what to do..what to do with ole 75

[storminnorman07]

so i was playing around on CL and came acrossed this ole xr 75 and at a price of 75 big ones. so needless to say i just had to have it. i need another project like i need a hole in my head. but i figured id get some ideas from you resto vintage guys that do this all the time. with that said how would you guys go about building this beast no budget sky is he limit. so what would you do?

[canammx1]

Make a thread in the vintage forum as well. A lot of guys over there have xr75's

[storminnorman07]

Make a thread in the vintage forum as well. A lot of guys over there have xr75's

wow didnt see theres a vintage forum..feel like a dumba$$ now. started one there thanks for the heads up

[canammx1]

wow didnt see theres a vintage forum..feel like a dumba$$ now. started one there thanks for the heads up

Love the mutant build by the way

[gman255]

Holey Crap! You freak'n stoled that thing! Looks like it pretty much all there to-boot!

Pimpage or vintage that is the question?

Personally I love the look of a period correct works racer. But, I'd be on the fence with adding some modern components- suspension and front brake...

Knowing your motor work It'll be stellar.

Can't wait to see what ya come up with

[theraymondguy]

I was going to build this, but you might like it too.

Period correct flat tracker.

CR60R front end (drum brake, same hub as XR 75/80/100);

XR100 swingarm, CR125M rear shocks

16"s front and rear (XR100 rear, XR75/80 front);

XL70 tank (touch smaller than XR80)

Early XR75 front fender

XR/CRF50 pegs

Power:

Big fat bore, little to no extra stroke

4 valve head to let it breath

4 speed trans (flat tracker, not motard)

DG intake & downpipe

JWRP style oil cooler

[storminnorman07]

lol thats why i couldn't pass it up. the post on craigs list was pretty vauge with no pics just said 76' xr 75 for sale 75. so i was thinking if its 75 bucks its prolly a parts lot or if its a whole bike they prolly meant a higher asking price. curiousity got the best of me so i sent a email inquiring about it. to my surprise i got a email back with a picture of the bike stating 75 big ones was the asking price. needless to say i couldnt type fast enough to tell them give me a time and day to pick up ill be there. looking it over the only things i have found its missing is the front number plate and rear brake return spring. everything else is there. not in the best shape (i'm not a vintage nut so i could be wrong)..but i think the tank is not right for the year and i'm certain the fenders are some aftermarket deal.

pimpage or vintage is the big question thats why i started the post hoping to get some good ideas. so that i don't commit a vintage fellony..lol as i stated earlier i'm not a vintage nut, i dont restore bikes to factory form. anything i touch gets modded for a certain purpose and to perform better at that purpose without worries if it looks factory or not.

if i don't get some ideas rolling from guys that was my thoughts of how to attack the bike. as much as i would love to restore it to its factory form it just wouldn't jive with the engine setup that i would really like to do. for chassis i would keep the twin shock setup but i would go with like a works shock setup with the frame mod that xrminiracers do, swinger depending if i'm feeling lazy at the time or not would either get a hand built swinger or if i'm lazy just purchase a dg or something like it, forks i don't know what forks guys are using that look like the factory forks but have more travel but if i figured that out i would set the front end up with those forks. would love to get my hands on factory fenders but god lord are they pricey! all the ones i have found that are not beat the snot and back are worth a pretty penny! i was looking at a complete front rear fender tank and plates on ebay last night they ONLY wanted a grand for the set.

engine is the only thing that will come easy for me. prolly cause i have been kicking this idea around for a while. head will get oversize valves prolly 28mm intake 23mm exhaust, oversized ampco seats to meet the needs of the bigger valves, valve stems will go on a diet. not sure if i'm feeling up to spinning my own guides again to do a 4.5mm setup i may keep it simple and just go with 5mm stems. i'm pretty certain this one guide i have in mind will be virtually a drop in deal. cam will be bearing like xrminiracers do. terry and i have been kicking an idea around to cut up a modern 80 cam to work within the 75 cam tower. so when it comes to that point in time i will further look into it to see if it can be done or not. bore will be set at 58mm stroke i'm undecided on. the one thing i do wanna modernize is get away from the points and go with cdi. i like the idea of leaving the shorter stroke of the factory 75 crank and making it a zinger but i'm not a big fan of fighting with trying to fit a cdi to that crank. so it may get a stock 80 crank or a modded one with a stroke of 51 or 57. trans will be kept at a 4 speed. exhaust will be custom tailored to whatever engine i decide to go with. Swiss on here has given me some useful exhaust tuning tips so i will be using this new found exhaust tuning knowledge for the exhaust on it.

[storminnorman07]

I was going to build this, but you might like it too.

Period correct flat tracker.

CR60R front end (drum brake, same hub as XR 75/80/100);

XR100 swingarm, CR125M rear shocks

16"s front and rear (XR100 rear, XR75/80 front);

XL70 tank (touch smaller than XR80)

Early XR75 front fender

XR/CRF50 pegs

Power:

Big fat bore, little to no extra stroke

4 valve head to let it breath

4 speed trans (flat tracker, not motard)

DG intake & downpipe

JWRP style oil cooler

i'm digging the idea but 4 valve head? i didn't know there was a 4 valver for the 1973-76 xr 75s?

[Swiss]

Chad, sending you some scans of the old Powroll build.

Swiss

[storminnorman07]

Chad, sending you some scans of the old Powroll build.

Swiss

got them. very interesting read as well as nice results.

[Swiss]

Chad, the one photo I sent you was the ARP replacement studs that I used to build the engine with. Never to worry about them breaking! HA!HA!

[theraymondguy]

i'm digging the idea but 4 valve head? i didn't know there was a 4 valver for the 1973-76 xr 75s?

They didn't. I figured you'd chop one up to fit. I believe the Hacienda Honda XR75's of the mid to late 70s had something called a 'Blonde head'.

[storminnorman07]

Chad, the one photo I sent you was the ARP replacement studs that I used to build the engine with. Never to worry about them breaking! HA!HA!

lol i made a set of studs very similar to those for my dohc crf 50 i did a while back. i had a gross amount of CR and it kept stretching studs and popping head gaskets so i eventually had enough of the weak aftermarket studs and made my own.

[storminnorman07]

They didn't. I figured you'd chop one up to fit. I believe the Hacienda Honda XR75's of the mid to late 70s had something called a 'Blonde head'.

lol was going to say if there were a 4v head for the old 75s someone needs to give me the info cause i'm on it...haha no chop/morphing on this one. i am going to try and keep the engine as stock looking in appearance as possible. i'd say worst case you'll see a spacer plate indicating a big ol stroker. however since you have mentioned chopping one up to make a 4v i had a goofy idea a lil while back. i got to see a daytona SOHC 4v head for the xr100 after a good while of looking the wheels started turning on what prolly would of been a nightmare to build. i was thinking take a stock head knock the guides out of it and seats out of it. weld in guide and seat bore weld up a divider in each port. then spot face mill for 2 valve springs on each port drill ream hone for 2 guide counter bores for each port and make a 2v head into a 4v head. as your reading through that your prolly thinking thats alotta work for min gains and why bother when you can buy a daytona. if you was thinking that, that makes 2 of us. so needless i bailed on the idea. now with the 73-76' xr 75 to my knowledge no one makes a aftermarket head for it so it may be something i try and tackle down the road. lol i really doubt i will but the ego factor to do so and make it live would be sweeeet.