Slow 2017 HiSun Strike 250

[Fun Dad 0]

Guys,

I need some expert help..  I just bought a 2017 HiSUN Strike 250 and was real disappointed to find out that there is an electronic spark cut out at 30 mph.  Every article that I read prior to purchase said that the unit could hit 45-50 mph with the pedal stop screw removed.  Not the case with my machine.  Never bothered to ask the dealer before purchase, so it is my fault...  My guess is that HiSun got some flack about thier "kids" machine doing 50 mph and were forced to add the electronic limiter..  Can anyone verify that previous to the 2017 model that the machine can actually could do 45-50mph with the just pedal screw removed?  If so, what RPM is it at when doing 45-50 mph.  Maybe I can get an older version of the Delphi ECU, assuming that is where the spark cut out is located...?

The machine is definitly full featured, but as you all mention, needs to be gone over after purchase.  A-men to stipped screws, and if you suffer from a crazy squeak sound that sounds like chains dragging, check the torque on the suspension a-arms and shocks.  Ours were so tight, we could barley get them loose and the suspension would not move, essentially zero travel.  Once we lightened up the torque, greased the plastic bushings, and added blue threadlocker, the suspension actually worked and all the squeaks went away.  Also have same problem with the shift linkage rubbing on pipe and also pipe rubbing on chassis.. This weeks project!

Any help on the speed would be awesome!

[strike250 39]

Hello there, there are a couple of things to address here. First off is to make sure when the throttle peddle pressed all the way down, that the throttle is also opening all the way. You can check this by removing the center cover. When you press down on the throttle, reach over to the butterfly valve and see if you can open the throttle any more on the throttle body. If so, adjust the throttle cable. But you need to make sure when the throttle is released that the throttle also closes as well. Meaning you will have just a little bit of slack in the throttle cable. You don't want the throttle body hanging up causing the engine to rev. After that, there is come control in the ECU, but there is also a electronic speed limiter, located under the dash by the winch control box. Try to make sure the throttle is adjusted properly first and let me know. Matt

[SlickNick 5]

Matt, any luck with Flashing the ECU as of yet? It’s a Delphi so I assume any Delphi Diag. Shop should be able to adjust the settings. I know Harley uses the Delphi setup, and I know the support for Harley is crazy good. Let me know if Hisun got you hooked up yet. I’m heading to the Pink Coral sand dunes for spring break. Imperial Sand dunes went good as well.


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[strike250 39]

Yes, I am very close to making a public flash for the OEM ECU's. As for just taking it to a local Delphi shop, it's not that easy. Yes others like Harley use the Delphi MT05, but they use different language. It took me a while to gain access to the language needed to rewrite the ECU. But I finally got it and am working on making more power while still being reliable. I will make everyone aware when its done. But I want it done right. I will either have it available to purchase as a new ECU, or have the customer send me their ECU to remap. I'm thinking some will want to keep a stock ECU for one reason or another.

[SlickNick 5]

Yes, I am very close to making a public flash for the OEM ECU's. As for just taking it to a local Delphi shop, it's not that easy. Yes others like Harley use the Delphi MT05, but they use different language. It took me a while to gain access to the language needed to rewrite the ECU. But I finally got it and am working on making more power while still being reliable. I will make everyone aware when its done. But I want it done right. I will either have it available to purchase as a new ECU, or have the customer send me their ECU to remap. I'm thinking some will want to keep a stock ECU for one reason or another.

Valid points. Yeah, let me know.


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[SlickNick 5]

Valid points. Yeah, let me know.


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Also, I noticed the 3 screws holding the spark arrest and exhaust cover/tip on the exhaust were completely stripped out and falling out. I removed them as well as the arrester, however the tapped threads were so stripped I can’t put it back. Any luck with a new exhaust being available as of yet?


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[strike250 39]

Just an update on the slow unit issue. I wanted to make sure I get back to everyone regarding the slow top speed on their Hisun 250's. After confirming with HiSUN, the 2017 and newer units have a different gearing inside the engine as well as a modified ECU. This was in response to customer feedback regarding top speed. Some customers were complaining about the units going too fast. So HiSUN changed some things to help control this. I am sure this is the new response from most manufactures now a days.  As no one wants to get sued or have legal issues. It has gotten to be a very liable state we live in now, and if just a few people complain about something, things get changed. I am working on new sprockets which should be here within a week. I am also working on the ECU and hopefully it will be done about the same time. I have yet to confirm if the old gearing will still be available or if it will automatically supersede to the new part number. I will keep everyone up to date on my website.

Matt

[DigitalDan 4]

I just purchased a new (5 miles on it) 2016 Sector 250 that has the same electronic spark cut-out at 7000 rpm / 30mph.  Ugh...  hate that sound.
The gauge's "red line" is 9500-10000, although I doubt that would be safe for the little engine that could...  What is the safest RPM these 250's can run?

[strike250 39]

Hello there,

I know about the early cut out on the newer models. As for the RPM limit, I have seen the gauge and know it says a high RPM, but a few things come into play about that. First off is that most gauges show a higher than capable limit, in cars, truck, motorcycles and more. This is to give the illusion that the vehicle can go crazy with the RPM range. Reality is that most vehicles have a RPM limit below what the gauge actually says. This is for reasons of reliability and engine safety. The HiSUN is good till about 8000 or so RPM. Anything over that and the horsepower starts to fall.  On the newer ones the gearing is also changed. The rear sprocket is a 42, and used to be a 38. The spark cut out to limit the speed to around 30 can be changed with some ECU programming.  We are changing the rear sprockets to 40 and opening up the ECU and installing the tune of the 2015 ones. They seem to run pretty good with this configuration. When an engine revs too high, some things can happen. One of the most dangerous things is to have the valves float and that could lead to the valves hitting the piston causing damage. The second thing is the loss of power when it revs too high. the engine and cams can only produce power until a certain level, so all that noise will no nothing for more power, just make it sound like a buzz box. So again, the answer to your question is that it can safely rev up to about 8750. but the power really stops at around 8000. In these small engines, they really rely on torque, and that is produced down low anyhow. Since they only have about 12 to 15 hp stock, even with a race set up, it will go to about 20 ish. which means not a lot of hp to get these things moving. they really crave the torque to get them up and going, and that is produced at a lower RPM rather than a high one.

 

I hope this answers your question.

[DigitalDan 4]

Yep, that answers my question perfectly.  Looks like there's a new ECU in my future (or some reprograming, at least), and possibly a new rear sprocket.

Thanks for the info!

[strike250 39]

Don't forget about the new exhaust pipe

[DigitalDan 4]

I'm not trying to ring every ounce of speed out of the little 250.  If that was the case, I'd start by losing some weight, lol.

It's that electronic cut-out / stutter that drives me crazy.  If it only went 30mph, but sounded like it was running right, I probably wouldn't even bother.
It might be a different story if I line up against someone in a different Sector 250 and they dust me, but that won't happen, I don't think.

[Fun Dad 0]

Hey thanks again everyone for helping me with my original question..  Bear with me, but I am still confused  as to how all of us that bought 2017 or newer units can get back to the prior models performance where the top speed was much faster.  (up to 50 mph per magazines reviews) .

If any Advanced Members can make it really clear what Hisun exactly did to slow the machine down, then the the rest of us with 2017 machines have a chance at getting the top speed back.

I have been told that the EFI module (Delphi MT05) has been reprogrammed and a spark cutoff has been added at 7000 rpm.  I can confirm the cutoff with my machine!  It makes it extremely annoying for anyone to ride behind this machine on the trails and roads while the engine continuously hits up against the cutoff.   It does not just happen once and a while, but all the time while riding!  It's terrible!  Sounds like the machine is constantly backfiring!  If this is really true, then we should be able to replace the current 2017 ECU with an older pre 2017 version with the old software, right?   If anyone can answer this question, that would be really good to know.  Not a cheap solution, but at least gets us back to where we expected the machine to perform and eliminates the extremely annoying lower spark cutout at 7000 rpm...    Also, for anyone that has a pre 2017 machine, can you confirm what is the max RPM you get off the dash when you have the machine at full throttle?  Is it 7500, 8000, 8500 or what?   This will help us understand what else was changed on the machine to effect the top speed.

I have also been told by people in the blog that the final ratio on the machine has been changed as well on the 2017.   I currently have 11 tooth drive gear and 42 teeth on the final sprocket.   It has been suggested to change the final sprocket to 38 to get some speed back.  Unfortunately when I do the math, you only gain  3.1 mph.   This helps a bit, but I am still way off in my mission to go from 30 mph to 50 mph...  So I am still confused.   See the math and the speed table I have attached.  I am not very smart, so if anyone can show me the error in my calcs, feel free to correct.  Note: Since I was not able to count the gear teeth in the gear transmission, I solved backwards for the gear transmission ratio in high gear to be 4:1.   At engine an speed of 7000 rpm, 4:1 ratio in the transmission, 11/42 ratio on the final sprockets, and a 22 in dia. tire,  it gives me my current measured speed off the machine (gps) of 30mph.   Just to be sure, if anyone can confirm the transmission ratio to be 4:1 in high, that would help as well as what is the tooth count for the Drive and Driven sprockets on machines pre 2017.  This would also be huge because then in addition to changing out the ECU, we could simply just buy the older sprockets (and chain) with the original ratio and get our speed back!

Now, I still have one more area that we did not address..  The CVT.  Did they change it to effect the top speed?   On my little 90 cc Kawasaki ATV, they put a spacer in the primary clutch to prevent it from closing all the way and get the final ratio.  I heard this was common on the smaller kids machines to slow them down when the kids were small, and could be removed by parents as the kids got older.  Can anyone comment as to whether Hisun would have modified the primary clutch on the 2017 models, limiting the travel of the two sheaves?  I still think about this one because when I ride the machine, it seem to climb to 7000 rpm very quickly and then cutout.  It definitely feels there should be more top speed prior to hitting the cutoff.   It feels as thought the  clutches cannot get to their final ratio.  (belt highest on Drive clutch, lowest on Driven clutch)   Any insights?

The last question I have is related to the response I got from Strike 250 Advanced Member:

Hello there, there are a couple of things to address here. First off is to make sure when the throttle peddle pressed all the way down, that the throttle is also opening all the way. You can check this by removing the center cover. When you press down on the throttle, reach over to the butterfly valve and see if you can open the throttle any more on the throttle body. If so, adjust the throttle cable. But you need to make sure when the throttle is released that the throttle also closes as well. Meaning you will have just a little bit of slack in the throttle cable. You don't want the throttle body hanging up causing the engine to rev. After that, there is come control in the ECU, but there is also a electronic speed limiter, located under the dash by the winch control box. Try to make sure the throttle is adjusted properly first and let me know. Matt

I have not got a chance to adjust the  throttle cable yet, but I will follow your advice.  Since I was accelerating good up to 7000 rpm and the cutout was kicking in, it did not seem like my issue was a partial throttle condition, but I will chack any how.  The big questions I have is the "electronic speed limiter under the dash" that you mentioned...   What exactly is this and what does it look like?   Is this the real problem?   Nobody else could confirm this existed..   Could not find it the first time I looked.  Any more information you can give on this would be AWESOME!!

BTW, my dealer has been totally useless since I gave him the check, so it anyone can recommend a good place to get parts for the unit, let me know.  Thanks! 

Please, if anyone can help out and make this speed thing simple, it would be great for the rest of us!    Even better would be if someone was to offer a kit will all the components to get the machine to perform at pre 2017,  I bet everyone would buy it!!

Love the machine, hate the performance!

Fun Dad

 

 

 

 

 

 

 

 

 

Strike 250 Speed Calculations.xlsx

[Fun Dad 0]

On 3/11/2018 at 1:32 PM, strike250 said:

Just an update on the slow unit issue. I wanted to make sure I get back to everyone regarding the slow top speed on their Hisun 250's. After confirming with HiSUN, the 2017 and newer units have a different gearing inside the engine as well as a modified ECU. This was in response to customer feedback regarding top speed. Some customers were complaining about the units going too fast. So HiSUN changed some things to help control this. I am sure this is the new response from most manufactures now a days.  As no one wants to get sued or have legal issues. It has gotten to be a very liable state we live in now, and if just a few people complain about something, things get changed. I am working on new sprockets which should be here within a week. I am also working on the ECU and hopefully it will be done about the same time. I have yet to confirm if the old gearing will still be available or if it will automatically supersede to the new part number. I will keep everyone up to date on my website.

Matt

When you say "gearing inside the engine"  what does that mean?   In the 2 speed geared transmission, in the CVT, or the final sprocket ratio?   This is great information,  please share more insight if possible.  Thanks!!

[strike250 39]

Wow, what great questions.

I will do my best to answer them.  First off you had asked about the EFI Delphi MT05 module has been altered since 2017. they did change things to slow down the UTV per customers complaints that it was going too fast. So, being the large company HiSUN is, they wanted to avoid any litigation in court and damages. They altered the vehicle in question to slow it down. They did this by doing a couple of things, one of them was to change the mapping in the ECU to control the top RPM limits. Second was to change the gearing. This was done in two ways, first was changing the final gear ratio from 11 front sprocket and 38 rear sprocket, to a 11 front sprocket and a 42 rear sprocket. The second thing was to change the internal gearing. They changed the main shaft in the transmission, the output shaft and the counter shaft. They all have gears that when changed with the final gear ratio helps keep the unit down on top end speed.

[strike250 39]

There is no change to the clutch assembly, both the primary and secondary clutch assemblies are the same in all years. They changed the gearing on the shafts in the transmission which has a direct relation to the output shaft speed. This along with the rear gearing and the modified ECU, keep the 250 at a to speed of about 32 is mph. It also controls the RPM so that the clutch wont engage all the way. I am able to open up the ECU through software programming. Also I have sprockets for the rear to allow a better top end speed. But to change everything back to the pre 2016 version, you would have to split the cases, and change the three shafts inside the transmission. This is not a realistic option for most. So, with the ECU opened up and set to pre-2016 flash, and the rear sprocket at about a 40 tooth, it seems to help a lot. You will get a higher top end but still keeping the off the line speed most of us enjoy. I call it a compromise.

[Fun Dad 0]

1 minute ago, strike250 said:

Wow, what great questions.

I will do my best to answer them.  First off you had asked about the EFI Delphi MT05 module has been altered since 2017. they did change things to slow down the UTV per customers complaints that it was going too fast. So, being the large company HiSUN is, they wanted to avoid any litigation in court and damages. They altered the vehicle in question to slow it down. They did this by doing a couple of things, one of them was to change the mapping in the ECU to control the top RPM limits. Second was to change the gearing. This was done in two ways, first was changing the final gear ratio from 11 front sprocket and 38 rear sprocket, to a 11 front sprocket and a 42 rear sprocket. The second thing was to change the internal gearing. They changed the main shaft in the transmission, the output shaft and the counter shaft. They all have gears that when changed with the final gear ratio helps keep the unit down on top end speed.

Awesome info!!!  So assuming we can get the ECU  rpm limit changed, via reprogramming or a getting an 2015 unit, then all we have to do is compensate for the gearing changes.   So it's unlikely that those of us with slow units will make the internal engine changes, but we should be able to compensate for the reduction on the final sprockets, right?   Are you confident that just changing the rear sprocket to 38 will help, or will we have to go much lower in tooth count?  Also, what does a stock 2015 unit max out on in respect to revs? 

[strike250 39]

The old parts numbers for the pre-2016 250's internal transmission are:

MAIN SHAFT P013000222010000 $75.00 (OLD PART #)

MAIN SHAFT P013000222010200  $75.00 (NEW PART #)

 

OUTPUT SHAFT 22300-013A-0000 $140.00 (OLD SHAFT)

OUTPUT SHAFT 22300-013-0000  $140.00 (NEW SHAFT)

 

COUNTER SHAFT 22220-013-0000  $105.50 (OLD SHAFT)

COUNTER SHAFT 22220-013-0001  $105.50 (NEW SHAFT)

 

 

[Fun Dad 0]

1 minute ago, strike250 said:

The old parts numbers for the pre-2016 250's internal transmission are:

MAIN SHAFT P013000222010000 $75.00 (OLD PART #)

MAIN SHAFT P013000222010200  $75.00 (NEW PART #)

 

OUTPUT SHAFT 22300-013A-0000 $140.00 (OLD SHAFT)

OUTPUT SHAFT 22300-013-0000  $140.00 (NEW SHAFT)

 

COUNTER SHAFT 22220-013-0000  $105.50 (OLD SHAFT)

COUNTER SHAFT 22220-013-0001  $105.50 (NEW SHAFT)

 

 

Thanks so much!!   Do you think I can still get them?  If so, do you know who can sell them to me?

[strike250 39]

On our 2015 unit we use for R&D, I think we have had the RPM close to 8750. But I am not sure how reliable the gauge is in the dash. We are doing some dyno testing currently. I will check the dyno for a good readout. I am not sure about going to a 38 in the rear with the newer internal gearing, but with our ECU flash and a 40 rear tooth, it should help a lot.  We are now selling rear sprockets that are split. This allows you to change the rear sprockets in the rear without removing the entire axle assembly. The new split sprockets will be up on the site by monday. But we do offer a new re-flash on the ECU. Just send in yours and we will re-flash it, or unlock it as it is sometimes called.

Keep in mind, with many rear sprocket changes, you might end up having to remove a link in the chain if you go to small in the rear due to the limits of the chain adjuster slot. We are also offering updated chain adjusters, easier to adjust than the OEM version.

 

 

[Fun Dad 0]

2 minutes ago, Fun Dad said:

Thanks so much!!   Do you think I can still get them?  If so, do you know who can sell them to me?

Let's say money wasn't an issue, do you know where I could get a new 2015 ECU?

[strike250 39]

I have a guy I use that is an authorized HiSUN parts supplier. You can get him at:
 

[email protected]

Let him know you hear of him from 250UTV.com and he will take care of you. He also does a great price for my customers.

[strike250 39]

I can get the 2015 ECU, but its pretty easy to just send me yours and I will re-flash it for you. I normally charge up to $100 for this, as a new ECU is about $344.00. You would only need to purchase a new ECU if you wanted a stock one and a modified one to exchange.  I will do it for $80.00 for any customers from this site.

[Fun Dad 0]

1 minute ago, strike250 said:

I have a guy I use that is an authorized HiSUN parts supplier. You can get him at:
 

[email protected]

Let him know you hear of him from 250UTV.com and he will take care of you. He also does a great price for my customers.

Awesome, for sure I will mention you!!   Also, can you explain what the Speed limiter 37910-120-0000 under the dash does?  I believe this is what you referred to in past comments?  What does it do and why would they have both a separate limiter and the rev limiter in the engine?

[strike250 39]

This is something I do for the folks out here on the westcoast that race these units. They want all the speed they can get. I do change out the transmission gears as well as rear sprockets, ECU tuning, and of course our exhaust system.