axa,
I agree with you about engine swaps however I keep looking for a CG400. :lol8:
Attachment 17010
Remind me how much you milled off the head?
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axa,
I agree with you about engine swaps however I keep looking for a CG400. :lol8:
Attachment 17010
Remind me how much you milled off the head?
I've already measured up a DF250 for a GS500 engine.It's a bit tall but could be made to work.It's more work than I want to do tho,unless I found one for peanuts.
you will never find it.Quote:
Originally Posted by barnone
yikes, thank god i write things down, seems i recall taking off 35mil for a 10:1 ratio not 10.5 as i posted... that would require 50mil off. i really want to try that but when you have a bike running nice, one gets complacent.Quote:
Originally Posted by barnone
Note 20mil would actually only bump to 9.5, though on this very forum one guy defending gardo in an argument with you barnone, mentioned 20 would take it higher...
here are the notes
by the way, that was a vid of my practice run on the blown head... i have vid of the head in use somewhere...
interestingly enough i tracked down the manufacturer of this piston, and the 'customer' who requested it was some garage in the vicinity of ccw i believe.Quote:
Originally Posted by barnone
but the funny part is i learned there was only perhaps a single order of perhaps the minimum of 4 pieces ever made... at least at that time... but i couldn't get them to sell me one even if they had made any more.
That said i really would love to get my hands on a half over piston.
id try boring out the original cylinder that i had the dropped the valve a valve and see the impact
again though from what ive learned, its more about the compression at this scale... but cant say for sure until its attempted
that's another interesting note, on the box they got wiseco to print something like "compression ratio 11:0"Quote:
Originally Posted by barnone
(there was a better picture at somewhere at sometime)
Of course there is no way for a piston alone to determine the ratio, but you can have them print anything you want on your box...
and knowing ccw dubious claim history, i am doubtful of that spec
Not that it couldn't be done. You could easily raise the gudgeon pin hole center easily.
Or increase the dome of the piston which would take more careful planning.
anyway a mass of wasted money for 18cc and a shady promise of higher compression.
hmmm, maybe i should start a head decking service... 50$ including return shipping in the US 48 seems reasonable... :deal:
[QUOTE=axa;75060
hmmm, maybe i should start a head decking service... 50$ including return shipping in the US 48 seems reasonable... :deal:[/QUOTE]
I'll be your first customer. I won't be in WNC where my DF is resting until early May.
What octane fuel is required for the increased compression ratio?
Just leave the valves in the head? Just need a new head gasket?
call me cheap or call me poor but just reused the same head gasket that the engine blew with. I didn't see anything wrong with it.Quote:
Originally Posted by barnone
Its a typical metal head gasket, and while i am sympathetic in the science of the proper crush of a new gasket, I don't believe it matters on this kind of low precision engine.
I just reassembled with carefully applied rtv silicon.
That said you can get a gasket on eBay for not too much if yours didn't come off well.
I should mention I ported the new head while i was at it. I can't rule out the impact that might have on performance as well.
sometimes I fell I'm rolling on a time bomb.
http://images.tapatalk-cdn.com/15/04...abe9877418.jpg
the remains of another blown engine from a 2010
Best advise for newbies... All though I understand the challenge to improve/modify an existing machine.Quote:
Originally Posted by axa
A used Japanese 250 ( over 20 years with same engine) would be a better investment, for a commuter that needs to hold highway speeds.
If you were to bore the crankcase out 2mm... This big bore kit would make it a real "sleeper".
334cc Big Bore Kit! http://www.scrappydogscooters.com/im...e8902_zphh.jpg This had NEVER been offered anywhere, for any price. Leave it to ScrappyDogs to get this on the market. Set of 55mm big bore cylinders with matching pistons and rings for the XV250 type engine found in the yamaha virago, Vento V-thunder, Vento Colt, Diamo Cruiser, and many customer small bore choppers that have been made for years. Get the extra grunt and oomph you need! $599.95 for a complete set of front and back top end kits. Forged piston kit available by special request and order. Add 100 dollars for forged option.
First you speak of good ole Japanese bike, then talk suggest putting not as good new Chinese hardware on it?Quote:
Originally Posted by SR.MAILMAN
Not sure you can have it both ways.
Well i suppose if you had something with high mileage/motor abuse to rework...
A while back I did see this vendor put one of these big bore kits on ebay. It had a cracked fin and was priced cheap...
I searched for cheap old vx250 for days after... no dice
Remember when anything made in Japan was crap ? I hate to say this but... China is catching up, if not slowly.(not all products)
Rumor has it that some Japanese small bikes/ parts are made in China under license.
I know of one person that did the big bore upgrade and once He got the crankcase bored out
the only problem he had was the proper maximum carb jetting. ( He had switched to a side draft carb)
Maybe when the Dong Fang has been around 20 years... their will be better/bigger parts out there.
I'd just buy a VX500 instead of the big bore kit.:lol8:
Attachment 17033
+1 on a bigger bike!
If I need to go faster/farther (highway)... I take My Triumph. L.O.L.Attachment 17034
and I'd drive one of my cars. way off point, I thought we were speaking of getting the most bang, pun intended, out of your dong fangs buck.
there's a world of other things you can do with an unspecified amount of money.
in fact Japanese bikes are now occasionally produced in China, as well as Thailand I'm aware.
but note I didn't say anything about crap, you did mailman, I said "not as good", which is an accurate assessment of the comparison.
I'm fine with Chinese stuff, got plenty of it.
but if I look at my cast Chinese kit top end and then my japanese originals i know why they perform better.
My 2014 Honda CB500X is made in Thailand.No problems yet.Quote:
Originally Posted by axa
In the of-chance you may not be aware... CB500X forum aside from ADVrider etc.Quote:
Originally Posted by ben2go
Way past aware.I joined that site a while back,and it's the reason I bought my CB-X.Quote:
Originally Posted by bikerdoc
Does anyone else have a PZ30 carb on their DF-RTB's ? I was curious what the line leading from the bottom is supposed to go to. I was looking over my engine today and noticed that this line was just dangling towards the bottom, not connected to anything. I have a feeling it should be connected somewhere perhaps that is just my noobism talking. heres a picture Attachment 17038
Just a drain from the carb mate need to hang down under the engine
All DF250RTB have PZ30 carbs as far as I know. That is a drain line for the float bowl. Just let it hang down and if you ever drain the bowl let the hose into a small container to catch the gas.Quote:
Originally Posted by heist222
If you look at page 4 in the PDF below you will see the drain screw on a PZ26 which is like our PZ30.
http://wem.walbro.com/distributors/s...CAEBURETOR.pdf
who might have a link to the Honda kush bolts part number. this site search stinks.
at least 2 of my 4 just spin in place. the other 2 were lose so they should all get replaced. thanks for the help
the kush bearings are part number:
41241 307 010
sent it to myself in a PM so I wouldn't lose it...
Searched and found the bolts mentioned here
http://www.mychinamoto.com/forums/sh...olts#post60863
Honda part number for the bolts is 90128-382-670
I bought four at https://www.partzilla.com/
thanks... at least the Tapatalk app doesn't come up with anything I search for, anyone else use it with success?Quote:
Originally Posted by barnone
and it seems Google keyword "site:" search doesn't work from my android chrome browser either...
I had the part number for the kush bearings which are still good... I didn't want to wait so measured and machined 4 new bolts.
ended up spending near an hour as I had to thread with an old school die.
but now I see 17$ plus shipping for 4 bolts, yikes. maybe that was actually time well spent after all
so I finally got the 30 tooth rear sprocket on and took it for a test ride...
first impression is that this bike should have come with a 30 tooth stock.
I read allot regarding this and never found anyone to recommend it, but i say there is plenty of power stock to find an appropriate spot in gears 1 to 4 on any terrain.
Perhaps not so much in 5th, but on those occasions were your on a decline and not power bottle necked, you end up quickly gear bottled necked. A 30 tooth in 5th would be quite useful and let you climb into the 60s on those declines.... then use it to cruise at a more responsible rpm.
idk, maybe I don't recall what the stock engine was like but I think I do.
now with my head work 30 is a no bringer. I can climb to 60 (indicated) in 4th, then shift to 5th and cruise at a fairly comfortable rpm on the highway. without redlining and worrying im going to blow the engine again..
(well truth be told im always worrying about this bike, especially the egine)
I had a 30 tooth on my DF for a while but thought it was a geared a little too high for the mountain of Western North Carolina where a cruise of 50 MPH is all I need. If axa decides to do the milling of the head like he mentioned then I might go back to the 30 and bring the DF to flat Florida where you need more speed to keep up with traffic even in town.
im quite willing to get into the head milling game, but as ive tried to make it known, there are actually quite a few variables that have gone into my engine... some which may not, but may well have made a difference.Quote:
Originally Posted by barnone
So in addition to the head deck itself from 9 to 10 CR:
1. there was a new head itself, non loncin, had to rework it a bit to fit the non loncin cylinder. what are the variables here...
2. porting and mild polish the new head.
3. aluminum to steel rods (rare and hard to find)
4. back cut valves
Then does all that account for why i can run 115 jet.
And i cant discount what my P-trap mini air ram can do for my air fuel mix at high speeds..
Now no doubt i have noticeably more power, but its really hard to say the root at this point.
If i do another it may well bring some answers.
ill can deck a head to a CR of your choice, id say include the valves for a back cut and some power ringz while at it. as well as a port/polish including the carb to engine manifold.
now finding a steel set of rods is a whole other story...
axa,
I just thinking about it for now since I have not ridden my DF for six months. I left it in WNC and I have been in SWFL. I'll be reunited with it in several weeks and will then decide what I want to do to it if anything.
Thanks
yea I'm thinking about it as well.Quote:
Originally Posted by barnone
I'd be interested to know how many people might be interested...
I'm sure if you go for it concur the results, some others might as well.
there was a forum member in Alabama who also blew his engine and asked me for help... but that was a while ago before I knew what was what and he was just too far away to work with...
so I'm putting the call out for anyone in the NY/NJ/CT area who might have blown their top end or wants to do the performance conversion otherwise...
I also thought about putting out a set of stainless steel rear sprocket bolts...
its something many will eventually need and I can make them cost competitive.
but unlike engine work having a set of quality bolts isn't going to do much for your ride, so really what's the interest all around anyway...
not sure I ever answered these questions.Quote:
Originally Posted by barnone
with 10CR I still use 87 octane and don't see any sign of detonation problems... this leads to the conclusion the dynamic CR of this engine is way low.
and it will stay that way, forget about ever finding a more aggressive cam, let alone the work required to get at it.
no I need the valves out in order to mount the head in my jig.
having the valves out also allows the other head work mentioned.
Reuse the metal film gasket. use rtv silicone as assurance. if it leaks it's probably for some other reason.
or... as they say, if doing all this work why not start with a new gasket... depends on your philosophy and skill level...
anyone ever try one of these...
http://pages.ebay.com/motors/link/?n...880746&alt=web
though I would argue the cylinder head spark plug gauge takes a more pertinent reading...
I have one like it on my Kawasaki W650. Oil never seems to get over 100 C.Quote:
Originally Posted by axa
I'll order one for my DF when I migrate to WNC in a few weeks. It comes from China so I'll won't be here in SWFL long enough for it to arrive. http://www.ebay.com/itm/321584880746
It will allow me to test the effectiveness of my oil cooler on the DF.
CHT gauge is interesting to watch. I also have one on the Ural and I see CHT of 425 F when running at 70 MPH.
It cools down when idling at stop light to 320 F.
Attachment 17063
DF CHT
Attachment 17064
Oil cooler probably not needed on a stock DF motor.
Attachment 17065
2015 Ural cT
Attachment 17066
CHT gauge on right cylinder of the Ural.