We've gathered the most frequently asked questions from our customers and explained them here. You can see the answer to a question by clicking on the question you want to know more about.
Most of our VHM inserts do not fit the standard heads, they only fit our billet VHM heads. These inserts can be found in the article group VHM head inserts.
However, we have developed a few special inserts for standard cylinder head covers. These inserts, which fit the OEM head, can be found in the article group OEM head inserts.
In addition, we can make a custom insert (to your specifications) for the following OEM cylinder heads:
More information about custom inserts can be found on our VHM project page.
These custom inserts can be requested by filling in the order form custom inserts, which can be downloaded by clicking on the link below. This form can then be send to your VHM dealer in your country or by sending it to info@vhm.nl.
For all our heads we offer a blind (blanc, unmachined) insert, so you can machine the combustion chamber yourself.
These blind insert part numbers mostly end with -A, which can be found on the insert box. The last three digits of the insert part number are also engraved on the insert itself.
For each VHM insert we've indicated which type of insert it is, so you can easily recognize if it's a blind insert. We have 4 types of VHM inserts;
For more information about these types of inserts we'd like to direct you to our VHM insert information page. Or check the video below.
All our inserts are engraved with the last numbers of the article number of that insert. This way you can always check which volume, squish and piston height your insert has, by searching for the part number on our website.
The engraved number could also indicate a blind insert (often ending with -A), of which we don't have the specifications as these are machined by someone else.
You can search your insert's specifications on our website by entering the article number into the search bar. See the video below for instructions.
In the combustion chamber, when the piston goes to the top (highest point, top dead center), gases are ''squished'' out. This effect depends on the squish bands, which has a certain (squish) size.
Measuring the squish is often not entirely accurate and usually you measure a slightly bigger squish (especially when measuring on one side). Measuring the squish simultaneously on two, or even four sides is more accurate then only on one side. Also, if you use tin that's too thick, then the measurment is also less accurate. Below an instruction video of how to measure the squish size. Also check our suiqsh measurement instruction page for more information.
When your piston height is different from what's on the label of the insert box, then you can use our insert calculator to calculate the actual squish.
When using our billet VHM head AND insert, you do not have to modify anything else for usage. So to use a VHM head, you only need a complementary VHM insert (which are seperately available). You can use the original seals.
In some cases the headset comes including some nutcaps, washers, extra O-rings or for example a seperate waterpipe. This is mentioned at the product page of the specific VHM head.
In addition, it's not necessary to change the ignition, keep it in the original state.
We do make custom inserts (to your specifications), but only for the engines we have developed VHM cylinder heads and for some specific OEM heads which are indicated in our assortment.
To request a custom insert, you can fill in our VHM order form custom inserts (see link below) and send it to your VHM dealer in your country.
You can read more information about our custom inserts on our VHM project page.
To make sure you have the correct volume and squish, you should check if you have the right piston height. If the piston height is the same as prescribed for the insert you are using, then you have the right squish as well.
Here you can see a video of how to measure the piston height with our VHM piston height measuring tools. You can read the whole manual on our piston height measuring page.
We also have written an instruction manual on how to measure the squish which you can consult.
The best insert depends on what you need from your engine. For more bottom power (but compromising top) you should use an insert with less volume. For more top power (but then compromising bottom power) you should use an insert with more volume. For an overall best performance, we would advise our VHM standard inserts. For specific advice you can always ask your VHM dealer or ask us.
Important to note is that we have two piston models. One is a standard, direct replacement model, which can be placed into your engine with no other adjustments needed. We also have some special piston models for maximum performance gain, which can only be used in combination with a special VHM insert or longer conrod. Whether a VHM piston is a direct replacement or special mode, is indicated for each piston in the filter information.
Click on the image below to see it in full size:
You can use different thickness of base gasket to setup the correct piston height and squish. If you don't do this, the volume will not be correct. Either the compression will be too high or too low. Best to check / measure the piston height when the cylinder (and gasket) is mounted and with the nuts tightened. We've developed a special VHM tool to measure the piston height. We've also written a piston height measure manual.
Here you can see a video of how to measure the piston height with our VHM piston height measuring tools.
We test a lot in our Dyno room and have several test graphs from many bikes and engines. However, as we get a lot of questions about dyno results, we've decided not to show any graphs on request. Hopefully you can understand our policy on this.
We did however gather all our Dyno test video's, pictures, VHM parts used and graphs at our VHM dyno test page, so you can easily see them in one overview.
At VHM we do not tune any complete engines ourselves. We only develop tuning parts, so our dealers and sales points, teams and customers can do the tuning, using our VHM parts.
For engine tuning, we'd like to refer you to our VHM dealers.
We have many dealers in Europe and all over the world who sell our products. You can easily find them through our dealer locator.
When there is no VHM dealer in your country, you send an email with the parts you'd like to order to info@vhm.nl. It will be handled from there.
Only when you have a company that's related to engine tuning / racing and you are interested in becoming a VHM dealer, you can fill out our dealer request form.
To know what VHM parts we have for your bike or engine, you can use the part finder on our homepage. You can fill in the application, make, model and year of your bike/engine choosing from presets. When there are no results, this means that we have not produced any parts for this specific bike or engine. You can always request for specific parts by sending an email to info@vhm.nl.
Our part finder starts with an application field, from which you can choose certain motorsport categories. You can also skip this field and directly select a make or model if you want to.
When you've clicked on a certain field (wheter it is the application, make, model or year field), you can also start typing the application/make/model/year you want to search for. The drop down menu will then automatically show you the results that fit your search term.
If you want to start searching for a new bike / engine, you can click on the black 'Reset' button to empty all the fields from the part finder at once and start a new search.
It's also possible to reset (or empty) a certain field from the part finder, by clicking on 'Reset filter' from the drop down menu.
When there are many parts available for your bike / engine, you can narrow your search further by using the extra filters like brand, group, category, article group, and so on.
Our prices are mentioned excl. VAT in our online assortment. To see a complete overview of our prices you can also go to our downloads page to download our VHM pricelist.
We have many crankshaft modifications we perform regularly. These are indicated on our VHM crankshaft modifications page or see the list here:
If your crankshaft is not on this list, you can always ask us for a possible modification on it. We then asses the possibilities (as not all crankshafts are fit for modification and rebuilding) and in some cases we'll calculate engineering costs for constructing the right inertia and balance, besides the modification costs. You can send your request to info@vhm.nl.
We sometimes work on a special project. We have 4 project categories: inserts, crankshafts, connecting rods and other projects. You can read more about this at our VHM project page.
If you are interested in becoming a VHM dealer, you can fill in and send us the dealer request form. We only review requests from motorsport related companies.
At our website, we've divided all our parts into 5 groups: Chassis parts, Engine parts, Merchandise, Tools and Sales corner. From our assortment page you can click on a group to see the categories of that group. Within these categories, there are certain article groups.
See the video 'How to view the complete assortment' for a short screencast instruction
If you want to search for a specific part on our website, you could best use the search bar. You can search by part number or by keywords.
If you know the part number you are looking for, you can type this in the search bar and the results will show you the part you are looking for (at least, if we have it in our assortment).
You can also use the search bar for keywords. When you do not know the part number, you could type in keywords that describe the part you want to find.
See the video 'How to search for a specific part' for a short screencast instruction
Quickest way to find out what parts we have for your bike or engine is through our part finder. You can fill in the application, make, model and year of your bike / engine choosing from presets. When there are no results, this means that we have not produced any parts for this specific bike or engine.
Our part finder starts with an application field, from which you can choose a certain motorsport categories. You can also skip this field and directly select a make or model if you want to.
When you've clicked on a certain field (application, make, model or year), you can also start typing what you are searching for. The drop down menu will then automatically show you the results that fit your search term.
If you want to start searching for a new bike / engine, you can click on the black 'Reset' button to empty all the fields from the part finder at once and start a new search.
It's also possible to reset a certain field from the part finder, by clicking on 'Reset filter' from the dropdown menu.
When there are many parts available for your bike or engine, you can narrow your search further by using the extra filters on the left on your screen like brand, group, category, article group and so on.
See the video 'How to find parts for my bike' for a short screencast instruction
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De Vlonder 208
5427 DH Boekel
Netherlands
+31 492 32 45 95
info@vhm.nl
Mon-Fri, 8am - 5pm