Top end speed gone? Where did it go?
#1
Ok, here's a question for anyone out there who may have had the same problem. Installed a stage 1 kit from RCR. I changed the main jet to a 270 and put in the brown primary spring that came with the stage 1 kit. The bike really pulls down low and through the mid, but now only has a top speed of 44-45 Mph. I just got a couple of more main jets(280 & 290). I installed the 290 today, but do to rain, I couldn't take it and try it out. I was told that I should keep going up one jet size at a time on the main jet until it begins to bog or sputter when the throttle is cracked fully open and then back down one size. Anyone else have this problem before?
#2
(98sport 400L)I just installed the stage 1(rcr and vforce reed cage with 270 main jet) and i to am impressed with the added bottm end grunt, but while i cannot say Ive lost some top speed, I can say It does not feel faster.(but thats is just feel,not fact). The brown spring defintley has a higher engagement speed. I know this because I cannot back up period, unless the reverse throttle over ride pressed. Like I said, the acceleration is great. Another thing I noticed was that the rcr kit seems to let the engine rev more freely, whereas in the stock for the engine sounded as if it had a rev limiter on it.( i know is does not have one but the engine made that rev stop rev stop rev sound).Just thought some others experiences might be insightful.
#4
I'm gonna try out the Scram tomorrow with the 290 main jet installed and see if that wil help any. May have to back off to a 280. Installed a speedo on it so now I can tell if it really lost its' top speed after installing the stage 1 from RCR. I think part of my problem may be in the air box mod. I not only installed the air box mod as per instructions,but I also drillied a hole completely through the seperator in the air box, thus increasing the main jet size larger than what was included in the stage 1 kit. Don't get me wrong, the kit is great, but I may not have taken into account the extra air flow I created when I furhter modified the airbox. And I did find a faulty clamp on my carb between the carb and the reeds. If it doesn't work out acccordingly, I'll give Rick a call and I'm sure he can straighten my problem out. That's one thing about Rick...he wil listen..he has patience(thank God)and he wil do his best to help someone out. It's just that I've called him enough in the past weeks and I don't want to bother him too much. After all, hands on experience is how you learn and most importantly, how you remember, right? I will say this though, it doe pull like a train from down low till it tops ouit!Thanks for the input.
#5
I also talked to Rick before I began installing the kit. Very helpful and patient with us mechanical layman.The air box mod insructions stated that the separater robs the engine of hp, but it also protects against water. Well I avoid water,(riding in rain, mudholes and wet trails, whatever)so I removed the divider completely and added th 3rd intake hole. Maybe I should try larger main jet?Where did you here about the jet selection process, some one reliable?Maybe it could help the top end.
#6
I read a article in the 04/02 issue of dirt wheels on carbs and jetting. Looks pretty staightfoward as far as I can tell. I don't think what was written in the article is eched in stone, but it does explain everything in language that almost anyone can understand. I saw a few suggestions in there that might help me out, so that's why I'm trying the larger main jet. It controls the the amount of fuel from 3/4 to full throttle and that's where my problem lies. I did also check for possible air leaks and did tighten up a possible one between the reeds and carb(clamp seemed to be off a bit), so I hope this might help. Now I just need some hands on, after all, you forget very little hands on as compared to just reading an article. Thanks
#7
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#9
#10
CED, How did the secondary mod help your acceleration?I mainly have to depend on magazine reviews for advice on mods, but first hand experiences are always helpful. I just read ATV SPORT buyers guide 2002 and its review stated that the scambler(500&400) have the problem as in the past, that the stock clutching( to light of wieght in the driven clutch) allows the engine to rev past its hp making rpm.Have you attempted to correct this? Not that I have, just trying to learn?
98 sport 400L
rcr stage1 top end kit w/270 main jet
v force reed cage
98 sport 400L
rcr stage1 top end kit w/270 main jet
v force reed cage