[wheeler]

So some of you may know that my new build has never achieved the same results as my last quad.. I can't handle it... Making me nuts...

Old 94' Honda 300 had 355BBK with 40B Webcam. Topped out at 60mph.

New build is 95' Honda 300 with same 355BBK & 40B Webcam. Tops out at a weak 50mph to be honest. Very weak....


So I've gone thru what I like to think is everything.. and all seems good. So IF I'm right and all is good, what would cause such a loss in RPM & power top gear??

1st-3rd pulls great! 4th not bad but 5th looses power when any incline ect... Plug looks half decent...

I will take ANY advice or tips, or ANYTHING!!!!! This quad should have more power/speed for what it is if you ask me!!!! It's making me nuts that my old one would out run a 420 or 500 and this one is SLOW compared....


Tomorrow I'm going to check my cam timing. Maybe I'm off a tooth?? Gawd I hope thats the issue...

 

[fishfiles]

I would think you know the feel for what you had and what you got , and you say the engine is weak in comparison to the newer one , and it very well might be a problem with the engine but something that fits a part of your problem is that = quote / " 1-3 is great but 4th and 4th loses power "/quote = my buddy just went thru the same thing with a 300 , it ran great 1-3 and fell on it's face in 4+5 , his problem was the clutch , he put a used one out another engine ----I actually rode with him when the problem was happening a couple of weekends back and again Saturday after he changed the clutch and his problem is solved

What is the compression of that 355 kit to start with ? Have you rechecked it lately

 

[SamUK]

Now mine is running half decent I’ve found the same, 4th is ok but 5th is a real sloth! I do have a new change clutch to fit though. I’m assuming your friend changed the centrifugal Fish?
Wheeler, I did notice mine got a little better the Richer the mixture was, obviously there’s a point where you can’t richen any further though. Are you using a 350 carb?

 

[UnkleRaRa]

I say clutch.

When you're in higher gears do you see the RPM's climb without feeling any change in speed or pull?

 

[SamUK]

Reading Wheelers signature, it shows he’s already upgraded the clutch to an EBC. Would be odd for an EBC to be bad I’d have thought, there one of the leading manufacturers.
Stranger things have happened though, could be clutch.

 

[Goober]

Tire size weight width, tread types; brake adjustment; drive component bearing surfaces can all contribute to friction potential. Unless you can dyno the engine at the crank it might be hard to isolate the causes

 

[shadetree]

have ya thought about the c.d.i. ?, they have built in rev limits in them, are the c.d.i.'s the same ?, different ?.

 

[misterclean59]

I like the ideas about the clutch, lean condition and cdi. Could be a fuel flow problem too? Perhaps slightly tight valves?

 

[wheeler]

Ok, a little more background....

Old one, I always ran Honda OEM clutch packs. New one I chose EBC.

Old one ran stock CDI. New one I tried an eBay, Now Ricks CDI.

Old one had a White Brothers Exhaust. (no longer exist) New one has FMF for 300ex. (larger diameter I don't know..)

Old elevation was sea level. New elevation 2200 upwards of 4000 depending on where I ride.

Old jetting was a 142main. New jetting is a 122main. (due to elevation)

Old tires were 26" Kenda Executioners. New Tires are 26" Zillas. I went saved around 20lbs of rotating mass.


Old quad fired up fine with electric start in cold. This one will not. Like the battery is almost dead as soon as there is a chill in the air. Put new battery in and no difference. Fires up first kick though.....



I'll be checking the timing & compression of the engine to make sure all is good. I have only re-checked the valves once and they were out. Webcam calls for .004 on both intake and exhaust. I have yet to do that. The quad pulls really good like mentioned 1-3. Its not like a slipping clutch in 5th, rather it won't rev out....This is why I"m baffled. I guess I could install the OEM CDI and see what happens. I as well should go buy a tach like Fish and then I can see where I"m at in the gears which may help diagnose my issue.

 

[shadetree]

Ok, a little more background....

Old one, I always ran Honda OEM clutch packs. New one I chose EBC.

Old one ran stock CDI. New one I tried an eBay, Now Ricks CDI.

Old one had a White Brothers Exhaust. (no longer exist) New one has FMF for 300ex. (larger diameter I don't know..)

Old elevation was sea level. New elevation 2200 upwards of 4000 depending on where I ride.

Old jetting was a 142main. New jetting is a 122main. (due to elevation)

Old tires were 26" Kenda Executioners. New Tires are 26" Zillas. I went saved around 20lbs of rotating mass.


Old quad fired up fine with electric start in cold. This one will not. Like the battery is almost dead as soon as there is a chill in the air. Put new battery in and no difference. Fires up first kick though.....



I'll be checking the timing & compression of the engine to make sure all is good. I have only re-checked the valves once and they were out. Webcam calls for .004 on both intake and exhaust. I have yet to do that. The quad pulls really good like mentioned 1-3. Its not like a slipping clutch in 5th, rather it won't rev out....This is why I"m baffled. I guess I could install the OEM CDI and see what happens. I as well should go buy a tach like Fish and then I can see where I"m at in the gears which may help diagnose my issue.

my money say's it's the c.d.i. !. reason : if it kicks on first start, but slow on electric start ?, this tells me that ricks c.d.i. is junk, I don't trust any c.d.i.'s other than oem from Honda.

 

[misterclean59]

It sounds like your main jet is way to small just going by the numbers. One size down (if any) should be enough. I also like Shade's idea about Rick's CDI

 

[SamUK]

With regards to the Ricks CDi’s, he uses stock Cdi's and modifies them for the extra 1000rpm and slightly hotter spark/timing advance. I don’t doubt his work at all unless of course the cdi was bad before he modded it.
Be nice if you could try your cdi in another 300 Wheeler just to confirm it’s not a bad cdi. I’m going to put money on it being a fuelling issue, my 300 is exactly the same as your description, I know for sure mine is a fuel issue as it only happened after I welded a big split up in the exhaust silencer/muffler.

 

[shadetree]

With regards to the Ricks CDi’s, he uses stock Cdi's and modifies them for the extra 1000rpm and slightly hotter spark/timing advance. I don’t doubt his work at all unless of course the cdi was bad before he modded it.
Be nice if you could try your cdi in another 300 Wheeler just to confirm it’s not a bad cdi. I’m going to put money on it being a fuelling issue, my 300 is exactly the same as your description, I know for sure mine is a fuel issue as it only happened after I welded a big split up in the exhaust silencer/muffler.

a lot of ricks c.d.i's are a china knock off, would not be surprised if he has a dud ?..lol. and I know for a fact, if they kick start, but won't elec start easy ?, this tells me the c.d.i. is bad, i'll bank on this.

 

[SamUK]

You mean a lot of Chinese knock offs are branded ‘ricks’... Ricks are Ricks, especially if bought from Ricks.

 

[shadetree]

You mean a lot of Chinese knock offs are branded ‘ricks’... Ricks are Ricks, especially if bought from Ricks.

lol same dang thing bro...lol. buy oem..or don't buy one !..lol.

 

[SamUK]

Pretty sure you’ll find Ricks (genuine) have Philips and the OEM numbers on them, along with an engraving that corresponds to Ricks programming. That suggests, being Philips, that they are in fact modified OEM CDi’s.

I love a good old debate haha.. Can’t teach you old guys :laugh:

 

[shadetree]

Pretty sure you’ll find Ricks (genuine) have Philips and the OEM numbers on them, along with an engraving that corresponds to Ricks programming. That suggests, being Philips, that they are in fact modified OEM CDi’s.

I love a good old debate haha.. Can’t teach you old guys :laugh:

i'd rather be old and wise, than young and dumb..huh ?!..lmfaooo.

 

[wheeler]

Ok, well I made the post for ideas, suggestions, & discussion. I will re-install the OEM CDI & see what the results are.

misterclean59 -

I had difficulties dialing in the main jet. I had talked to a custom speed shop. He explained that he sees this all the time. You install a BBK like I have, & have now created more vacuum by the larger diameter piston & compression. So what happens is due to the vacuum increase it pulls fuel faster thru the jet causing a rich condition. He suggested after looking at my plug to keep going down in jet size until the plug looked good & quad ran better. So I kept going down until the top end stumble went away and power increased. I'm running a DynoJet 116 which is equivalent to a Kehien 122. So I'm only 1 size down from stock. I had to do some googling to make sure what he said checked out, and it does. With that being said, maybe I still can go down 1 more jet size I dunno. I'll take a pic of the plug and post it up. No keep in mind it won't be a plug chop, just a general idea how the engine is working...


I also booked in at a speed shop that has a dyno. They are going to weld on a bung, hook up an AFR and get readings thru the gears. Come hell or high water, I'll figure it out.

 

[SamUK]

Be nice to get the next jet down and take it along to the dyno with you, dona run as it is now and then a run with the lower jet.

I’m still learning so this is only what I’ve read... I was always under the assumption that folks used the 300ex carb or 350d carb when running a BBK. Have you considered those options?

 

[wheeler]