TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: mrtwidster1 on November 22, 2013, 05:20:40 PM
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I have a set of decent 85 r cases. I have been saving them for a big bore. Do I need to buy a year specific +4 crank or will any 85-89 work?
Also, what are the tranny differences between 85/86 and up
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The +4 hotrods crank is only sold with a 87-89 long rod on them. So you may have to run a spacer plate depending what cylinder you are using.
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As far as using 85 case's I should be good? Understood on the spacer plate. I am assuming that the 87 up cases's are "taller" ?
I guess it boils down to this question. Will a 87 and up crank work in the 85 engine?
LOL I have just about confused myself!!! (UH EXCUSE ME!! WHAT WAS MY QUESTION AGAIN???) Ha Ha :culpability:
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The cases are interchangeable on all years. The 85-86 motors used a short rod and the 87-89 motors used a long rod. The cylinders are the same but the pistons have different pin heights to compensate for the rod length.
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The +4 hotrods crank is only sold with a 87-89 long rod on them. So you may have to run a spacer plate depending what cylinder you are using.
Are you sure??
http://www.ebay.com/itm/like/280580476692?lpid=82
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Are you sure??
Damn right:sign0108: Yes Wayne, can't you tell they exchanged the long rod with a short rod? That is why it is $180 more. Go to the Hotrods website and search for the part # Carlos made up... HR4106-S does not exist. What do you expect from a snake?
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The OP meantions transmission also. Where they the same 85-88 and 89 had a "close ratio" trans?
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I'll try to help.
That crank deal on e bay is kinda confusing, cause if your going to use it, what piston could you use that wouldnt hit the crank tins. Maybe I've not built enough different types of 250R engines to know, so the only piston I could think of would be the old 85/86 version.
As Tony stated, all years of the TRX250R cases will interchange & can be mix/matched with different year model internal parts.
Some differences in how the cases are cast should be noted, like the width of the front engine mount is wide cast & other years it is narrower. The narrow type front mount, say like if attention is not paid to the engine to frame mounting bolts & most have for some reason came loose, that little narrow front mount could break off, but theres been very few that I have seen broken.
The 85/86 cases, how they are cast, they are thicker cast directly under the crankshaft area, so they are good to use like if your building a stroker crank build that the cases must be trenched, from using an abnormal type of con rod that the big end of the rod not clearanced. By those being thicker in that area, if trenching is needed they tend to retain a bit more strength because of that thickness.
The transmissions, early 85/86, some of those gears are different ratios than the 87 & up gears. The ratios between the years I do not know, just that some are different. Early year gears were more prone to busting, reason why could be many reasons. Maybe they were hardened to much, so they were in turn more brittle or maybe to soft, not hardened enough.
I do know this about them, the ratios of the early years, those ratios when used with a high compression big bore grunt engine build, in a race when you shift to third, every body else on the line is history, but you have in the back of your mind wondering when they will bust.
The 87 & up being the best, will last the longest & has the closest ratios, but one of those can still be busted.
If there has ever been a late model transmission been through a test, it has been my daughters, because once she leaves the start line in a race, that clutch lever not touched up shift or down shift. I guess she must think its an automatic, but I know she knows better. Since 04 her engines only been rebuilt once & we've only had one gear to bust in all those years & believe me, in those years the engine has been beat on racing national level & local EDT racing.
Do not, mix & match transmission gears from different years.
If you have a problem with a trans & need to replace an item, do the research & be sure to get the proper year replacement part. Keep 85/86 parts together & dont mix with the newer years.
You can to some extent research, go to like an OEM parts site, pull up the micro fisch & look up the transmissions of different years & it will list the gears & how many teeth that each has. Make a list of each year & each gear & the teeth count & you'll know which gear matches up with which year model.
After you have that list in hand, if you pull a transmission out, all you'll need to do is count the gear numbers to know which year trans your dealing with.
TRX250R OEM cylinders, if you measure them they all measure the same from base to deck, can be mismatched between years on all year cases & just a mater of using the correct year piston & crank combination.
Neil
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Thanks! That info helps as well.
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OK I did some searching so i'll bring this post back to the top.
What is required to run the +4 crank? If I install this crank in my 86 engine using my topend what is needed? Porting changes? Spacer plate? Both?
thanks
Joe
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FYI that crank is specially built for BDT. So what proof do you have that he isnt getting a Short rod +4mm crank? Im just trying to keep the facts straight. Sorry for the ensuing argument.
BDT Link Removed
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I'm talking about a standard HotRod +4 crank. Sorry for the confusion
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:fighting0071:
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JoePA,
If you're running a +4 Crank (assuming the Long Rod version - 130.5mm Center to Center) with a '86 Cylinder & '86 Piston....you will need a Spacer plate to take into acount the 2mm of extra vertical travel that the piston will have (+4 = 2mm up & 2mm down)
Also, with the rod being 5mm longer you'll need the spacer plate to account for that too! (Most people use a 3/16" Aluminum spacer plate....or a 0.190" as some sell them in this size too) - PUMASHINE is the man for these!
So you could start with a 7mm (0.275") spacer plate.....or 1/4" (0.25") and then check your Port Timings & SQUISH....Let us know your values and we can direct you in the right direction. - C-Leigh Racing will chime in once we know what type of motor you want to build.
:)
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Are you sure??
http://www.ebay.com/itm/like/280580476692?lpid=82
HAHAHA. $100 markup for a Wurks crankshaft
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OK I did some searching so i'll bring this post back to the top.
What is required to run the +4 crank? If I install this crank in my 86 engine using my topend what is needed? Porting changes? Spacer plate? Both?
thanks
Joe
The spacer plate depends on the piston. The crank is a long-rod crank. If you have a piston that is designed for a short-rod crank (either a new piston or re-using your current one), you will need a spacer plate in order to use that piston with a long-rod crank.
As for the rest of the engine, all the port timing is based on the movement of the piston. Since the stroker crank changes the movement of the piston, it also changes all your port timing. Your cylinder would need to be ported specifically for your new stroker crankshaft. If it has already been ported once for a stock-stroke crankshaft, there is a very good chance it cannot be used for your stroker, you would need to get a new cylinder that has never been ported.
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Langbolt,
OK now that makes sense. Can I also try this setup.....+4 crank, an 87-89 piston with my 86 cylinder, use a standard spacer plate and just make sure port timing looks right as well as squish?
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HAHAHA. $100 markup for a Wurks crankshaft
ebays seller fees are now rediculous they have removed all profit i had in stickers and other things i was selling. So expect to see all things Ebay going up across the board with their new seller fees.
that Buy it now option is likely 59$ ebay fee. if it scales from 200-394$ the same rate they are charging me
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ebays seller fees are now rediculous they have removed all profit i had in stickers and other things i was selling. So expect to see all things Ebay going up across the board with their new seller fees.
that Buy it now option is likely 59$ ebay fee. if it scales from 200-394$ the same rate they are charging me
Wow that's ridiculous. What a ripoff. It's just too easy to take a swipe at the coc i couldn't resist
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FYI that crank is specially built for BDT. So what proof do you have that he isnt getting a Short rod +4mm crank? Im just trying to keep the facts straight. Sorry for the ensuing argument.
BDT Link Removed
website says they offer crank stroking and balancing. aparently they dont do this service in house but just contract it off to another shop ?
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Where do you see they dont do that in house? I dont see it anywhere. I guess if they dont say they contract it out, they must do it in house. I believe that we have seen there jig for rebuilding cranks actually as well.
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When using a STD stroke long rod crank & 85/86 piston, regardless of which year cylinder, if you want the piston crown to come up flush with the cylinder deck at TDC, you'll need a 3mm spacer plate & 2 base gaskets to go under the cylinder.
Now when adding a +4 stroker crank into the mix, you know the piston will travel 2 more mm higher at TDC & then 2 more mm lower at BDC, so when using a + 4 stroker crank with a long rod & using the old 85/86 piston, a 5mm spacer plate & 2 base gaskets must be used.
Another way to do it, not the best way, but some will just use the 3mm spacer plate & 2 base gaskets, then they will machine the head squish area so that when the piston crown comes up out of the cylinder, that extra 2 mms of piston sticking up past the cylinder deck can run up into the head.
When adding a +4 stroker, the Hot Rods will have the big end of the rod clearanced, so no trenching of the cases will be needed, but you'll still need to clearance the cases right at the top right in the middle to clear the front & rear I beam part of the rod.
Best way to see what I'm say, if you have one of those clearanced main bearings for the clutch side case half, where the crank will slip right into the bearing, put that crank in the clutch side half, mount the piston on the rod & then sit the cylinder down on that case half & slowly rotate the crank.
You should notice as your rotating the crank, see the front & rear of the rod litely hit the case right at the top, so you'll need to clearance the cases in those areas. As far as I know, the ESR stroker cranks, the rods on those have been clearanced a bit more in that area of the rod, so probably no clearancing needed if using one of theirs.
Neil
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If you install the plus 4 stroke (76mm) crank into your 86 TRX 250R it will advance all your port timings. For example if the exhaust port is stock it would be about 43.20 mm from the top of the cylinder. With the stock stroke this would give you total exhaust port duration of about 176'. If you installed the 76mm stroke crank with the 86 piston and a 3/16" spacer plate the exhaust duration would be increased to about 180' . The stock transfer timing stock is about 120' (59.10 mm). The stroker crank would advance it to about 126'. The piston would come out of the top of the cylinder about .030".
I would probably machine the head for deck clearance rather than space the cylinder to 0 deck. 126' degree's transfer is enough for that cylinder but it could use more exhaust timing. So depending on what the engine is being used for I would raise the exhaust port to 183-186 degree's. Of course for best results a lot of other work could be done to improve the porting.
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Great info. I just pulled a '86 cylinder that was "ported" by some one (they ground on the easy to reach areas). Anyway I just measured the port heights and they match your numbers exactly. Fyi I don't port and likely never will.
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Great info. I just pulled a '86 cylinder that was "ported" by some one (they ground on the easy to reach areas). Anyway I just measured the port heights and they match your numbers exactly. Fyi I don't port and likely never will.
Porting will really wake that cylinder up. Porting is worth more than the crank for sure. Improving the transfer port angles will make a big increase in acceleration. The cylinder stock also has very mild port timings. It will make close to 50 hp with the right port, pipe reed valve and carb combination. And it will have a wide power band with killer low end and strong midrange power.
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That '86 is an R rescue, I'm like the humane society for R's lol. I saving up for a sphinx. Hopefully you keep a few in stock.
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Where do you see they dont do that in house? I dont see it anywhere. I guess if they dont say they contract it out, they must do it in house. I believe that we have seen there jig for rebuilding cranks actually as well.
well the ebay add says they had the crank specially made for them. sounds like somebody else is doing the work.
they probly have a press for installing new rods but stroking is a whole different ballgame with different machining equipment needed
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That '86 is an R rescue, I'm like the humane society for R's lol. I saving up for a sphinx. Hopefully you keep a few in stock.
It may be a sickness! But I don't judge! lol
Anyone that rescues 250 R's is ok by me!
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I believe Hot Rods is building them new cranks is what is happening. So i guess if that means some one outside is building there cranks then i guess you can say that. But thats no more than any other shop that sells new cranks.
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any joe blow can buy that crank so it aint special for nobody. just marked up $160 more . too funny
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Seeing how Hot Rods doesnt list it. Im not sure you can.
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http://www.hotrodsproducts.com/ProductInfo.aspx?item_id=643
can get em on ebay $240 with free shipping http://www.ebay.com/itm/Honda-1987-1989-TRX250R-Stroker-4mm-Hotrods-Crankshaft-Crank-/181160546786?pt=Motors_ATV_Parts_Accessories&hash=item2a2e0291e2&vxp=mtr
not sure why bdt is $400. maybe they sprinkle some magic dust on the bearing
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Same thing he does with the Chinese radiators
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http://www.hotrodsproducts.com/ProductInfo.aspx?item_id=643
can get em on ebay $240 with free shipping http://www.ebay.com/itm/Honda-1987-1989-TRX250R-Stroker-4mm-Hotrods-Crankshaft-Crank-/181160546786?pt=Motors_ATV_Parts_Accessories&hash=item2a2e0291e2&vxp=mtr
not sure why bdt is $400. maybe they sprinkle some magic dust on the bearing
Umm those are all 87-89 Cranks. the one listed above for BDT that is specially made is a 86 crank with the short rod. That is the difference.
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Same thing he does with the Chinese radiators
:nose-pick:
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Your IP adress matches others we have banned. Bood bye!(http://www.planetsand.com/forums/images/graemlins/default_dark/1076080-1.gif)
lol that coc is a sneaky little bugger
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yea the coc is on this site more than he is on the net.I think he misses us
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guys I have a 4mm stroker long rod trx and I'm putting a cr 250r top end on it. does any body know what the port timing should be. the motor is for drag.
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i dont like to think of it as just timing. you have width to consider also. i believe this is where knowing your angle area becomes important. PV cylinders can be tricky because you dont always have the same freedom to do what you want like a non PV cylinder
you talking about the '01 style cylinder ? im not familiar with that engine but if you know what rpm the valve is full open that might help. if your always above the rpm when the valve is open then you might be better with the valve gone and use a plug. im sure somebody makes a plug for those. this may allow a better shaped port. im speaking hypothetically here because im not familiar with your engine but you might check into it