750RL/900 models used a flat rotor with no central hub).

Yes, those forks/bike are an XJ750RL.....very rare bike. See if he has the front fairing and all the attaching hardware for it, very hard to come by!

Again, to make your life a lot easier and less expensive, I would recommend that you locate a complete front fork system off of an XJ750 "Seca" (specified as an 11M model in the UK/Europe), rather than trying to retrofit those 750RL/900 forks to your bike......unless, of course, you like engineering challenges and "blazing new trails via the trial-and-error process" through hitherto unknown jungles..........

 

chacal -I should have done my research better, I will sell the forks and get some 11M model forks. can you send me your email address to simusix12@o2.co.uk and I will put you in touch with the seller off my ebay.
thanks guys for your replies. regards simon