416 question and xr motor

[jpfmotors]

I just picked up a 400ex with a blown top end I was thinking i mine as well bore it to a 416 how would it compare to my present 450r 06 cam and jetting I race xc also I was wondering If there is mutch difference between the xr 400 motor and the 400ex motor has anyone put the xr400 motor into the ex so its only kick start . any suggestion or comments would be great thank you

[400exrider36]

my guess at it would be stator wire MIGHT be different, and i believe the xr has a slightly bigger cam. other than that all i could think is the gear ratios could be different... but i dont know. And im not sure how the backward kickstart would fit, could hit the frame or fender... but like i said im just guessing

For 416 to 450r comparison, it all depends what other mods are on the ex because it generally takes a bit of work to compare to 450s

416 is ok but if you want to run with or out run a 450. you will need to go up to a 440 kit and a good pipe carb.

[PaRedneckRiders]

A well built 426 will run circles around stock or light mod 450s

[jpfmotors]

ya I was not shore if the kick start would hit the frame but I would have to cut the plastics to. the xc racing is pretty tight up in new england most times i only get my 450 into 3rd maybe as far as what i had in mind was just maybe polish the head clean up the exhust port in the pipe and pro circuit slip on open air box

[JOHNDOE83]

Theres a few threads on the kick start EXs, the xr wont fit without modifications, the rear mount is lower or higher I cant remember?

look up the thread, its just a conversion that you can do.

use the search engine at the bottom of the page.

[parts eeter]

I had the pump fuel 416 and a stage 1 cam and all the rest of the goodies to go fast and I could eat other 400s but my buddies HRC 450s would pull 2 or 3 lengths outta the hole when drag racing them. We topped ot at ver similar speeds usually right around 70MPH.

Just a note I had GT Thunder do the HD studs in my cylinder and he did such a crappy job on them that my head would barely bolt on cuz the studs were so misaligned.
I wouldnt have studded it if I do it again.
I have ridden some 440 kits that ran like crap. Maybe they werent built correctly. I dunno, but I like 416 and 426 builds best.

[JOHNDOE83]

The 440s that run like crap are usually not jetted correctly.

[brewster426]

i read a thread somewhere that said the xr motor crank is longer on the mag side..or something to that effect. i may be wrong

[CJM]

FWIW I had Gt thunder do mine, no issues at all.

[parts eeter]

Originally posted by CJM
FWIW I had Gt thunder do mine, no issues at all.

I was surprised as well, I had many good referrals to him. I had no issues once I was able to get the head to get past all the crooked studs!

[CJM]

I woulda sent it back and made him gimme a new head or fixed it.

[parts eeter]

At the time I was building a house and really was tryin to build a quad in between. So I just forced the head on knowing what he had done was wrong. I didnt even call him to let him know it was messed up. I could have done a better job in a drill press honestly. It was along time ago and I never was mad about it, I just wanted the original poster to beware of shoddy workmanship as he mentioned a big bore with studs. I would never use him again for machine work of any kind.

[beags86]

Originally posted by parts eeter
At the time I was building a house and really was tryin to build a quad in between. So I just forced the head on knowing what he had done was wrong. I didnt even call him to let him know it was messed up. I could have done a better job in a drill press honestly. It was along time ago and I never was mad about it, I just wanted the original poster to beware of shoddy workmanship as he mentioned a big bore with studs. I would never use him again for machine work of any kind.

i personally think that it's a bit unfair to be badmouthing someones workmanship if you never gave the guy a chance to make it right, or even bother to pick up the phone and let him know about it. if the guy would have charged you to make it right, or refused to do so then i say badmouth away.

[TRXRacer1]

I agree that he should have given GT a chance to rectify the issue but he has the right to tell us of shotty work. Even if they did fix or refund they put him in a position that good work/service would not have done.

[beags86]

trx, i agree with you as well. everyone has a right to tell other people of good/bad service. i like hearing all sides of stories. i also want to know what anyone has to say about a shop/service good or bad.

but i only piped up on this do to one experience.

In the summer of 08 i fully built a nitrous'd oldsmoblie rocket 350 for my cutlass.

i already had it at the engine machine shop when i found the set of heads i was going to use. a set of #5 heads. i had bought them knowing that there several broken exhaust bolts.

so when i took them into the shop to have them checked for cracks, put harden seats and studs put in i told him to fix the broken bolts for me as well.

well he went ahead and "fixed" them and put in my valve seats and and my studs in. had them done in one day. GREAT! i thought i can start porting and polishing tonight!

well i got the porting done and started a mock up in my car with another 350 because i had to do some header clearancing.

well i couldn't get my headers on at all, i thought to myself, f**king junk as* hedman header i'll never "go cheap" again
(side note: even though it wasn't the header i still never buy hedmans again) well as it turned out the exhaust bolt holes had all been redrilled wrong,(he said he couldn't save the original threads, so he redrilled for a bigger bolt.)
nothing was straight. i was pissed.

so i took them off and took them the day and bi*ched like crazy.
he fixed them and put in head studs in the block for free along with a free valve job.

not only did he fix it, he went above and beyond what he needed to. i was happy with everything for the most part.

but the one thing that sucks is i have to a allen head exhaust bolt because of header clearance- which puts me in a position that good work the first time would not have done.

but since he did fix it and cut a better deal on my overall project i wouldn't badmouth him. but i will tell the truth to people what happened.

just think thats parts eeter should had contacted the shop. thats all

been there done that. been on both sides before.

[TRXRacer1]

Originally posted by beags86
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just think thats parts eeter should had contacted the shop. thats all

been there done that. been on both sides before. Agreed:cool: