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cajun

680 Big Bore Kit Install?

11 posts in this topic

Okay I know I've read about this on here before but I've been searching and searching and can't find it.

I'm considering doing a 680 big bore kit on my Pig. I don't think I have the time to do it myself and I don't want it sitting in my garage for months waiting for me to get back to it. So where is the best place to get it done?

I ride off road desert and tight trail and SM on road only no track. I want it to be as dependable as possible, but want to add some more fun to it.

Thanks for any help.

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Found this stuff,

Go with nikasil cylinder not steel sleeve. I would go with a 1mm over sized intake valve. I have the 3mm over sized intake and it does move a lot of power up into the higher rpms and makes the bike much smoother to ride but, I would like a little more bottom end hit and the option to go 3mm on the next rebuild if I would have gone 1mm over the first go around. You can't have both the 3mm over sized intake and the 1mm over sized exhaust valves, they will hit each other. 3mm over sized intake take a lot of grinding to work and you do not have much valve seat left. Well, you have almost none! I was told this and saw it for myself after I did it anyways. I wouldn't do it again. 1mm intake is more then enough take my word for it. Yes, the bike will be faster with the 3mm over sized intake valve and that sounds great but, it's where it puts the horsepower that counts and I have enough at 120mph not to need the little more the 3mm O/S valve gave me up there. The smoother power band is nice but, after a while radical power doesn't sound to bad. The Nikasil cylinder is the way to go. I like the Carrillo rod better but, your crank setup sounds slick. The Carrillo rod is rebuildable. I really like the over bore on my Edelbrock carb. and recommend it for your 680cc monster. It was a 2hp increase on the Dyno for my 680cc motor. Iridium plug, Nology 45,000 volt coil, (stock is 35,000) Fluidyne Radiators are nice as is Evens coolant, (got to keep that extra power form heating your bike up) I got tired of my S/S oil filter , went back to stock for now till I get around to cleaning the two S/S filters I have now. #19 needle 16 clicks out and you will be there on the jetting. We have a bike that has the intake and exhaust ports honed, I wouldn't do it again, maybe a little clean up but, not as much as a port job. I would love to have rocker arms with cam rollers!

I am using Barnum's Mid cam, it is a stage two (HRC) cam with more lift, I like it for the power it gives from 5200 to the limiter, most cams fall off just a tad as you climb into the top rpm's but, this cam holds the horsepower gain flat to the end. I would stay with stock sized exhaust valve. I have the Weisco 102.4mm 11:1 piston machined for the bigger intake valves and extra lift. The valve guides were decked .030 for the extra lift also. Clay tested to make sure piston to valve clearance was right. The coil is a hot something....they also make a spiecal plug wire but, I have to go look at it to remember what make it is. Maybe someone can chime in and help my failing mind. It is 45,00 volts instead of 35,000 like stock. The new coil won't fit where the stock one does so, I moved it bake and it is mounted to the frame just above the intake valve adjustment cover. NGK IX Iridium 6988 BKR7EIX-11 $6.95

I got all these prices from www.sparkplugs.com

The Hot Cams have the stock lift as does the HRC. Barnum also sells a radical cam that is more then the stage two and has the higher lift, I rode his bike with it and it was about the same with more high end punch. He was running a one pound lighter flywheel also, so, there was more bottom end snap. Making it hard to decide what you would loose (bottom end) with just the radical cam. With the much better connecting rod, and crank, heavy duty clutch springs, cam chain, sooner or later the ground becomes the week link

I live less then thirty minutes from Edelbrock and they bored all of my Edelbrocks as well as Jays. I have Edelbrocks on the XR400 also. I think the Mikuni is better but, for ease of starting and tuning the Edelbrock is much better. I Mikuni has six jets and the pump adjustment, the Edelbrock you only change the needle and adjust the pump squirt and pump throw if it is off. There is a jet in it but, you don't change it. The Edelbrock is not a race carburetor but, many, many use it for that. I have used the Kehin FCR41, Mikuni HRS42, TM40 and ridden a bike with a TMR41, The Kehin 41 is awesome but, it is a pain to fit (Heating and bending the plastic tank and grinding off a lot of the valve chain adjustment housing) I loved the way the HRS42 worked but, I didn't take the time to change the pump nozzle and it ran wet in a stock bike I wish I would have kept it, The TM40 took a lot of time till I found the magic that worked for me (TM40's, HRS40,42,45 &48mm are for Harley's and run like junk setup that way on our bike). It was supper smooth. The TMR41 was flawless.

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Wow thanks for all the info there BWB63! So do you think that Barnums would be the best people to do the work or can you recomend anyone else?

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Wow thanks for all the info there BWB63! So do you think that Barnums would be the best people to do the work or can you recomend anyone else?

Barnum does great work, send it over.

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Barnum does great work, send it over.

Well I sent him an email inquiring about this service and haven't a word from him in two weeks. I have heard from XR's Only and Bare Bones. Jay at Bare Bones really sounds like he's on top of it. If I don't hear anything more I'm probably going with him.

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well mine's a xr's only right now i should be getting it back next week everything seems to be moving along very well i have been checking in with them and so far progress is good it's been 2 weeks so far. here's what i'm getting done 630 big bore,hrc cam,rockers,timing chain,keihin fcr carb,revalving and springs in front forks i will keep you updated on how it turns out. rob barnum is a very nice guy and we have talked a few times and he has been very helpful i didn't no he was doing machine work i thought he was just selling parts. I talked before with him before he opened his business completely been awhile i guess lol if you do go with him i am sure he will take good care of you he is a stand up guy and knows what he is doing now i am shocked he hasn't got back to you every time i contact him it's only minutes before i hear from him well i'm sure who ever you go with you will be happy

:thumbsup:

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well mine's a xr's only right now i should be getting it back next week everything seems to be moving along very well i have been checking in with them and so far progress is good it's been 2 weeks so far. here's what i'm getting done 630 big bore,hrc cam,rockers,timing chain,keihin fcr carb,revalving and springs in front forks i will keep you updated on how it turns out. rob barnum is a very nice guy and we have talked a few times and he has been very helpful i didn't no he was doing machine work i thought he was just selling parts. I talked before with him before he opened his business completely been awhile i guess lol if you do go with him i am sure he will take good care of you he is a stand up guy and knows what he is doing now i am shocked he hasn't got back to you every time i contact him it's only minutes before i hear from him well i'm sure who ever you go with you will be happy

:devil:

Rob is good people,my bike hauls ass....:thumbsup: he is more than likely pretty slammed w/ the holidays, and I did speak w/ him Monday, their server has been acting up, I would call and leave a message.

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