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Discussion Starter #1
I am fixing to Grampsize my 1996 800 Classic per Russian Wolf's website; all parts are ordered. I'm going the route that uses the OEM needle. The only thing I have not decided whether or not to do is to drill the hole larger in the throttle slide, it's optional. RussianWolf states:

"This hole can be drilled out larger (1/8”), which theoretically allows the slide to move up and down more rapidly, thus decreasing throttle response time." (He put the word theoretically in italics.)

So, I thought I'd ask folks here who have drilled out their slides if they experienced any differences in performance. Thanks!

For those who are unfamiliar with Grampsizing: http://www.angelfire.com/ak5/russwolf/documents/grampsize.PDF
 

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I have scooterised my VN800A and drilled the slide, as per Russian Wolf instructions.
The bike is running very well, good throttle response. But I cannot say that I have notice an improvement ...
Definitely is not running worse, after drilling.
 

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Discussion Starter #3
Thanks marcelm, good info. Was there an noticeable change in performance when you Scooterized? Gas mileage better/worse?
 

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Maybe there is an increase in power, but is not noticeable, at least in my case. Maybe other guys here, have different opinion...
Regarding the mileage, is the same, about 5,5l/100km (42,8 mpg), before and after.
 

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Discussion Starter #6
Be very very careful about taking a drill bit to any carb at any time.
How so, as it pertains to drilling out this hole? Careful by doing a good, neat, thorough job? Careful by not knowing what you will get once it's drilled and you twist the throttle? Careful by affecting your entire fuel delivery system?

We value your input sfair. I (and others) are trying to decide whether or not to drill, or not to drill. Any insight other than 'be very, very careful' would be greatly appreciated. I shutter at the thought of drilling on a perfectly good carb, but I'm also curious. LOL Thanks!
 

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I have drilled the slide carb, cut about 2 turns of the sprind slide, 50 pilot jet, 170 main jet, stock needle raised up 2 mm ... and no issue.
But, this is me ... as each bike is different, I think same with the carburetors.
 

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Discussion Starter #9 (Edited)
No issues, bike runs perfectly. (Cobra tapered exhaust with welded in baffles, 150 pilot, stock air system.)

Just trying to decide whether or not to enlarge the hole to 1/8" in the vacuum valve (aka throttle slide) when I experiment by Grampsizing. Risk/benefits, I guess. Not a fan of drilling unless I can reap some rewards.
 

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Discussion Starter #11
The issue isn't whether or not my bike runs perfectly, I understand that and I understand dyno tune. My question is: When I Grampsize, are there any positive benefits to drilling out the hole? If not, I'm not going to. Just trying to educate myself, not as experienced as some. Thanks!
 

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I feel that the only way to assess that mod is on the dyno where the dyno information would require the drilling to correct a fuel metering issue. Any other way would be conjecture.

My opinion only.
 

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Discussion Starter #13
I feel that the only way to assess that mod is on the dyno where the dyno information would require the drilling to correct a fuel metering issue. Any other way would be conjecture.

My opinion only.
Gotcha, and agree. Thanks sfair! Anyone else have first hand knowledge of grampsizing or drilling?
 

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I have scooterised my VN800A and drilled the slide, as per Russian Wolf instructions.
The bike is running very well, good throttle response. But I cannot say that I have notice an improvement ...
Definitely is not running worse, after drilling.
Hi marcelm, so the Russian wolf website is the go to instruction site for Don the scooterizing mod?

And in your opinion, after riding with the stock airbox set up and the scooterizing set up..... is it worth it? Does it make a big difference?

Thanks for your feedback.
 

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Discussion Starter #15
I am not giving up on grampsizing. When I had it modified, the bike ran cooler (I have an aftermarket temp gauge) and there was indeed a noticiable difference in HP, just seemed to have a bit more zip--nothing dramatic. The bike ran GREAT until 45-65 mph where it would start 'coughing'. If I gave it throttle, it was OK again. But when cruising at a steady speed, it started stuttering. I just couldn't get the jetting right, so I gave up for now. Like sfair said, the only way to get it right is to put it on a dyno. Marcelm seems to have his tuned! NOTE: I found a cheap airbox on eBay and used it for grampsizing, so I could go back OEM if I wanted to which I did. It was a fun project!
 

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Hi marcelm, so the Russian wolf website is the go to instruction site for Don the scooterizing mod?

And in your opinion, after riding with the stock airbox set up and the scooterizing set up..... is it worth it? Does it make a big difference?

Thanks for your feedback.
Yes, I followed Russian wolf instructions 100%.
BUT, I did not see any BIG improvement. Bike runs well, before and also after the change.

To summarise : if you want a big improvement you should follow "sfair" instructions and go to dyno tune. If you just cannot stay and need to do something to your bike ... (like me :D....) .... then you can do the scooterising .... big opportunity to learn.

... just my 2 cents ...
 
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